ULE-3.3/20-D24NM-C - Murata Power Solutions

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ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 1 of 28

FEATURES

 RoHS compliant

 New 1/8-brick package, 1/4-brick pinout

in through-hole or SMT version

 0.89 x 2.22 x 0.36 in. (22.6 x 56.4 x 9.1mm)

 Output current: 1.25-20 Amps

 Output voltages: 1.5V to 48V

 Input voltage: 12V, 24V and 48V nominal

 Interleaved, synchronous-rectiﬁ er

topology delivers:

Outstanding efﬁ

ciency (to 94%)

Low noise

Stable no-load operation

No output reverse conduction

 Excellent thermal performance

 On/off control, trim and sense pins

 Fully isolated (2250Vdc BASIC)

 Fully I/O protected; Thermal shutdown

 Certiﬁ ed to UL/IEC/EN 60950-1 and CAN/CSA

C22.2 No.60950-1, 2nd edition



Lead-free construction/attach

Measuring just 0.89 × 2.22 × 0.36 inches (22.6

× 56.4 × 9.1mm), these open-frame, low-proﬁ le

E-bricks ﬁ t the industry-standard quarter-brick

footprint. Now you can “cut-and-paste” the layout

from your last Q-brick design to save time and save

44% board space (1.86 square inches versus 3.3)

in the process.

From a 9-18V, 18-36V or 36-75V input, ULEs

deliver 1.5 to 48 Volt outputs with current up to

20 Amps. They employ an interleaved, synchro-

nous-rectiﬁ er topology that exploits 100% of their

duty cycle. They simultaneously achieve high

efﬁ ciency, low noise, tight line/load regulation, and

quick step response.

An open-frame design, high efﬁ ciency, low-on-

resistance FETs, and planar magnetics embedded

in heavy-copper pc boards all contribute to

impressive thermal derating. The ULEs feature set

includes high isolation (2250Vdc, 48V models),

input pi ﬁ lters, input undervoltage shutdown,

output overvoltage protection, current limiting,

short-circuit protection, and thermal shutdown. The

standard footprint carries VOUT trim, on/off control,

and sense pins (sense pins are not available on

12V or higher models).

All ULE E-Bricks are certiﬁ ed to the BASIC-

insulation requirements of UL/EN/IEC60950-1,

2nd edition, and all “D48” models (36-75V input

ranges) carry the CE mark. Safety certiﬁ cations,

EMC compliance testing and qualiﬁ cation testing

are available.

PRODUCT OVERVIEW

The ULE Series "Eighth-Brick" DC-DC Converters are high-current isolated

power converters designed for use in high-density system boards.

Typical unit

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ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 2 of 28

PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE

Model Family 

Output Input Efﬁ ciency

VOUT

(V)

IOUT

(A)

Power

(W)

R/N (mVp-p) Regulation (Max.)

VIN

Nom.

(V)

Range

(V)

IIN no

load

(mA)

IIN full

load

(A) Min. Typ.Typ. Max. Line Load

ULE-1.5/20-D24xx-C 1.5 20 30 25 60 ±0.15% ±0.15% 24 18-36 40 1.42 86% 88%

ULE-1.5/20-D48xx-C 1.5 20 30 25 60 ±0.15% ±0.15% 48 36-75 40 0.74 84% 84.5%

ULE-1.8/20-D24xx-C 1.8 20 36 40 80 ±0.1% ±0.1% 24 18-36 40 1.72 85% 87%

ULE-1.8/20-D48xx-C 1.8 20 36 40 80 ±0.25% ±0.25% 48 36-75 40 0.87 84.5% 86.5%

ULE-2.5/20-D24xx-C 2.5 20 50 30 50 ±0.05% ±0.05% 24 18-36 95 2.35 87% 88.5%

ULE-2.5/20-D48xx-C 2.5 20 50 50 75 ±0.05% ±0.1% 48 36-75 55 1.17 88% 89%

ULE-3.3/20-D12x-C 3.3 20 66 60 100 ±0.05% ±0.05% 12 9-18 100 6.15 88.9% 89.4%

ULE-3.3/20-D12xM-C 3.3 20 66 60 100 ±0.05% ±0.05% 12 9-18 100 6.15 88.9% 89.4%

ULE-3.3/20-D24x-C 3.3 20 66 50 80 ±0.05% ±0.05% 24 18-36 60 3.09 88% 89%

ULE-3.3/20-D24xM-C 3.3 20 66 50 80 ±0.05% ±0.05% 24 18-36 60 3.09 88% 89%

ULE-3.3/20-D48x-C 3.3 20 66 50 100 ±0.1% ±0.25% 48 36-75 60 1.54 87% 89%

ULE-3.3/20-D48xM-C 3.3 20 66 50 100 ±0.1% ±0.25% 48 36-75 60 1.54 87% 89%

ULE-5/10-D12x-C 5 10 50 60 125 ±0.05% ±0.05% 12 9-18 160 4.63 87% 90%

ULE-5/12-D24x-C 512 60 50 100 ±0.1% ±0.25% 24 19-36 160 2.78 88% 90%

ULE-5/12-D24xM-C 512 60 50 100 ±0.1% ±0.25% 24 19-36 160 2.78 88% 90%

ULE-5/12-D48x-C 5 12 60 50 100 ±0.1% ±0.25% 48 36-75 90 1.38 88.5% 90.5%

ULE-5/12-D48xM-C 5 12 60 50 100 ±0.1% ±0.25% 48 36-75 90 1.38 88.5% 90.5%

ULE-12/4.2-D24x-C 12 4.2 50.4 50 150 ±0.05% ±0.075% 24 18-36 55 2.31 89.5% 91%

ULE-12/4.2-D24xM-C 12 4.2 50.4 50 150 ±0.05% ±0.075% 24 18-36 55 2.31 89.5% 91%

ULE-12/4.2-D48x-C 12 4.2 50.4 50 150 ±0.05% ±0.075% 48 36-75 55 1.14 91% 92%

ULE-12/4.2-D48xM-C 12 4.2 50.4 50 150 ±0.05% ±0.075% 48 36-75 55 1.14 91% 92%

ULE-24/3-D48x-C 24 3 72 400 700 ±0.3% ±1.25% 48 36-75 45 1.63 90.8% 92%

ULE-48/1.25-D48x-C 48 1.25 60 640 750 ±0.175% ±3.2% 48 36-75 75 1.35 91% 92.5%

ULE-48/1.25-D48xM-C 48 1.25 60 640 750 ±0.175% ±3.2% 48 36-75 75 1.35 91% 92.5%

 Please refer to the full model number structure for additional ordering part numbers and

options.

 All speciﬁ cations are at nominal line voltage and full load, +25ºC unless otherwise noted.

See detailed speciﬁ cations.

If VIN = 19−20V, IOUT = 8A Max.

 Min. load = 10%.

If VIN = 9−10V, IOUT = 18A Max.

ULE-1.2/30-D48N-C ULE-1.8/20-D24N-C ULE-12/4.2-D48NM-C ULE-3.3/20-D12PM ULE-48/1.25-D48NM-C

ULE-1.2/30-D48P-C ULE-1.8/20-D24NM-C ULE-12/4.2-D48PM-C ULE-3.3/20-D12PM-C ULE-48/1.25-D48PM-C

ULE-1.5/20-D24N-C ULE-1.8/20-D24P-C ULE-2.5/20-D24N-C ULE-3.3/20-D24PM-C ULE-5/10-D12N-C

ULE-1.5/20-D24NM-C ULE-1.8/20-D24PM-C ULE-2.5/20-D24PM ULE-3.3/20-D48NM-C ULE-5/10-D12NM

ULE-1.5/20-D24P-C ULE-1.8/20-D48N-C ULE-2.5/20-D24PM-C ULE-3.3/20-D48PM-C ULE-5/10-D12NM-C

ULE-1.5/20-D24PM-C ULE-1.8/20-D48NL2-C ULE-2.5/20-D48N-C ULE-31103 ULE-5/10-D12P-C

ULE-1.5/20-D48N-C

ULE-1.8/20-D48NM-C

ULE-2.5/20-D48NL2 ULE-31104 ULE-5/10-D12PM-C

ULE-1.5/20-D48NM ULE-1.8/20-D48P ULE-2.5/20-D48NM-C ULE-31106 ULE-5/12-D24PM

ULE-1.5/20-D48NM-C ULE-1.8/20-D48P-C ULE-2.5/20-D48P-C ULE-31131-C ULE-5/12-D24PM-C

ULE-1.5/20-D48P-C ULE-1.8/20-D48PM-C ULE-2.5/20-D48PM ULE-31131-Y ULE-5/12-D48NM-C

ULE-1.5/20-D48PM ULE-12/4.2-D24NM-C ULE-2.5/20-D48PM-C ULE-31199-C ULE-5/12-D48PM-C

ULE-1.5/20-D48PM-C ULE-12/4.2-D24PM-C ULE-3.3/20-D12NM-C ULE-12/4.2-D48NL2-C ULE-12/4.2-D48PL1-C

ULE-3.3/20-D48NL1-C ULE-3.3/20-D48NL2-C ULE-3.3/20-D48PL1-C ULE-3.3/20-D48PL2-C ULE-5/12-D48NL1-C

ULE-5/12-D48NL2-C

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PART NUMBER STRUCTURE

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 3 of 28

Maximum Rated Output

Current in Amps

Eighth-Brick Package

Output Conﬁ guration:

U = Unipolar/Single Output

Nominal Output Voltage

U LE -/D48-1.5 20 N M

Input Voltage Range:

D12 = 12V nominal

D24 = 24V nominal

D48 = 48V nominal

Surface (Gullwing) Mount Package ➁

(ULE-12/4.2-D48, ULE-24/3-D48, and

ULE-48/1.25-D48 have no surface mount option.)

RoHS-6 hazardous substance compliant

Does not claim EU RoHS exemption 7b, lead in solder

Remote On/Off Control Polarity:

P = Positive polarity (standard for D12 and

D24 models, optional special order for D48 models)

N = Negative polarity (standard for D48 models,

optional special order for D12 and D24 models)

(Through-hole packages only)

Blank = standard length 0.180˝ (4.6mm)

L1 = Pin length 0.110±0.010˝ (2.79±0.25mm ➀

L2 = Pin length 0.145±0.010˝ (3.68±0.25mm) ➀

Pin Length Option

➀ Special quantity order is required; samples available with standard pin length only.

➁ SMT (M) versions not available in sample quantities.

➂ Some model number combinations may not be available. See website or contact your local Murata sales representative.

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ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 4 of 28

See notes on page 5.

INPUT CHARACTERISTICS

Model Family 

Start-up

threshold

Min.

(V)

Under

Voltage

Shut-

down

(V)

Reﬂ ected

(back)

Ripple

Current

(mA)

Load Current Inter-

nal

Input

Filter

Type

Reverse

Polarity

Protec-

tion

Remote On/Off Control Start-up Time

Full

Load

Condi-

tions

Inrush

Transient

Conditions

(A2sec)

Output

Short

Circuit

No Load

(mA)

Low

Line

(A)

Standby

Mode

(mA)

Cur-

rent

(mA)

Positive

Logic

“P” model

sufﬁ x

Negative

Logic

“N” model

sufﬁ x

VIN to VOUT

regulated

(Max.)

mSec

Remote On/Off

to VOUT regu-

lated (Max.)

mSec

ULE-1.5/20-D24 17.0 16.0

15−45,

model

dependent

See

Ordering

Guide

0.5−1

40−250

model

depen-

dent

40−160

model

depen-

dent

1.96

1−8

model

depen-

dent

L-C

None,

install

external

fuse

1.0

OFF=Ground pin

to +0.8V max.

ON=open or

3.5V to +13.5V

max.

OFF=open or

+3.5V to

+13.5V max.

ON=Ground pin

to +0.8V max.

6-90, model

dependent

6-90, model

dependent

ULE-1.5/20-D48 34.0 33.0 0.98

ULE-1.8/20-D24 17.0 16.0 2.3

ULE-1.8/20-D48 33.0 31.0 1.16

ULE-2.5/20-D24 17.0 16.0 3.23

ULE-2.5/20-D48 33.0 32.0 1.55

ULE-3.3/20-D12 8.5 8.0 7.42

ULE-3.3/20-D24 17.0 16.0 4.10

ULE-3.3/20-D48 34.5 33.5 2.05

ULE-5/10-D12 8.5 8.0 6.14

ULE-5/12-D24 19.0 17.5 3.30

ULE-5/12-D48 34.5 33.5 1.82

ULE-12/4.2-D24 17.0 16.0 3.04

ULE-12/4.2-D48 35.0 34.0 1.51

ULE-24/3-D48 35.0 33.0 2.17 150 150

ULE-48/1.25-D48 35.0 33.5 1.46 6-90 6-90

OUTPUT CHARACTERISTICS

Model Family

VOUT

(V)

VOUT

Accuracy

50% Load

% of VNOM

Capacitive Loading

Max.

Low ESR <0.02Ω Max.

resistive load

(μF)

Adjustment

Range

Temperature

Coefﬁ cient

Minimum

Remote Sense

Compensation

Ripple/Noise

(20 MHz

bandwidth)

Line/Load

Regulation Efﬁ ciency

Current Limit

Inception

98% of VOUT

after warmup

(A)

ULE-1.5/20-D24 1.5

±1 to ±2

of VNOM,

model

dependent

10,000

−20 to +10%

of VNOM, model

dependent

±0.02% of

VOUT range/°C

No Minimum

Load +10%

See Ordering Guide

ULE-1.5/20-D48 1.5 24

ULE-1.8/20-D24 1.8 24

ULE-1.8/20-D48 1.8 25

ULE-2.5/20-D24 2.5 24

ULE-2.5/20-D48 2.5 24

ULE-3.3/20-D12 3.3 24

ULE-3.3/20-D24 3.3 24

ULE-3.3/20-D48 3.3 26

ULE-5/10-D12 5 13

ULE-5/12-D24 5 15

ULE-5/12-D48 5 16

ULE-12/4.2-D24 12 2000 420 mA

none

ULE-12/4.2-D48 12 6.25

ULE-24/3-D48 24 680 300 mA 4.25

ULE-48/1.25-D48 48 470 No Minimum 2.5

FUNCTIONAL SPECIFICATIONS

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ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 5 of 28

ISOLATION CHARACTERISTICS

Model Family

Input to

Output

Min.

(V)

Isolation

Resistance

(MΩ)

Isolation

Capacitance

(pF)

Isolation

Safety Rating

ULE-1.5/20-D24

2000-

2250 min.,

model

dependent

100

1750

Basic

Insulation

ULE-1.5/20-D48

ULE-1.8/20-D24

ULE-1.8/20-D48

ULE-2.5/20-D24

ULE-2.5/20-D48

ULE-3.3/20-D12

ULE-3.3/20-D24

ULE-3.3/20-D48

ULE-5/10-D12 470

ULE-5/12-D24

ULE-5/12-D48

1750ULE-12/4.2-D24

ULE-12/4.2-D48

ULE-24/3-D48 2000

ULE-48/1.25-D48 1500

DYNAMIC CHARACTERISTICS

Model Family

Dynamic Load Response

(50-75-50% load step)

Switching

Frequency

KHz

ULE-1.5/20-D24 100µSec to ±1.5% of ﬁ nal value 280±15

ULE-1.5/20-D48 100µSec to ±1.5% of ﬁ nal value 280±15

ULE-1.8/20-D24 100µSec to ±1.5% of ﬁ nal value 340±15

ULE-1.8/20-D48 100µSec to ±1.5% of ﬁ nal value 340±15

ULE-2.5/20-D24 150µSec to ±1% of ﬁ nal value 385±15

ULE-2.5/20-D48 80µSec to ±1.5% of ﬁ nal value 385±45

ULE-3.3/20-D12 150µSec to ±1.25% of ﬁ nal value 310±15

ULE-3.3/20-D24 150µSec to ±1.5% of ﬁ nal value 385±15

ULE-3.3/20-D48 150µSec to ±1% of ﬁ nal value 365±15

ULE-5/10-D12 75µSec to ±2% of ﬁ nal value 325±15

ULE-5/12-D24 75µSec to ±2% of ﬁ nal value 450±15

ULE-5/12-D48 100µSec to ±1% of ﬁ nal value 450±15

ULE-12/4.2-D24 150µSec to ±1.25% of ﬁ nal value 400±15

ULE-12/4.2-D48 150µSec to ±1.25% of ﬁ nal value 380±15

ULE-24/3-D48 200µSec to ±2% of ﬁ nal value 240±30

ULE-48/1.25-D48 200µSec to ±1% of ﬁ nal value 250±15

*No derating is required up to 85°C.

See notes on page 5.

MISCELLANEOUS CHARACTERISTICS

Model Family

Calculated

MTBF

Operating Temperature Range

Operating PCB

Temperature

(no derating)

Storage

Temperature

Range

Thermal

Protection/

Shutdown

Short

Circuit

Current

Overvoltage

Protection

via magnetic

feedback

(V)

Short Circuit

Protection

Method 

Short Circuit

Duration

Relative

Humidity

See

derating curves

ULE-1.5/20-D24

TBC −40 to +85ºC with derating −40 to

+105ºC

−55 to

+125ºC

+105 to

+125ºC,

model

dependent

3A 2.3

Current

limiting,

hiccup

autorestart.

Remove

overload for

recovery

Continuous,

output

shorted to

ground.

No damage.

+85ºC/85%

non-

condensing

ULE-1.5/20-D48 3A 2.0

ULE-1.8/20-D24 3A 2.3

ULE-1.8/20-D48 3A 2.3

ULE-2.5/20-D24 3A 3.5

ULE-2.5/20-D48 3A 3.0

ULE-3.3/20-D12 300mA 3.96

ULE-3.3/20-D24 3A 3.96

ULE-3.3/20-D48 3A 3.96

ULE-5/10-D12 5A 6.0

ULE-5/12-D24 5A 6.0

ULE-5/12-D48 2A 6.4

ULE-12/4.2-D24 3A 15.0

ULE-12/4.2-D48 3A 14.0

ULE-24/3-D48* 0.65A 28.0

ULE-48/1.25-D48 500mA 55.0

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Input Voltage:

Continuous:

12 Volt input models 18 Volts

24 Volt input models 36 Volts

48 Volt input models 75 Volts

Transient (100 mSec. Max.)

12 Volt input models 25 Volts

24 Volt input models 50 Volts

48 Volt input models 100 Volts

On/Off Control (pin 2) See speciﬁ cations

Input Reverse Polarity Protection 5 Amps, 10 sec. max.

Output Overvoltage Protection Magnetic feedback. See note (7).

Output Current * Current-limited. Devices can with stand

sustained short circuit without damage.

Storage Temperature –55 to +125°C.

Lead Temperature Refer to solder proﬁ le.

These are stress ratings. Exposure of devices to greater than any of these conditions

may adversely affect long-term reliability. Proper operation under conditions other than

those listed in the Performance/Functional Speciﬁ cations Table is not implied.

Absolute Maximum Ratings

* The outputs are not intended to sink reverse current.

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 6 of 28

1. All models are tested and speciﬁ ed with external 1||10 µF ceramic/tantalum output

capacitors and a 22 µF external input capacitor. All capacitors are low ESR types.

These capacitors are necessary to accommodate our test equipment and may not

be required to achieve speciﬁ ed performance in your applications. The ULE-12/4.2

and ULE-24/3 modules require minimum load; all other models regulate within spec

and are stable under no-load to full load conditions. General conditions for Speciﬁ -

cations are +25 deg.C, VIN=nominal, VOUT=nominal, full load. Adequate airﬂ ow must

be supplied for extended testing under power.

2. Input Ripple Current is tested and speciﬁ ed over a 5 Hz to 20 MHz bandwidth. Input

ﬁ ltering is CIN=33 µF tantalum, CBUS=220 µF electrolytic, LBUS=12 µH.

3. Note that Maximum Power Derating curves indicate an average current at nominal

input voltage. At higher temperatures and/or lower airﬂ ow, the DC-DC converter will

tolerate brief full current outputs if the total RMS current over time does not exceed

the Derating curve. All Derating curves are presented at sea level altitude. Be aware

of reduced power dissipation with increasing density altitude.

4. Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1,

Case 3, ground ﬁ xed conditions, Tpcboard=+25ºC, full output load, natural air convection.

5. The On/Off Control is normally controlled by a switch. But it may also be driven with

external logic or by applying appropriate external voltages which are referenced to

Input Common. The On/Off Control Input should use either an open collector or open

drain transistor.

6. Short circuit shutdown begins when the output voltage degrades approximately 2%

from the selected setting.

7. The outputs are not intended to sink appreciable reverse current..

8. Output noise may be further reduced by adding an external ﬁ lter. See I/O Filtering

and Noise Reduction.

9. All models are fully operational and meet published speciﬁ cations, including “cold

start” at –40ºC.

10. Regulation speciﬁ cations describe the deviation as the line input voltage or output

load current is varied from a nominal midpoint value to either extreme.

11. Alternate pin length and/or other output voltages are available under special quantity

order.

12. Electronic overvoltage shutdown is not included on 48V input models to comply

with certain telecom reliability requirements. These requirements attempt continued

operation despite input overvoltage. The converter is rated only to the maximum

input voltage.

13. Do not exceed maximum power speciﬁ cations when adjusting the output trim.

14. At zero output current, the output may contain low frequency components which

exceed the ripple speciﬁ cation. The output may be operated indeﬁ nitely with no load.

15. If reverse polarity is accidentally applied to the input, a body diode will become

forward biased and will conduct considerable current. To ensure reverse input

protection with full output load, always connect an external input fuse in series with

the +VIN input. Use approximately twice the full input current rating with nominal

input voltage.

16. Output current limit is non-latching. When the overcurrent fault is removed, the

converter will immediately recover.

17. The Sense inputs are not included on lower current output models.

18. ULE-5/12-D24 IOUT=8A max. if VIN=19-20V.

FUNCTIONAL SPECIFICATION NOTES

PHYSICAL CHARACTERISTICS AND SAFETY

Outline dimensions See mechanical specs (below)

Pin material Copper alloy

Pin diameter 0.04/0.062" (1.016/1.524mm)

Pin ﬁ nish Nickel underplate with gold overplate

Weight 1 ounce (28 grams)

Electromagnetic interference (external ﬁ lter required) Designed to meet EN55022/CISPR22 with external ﬁ lter

Safety Certiﬁ ed to UL/cUL 60950-1, CSA-C22.2 No. 60950-1, IEC/EN 60950-1, 2nd edition

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TYPICAL PERFORMANCE CURVES

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20 25 30 40 50 60 70 80

35 45 55 65 75 85

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VIN = 24V, transverse air flow at sea level

Output Current (Amps)

Ambient Temperature (°C)

19.5

18.5

17.5

16.5

Natural convection

100 lfm

200 lfm

300 lfm

400 lfm

ULE-2.5/20-D24N

Efficiency vs. Line Voltage and Load Current @ +25°C

2 4 6 8 10 12 14 16 18 20

Load Current (Amps)

Efficiency (%)

= 19V

= 24V

= 36V

–40 0 25 35 45 55 65 75 85

30 40 50 60 70 80

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(VIN = 48V, air ﬂow direction is transverse)

Output Current (Amps)

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400 lfm

200 lfm

300 lfm

ULE-1.5/20-D48N

Efﬁciency vs. Line Voltage and Load Current @ +25°C

2 4 6 8 10 12 14 16 18 20

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Efﬁciency (%)

= 36V

= 48V

= 75V

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 7 of 28

www.murata-ps.com/support

TYPICAL PERFORMANCE CURVES

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.ATURAL#ONVECTION

LFM

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 8 of 28

www.murata-ps.com/support

TYPICAL PERFORMANCE CURVES

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/UTPUT#URRENT!MPS

!MBIENT4EMPERATUREo#

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6).6AIRFLOWDIRECTIONISTRANSVERSE

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!MBIENT4EMPERATUREo#

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ULE-5/10-D12

Efﬁciency vs. Line Voltage and Load Current @ +25°C

1.2 2.4 3.6 4.8 6 7.2 8.4 9.6 10.8 12

Load Current (Amps)

Efﬁciency (%)

= 9V

= 12V

= 18V

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 9 of 28

www.murata-ps.com/support

TYPICAL PERFORMANCE CURVES



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–40 0 30 40 50 60 70 80 90 35 45 55 65 75 85

ULE-5/12-D48 Maximum Current Temperature Derating

(VIN = 48V, air flow direction from input to output)

Output Current (Amps)

Ambient Temperature (oC)

12.5

11.5

10.5

9.5

8.5

100 lfm

200 lfm

300 lfm

ULE-12/4.2-D24

Efﬁciency Vs. Line Voltage and Load Current @25ºC

Efﬁciency (%)

Load Current (Amps)

= 18V

= 24V

= 26V

0.20 0.60 1.00 1.40 1.80 2.20 2.60 3.00 3.40 3.80 4.20 20 25 30 40 50 60 70 80

35 45 55 65 75 85

ULE-12/4.2-D24N Maximum Current Temperature Derating

(VIN=24V, transverse airflow at sea level)

Output Current (Amps)

Ambient Temperature (°C)

4.2

4.1

4.0

3.9

3.8

3.7

3.6

3.5

3.4

3.3

3.2

Natural convection

100 lfm

200 lfm

300 lfm

400 lfm

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ULE-12/4.2-D48N Maximum Current Temperature Derating

(VIN=48V, transverse airflow at sea level)

Output Current (Amps)

Ambient Temperature (°C)

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

Natural convection

100 lfm

200 lfm

300 lfm

400 lfm

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 10 of 28

www.murata-ps.com/support

TYPICAL PERFORMANCE CURVES

0.10 0.22 0.33 0.45 0.56 0.68 0.79 0.91 1.02 1.14 1.2

ULE-48/1.25-D48

Efficiency vs. Line Voltage and Load Current @ +25°C

Load Current (Amps)

Efficiency (%)

VIN = 60V

VIN = 48V

VIN = 36V

VIN = 75V

ULE-24/3-D48

Efficiency vs. Line Voltage and Load Current @ +25°C

Load Current (Amps)

Efficiency (%)

0.3 0.65 1 1.3 1.65 2 2.3 2.65 3

VIN = 60V

VIN = 48V

VIN = 36V

VIN = 75V

30 35 40 45 50 55 60 65 70 75 80 8

0.5 m/s (100 LFM); 1.0 m/s (200 LFM);

1.5 m/s (300 LFM); 2.0 m/s (400 LFM)

Natural Convection

ULE-24/3-D48N-C Temperature Derating

Vin 36 (air ﬂow from Pin 1 to Pin 3 on PCB)

Output Current (Amps)

Ambient Temperature (°C)

30 35 40 45 50 55 60 65 70 75 80 8

0.5 m/s (100 LFM); 1.0 m/s (200 LFM);

1.5 m/s (300 LFM); 2.0 m/s (400 LFM)

Natural Convection

ULE-24/3-D48N-C Temperature Derating

Vin 60 (air ﬂow from Pin 1 to Pin 3 on PCB)

Output Current (Amps)

Ambient Temperature (°C)

30 35 40 45 50 55 60 65 70 75 80 8

0.5 m/s (100 LFM); 1.0 m/s (200 LFM);

1.5 m/s (300 LFM); 2.0 m/s (400 LFM)

Natural Convection

ULE-24/3-D48N-C Temperature Derating

Vin 48 (air ﬂow from Pin 1 to Pin 3 on PCB)

Output Current (Amps)

Ambient Temperature (°C)

30 35 40 45 50 55 60 65 70 75 80 8

0.5 m/s (100 LFM); 1.0 m/s (200 LFM);

1.5 m/s (300 LFM); 2.0 m/s (400 LFM)

Natural Convection

ULE-24/3-D48N-C Temperature Derating

Vin 72 (air ﬂow from Pin 1 to Pin 3 on PCB)

Output Current (Amps)

Ambient Temperature (°C)

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 11 of 28

www.murata-ps.com/support

TYPICAL PERFORMANCE CURVES

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ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 12 of 28

www.murata-ps.com/support

TYPICAL PERFORMANCE CURVES

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ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 13 of 28

www.murata-ps.com/support

TYPICAL PERFORMANCE CURVES

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0.1 0.2 0.3 0.4 0.6 0.7 0.8 0.9 1.0 1.1 1.

ULE-48/1.25-D48 Power Dissipation vs. Load Current @ +25°C

Load Current (Amps)

Power Dissipation (Watts)

= 75V

= 60V

= 48V

= 36V

ULE-24/3-D48 Power Dissipation vs. Load Current @ +25°C

Load Current (Amps)

Power Dissipation (Watts)

1.5

2.5

3.5

4.5

5.5

6.5

0.3 0.65 1 1.3 1.65 2 2.3 2.65 3

= 75V

= 60V

= 48V

= 36V

0 20 40 60 80 100 120

1.25

1.0

0.75

0.5

0.25

Output Current (Amps)

Ambient Temperature (°C)

Natural convection

100 lfm

ULE-48/1.25-D48 Maximum Current Temperature Derating at sea level

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 14 of 28

www.murata-ps.com/support

MECHANICAL SPECIFICATIONS

–V

OPTO

ISOLATION

PWM

CONTROLLER

REFERENCE &

ERROR AMP

UV, OV AND

OVER-TEMPERATURE

COMPARATORS

ON/OFF

CONTROL

+SENSE

−SENSE

OUT

−V

OUT

GATE

DRIVE

FEEDBACK

TRIM

ULE-3.3/20-D48N

Typical topology is shown.

–V

PWM

CONTROLLER

REFERENCE &

ERROR AMP

UV, OV AND

OVER-TEMPERATURE

COMPARATORS

ON/OFF

CONTROL

OUT

−V

OUT

FEEDBACK

ULE-12/4.2-D48N

Typical topology is shown.

TRIM

The ULE series consist of a number of unique high performance designs

sharing similar mechanical outlines and pinouts. The internal architecture

uses several different topologies including push-pull, ﬂ yback and others.

The block diagrams below are typical examples and are not intended to be

exact representations. Some models do not include Sense and Trim pins. Please

be aware that Murata Power Solutions may change these designs as needed.

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 15 of 28

www.murata-ps.com/support

MECHANICAL SPECIFICATIONS

–V

OPTO

ISOLATION

PWM

CONTROLLER

REFERENCE &

ERROR AMP

UV, OV AND

OVER-TEMPERATURE

COMPARATORS

ON/OFF

CONTROL

OUT

−V

OUT

FEEDBACK

ULE-24/3-D48N and ULE-48/1.25-D48N

Typical topology is shown.

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 16 of 28

www.murata-ps.com/support

Pin shoulder, 0.072 ±0.002 dia. (1.83 ±0.05)

0.040 (1.02) dia. pin

Pin depth, see table

Keep-out area

Seating plane

User’s host

PC Board

ULE Converter

Drawing not to scaleDimensions are in inches (mm)

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 17 of 28

MECHANICAL SPECIFICATIONS

Through-hole Pin Changes for 2008

In 2008, for through-hole models only, Murata Power Solutions will gradually

phase over to a different extruded 0.040” (1.02 mm) diameter pin design and

elimination of the spacer standoffs on most models. This will have no effect on

installation, interchangeability, electrical or mechanical speciﬁ cations. Any

machined 0.062” (1.57 mm) diameter pin will transition to a straight wire 0.062”

pin. The new 0.040” pins will insert properly to existing host PC boards and

include an integral pin shoulder to form the mounting plane (Figure 1). There is

no model number change, only a slightly changed appearance. Use the drawings

and table below to identify the new pin design. And, surface mount ULEs are not

affected.

All new production models are RoHS-6 compliant and always use the –C

model number sufﬁ x. Older non-RoHS models are also being changed over to

the new extruded pins; however non-RoHS models are not listed in this table.

Extruded 0.040-inch Pin Conﬁ gurations

RoHS Models (-C) 0.040" Pin depth*

ULE-1.5/20-D24P-C 0.25 (6.4)

ULE-1.5/20-D48-C 0.25 (6.4)

ULE-1.8/20-D24-C 0.25 (6.4)

ULE-1.8/20-D48-C 0.25 (6.4)

ULE-2.5/20-D24-C 0.19 (4.8)

ULE-2.5/20-D48-C 0.19 (4.8)

ULE-3.3/20-D12-C 0.19 (4.8)

ULE-3.3/20-D24-C 0.25 (6.4)

ULE-3.3/20-D48N-C 0.25 (6.4)

ULE-3.3/20-D48P-C 0.19 (4.8)

ULE-5/10-D12-C 0.19 (4.8)

ULE-5/12-D24-C 0.19 (4.8)

ULE-5/12-D48-C 0.25 (6.4)

ULE-12/4.2-D24-C 0.25 (6.4)

ULE-12/4.2-D48-C 0.25 (6.4)

ULE-24/3-D48N-C 0.25 (6.4)

ULE-48/1.25-D48-C 0.25 (6.4)

*The “0.040-inch pin depth” is the distance between the mounting plane of the ULE

converter (at the pin shoulder) and the inserted tip of the pin. Therefore it is the length of

pin which the host receiving PC board must accept. The ULE mounting plane interfaces

to the top mounting surface (seating plane) of the user’s PC board. The ULE mounting

plane is established either by an integral pin shoulder (new) or a plastic standoff (older)

but not both. Users should avoid placing components immediately below the converter.

The pin ﬁ nish for all models remains as gold plate over nickel underplate.

The pin material is a copper alloy. The pin ﬁ nish is suitable for both leaded

and lead-free solders.

Figure 1. Extruded 0.040-inch Pin

The “integral” pin shoulder is formed as part of the extruded pin fabrica-

tion and replaces the plastic standoff spacer. The shoulder diameter is 0.072

+/−0.002" and forms the mounting plane of the converter. The user should

provide sufﬁ cient clearance for a 0.040" pin hole but well below the 0.072"

shoulder diameter. This mounting plane avoids mechanical stress placed on

the converter components. Do not place the components below the converter.

Dimensions in inches (mm)

ULE Connections

The ULE series consists of several different PC board layouts sharing a

common outline speciﬁ

cation and overall size. This simpliﬁ es interchange-

ability in case the user needs different input or output speciﬁ cations.

Certain models do not include Sense or Trim connections. All models

include Remote On/Off control pins. Please refer to the following table:

Model Number Vout

(Volts)

Iout

(Amps,

max.)

Number

of Pins

On/Off

pin?

Trim

pin?

Sense

pins?

ULE-1.5/20-D24P-C 1.5 20 8 yes yes yes

ULE-1.5/20-D48N-C 1.5 20 8 yes yes yes

ULE-1.8/20-D24P-C 1.8 20 8 yes yes yes

ULE-1.8/20-D48N-C 1.8 20 8 yes yes yes

ULE-2.5/20-D24P-C 2.5 20 8 yes yes yes

ULE-2.5/20-D48N-C 2.5 20 8 yes yes yes

ULE-3.3/20-D12P-C 3.3 20 8 yes yes yes

ULE-3.3/20-D24P-C 3.3 20 8 yes yes yes

ULE-3.3/20-D48N-C 3.3 20 8 yes yes yes

ULE-5/10-D12P-C 5 10 8 yes yes yes

ULE-5/12-D24P-C 5 12 8 yes yes yes

ULE-5/12-D48N-C 5 12 8 yes yes yes

ULE-12/4.2-D24P-C 12 4.2 6 yes yes no

ULE-12/4.2-D48N-C 12 4.2 6 yes yes no

ULE-24/3-D48N-C 24 3 5 yes no no

ULE-48/1.25-D48N-C 48 1.25 5 yes no no

www.murata-ps.com/support

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 18 of 28

MECHANICAL SPECIFICATIONS, THROUGH-HOLE (PINNED) MODELS

DOSA-Compliant

Input/Output Connections

Pin Function

1 +Vin

2 On/Off Control*

3 −Vin

4 −Vout

5 −Sense**

6 Trim†

7 +Sense**

8 +Vout

* The Remote On/Off can be provided

with either positive (P sufﬁ x) or negative

(N sufﬁ x) polarity.

** Sense Pins omitted for 12Vout, 24Vout,

and 48Vout models.

† Trim pin omitted for 24Vout and 48Vout

models.

THIRD ANGLE PROJECTION

4.78

0.188

See

Table

0.071±.002 SHOULDER

AT PINS 1-3, 5-7

1.80±0.05

PLATED THRU HOLES

TYP±.010.061

58.4

2.30

50.80

2.000 3.81

0.150

22.9

0.90 11.4

0.45

7.62

0.300

7.62

3.81

0.150

3.81

0.083±0.010

PLATED THRU HOLES

2x (Pins 4 & 8)

MOUNTING PLANE

SIDE VIEW

0.040±0.002

PINS 1-3, 5-7

1.02±0.05

0.062±0.002

PINS 4 & 8

1.57±0.05

DIMENSIONS ARE IN INCHES [mm]

TOLERANCES:

2 PLACE 0.02 ANGLES: 1

3 PLACE 0.010

COMPONENTS SHOWN ARE FOR REFERENCE ONLY

MATERIAL:

SMT PINS: COPPER ALLOY

FINISH: (ALL PINS)

GOLD (5u"MIN) OVER NICKEL (50u" MIN)

BOTTOM VIEW

PIN 1

PIN 2

PIN 3

PIN 6

PIN 8

PIN 4

PIN 5†

PIN 7†

2.22

56.4

0.89

22.6 0.300

7.62

0.300

7.62

2.000

50.80 0.150

3.81

0.150

3.81

0.300

7.62

0.300

7.62

ISOMETRIC VIEW

RECOMMENDED FOOTPRINT

(VIEW THROUGH CONVERTER)

6†

5**

7**

END VIEW

www.murata-ps.com/support

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 19 of 28

MECHANICAL SPECIFICATIONS, SURFACE-MOUNT (GULLWING) MODELS

THIRD ANGLE PROJECTION

Table

See 0.025

0.63

0.150

7.62

59.44

2.340

4.64

0.183 4.64

0.183

58.4

2.30

22.9

0.90

7.62

0.300

0.300 0.300

7.62

3.30

0.130 3.81

0.150

3.81

7.62

0.300

0.020

0.51

0.300

7.62

0.300

7.62

3.81

0.150

3.81

0.150

0.300

7.62

PINS COPLANAR WITHIN 0.004"

SIDE VIEW

RECOMMENDED FOOTPRINT

(VIEW THROUGH CONVERTER)

7**

6†

5**

BOTTOM VIEW

PIN 3

PIN 2

PIN 1 PIN 6

PIN 7**

PIN 8

PIN 5**

PIN 4

0.89

22.6

0.125 TYP

2.30

58.4

DIMENSIONS ARE IN INCHES [mm]

TOLERANCES:

2 PLACE 0.02 ANGLES: 1

3 PLACE 0.010

COMPONENTS SHOWN ARE FOR REFERENCE ONLY

MATERIAL:

SMT PINS: COPPER ALLOY

FINISH: (ALL PINS)

PURE TIN (100u"MIN) OVER NICKEL (75u" MIN)

ISOMETRIC VIEW

END VIEW

Please refer to the “ULE Connections” table.

Input/Output Connections

Pin Function

1 +Vin

2 On/Off Control*

3 −Vin

4 −Vout

5 −Sense**

6 Trim†

7 +Sense**

8 +Vout

* The Remote On/Off can be provided

with either positive (P sufﬁ x) or negative

(N sufﬁ x) polarity.

** Sense Pins omitted for 12Vout, 24Vout,

and 48Vout models.

† Trim pin omitted for 24Vout and 48Vout

models.

www.murata-ps.com/support

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 20 of 28

Table

See

Table

See

0.122 REF OR 0.150 REF*

NOMINAL

DEPENDING ON MODEL

TYPE 'M' GULL WING SMT PACKAGE

0.130 REF

DIMENSIONS ARE IN INCHES [mm]

TOLERANCES:

2 PLACE 0.02 ANGLES: 1

3 PLACE 0.010

COMPONENTS SHOWN ARE FOR REFERENCE ONLY

THRU-HOLE STANDARD PACKAGE

MECHANICAL SPECIFICATIONS, Continued

ULE THRU-HOLE SERIES MAXIMUM HEIGHTS

Model Family Height (Max) Model Family Height (Max)

ULE-1.5/20-D24 0.404 [10.26] *ULE-5/12-D24 0.405 [10.29]

ULE-1.5/20-D48 0.381 [9.68] ULE-5/12-D48 0.377 [9.58]

ULE-1.8/20-D24 0.404 [10.26] ULE-12/4.2-D24 0.377 [9.58]

ULE-1.8/20-D48 0.381 [9.68] ULE-12/4.2-D48 0.377 [9.58]

ULE-2.5/20-D24* 0.409 [10.39] ULE-24/3-D48 0.425 [10.80]

ULE-2.5/20-D48* 0.409 [10.39] ULE-48/1.25-D48 0.448 [11.38]

ULE-3.3/20-D12* 0.409 [10.39] ULE-68/1.5-D48 0.377 [9.58]

ULE-3.3/20-D24 0.381 [9.68]

ULE-3.3/20-D48* 0.409 [10.39]

ULE 'M' TYPE SMT (GULL WING) SERIES MAXIMUM HEIGHTS

Model Family Height (Max) Model Family Height (Max)

ULE-1.5/20-D24 M 0.404 [10.26] ULE-5/10-D12 M 0.400 [10.16]

ULE-1.5/20-D48 M 0.404 [10.26] ULE-5/12-D24 M 0.400 [10.16]

ULE-1.8/20-D24 M 0.404 [10.26] ULE-5/12-D48 M 0.400 [10.16]

ULE-1.8/20-D48 M 0.404 [10.26] ULE-12/4.2-D24 M 0.400 [10.16]

ULE-2.5/20-D24 M 0.404 [10.26] ULE-48/1.25-D48 M 0.446 [11.33]

ULE-3.3/20-D12 M 0.404 [10.26]

ULE-3.3/20-D24 M 0.404 [10.26]

ULE-3.3/20-D48 M 0.404 [10.26]

www.murata-ps.com/support

TECHNICAL NOTES

Input Fusing

Certain applications and/or safety agencies may require the installation of

fuses at the inputs of power conversion components. Fuses should also be

used if the possibility of sustained, non-current-limited, input-voltage polarity

reversals exist. For Murata Power Solutions ULE 24-60 Watt DC-DC Converters,

you should use fast-blow type fuses, installed in the ungrounded input supply

line, with values no greater than the following.

Model Fuse Values

12 Volt Input 10 Amps

24 Volt input 5 Amps

48 Volt Input 4 Amps

All relevant national and international safety standards and regulations must

be observed by the installer. For system safety agency approvals, the convert-

ers must be installed in compliance with the requirements of the end-use

safety standard.

Input Undervoltage Shutdown and Start-Up Threshold

Under normal start-up conditions, devices will not begin to regulate until

the ramping-up input voltage exceeds the Start-Up Threshold Voltage. Once

operating, devices will not turn off until the input voltage drops below the

Undervoltage Shutdown limit. Subsequent re-start will not occur until the input

is brought back up to the Start-Up Threshold. This built in hysteresis prevents

any unstable on/off situations from occurring at a single input voltage.

Start-Up Time

The VIN to VOUT Start-Up Time is the interval of time between the point at which

the ramping input voltage crosses the Start-Up Threshold and the fully loaded

output voltage enters and remains within its speciﬁ ed accuracy band. Actual

measured times will vary with input source impedance, external input/output

capacitance, and load. The ULE Series implements a soft start circuit that limits

the duty cycle of its PWM controller at power up, thereby limiting the input

inrush current.

The On/Off Control to VOUT start-up time assumes the converter has its

nominal input voltage applied but is turned off via the On/Off Control pin. The

speciﬁ cation deﬁ nes the interval between the point at which the converter is

turned on and the fully loaded output voltage enters and remains within its

speciﬁ ed accuracy band. Similar to the VIN to VOUT start-up, the On/Off Control

to VOUT start-up time is also governed by the internal soft start circuitry and

external load capacitance.

The difference in start up time from VIN to VOUT and from On/Off Control to

VOUT is therefore insigniﬁ cant.

Input Source Impedance

ULE converters must be driven from a low ac-impedance input source. The

DC-DC’s performance and stability can be compromised by the use of highly

inductive source impedances. The input circuit shown in Figure 2 is a practical

solution that can be used to minimize the effects of inductance in the input

traces. For optimum performance, components should be mounted close to

the DC-DC converter. If the application has a high source impedance, low VIN

models can beneﬁ

t of increased external input capacitance.

I/O Filtering, Input Ripple Current, and Output Noise

All models in the ULE 24-60 Watt DC-DC Converters are tested/speciﬁ ed for

input reﬂ

ected ripple current and output noise using the speciﬁ ed external input/

output components/circuits and layout as shown in the following two ﬁ gures.

External input capacitors (CIN in Figure 2) serve primarily as energy-storage

elements, minimizing line voltage variations caused by transient IR drops in

conductors from backplane to the DC-DC. Input caps should be selected for bulk

capacitance (at appropriate frequencies), low ESR, and high rms-ripple-current

ratings. The switching nature of DC-DC converters requires that dc voltage

sources have low ac impedance as highly inductive source impedance can affect

system stability. In Figure 2, CBUS and LBUS simulate a typical dc voltage bus. Your

speciﬁ c system conﬁ guration may necessitate additional considerations.

CINVIN CBUS

LBUS

CIN = 33µF, ESR < 700mΩ @ 100kHz

CBUS = 220µF, ESR < 100mΩ @ 100kHz

LBUS = 12µH

+VIN

–VIN

CURRENT

PROBE

OSCILLOSCOPE

–

Figure 2. Measuring Input Ripple Current

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 21 of 28

www.murata-ps.com/support

In critical applications, output ripple/noise (also referred to as periodic and

random deviations or PARD) may be reduced below speciﬁ ed limits using ﬁ lter-

ing techniques, the simplest of which is the installation of additional external

output capacitors. These output caps function as true ﬁ lter elements and

should be selected for bulk capacitance, low ESR and appropriate frequency

response. All external capacitors should have appropriate voltage ratings and

be located as close to the converter as possible. Temperature variations for all

relevant parameters should also be taken carefully into consideration. The most

effective combination of external I/O capacitors will be a function of line volt-

age and source impedance, as well as particular load and layout conditions.

In Figure 3, the two copper strips simulate real-world pcb impedances

between the power supply and its load. In order to minimize measurement

errors, scope measurements should be made using BNC connectors, or the

probe ground should be less than ½ inch and soldered directly to the ﬁ xture.

rise above the designed operating temperature, a precision temperature sensor

will power down the unit. When the internal temperature decreases below the

threshold of the temperature sensor, the unit will self start. See Performance/

Functional Speciﬁ cations.

Output Overvoltage Protection

ULE output voltages are monitored for an overvoltage condition via magnetic

feedback. The signal is coupled to the primary side and if the output voltage

rises to a level which could be damaging to the load, the sensing circuitry will

power down the PWM controller causing the output voltages to decrease. Fol-

lowing a time-out period the PWM will restart, causing the output voltages to

ramp to their appropriate values. If the fault condition persists, and the output

voltages again climb to excessive levels, the overvoltage circuitry will initiate

another shutdown cycle. This on/off cycling is referred to as "hiccup" mode.

Contact Murata Power Solutions for an optional output overvoltage monitor

circuit using a comparator which is optically coupled to the primary side thus

allowing tighter and more precise control.

Current Limiting

As soon as the output current increases to 10% to 50% above its rated value,

the DC-DC converter will go into a current-limiting mode. In this condition, the

output voltage will decrease proportionately with increases in output current,

thereby maintaining somewhat constant power dissipation. This is commonly

referred to as power limiting. Current limit inception is deﬁ ned as the point at

which the full-power output voltage falls below the speciﬁ ed tolerance. See

Performance/Functional Speciﬁ cations. If the load current, being drawn from

the converter, is signiﬁ cant enough, the unit will go into a short circuit condition

as speciﬁ ed under "Performance."

Short Circuit Condition

When a converter is in current-limit mode, the output voltage will drop as

the output current demand increases. If the output voltage drops too low, the

magnetically coupled voltage used to develop primary side voltages will also

drop, thereby shutting down the PWM controller. Following a time-out period,

the PWM will restart causing the output voltages to begin ramping to their

appropriate values. If the short-circuit condition persists, another shutdown

cycle will be initiated. This on/off cycling is referred to as "hiccup" mode. The

hiccup cycling reduces the average output current, thereby preventing internal

temperatures from rising to excessive levels. The ULE is capable of enduring an

indeﬁ nite short circuit output condition.

Features and Options

On/Off Control

The input-side, remote On/Off Control function can be ordered to operate with

either polarity:

Standard models are equipped with Positive-polarity (“P" part-number

sufﬁ x) and these devices are enabled when the On/Off Control is left open or

is pulled high, as per Figure 4. Positive-polarity devices are disabled when the

On/Off Control is pulled low.

Figure 3. Measuring Output Ripple/Noise (PARD)

Floating Outputs

Since these are isolated DC-DC converters, their outputs are "ﬂ oating" with

respect to their input. Designers will normally use the –Output (pin 4) as the

ground/return of the load circuit. You can, however, use the +Output (pin 8) as

ground/return to effectively reverse the output polarity.

Minimum Output Loading Requirements

ULE converters employ a synchronous-rectiﬁ er design topology. The ULE-

12/4.2 and ULE-24/3 modules require minimum load; all other models regulate

within spec and are stable under no-load to full load conditions. Operation

under no-load conditions however might slightly increase the output ripple and

noise.

Thermal Shutdown

These ULE converters are equipped with thermal-shutdown circuitry. If envi-

ronmental conditions cause the internal temperature of the DC-DC converter to

C1 = 0.47μF CERAMIC

C2 = NA

LOAD 2-3 INCHES (51-76mm) FROM MODULE

C2 R

LOAD

SCOPE

+VOUT

–VOUT

+SENSE

–SENSE

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 22 of 28

www.murata-ps.com/support

Figure 4. Driving the Positive Polarity On/Off Control Pin

Optional Negative-polarity devices (“N” sufﬁ x) are off when the On/Off Control

is open (or pulled high), and on when the On/Off Control is pulled low with

respect to –VIN as shown in Figure 5.

Figure 6. Trim Connections Using A Trimpot

Figure 5. Driving the Negative Polarity On/Off Control Pin

Dynamic control of the remote on/off function is facilitated with a mechanical

relay or an open-collector/open-drain drive circuit (optically isolated if appropri-

ate). The drive circuit should be able to sink appropriate current (see Performance

Specs) when activated and withstand appropriate voltage when deactivated.

Applying an external voltage to the On/Off Control when no input power is

applied to the converter can cause permanent damage to the converter.

Trimming Output Voltage

ULE converters have a trim capability that allows users to adjust the output

voltages as listed in the speciﬁ cations. Adjustments to the output voltages can

be accomplished via a trim pot (Figure 6) or a single ﬁ xed resistor as shown

in Figures 7 and 8. A single ﬁ xed resistor can increase or decrease the output

voltage depending on its connection. The resistor should be located close to

the converter and have a TCR less than 100ppm/°C to minimize sensitivity

to changes in temperature. If the trim function is not used, leave the trim pin

ﬂ oating.

Figure 7. Trim Connections To Increase Output Voltages Using a Fixed Resistor

ON/OFF CONTROL

CONTROL

+ Vcc

-VIN

Figure 8. Trim Connections To Decrease Output Voltages

A single resistor connected from the Trim to the +Output, or +Sense where

applicable, will increase the output voltage in this conﬁ guration. A resistor con-

nected from the Trim to the –Output, or –Sense where applicable, will decrease

the output voltage in this conﬁ guration.

Trim adjustments greater than the speciﬁ ed range can have an adverse

affect on the converter's performance and are not recommended. Excessive

voltage differences between VOUT and Sense, in conjunction with trim adjust-

ment of the output voltage, can cause the overvoltage protection circuitry to

activate (see Performance Speciﬁ cations for overvoltage limits). Power derating

is based on maximum output current and voltage at the converter’s output

pins. Use of trim and sense functions can cause output voltages to increase,

thereby increasing output power beyond the converter's speciﬁ ed rating or

cause output voltages to climb into the output overvoltage region. Therefore:

(VOUT at pins) x (IOUT) <= rated output power

+ VIN +VCC

–VIN

O N /O F F

C O N TR O L

1M

5-20

TURNS

LOAD

+VOUT

+VIN

–VIN

ON/OFF

CONTROL TRIM

+SENSE

–VOUT

–SENSE

LOAD

+VOUT

+VIN

–VIN

ON/OFF

CONTROL TRIM

+SENSE

–VOUT

–SENSE

LOAD

+VOUT

+VIN

–VIN

ON/OFF

CONTROL TRIM

+SENSE

–VOUT

–SENSE

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 23 of 28

www.murata-ps.com/support

Note: Resistor values are in k. Adjustment accuracy is subject to resistor

tolerances and factory-adjusted output accuracy. VO = desired output voltage.

Remote Sense Note: The Sense and VOUT lines are internally connected

through low value resistors. Nevertheless, if the sense function is not used for

remote regulation the user should connect the +Sense to +VOUT and –Sense

to –VOUT at the DC-DC converter pins.

ULE series converters have a sense feature to provide point of use regula-

tion, thereby overcoming moderate IR drops in pcb conductors or cabling.

The remote sense lines carry very little current and therefore require minimal

cross-sectional-area conductors. The sense lines are used by the feedback

control-loop to regulate the output. As such, they are not low impedance points

and must be treated with care in layouts and cabling. Sense lines on a pcb

should be run adjacent to dc signals, preferably ground. In cables and discrete

wiring applications, twisted pair or other techniques should be implemented.

ULE series converters will compensate for drops between the output voltage

at the DC-DC and the sense voltage at the DC-DC provided that:

[VOUT(+) –VOUT(–)] –[Sense(+) –Sense (–)]  5% VOUT

Output overvoltage protection is monitored at the output voltage pin, not

the Sense pin. Therefore, excessive voltage differences between VOUT and

Sense in conjunction with trim adjustment of the output voltage can cause the

overvoltage protection circuitry to activate (see Performance Speciﬁ cations

for overvoltage limits). Power derating is based on maximum output current

and voltage at the converter’s output pins. Use of trim and sense functions can

cause output voltages to increase thereby increasing output power beyond the

ULE’s speciﬁ ed rating or cause output voltages to climb into the output over-

voltage region. Also, the use of Trim Up and Sense combined may not exceed

+10% of VOUT. Therefore, the designer must ensure:

(VOUT at pins) x (IOUT)  rated output power

Trim Equations

Trim Up Trim Down

UP VO– 3.3

RT (k ) = –10.2

13.3(VO– 1.226)

3.3 – VO

RT (k ) = –10.2

16.31

DOWN

3.3 Volt Output

UP VO– 5

RT (k ) = –10.2

20.4(VO– 1.226)

5– VO

RT (k ) = –10.2

25.01

DOWN

5 Volt Output

UP VO– 12

RT (k ) = –10.2

49.6(VO– 1.226)

UP VO– 15

RT (k ) = –10.2

62.9(VO– 1.226)

12 – VO

RT (k ) = –10.2

60.45

DOWN

15 – VO

RT (k ) = –10.2

76.56

DOWN

12 Volt Output

15 Volt Output

UP VO – 1.5

RT (kΩ) = –10.2

6.23(VO – 1.226)

1.5 – VO

RT (kΩ) = –10.2

7.64

DOWN

UP VO – 1.8

RT (kΩ) = –10.2

7.44(VO – 1.226)

1.8 – VO

RT (kΩ) = –10.2

9.12

DOWN

UP VO – 2.5

RT (kΩ) = –10.2

10(VO – 1.226)

2.5 – VO

RT (kΩ) = –10.2

12.26

DOWN

1.5 Volt Output

1.8 Volt Output

2.5 Volt Output

Figure 9. Remote Sense Circuit Conﬁ guration

LOAD

+VOUT

+VIN

Sense Current

Contact and PCB resistance

losses due to IR drops

Contact and PCB resistance

losses due to IR drops

Sense Return

–VIN

ON/OFF

CONTROL TRIM

+SENSE

–VOUT

–SENSE

IOUT Return

IOUT

Wave Solder Operations for through-hole mounted products (THMT)

For Sn/Ag/Cu based solders: For Sn/Pb based solders:

Maximum Preheat Temperature 115° C. Maximum Preheat Temperature 105° C.

Maximum Pot Temperature 270° C. Maximum Pot Temperature 250° C.

Maximum Solder Dwell Time 7 seconds Maximum Solder Dwell Time 6 seconds

Soldering Guidelines

Murata Power Solutions recommends the speciﬁ cations below when installing these

converters. These speciﬁ cations vary depending on the solder type. Exceeding these

speciﬁ cations may cause damage to the product. Be cautious when there is high atmo-

spheric humidity. We strongly recommend a mild pre-bake (100 ºC. for 30 minutes). Your

production environment may differ therefore please thoroughly review these guidelines

with your process engineers.

Reﬂ ow Solder Operations for surface-mount products (SMT)

For Sn/Ag/Cu based solders: For Sn/Pb based solders:

Preheat Temperature Less than 1 ºC. per second Preheat Temperature Less than 1 ºC. per second

Time over Liquidus 45 to 75 seconds Time over Liquidus 60 to 75 seconds

Maximum Peak Temperature 260 ºC. Maximum Peak Temperature 235 ºC.

Cooling Rate Less than 3 ºC. per second Cooling Rate Less than 3 ºC. per second

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 24 of 28

www.murata-ps.com/support

Surface-Mount Package ("M" sufﬁ x)

Murata Power Solutions’ ULE series SMT DC-DC converters are the only higher-

power DC-DCs that can be automatically “pick-and-placed” using standard

vacuum-pickup equipment and subsequently reﬂ owed using high-temperature,

lead-free solder.

Virtually all SMT DC-DCs today are unprotected "open-frame" devices as-

sembled by their vendors with high-temperature solder (usually Sn96.5/Ag3.5

with a melting point +221°C) so that you may attach them to your board using

low-temperature solder (usually Sn63/Pb37 with a melting point of +183°C).

Conceptually straightforward, this "stepped" solder approach has its limita-

tions . . . and is clearly out of step with an industry trending toward the broad

use of lead-free solders. Users need to experiment and develop reﬂ ow proﬁ les

that ensure the components on their DC-DC never exceed 215-216°C. If those

components get too hot, "double-reﬂ ow" could compromise the reliability of

their solder joints. Virtually all these devices demand you "cool down" the Sn63

proﬁ le you are likely using today.

Murata Power Solutions is not exempted from the Laws of Physics. And we

do not have magic solders no one else has. We do have a simple and practical,

straightforward approach that works. We assemble our SMT DC-DCs on a

thermally-stable plastic lead-frame (nylon 46, UL94V-0 ﬂ ammability rated) using

a high temperature lead-free solder. The lead-frame ensures coplanarity (to

within 0.004 in.) of the unit's tin-plated (150 microinches) copper leads and

also supports a removable heat shield.

The disposable heat shield, with a cutaway exposing the package leads,

provides thermal insulation to internal components during reﬂ ow and doubles as

the vacuum pick-up location. The insulation properties of the heat shield are so

effective that temperature differentials as high as 50°C develop inside-to-outside

the shield. Oven temperature proﬁ les with peaks of 250-260°C and dwell times

exceeding 2 minutes above 221°C are easily achieved. Murata Power Solutions’

new-generation SMT units are shipped in stackable, JEDEC-style plastic trays

(Figure 13).

Automated Assembly Production Notes

Murata Power Solutions’ new high-efﬁ ciency DC-DC converters are designed

for modern surface-mount technology (SMT) automated assembly using

screened solder paste, "pick and place" component positioning and forced

hot air reﬂ ow oven soldering. If you are new to SMT techniques and have a

volume application, these features save time, cost and improve manufacturing

efﬁ ciency. Murata Power Solutions’ DC-DC assembly operations themselves

make extensive use of such techniques.

Even if you have previous SMT experience, you should read the sections be-

low on solder reﬂ ow proﬁ les and heat shields. This information is not intended

to replace the documentation for your SMT system. We assume that you are

already experienced with all the components of your SMT system.

This section will discuss several SMT issues, including:

I/O Mechanical Conﬁ guration

Part Handling and Supply

Printed Circuit Board (pcb) Mounting

Soldering using Reﬂ ow Technology

Temperature Proﬁ ling

Heat Shields and Removal

Mechanical Conﬁ guration of Input/Output Connections

These new converters are supplied either using traditional through-hole pins

or SMT leads. (Note that some models are offered only with lead mounting).

The pin options insert into plated-through holes in the host pcb. Be aware that

some heat dissipation is carried off by either the pins or leads. The Derating

Curves assume that some additional pad area is available on your host pcb to

absorb the heat.

The lead option uses either short tabs in "gullwing" style or standoff leads

under the converter. The gullwing leads typically are copper alloy with 150

microinches of tin plating. Solder paste (typically 0.008" to 0.009" thick) is ap-

plied to the host pcb using a solder mask pressure screening technique and the

board is heated and cooled long enough for the solder to reﬂ ow and adhere to

both the host pads and the converter’s mounting leads.

After such mounting, the entire mechanical mounting load is carried by the

solder. Obviously the converters must be accurately positioned all during the

solder reﬂ ow period. Where solder surface tension is sufﬁ cient to force tiny

components into position, these larger converters may not move and must be

accurately positioned by your SMT system.

Part Handling and Supply

SMT eighth- and quarter-brick DC-DC converters (plus installed heat shields if

used) are supplied in JEDEC-standard 5.35" by 12.4" wafﬂ

e trays which are

compatible with the feeders on industry-standard pick-and-place machines.

Since the converters are larger and heavier than many other components,

make sure your system can reliably remove the units from their trays, move

them to the host pcb and accurately position them. The plastic heat shield

(Figure 10) doubles as a vacuum pickup area.

Figure 10. ULE SMT DC-DC with Disposable Heat Shield

Solder Balls

ULE converters are thoroughly inspected according to military standard

J-STD-001B for the presence of solder balls. The speciﬁ cation allows small

solder balls as long as they are rigidly attached and do not compromise the

spacing and clearance requirements needed to maintain electrical isolation.

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 25 of 28

www.murata-ps.com/support

0.150 TYP.

(3.81)

2.340 (59.44)

0.020 (0.51)

1.975 (50.17)

SMT UNIT

PCB

SMT LEAD

Copper Pad

0.183

(4.65)

0.020 REF.

(0.51)

0.130 TYP.

(3.30)

DIMENSIONS ARE IN INCHES (MM)

0.300 TYP.

(7.62)

Orientation: When loaded into JEDEC trays, the converters

are oriented in the same direction. See the diagram below. For

the ULE series, a notch is placed on the top of the case (on the

removal tabs) to indicate the pin 1 position. You should visually

inspect the tray to be sure of this orientation.

Most pick-and-place automatic assembly systems use a

camera which must be trained to recognize the orientation of

the converter before it is assembled onto the host PC board.

This “training” locates and identiﬁ es prominent, dimensionally

stable landmarks such as the board corners or ﬁ ducial marks.

On the bottom of the converter, the ULE series include

optical ﬁ ducial marks viewable by your SMT imaging system. Observing from

the bottom, your SMT imaging camera should ﬁ nd these marks to identify the

converter and verify pin 1. On most pick-and-place systems, during head transit,

the imaging system will automatically ﬁ ne tune the end mounting position of

the converter using image comparisons from these ﬁ ducials or other reference

marks you have chosen.

The ﬁ ducial marks are placed fairly close together because many imaging

systems have a one inch or less observing area since most SMT parts are con-

siderably smaller than these converters. You may prefer to train your imaging

system to use a corner of the converter or an I/O lead.

The ﬁ ducial marks will remain identical within any date code lot of converters.

In the remote possibility that the ﬁ ducials may have changed position with a PC

board revision, you should not mix different date lots on any one production as-

sembly session. In addition, to avoid non-recognition or misplacement of the con-

verter, retrain your imaging system at the beginning of each series of assembly

sessions. There may be tiny variations in the absolute position from unit to unit.

If you use a camera above the pcb after placement on the solder paste, do

not rely on the inkjet marking on the heat shield to verify proper orientation.

Use the pin 1 notch instead.

Coplanarity: Murata Power Solutions manufactures these converters with

very ﬂ at mounting leads (see coplanarity specs) however your host pcb must

also be ﬂ at for a successful mounting. Be aware of possible warping of the pcb

under heat gradients and/or humidity conditions. The solder paste will tolerate

a small amount of mismatch and will tend to “wet” the entire pad area by

capillary action if the temperatures are correct.

Vacuum Pickup: Select the vacuum collet on your SMT placement system

for the weight and size of the DC-DC converter. Note that units with heatsinks

are slightly heavier. Tests at Murata Power Solutions have shown that excellent

acceleration and transit head speed are available for these converters if the

collet size is proper and the vacuum is sufﬁ cient. When positioning the vacuum

collet, use the geometric center of the heat shield as the pickup area since the

center of gravity is very close.

Soldering

Reﬂ ow technology works well for small parts. However, larger components

such as these DC-DC’s with higher thermal mass may require additional reﬂ ow

time (but not enough to disturb smaller parts also being reﬂ owed concurrently

with the DC-DC). When this is combined with higher temperature lead-free sol-

ders (or solders with reduced heavy metals), there is increased risk of reheat-

ing components inside the DC-DC enough so that they either change positions

(and possibly stop functioning) or the components are damaged by the heat.

Figure 11. Recommended Solder Proﬁ le

(When the Heat-shield temperature exceeds +250°C,

the air within is 50°C cooler)

Post Reﬂ ow Procedures

After successful solder reﬂ ow, be sure to completely clean and dry your assem-

bled boards using a recommended wash solution and dryer. Failure to remove all

ﬂ ux may cause long term deterioration of on-board conductors and components.

And, traces of contaminants which are not removed may reduce isolation volt-

ages or risk a safety hazard. Be aware that low remaining concentrations of ﬂ ux

or other assembly compounds can be very difﬁ cult to detect by eye.

Pick and Place pcb Mounting

The main issues here are pad area, orientation, positioning accuracy, vacuum

pickup and coplanarity. Murata Power Solutions recommends that pcb pads to

interface with the DC-DC converter should be sized as shown in the diagram

below. The pads footprint accommodates the positioning accuracy of your SMT

equipment and manufactured tolerances of the DC-DC mounting leads.

Z1 Z2 Z3 Z4 Z5 Z6 Z7

100

Seconds

Degrees Celsius

250

200

150

100

200 300 400 500 600

Heat Shield

Test Board

Air Under Shield

Figure 12. Recommended SMT Mounting Pad Dimensions

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 26 of 28

www.murata-ps.com/support

5.35 (135.89)

12.40

(314.96)

2.875

(73.03)

2.875

(73.03)

2.875

(73.03)

1.032

(26.21)

1.50

(38.1)

1.50

(38.1)

PIN 1

DIMPLE

DIMENSIONS ARE IN INCHES (MM)

For these reasons, Murata Power Solutions developed disposable heat

shields using high temperature plastic. The DC-DC is installed and reﬂ owed

with the shield in place. After successful reﬂ ow and cooling, and before wash-

ing, the heat shield should be removed.

Temperature Proﬁ ling

We wish to ramp the temperature up and down to successfully reﬂ ow the

solder without heat damage. Each reﬂ ow oven, humidity conditions, solder

paste type, oven feed rate, and the number of heat zones all require a different

proﬁ le. Therefore you may have to experiment.

Since these converters are constructed using high temperature solders,

there will be no heat problems on your host pcb using traditional solder with

63% lead and 37% tin with a melting point of +183°C. Device lead tempera-

ture must remain below 230°C for less than 75 seconds, assuming that the

heat shield is in place. Murata Power Solutions uses a 216°C melt lead-free

tin/silver/copper alloy to assemble these converters.

There are several lead-free solders suitable for your host pcb depending on

your SMT system and whatever local certiﬁ cation and environmental regulations

you must observe. Contact Murata Power Solutions if you need speciﬁ c advice.

Heat Shield

Careful thermocouple testing has shown that the interior of the DC-DC under

the heat shield is tens of degrees cooler than the outside ambient temperature

for typical reﬂ ow proﬁ les. This protects internal components and limits the

amount of reﬂ ow where it is not desired. The heat shield also includes marking

for product identiﬁ cation and a date/lot code.

On ULE models, the heat shield is attached to the converter using molded

plastic pins on the heat shield interior which insert into recessed dimples in

the pinframe. An extra molded pin on the heat shield at the pin 1 location (and

corresponding notch on the pcb) can only be installed one way properly on the

pinframe. If the shield accidentally comes loose, it may be reinstalled by align-

ing the pins and dimples.

To remove the shield from the converter, after successful mounting and cool-

ing, squeeze the heat shield ears inward toward the converter body and pull the

shield upwards. Discard or recycle the shield. If you are using a ﬂ ux wash cycle,

remove the heat shield before washing to avoid coming loose inside the washer.

Figure 13. Shipping Tray

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 27 of 28

www.murata-ps.com/support

Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other

technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply

the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Speciﬁ cations are subject to change

Murata Power Solutions, Inc.

129 Flanders Road, Westborough, MA 01581 U.S.A.

ISO 9001 and 14001 REGISTERED

This product is subject to the following operating requirements

and the Life and Safety Critical Application Sales Policy:

Refer to: http://www.murata-ps.com/requirements/

Figure 14. Vertical Wind Tunnel

IR Video

Camera

IR Transparent

optical window Variable

speed fan

Heating

element

Ambient

temperature

sensor

Airﬂow

collimator

Precision

low-rate

anemometer

3” below UUT

Unit under

test (UUT)

Vertical Wind Tunnel

Murata Power Solutions employs a computer controlled

custom-designed closed loop vertical wind tunnel, infrared

video camera system, and test instrumentation for accurate

airﬂ ow and heat dissipation analysis of power products.

The system includes a precision low ﬂ ow-rate anemometer,

variable speed fan, power supply input and load controls,

temperature gauges, and adjustable heating element.

The IR camera monitors the thermal performance of the

Unit Under Test (UUT) under static steady-state conditions. A

special optical port is used which is transparent to infrared

wavelengths.

Both through-hole and surface mount converters are

soldered down to a 10" x 10" host carrier board for realistic

heat absorption and spreading. Both longitudinal and trans-

verse airﬂ ow studies are possible by rotation of this carrier

board since there are often signiﬁ cant differences in the heat

dissipation in the two airﬂ ow directions. The combination of

adjustable airﬂ ow, adjustable ambient heat, and adjustable

Input/Output currents and voltages mean that a very wide

range of measurement conditions can be studied.

The collimator reduces the amount of turbulence adjacent

to the UUT by minimizing airﬂ ow turbulence. Such turbu-

lence inﬂ uences the effective heat transfer characteristics

and gives false readings. Excess turbulence removes more

heat from some surfaces and less heat from others, possibly

causing uneven overheating.

Both sides of the UUT are studied since there are different

thermal gradients on each side. The adjustable heating element

and fan, built-in temperature gauges, and no-contact IR camera mean

that power supplies are tested in real-world conditions.

ULE Series

Isolated, High Density, Eighth-Brick

1.25–20 Amp, DC-DC Converters

MDC_ULE Series.H03 Page 28 of 28

Mouser Electronics

Authorized Distributor

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