The HPQ-12/25-D48 series offers high output
current (up to 25 Amps) in an industry standard
“quarter brick” package requiring no heat sink for
most applications. The HPQ-12/25-D48 series de-
livers fi xed 12 Vdc output at 300 Watts for printed
circuit board mounting. Wide range inputs on the
2.3” x 1.45” x 0.49” converter are 36 to 75 Volts
DC (48 Volts nominal), ideal for datacom and telecom
systems. The fi xed output voltage is regulated to
within ±0.25%.
Advanced automated surface mount assembly
and planar magnetics deliver galvanic isolation
rated at 2250 Vdc for basic insulation. To power
digital systems, the outputs offer fast settling to
current steps and tolerance of higher capacitive
loads. Excellent ripple and noise specifi cations as-
sure compatibility to CPU’s, ASIC’s, programmable
logic and FPGA’s. No minimum load is required. For
systems needing controlled startup/shutdown, an
external remote On/Off control may use either posi-
tive or negative logic. Remote Sense inputs com-
pensate for resistive line drops at high currents.
A wealth of self-protection features avoid prob-
lems with both the converter and external circuits.
These include input undervoltage lockout and
overtemperature shutdown using an on-board tem-
perature sensor. Overcurrent protection using the
“hiccup” autorestart technique provides indefi nite
short-circuit protection. Additional safety features
include output overvoltage protection and reverse
conduction elimination. The synchronous rectifi er to-
pology offers high effi ciency for minimal heat buildup
and “no heat sink” operation. The HPQ-12/25-D48
series is certifi ed to full safety standards UL/EN/IEC/
CSA 60950-1, 2nd edition and RFI/EMI conducted/
radiated emission compliance to EN55022, CISPR22
with external fi lter.
PRODUCT OVERVIEW

Embedded systems, datacom and telecom
installations

Disk farms, data centers and cellular repeater sites

Remote sensor systems, dedicated controllers

Instrumentation systems, R&D platforms, auto-
mated test fi xtures

Data concentrators, voice forwarding and
speech processing systems
APPLICATIONS
FEATURES

12 Volts DC fi xed output up to 25 Amps

Industry standard quarter brick 2.3” x 1.45” x
0.49” open frame package

Wide range 36 to 75 Vdc input voltages with
2250 Volt Basic isolation

Double lead-free assembly and attachment for
RoHS standards

Up to 300 Watts total output power

High effi ciency (94.5%) synchronous rectifi er
topology

Stable no-load operation with no required external
components

Operating temperature range -40 to +85° C.
with no heat sink required

Certifi ed to UL/EN 60950-1, CSA-C22.2 No.
60950-1, 2nd edition safety approvals

Extensive self-protection, current limiting and
shut down features

“X” optional version omits trim and sense pins
Output (V) Current (A) Nominal Input (V)
12 25 48
F1
External
DC
Power
Source
Reference and
Error Amplifier
t4XJUDIJOH
t'JMUFST
t$VSSFOU4FOTF
-Vout (4)
+Vout (8)
4FOTF
4FOTF
5SJN
On/Off
Control
(2)
-Vin (3)
Open = On
$MPTFE0GG
+Vin (1)
1PTJUJWF
MPHJD
Controller
and Power
5SBOTGFS
*TPMBUJPO
Barrier
Figure 1. Connection Diagram
Typical unit
Typical topology is shown. Murata Power Solutions
recommends an external fuse.
* “X” option omits trim and sense pins.
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 1 of 16
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www.murata-ps.com/support
For full details go to
www.murata-ps.com/rohs
　
➀ Please refer to the part number structure for additional ordering information and options.
➁ All specifi cations are at nominal line voltage and full load, +25 deg.C. unless otherwise noted.
See detailed specifi cations. Output capacitors are 1 µF ceramic in parallel with 10 µF electrolytic
with no input caps.These caps are necessary for our test equipment and may not be needed for
your application.
➂ Ta=25C, Vin=48V, Full load condition.
PEFORMANCE SPECIFICATION SUMMARY AND ORDERING GUIDE ➀
Root Model ➀
Output Input
Effi ciency Package (C59)
VOUT
(Volts)
IOUT
(Amps,
max.)
Power
(Watts)
R/N (mV
pk-pk) Regulation (Max.) ➁
VIN Nom.
(Volts)
Range
(Volts)
IIN no
load (mA)
IIN full
load
(Amps)Typ. Max. Line Load Min. ➂Typ.
Dimensions
(inches)
Dimensions
(mm)
HPQ-12/25-D48
HPQ-12/25-D48 12 25 300 80 120 ±0.125% ±0.25% 48 36-75 150 6.61 94% 95%
2.3x1.45x0.49 max.
2.3x1.45x0.49 max.
58.4x36.8x12.45
58.4x36.8x12.45
PART NUMBER STRUCTURE
Pin length option
Blank = standard pin length 0.180 in. (4.6 mm)
L1 = 0.110 in. (2.79 mm)*
L2 = 0.145 in. (3.68 mm)*
Lx
D48
Input Voltage Range:
D48 = 36-75 Volts (48V nominal)
/
Nominal Output Voltage
12 25
Maximum Rated Output
Current in Amps
-N
On/Off Control Logic
N = Negative logic, standard
P = Positive logic, optional
-
HPQ
Family
Series:
High Power
Quarter Brick
Baseplate (optional)
Blank = No baseplate, standard
B = Baseplate installed, optional
B
RoHS Hazardous Materials compliance
C = RoHS-6 (does not claim EU RoHS exemption 7b–lead in solder), standard
Y = RoHS-5 (with lead), optional, special quantity order
-C
Conformal coating (optional)
Blank = no coating, standard
H = Coating added, optional
H
Trim & Sense Pins Option
Blank = Trim and Sense installed, standard
X = Trim and Sense removed
Z = Sense removed (Trim included)
X
Complete Model Number Example:
Negative On/Off logic, baseplate installed, conformally coated, trim and sense pins removed, 0.110˝ pin length, RoHS-6 compliance
HPQ-12/25-D48NBHXL1-C
Special Customer Confi guration part numbers:
1) HPQ-12/25-D48NXL2-C-CIS
2) HPQ-12/25-D48NBZL2-C-CIS
3) HPQ-12/25-D48NL2-C-CIS
Note:
Some model number combinations
may not be available. Please contact
Murata Power Solutions.
*Special quantity order is required;
no sample quantities available.
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 2 of 16
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HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 3 of 16
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FUNCTIONAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS Conditions ➀Minimum Typical/Nominal Maximum Units
Input Voltage, Continuous Full power operation 36 80 Vdc
Input Voltage, Transient Operating or non-operating,
100 mS max. duration 100 Vdc
Isolation Voltage Input to output tested 100 mS 2250 Vdc
Input Reverse Polarity None, install external fuse None Vdc
On/Off Remote Control Power on or off, referred to -Vin 0 13.5 Vdc
Output Power 0 300 W
Output Current Current-limited, no damage,
short-circuit protected 025A
Storage Temperature Range Vin = Zero (no power) -55 125 °C
Absolute maximums 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 or recommended.
INPUT Conditions ➀ ➂
Operating voltage range 36 48 75 Vdc
Recommended External Fuse Fast blow 20 A
Start-up threshold Rising input voltage 33 34 35 Vdc
Undervoltage shutdown Falling input voltage 31 32 34 Vdc
Overvoltage protection Rising input voltage None Vdc
Reverse Polarity Protection None, install external fuse None Vdc
Internal Filter Type Pi-type
Input current
Full Load Conditions Vin = nominal 6.61 6.82 A
Low Line Vin = minimum 8.82 9.1 A
Inrush Transient Vin = 48V. 0.3 A2-Sec.
Output in Short Circuit 50 100 mA
No Load Iout = minimum, unit=ON 150 250 mA
Standby Mode (Off, UV, OT) 510mA
Refl ected (back) ripple current ➁Measured at input with specifi ed fi lter 50 70 mA, RMS
Pre-biased startup External output voltage < Vset Monotonic
GENERAL and SAFETY
Effi ciency Vin=48V, full load 94 95 %
Isolation
Isolation Voltage, input to output No baseplate 2250 Vdc
Isolation Voltage, input to output With baseplate 2250 Vdc
Isolation Voltage, input to baseplate With baseplate 1500 Vdc
Isolation Voltage, output to baseplate With baseplate 1500 Vdc
Insulation Safety Rating basic
Isolation Resistance 10 M
Isolation Capacitance 1000 pF
Safety Certifi ed to UL-60950-1, CSA-C22.2 No.60950-1,
IEC/EN60950-1, 2nd edition Yes
Calculated MTBF Per MIL-HDBK-217F, ground benign,
Tambient=+TBD°C TBD Hours x 103
Calculated MTBF Per Telcordia SR-332, issue 1, class 3, ground
fi xed, Tcase=+25°C 1500 Hours x 103
DYNAMIC CHARACTERISTICS
Fixed Switching Frequency 260 KHz
Startup Time ➈Power On, to Vout regulation band,
100% resistive load 25 mS
Startup Time Remote ON to Vout Regulated 25 mS
Dynamic Load Response 50-75-50% load step to 1% error band 550 825 µSec
Dynamic Load di/dt 0.1 A / µSec
Dynamic Load Peak Deviation same as above ±500 ±750 mV
FEATURES and OPTIONS
Remote On/Off Control ➃
“N” suffi x:
Negative Logic, ON state ON = pin grounded or external voltage -0.1 0.8 Vdc
Negative Logic, OFF state OFF = pin open or external voltage 3.5 13.5 Vdc
Control Current open collector/drain 2 mA
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 4 of 16
www.murata-ps.com/support
FEATURES and OPTIONS (cont.) Conditions ➀Minimum Typical/Nominal Maximum Units
Remote On/Off Control (cont.) ➃
“P” suffi x:
Positive Logic, ON state ON = pin open or external voltage 3.5 13.5 V
Positive Logic, OFF state OFF = ground pin or external voltage 0 0.8 V
Control Current open collector/drain 2 mA
Remote Sense Compliance ➆Vsense=Vout - Vload, Sense pins connected
externally to respective Vout’s 0.5 V
Base Plate "B" suffi x optional
OUTPUT
Total Output Power 0.0 300 306 W
Voltage
Setting Accuracy At 50% load, no trim 11.76 12 12.24 Vdc
Output Voltage Range ➆User-adjustable -10 +10 % of Vnom.
Overvoltage Protection Via magnetic feedback 14.4 18 V
Current
Output Current Range 0.0 25.0 A
Minimum Load No minimum load
Current Limit Inception 98% of Vnom., after warmup 28.5 32 39 A
Short Circuit
Short Circuit Current Hiccup technique, autorecovery within 1.25%
of Vout 0.8 1.0 A
Short Circuit Duration
(remove short for recovery) Output shorted to ground, no damage Continuous
Short circuit protection method Hiccup current limiting Non-latching
Regulation ➄
Line Regulation Vin=min. to max., Vout=nom., full load ±0.125 % of Vout
Load Regulation Iout=min. to max., Vin=nom. ±0.25 % of Vout
Ripple and Noise ➅Vin=48V, full load, 5 Hz- 20 MHz BW, Cout=1F
MLCC paralleled with 10F 80 100 mV pk-pk
Temperature Coeffi cient At all outputs 0.02 % of Vout./°C
Maximum Capacitive Loading Full resistive load, low ESR 0 4,700 F
MECHANICAL (Through Hole Models)
Outline Dimensions (no baseplate) C59 case 2.3x1.45x0.49 max. Inches
(Please refer to outline drawing) LxWxH 58.4x36.8x12.45 mm
Outline Dimensions (with baseplate) 2.3x1.45x0.5 Inches
58.4x36.8x12.7 mm
Weight No baseplate 1.51 Ounces
No baseplate 47 Grams
With baseplate 2.4 Ounces
With baseplate 68 Grams
Through Hole Pin Diameter 0.04 & 0.062 Inches
1.016 & 1.575 mm
Through Hole Pin Material Copper alloy
TH Pin Plating Metal and Thickness Nickel subplate 100-299 µ-inches
Gold overplate 3.9-19.6 µ-inches
Baseplate Material Aluminum
ENVIRONMENTAL
Operating Ambient Temperature Range See derating curves -40 85 °C
Operating Case Temperature No derating required -40 110 °C
Storage Temperature Vin = Zero (no power) -55 125 °C
Thermal Protection/Shutdown Measured at hotspot 105 110 125 °C
Electromagnetic Interference External fi lter is required
Conducted, EN55022/CISPR22 B Class
Radiated, EN55022/CISPR22 B Class
Relative humidity, non-condensing To +85°C 10 90 %RH
Altitude must derate -1%/1000 feet -500 10,000 feet
-152 3048 meters
Acceleration 50 g
Shock Halfsine wave, 3 axes 1 g
Sinusoidal Vibration GR-63-Core, Section 5.4.2
RoHS rating RoHS-6
FUNCTIONAL SPECIFICATIONS (CONT.)
TYPICAL PERFORMANCE DATA
Effi ciency vs. Output Current @ +25°C
Effi ciency vs. Output Current @ +60°C Output Voltage vs Load Current at -40°C.
Effi ciency vs. Output Current @ -40°C
3 5 7 9 11 13 15 17 19 21 23 25
75
80
85
90
95
100
V
IN
= 36 V
V
IN
= 48 V
V
IN
= 75 V
Efficiency (%)
Iout (Amps)
0102030
70
75
80
85
90
95
100
V
IN
= 36V
V
IN
= 48V
V
IN
= 75V
Efficiency (%)
Iout (Amps)
01020
0
2
4
6
9
10
12
V
IN
= 36V, 48V, 75V
Output (Volts)
Load (Amps)
0102030
70
75
80
85
90
95
100
V
IN
= 36V
V
IN
= 48V
V
IN
= 75V
Efficiency (%)
Iout (Amps)
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 5 of 16
www.murata-ps.com/support
Notes
➀ Unless otherwise noted, all specifi cations apply over the input voltage range, full temperature
range, nominal output voltage and full output load. General conditions are near sea level altitude,
no base plate installed and natural convection airfl ow unless otherwise specifi ed. All models are
tested and specifi ed with external parallel 1 µF and 10 µF multi-layer ceramic output capacitors.
No external input capacitor is used (see Application Notes). All capacitors are low-ESR types wired
close to the converter. These capacitors are necessary for our test equipment and may not be
needed in the user’s application.
➁ Input (back) ripple current is tested and specifi ed over 5 Hz to 20 MHz bandwidth. Input fi ltering is
Cin = 33 µF, Cbus = 220µF and Lbus = 4.7 µH.
➂ All models are stable and regulate to specifi cation under no load.
➃ The Remote On/Off Control is referred to -Vin.
➄ Regulation specifi cations describe the output voltage changes as the line voltage or load current
is varied from its nominal or midpoint value to either extreme. The load step is ±25% of full load
current.
➅ Output Ripple and Noise is measured with Cout = 1µF MLCC paralleled with 10µF tantalum, 20
MHz oscilloscope bandwidth and full resistive load.
➆ The Sense and Trim pins are removed for the “X” model option.
➇ NOTICE—Please use only this customer data sheet as product documentation when laying out your
printed circuit boards and applying this product into your application. Do NOT use other materials as
offi cial documentation such as advertisements, product announcements, or website graphics.
We strive to have all technical data in this customer data sheet highly accurate and complete. This cus-
tomer data sheet is revision-controlled and dated. The latest customer data sheet revision is normally
on our website (www.murata-ps.com) for products which are fully released to Manufacturing. Please be
especially careful using any data sheets labeled “Preliminary” since data may change without notice.
The pinout (Pxx) and case (Cxx) designations (typically P65 or C59) refer to a generic family of
closely related information. It may not be a single pinout or unique case outline. Please be aware
of small details (such as Sense pins, Power Good pins, etc.) or slightly different dimensions
(baseplates, heat sinks, etc.) which may affect your application and PC board layouts. Study the
Mechanical Outline drawings, Input/Output Connection table and all footnotes very carefully.
Please contact Murata Power Solutions if you have any questions.
➈ HPQ restart delay (see technical notes, page 12).
TYPICAL PERFORMANCE DATA
Maximum Current Temperature Derating vs. Airfl ow (Vin=Vnom., airfl ow direction is
from -Vin to +Vin, with baseplate, at sea level)
0
5
10
15
20
25
30
30 35 40 45 50 55 60 65 70 75 80 85
Output Current (Amps)
Ambient Temperature
(°C)
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
Maximum Current Temperature Derating vs. Airfl ow (Vin=Vnom., airfl ow direction is
from Vin to Vout, no baseplate, at sea level)
0
5
10
15
20
25
30
30 35 40 45 50 55 60 65 70 75 80 85
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
Output Current (Amps)
Ambient Temperature
(°C)
Output Voltage vs Load Current at +60°C. Output Voltage vs Load Current at +25°C.
01020
0
2
4
6
9
10
12
V
IN
= 36V, 48V, 75V
Output (Volts)
Load (Amps)
01020
0
2
4
6
9
10
12
V
IN
= 36V, 48V, 75V
Output (Volts)
Load (Amps)
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 6 of 16
www.murata-ps.com/support
TYPICAL PERFORMANCE DATA
Max = 81A, Period = 1.180s, Pulse width = 6.4ms
Step Load Transient Response (Vin = 48V, Cload = 1F ceramic and 10F tantalum,
Iout = 50-75-50% lmax, Slew = 0.1A/Sec., Ta = +25°C)
Power On Startup Delay Output
(Vin = 0 to 48V, Iout = 0A, Cload = 0, Ta = +25°C)
Output Short Circuit Hiccup
(Vin = Nom., Iout = Imax, Cload = 0, Ta = +25°C)
Power On Startup Delay Output
(Vin = 0 to 48V, Iout = 25A, Cload = 0, Ta = +25°C)
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 7 of 16
www.murata-ps.com/support
TYPICAL PERFORMANCE DATA
Output Ripple and Noise (Vin=48V, Iout=0A, Cload=0, Ta=+25˚C., ScopeBW=20MHz)
Output Ripple and Noise (Vin=75V, Iout=0A, Cload=0, Ta=+25˚C., ScopeBW=20MHz)
Output Ripple and Noise (Vin=48V, Iout=25A, Cload=0, Ta=+25˚C., ScopeBW=20MHz)
Output Ripple and Noise (Vin=75V, Iout=25A, Cload=0, Ta=+25˚C., ScopeBW=20MHz)
Output Ripple and Noise (Vin=36V, Iout=25A, Cload=0, Ta=+25˚C., ScopeBW=20MHz)Output Ripple and Noise (Vin=36V, Iout=0A, Cload=0, Ta=+25˚C., ScopeBW=20MHz)
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 8 of 16
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TYPICAL PERFORMANCE DATA
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 9 of 16
www.murata-ps.com/support
HPQ Restart Delay (See Specifi cation Note 10)
When the HPQ undergoes shutdown through loss or cycling of the input power,
a 555 timer enable block circuit is triggered to provide a restart delay to assure
systematic restart of the converter. The delay time is a function both of the
recovery time of the input voltage and the 555 reset time.
Thus, there are two distinct scenarios for the restart delay, which are detailed
below.
Scenario I: Vin recovers quickly.
When the input voltage recovers quickly, the VCC for the 555 timer remains
active to lockout the output for the programmed delay time. The delay time in
this scenario is then equal to the 555 hiccup recovery time. This is internally
set to a nominal value of 3s. This is illustrated in the scope shot below:
Vin (20V per division), Vout (5V per division) at 500ms (1/2 S per division).
Scenario II: Vin recovers after more than 2.5s (restart delay time less than
15ms)
When the input voltage is absent greater than 2.5s, the energy for the Vcc to
the 555 timer enable block will be exhausted. Since this is a suffi cient period
to guarantee systematic restart of the converter, the output will start after just
a 15ms delay from the application of input power. This scenario is illustrated in
the scope shot below.
Third Angle Projection
Dimensions are in inches (mm shown for ref. only).
Components are shown for reference only.
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
➀ M3 bolts must not exceed 0.118˝ (3mm) depth below the baseplate surface.
➁ Applied screw torque must not exceed 5.3 in-lb. (0.6 N-m).
The standard 0.180˝ pin length is shown. Please refer to the part number structure
for alternate pin lengths.
LABEL
0.600
15.24
0.300
7.62
0.600
15.24
2.30
58.4
1.45
36.8
3
2
18
7
6
5
4
8
7
6
5
4
0.600
15.24
0.300
7.62
0.600
15.24
3
2
1
2.000
50.80
L
0.49 Max
12.4
0.165
4.20
0.005 minimum clearance
between standos and
highest component
PINS 1-3,5-7:
φ0.040±0.001(1.016±0.025)
PINS 4,8:
φ0.062±0.001(1.575±0.025)
2.000
50.80
0.50
12.7
PINS 1-3,5-7:
φ0.040±0.001(1.016±0.025)
PINS 4,8:
φ0.062±0.001(1.575±0.025)
0.005 minimum clearance
between standos and
highest component
2.210
56.13
1.360
34.54
LABEL
1.860 ±0.008
47.24 ±0.20
1.030 ±0.008
26.16 ±0.20
1.45
36.8
2.30
58.4
0.180
4.6
M3 THREADED INSERT
4 PLACES SEE NOTE 1&2
BOTTOM PIN SIDE VIEW BOTTOM PIN SIDE VIEW
SIDE VIEW
Case C59
TOP VIEW
NO BASEPLATE
TOP VIEW
WITH BASEPLATE
DOSA-Compatible I/O Connections (pin side view)
Pin Function P32 Pin Function P32
1 Pos. Vin 5 Neg. Sense*
2 Remote On/Off Control 6 Trim*
3 Neg. Vin 7 Pos. Sense*
4 Neg. Output 8 Pos. Output
* The Sense and Trim pins are removed for the “X” model option.
MECHANICAL SPECIFICATIONS (THROUGH-HOLE MOUNT)—DOSA COMPLIANT
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 10 of 16
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HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 11 of 16
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Each static dissipative polyethylene
foam tray accommodates
15 converters in a 3 x 5 array.
9.92
(251.97)
REF
9.92
(251.97)
REF
0.88 (22.35)
REF
Carton accommodates two (2) trays yielding 30 converters per carton
10.50 (266.7) ±.25
11.00 (279.4) ±.25
2.75 (69.85) ±.25
closed height
STANDARD PACKAGING
Third Angle Projection
Dimensions are in inches (mm) shown for ref. only.
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 12 of 16
www.murata-ps.com/support
Input Fusing
Certain applications and/or safety agencies may require fuses at the inputs of
power conversion components. Fuses should also be used when there is the
possibility of sustained input voltage reversal which is not current-limited. For
greatest safety, we recommend a fast blow fuse installed in the ungrounded
input supply line.
The installer must observe all relevant safety standards and regulations. For
safety agency approvals, install the converter in compliance with the end-user
safety standard.
Input Reverse-Polarity Protection
If the input voltage polarity is reversed, an internal diode will become forward
biased and likely draw excessive current from the power source. If this source
is not current-limited or the circuit appropriately fused, it could cause perma-
nent damage to the converter.
Input Under-Voltage Shutdown and Start-Up Threshold
Under normal start-up conditions, converters will not begin to regulate properly
until the rising input voltage exceeds and remains at the Start-Up Threshold
Voltage (see Specifi cations). Once operating, converters will not turn off until
the input voltage drops below the Under-Voltage Shutdown Limit. Subsequent
restart will not occur until the input voltage rises again above the Start-Up
Threshold. This built-in hysteresis prevents any unstable on/off operation at a
single input voltage.
Users should be aware however of input sources near the Under-Voltage Shut-
down whose voltage decays as input current is consumed (such as capacitor
inputs), the converter shuts off and then restarts as the external capacitor re-
charges. Such situations could oscillate. To prevent this, make sure the operating
input voltage is well above the UV Shutdown voltage AT ALL TIMES.
Start-Up Delay
Assuming that the output current is set at the rated maximum, the Vin to Vout Start-
Up Delay (see Specifi cations) is the time interval between the point when the rising
input voltage crosses the Start-Up Threshold and the fully loaded regulated output
voltage enters and remains within its specifi ed regulation band. Actual measured
times will vary with input source impedance, external input capacitance, input volt-
age slew rate and fi nal value of the input voltage as it appears at the converter.
These converters include a soft start circuit to moderate the duty cycle of the
PWM controller at power up, thereby limiting the input inrush current.
The On/Off Remote Control interval from inception to VOUT regulated assumes that
the converter already has its input voltage stabilized above the Start-Up Threshold
before the On command. The interval is measured from the On command until the
output enters and remains within its specifi ed regulation band. The specifi cation
assumes that the output is fully loaded at maximum rated current.
Input Source Impedance
These converters will operate to specifi cations without external components,
assuming that the source voltage has very low impedance and reasonable in-
put voltage regulation. Since real-world voltage sources have fi nite impedance,
performance is improved by adding external fi lter components. Sometimes only
a small ceramic capacitor is suffi cient. Since it is diffi cult to totally characterize
all applications, some experimentation may be needed. Note that external input
capacitors must accept high speed switching currents.
TECHNICAL NOTES Because of the switching nature of DC/DC converters, the input of these
converters must be driven from a source with both low AC impedance and
adequate DC input regulation. Performance will degrade with increasing input
inductance. Excessive input inductance may inhibit operation. The DC input
regulation specifi es that the input voltage, once operating, must never degrade
below the Shut-Down Threshold under all load conditions. Be sure to use
adequate trace sizes and mount components close to the converter.
I/O Filtering, Input Ripple Current and Output Noise
All models in this converter series are tested and specifi ed for input refl ected
ripple current and output noise using designated external input/output compo-
nents, circuits and layout as shown in the fi gures below. External input capaci-
tors (CIN in the fi gure) serve primarily as energy storage elements, minimizing
line voltage variations caused by transient IR drops in the input conductors.
Users should select input capacitors for bulk capacitance (at appropriate
frequencies), low ESR and high RMS ripple current ratings. In the fi gure below,
the CBUS and LBUS components simulate a typical DC voltage bus. Your specifi c
system confi guration may require additional considerations. Please note that the
values of CIN, LBUS and CBUS may vary according to the specifi c converter model.
In critical applications, output ripple and noise (also referred to as periodic and
random deviations or PARD) may be reduced by adding fi lter elements such as
multiple external capacitors. Be sure to calculate component temperature rise
from refl ected AC current dissipated inside capacitor ESR.
Floating Outputs
Since these are isolated DC/DC converters, their outputs are “fl oating” with
respect to their input. The essential feature of such isolation is ideal ZERO
CURRENT FLOW between input and output. Real-world converters however do
exhibit tiny leakage currents between input and output (see Specifi cations).
These leakages consist of both an AC stray capacitance coupling component
and a DC leakage resistance. When using the isolation feature, do not allow
the isolation voltage to exceed specifi cations. Otherwise the converter may
be damaged. Designers will normally use the negative output (-Output) as
the ground return of the load circuit. You can however use the positive output
(+Output) as the ground return to effectively reverse the output polarity.
Minimum Output Loading Requirements
These converters employ a synchronous rectifi er design topology. All models
regulate within specifi cation and are stable under no load to full load conditions.
Operation under no load might however slightly increase output ripple and noise.
C
IN
V
IN
C
BUS
L
BUS
C
IN
= 33µF, ESR < 200mΩ @ 100kHz
C
BUS
= 220µF, 100V
L
BUS
= 4.7µH
+INPUT
−INPUT
CURRENT
PROBE
TO
OSCILLOSCOPE
+
–
+
–
Figure 2. Measuring Input Ripple Current
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 13 of 16
www.murata-ps.com/support
Thermal Shutdown
To protect against thermal over-stress, these converters include thermal shut-
down circuitry. If environmental conditions cause the temperature of the DC/
DC’s to rise above the Operating Temperature Range up to the shutdown tem-
perature, an on-board electronic temperature sensor will power down the unit.
When the temperature decreases below the turn-on threshold, the converter
will automatically restart. There is a small amount of hysteresis to prevent
rapid on/off cycling. CAUTION: If you operate too close to the thermal limits, the
converter may shut down suddenly without warning. Be sure to thoroughly test
your application to avoid unplanned thermal shutdown.
Temperature Derating Curves
The graphs in this data sheet illustrate typical operation under a variety of condi-
tions. The Derating curves show the maximum continuous ambient air temperature
and decreasing maximum output current which is acceptable under increasing
forced airfl ow measured in Linear Feet per Minute (“LFM”). Note that these are
AVERAGE measurements. The converter will accept brief increases in temperature
and/or current or reduced airfl ow as long as the average is not exceeded.
Note that the temperatures are of the ambient airfl ow, not the converter itself
which is obviously running at higher temperature than the outside air. Also note
that “natural convection” is defi ned as very low fl ow rates which are not using
fan-forced airfl ow. Depending on the application, “natural convection” is usu-
ally about 30-65 LFM but is not equal to still air (0 LFM).
Murata Power Solutions makes Characterization measurements in a closed
cycle wind tunnel with calibrated airfl ow. We use both thermocouples and an
infrared camera system to observe thermal performance. As a practical matter,
it is quite diffi cult to insert an anemometer to precisely measure airfl ow in
most applications. Sometimes it is possible to estimate the effective airfl ow if
you thoroughly understand the enclosure geometry, entry/exit orifi ce areas and
the fan fl owrate specifi cations.
CAUTION: If you exceed these Derating guidelines, the converter may have an
unplanned Over Temperature shut down. Also, these graphs are all collected
near Sea Level altitude. Be sure to reduce the derating for higher altitude.
Output Overvoltage Protection (OVP)
This converter monitors its output voltage for an over-voltage condition using
an on-board electronic comparator. The signal is optically coupled to the pri-
mary side PWM controller. If the output exceeds OVP limits, the sensing circuit
will power down the unit, and the output voltage will decrease. After a time-out
period, the PWM will automatically attempt to restart, causing the output volt-
age to ramp up to its rated value. It is not necessary to power down and reset
the converter for this automatic OVP-recovery restart.
If the fault condition persists and the output voltage climbs to excessive levels,
the OVP circuitry will initiate another shutdown cycle. This on/off cycling is
referred to as “hiccup” mode.
Output Fusing
The converter is extensively protected against current, voltage and temperature
extremes. However, your application circuit may need additional protection. In the
extremely unlikely event of output circuit failure, excessive voltage could be applied
to your circuit. Consider using an appropriate external protection.
Output Current Limiting
As soon as the output current increases to approximately its overcurrent limit,
the DC/DC converter will enter a current-limiting mode. The output voltage will
decrease proportionally with increases in output current, thereby maintaining a
somewhat constant power output. This is commonly referred to as power limiting.
Current limiting inception is defi ned as the point at which full power falls below
the rated tolerance. See the Performance/Functional Specifi cations. Note
particularly that the output current may briefl y rise above its rated value. This
enhances reliability and continued operation of your application. If the output
current is too high, the converter will enter the short circuit condition.
Output 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 PWM bias voltage will also drop,
thereby shutting down the PWM controller. Following a time-out period, the
PWM will restart, causing the output voltage to begin rising to its appropriate
value. If the short-circuit condition persists, another shutdown cycle will initi-
ate. This on/off cycling is called “hiccup mode.” The hiccup cycling reduces the
average output current, thereby preventing excessive internal temperatures.
Trimming the Output Voltage (See Specifi cation Note 7)
The Trim input to the converter allows the user to adjust the output voltage over
the rated trim range (please refer to the Specifi cations). In the trim equations
and circuit diagrams that follow, trim adjustments use a single fi xed resistor
connected between the Trim input and either Vout pin. Trimming resistors should
have a low temperature coeffi cient (±100 ppm/deg.C or less) and be mounted
close to the converter. Keep leads short. If the trim function is not used, leave
the trim unconnected. With no trim, the converter will exhibit its specifi ed output
voltage accuracy.
There are two CAUTIONs to observe for the Trim input:
CAUTION: To avoid unplanned power down cycles, do not exceed EITHER the
maximum output voltage OR the maximum output power when setting the
trim. If the output voltage is excessive, the OVP circuit may inadvertantly shut
down the converter. If the maximum power is exceeded, the converter may
enter current limiting. If the power is exceeded for an extended period, the
converter may overheat and encounter overtemperature shut down.
Figure 3. Measuring Output Ripple and Noise (PARD)
C1
C1 = 1µF
C2 = 10µF
LOAD 2-3 INCHES (51-76mm) FROM MODULE
C2 R
LOAD
SCOPE
+OUTPUT
−OUTPUT
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 14 of 16
www.murata-ps.com/support
CAUTION: Be careful of external electrical noise. The Trim input is a senstive
input to the converter’s feedback control loop. Excessive electrical noise may
cause instability or oscillation. Keep external connections short to the Trim
input. Use shielding if needed.
Trim Equations
Where Vo = Desired output voltage. Adjustment accuracy is subject to resistor
tolerances and factory-adjusted output accuracy. Mount trim resistor close
to converter. Use short leads. Note that “∆” is given as a small fraction, not a
percentage.
Remote On/Off Control
On the input side, a remote On/Off Control can be specifi ed with either positive
or negative logic as follows:
Positive: Models equipped with Positive Logic are enabled when the On/Off pin
is left open or is pulled high to +13.5VDC with respect to –VIN. An internal bias
current causes the open pin to rise to +VIN. Positive-logic devices are disabled
when the On/Off is grounded or brought to within a low voltage (see Specifi ca-
tions) with respect to –VIN.
On positive-logic models, to reduce noise coupling on the external on/off
control, use the circuit shown in fi gure 6.
Negative: Models with negative logic are on (enabled) when the On/Off is
grounded or brought to within a low voltage (see Specifi cations) with respect to
–VIN. The device is off (disabled) when the On/Off is left open or is pulled high
to +13.5VDC Max. with respect to –VIN.
Dynamic control of the On/Off function should be able to sink the specifi ed
signal current when brought low and withstand specifi ed voltage when brought
high. Be aware too that there is a fi nite time in milliseconds (see Specifi cations)
between the time of On/Off Control activation and stable, regulated output. This
time will vary slightly with output load type and current and input conditions.
There are two CAUTIONs for the On/Off Control:
CAUTION: While it is possible to control the On/Off with external logic if you
carefully observe the voltage levels, the preferred circuit is either an open
drain/open collector transistor or a relay (which can thereupon be controlled
by logic). The On/Off prefers to be set at approx. +13.5V (open pin) for the ON
state, assuming positive logic.
CAUTION: Do not apply voltages to the On/Off pin when there is no input power
voltage. Otherwise the converter may be permanently damaged.
Radj_up (in kΩ) = - - 2
Vnominal x (1+∆) 1
∆
1.225 x ∆
where ∆ = Vnominal -Vout
Vnominal
Radj_down (in kΩ) = - 2
1
∆
where ∆ = Vout -Vnominal
Vnominal
Figure 4. Trim adjustments to Increase Output Voltage using a Fixed Resistor
LOAD
RTRIM UP
+OUTPUT
+SENSE
TRIM
-SENSE
-OUTPUT
-INPUT
ON/OFF
CONTROL
+INPUT
Figure 5. Trim adjustments to Decrease Output Voltage using a Fixed Resistor
+OUTPUT
+SENSE
TRIM
-SENSE
-OUTPUT
-INPUT
ON/OFF
CONTROL
+INPUT
LOAD
RTRIM DOWN
Figure 7. Driving the On/Off Control Pin (suggested circuit)
ON/OFF
CONTROL
-INPUT
+VCC
Figure 6. On/Off Control Filter
ON/OFF
-INPUT
316 K
47 K 0.1 F
2.5V CIRCUIT
+INPUT
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 15 of 16
www.murata-ps.com/support
Remote Sense Input (See Specifi cation Note 7)
Sense inputs compensate for output voltage inaccuracy delivered at the load.
This is done by correcting voltage drops along the output wiring such as mod-
erate IR drops and the current carrying capacity of PC board etch. Sense inputs
also improve the stability of the converter and load system by optimizing the
control loop phase margin.
Note: The Sense input and power Vout lines are internally connected through
low value resistors to their respective polarities so that the converter can
operate without external connection to the Sense. Nevertheless, if the Sense
function is not used for remote regulation, the user should connect +Sense to
+Vout and –Sense to –Vout at the converter pins.
The remote Sense lines carry very little current. They are also capacitively
coupled to the output lines and therefore are in the feedback control loop to
regulate and stabilize the output. As such, they are not low impedance inputs
and must be treated with care in PC board layouts. Sense lines on the PCB
should run adjacent to DC signals, preferably Ground. In cables and discrete
wiring, use twisted pair, shielded tubing or similar techniques
Please observe Sense inputs tolerance to avoid improper operation:
[Vout(+) –Vout(-)] – [ Sense(+) – Sense(-)] ≤ 10% of Vout
Output overvoltage protection is monitored at the output voltage pin, not the
Sense pin. Therefore excessive voltage differences between Vout and Sense
together with trim adjustment of the output can cause the overvoltage protec-
tion circuit to activate and shut down the output.
Power derating of the converter is based on the combination of maximum
output current and the highest output voltage. Therefore the designer must
ensure:
(Vout at pins) x (Iout) ≤ (Max. rated output power)
Figure 8. Remote Sense Circuit Confi guration
LOAD
Contact and PCB resistance
losses due to IR drops
Contact and PCB resistance
losses due to IR drops
+OUTPUT
+SENSE
TRIM
-SENSE
-OUTPUT
-INPUT
ON/OFF
CONTROL
+INPUT
Sense Current
IOUT
Sense Return
IOUT Return
Vertical Wind Tunnel
Murata Power Solutions employs a custom-designed enclosed
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 can watch thermal characteristics of the Unit
Under Test (UUT) with both dynamic loads and static steady-
state conditions. A special optical port is used which is transpar-
ent to infrared wavelengths. The computer fi les from the IR
camera can be studied for later analysis.
Both through-hole and surface mount converters are soldered
down to a host carrier board for realistic heat absorption and
spreading. Both longitudinal and transverse 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 both 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 airfl ow collimator mixes the heat from the heating element
to make uniform temperature distribution. The collimator also
reduces the amount of turbulence adjacent to the UUT by restor-
ing laminar airfl ow. Such turbulence can change the effective
heat transfer characteristics and give 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.
Figure 9. Vertical Wind Tunnel
HPQ-12/25-D48 Series
Isolated 300-Watt Quarter Brick DC/DC Converters
MDC_HPQ-12/25-D48 Series.B03 Page 16 of 16
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 without
notice. © 2012 Murata Power Solutions, Inc.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfi eld, MA 02048-1151 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/
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 ca-
tions may cause damage to the product. Your production environment may differ; therefore please thoroughly review these guidelines with your process engineers.
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