MCD10048 Rev. 1.0 Page 1 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Applications
• Telecommunications
• Data communications
• Wireless communications
• Servers, workstations
Benefits
• High efficiency – no heat sink required
• Higher current capability at 70 ºC than most
competitors’ 40 A half-bricks
Features
• RoHS lead-free solder and lead-solder-exempted
products are available
• Delivers up to 40 A (132 W)
• Industry-standard quarter-brick pinout
• On-board input differential LC-filter
• Outputs available: 3.3, 2.5, 2.0, 1.8, 1.5, 1.2 & 1.0 V
• Start-up into pre-biased load
• No minimum load required
• Low profile: 0.31” [7.9 mm]
• Low weight: 1.06 oz [30 g]
• Meets Basic Insulation requirements of EN60950
• Withstands 100 V input transient for 100 ms
• Fixed-frequency operation
• Remote output sense
• Fully protected with automatic recovery
• Positive or negative logic ON/OFF option
• Output voltage trim range: +10%/20% with industry-
standard trim equations (except 1.2 V and 1.0 V
outputs with trim range ±10%)
• High reliability: MTBF = 2.6 million hours, calculated
per Telcordia TR-332, Method I Case 1
• UL60950 recognized in US and Canada and DEMKO
certified per IEC/EN60950
• Designed to meet Class B conducted emissions per
FCC and EN55022 when used with external filter
• All materials meet UL94, V-0 flammability rating
Description
The QmaXTM Series of high current single output DC-DC converters set new standards for thermal performance and power
density in the quarter-brick package.
The 40 A QM48 converters of the QmaXTM Series provide outstanding thermal performance in high temperature environments
that is comparable to or exceeds the industry’s leading 40 A half-bricks. This performance is accomplished through the use of
patended/patent-pending circuit, packaging, and processing techniques to achieve ultra-high efficiency, excellent thermal
management, and a very low-body profile.
The low-body profile and the preclusion of heat sinks minimize impedance to system airflow, thus enhancing cooling for both
upstream and downstream devices. The use of 100% automation for assembly, coupled with advanced electronic circuits and
thermal design, results in a product with extremely high reliability.
Operating from a 36-75 V input, the QmaXTM Series converters provide any standard output voltage from 3.3 V down to 1.0 V.
Outputs can be trimmed from –20% to +10% of the nominal output voltage (±10% for output voltages 1.2 V and 1.0 V), thus
providing outstanding design flexibility.
MCD10048 Rev. 1.0 Page 2 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Electrical Specifications (common to all versions)
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, All output voltages, unless otherwise specified.
Parameter Notes Min Typ Max Units
Absolute Maximum ratings
In
p
ut Volta
g
e Continuous 0 80 VDC
O
p
eratin
g
Ambient Tem
p
erature -40 85 °C
Stora
g
e Tem
p
erature -55 125 °C
Input Characteristics
O
p
eratin
g
In
p
ut Volta
g
e Ran
g
e 36 48 75 VDC
In
p
ut Under Volta
g
e Lockout Non-latchin
g
Turn-on Threshold 33 34 35 VDC
Turn-off Threshold 31 32 33 VDC
In
p
ut Volta
g
e Transient 100 ms 100 VDC
Isolation Characteristics
I/O Isolation 2000 VDC
Isolation Ca
p
acitance 1.4 nF
Isolation Resistance 10 M
Feature Characteristics
Switchin
Fre
uenc
415 kHz
Out
p
ut Volta
g
e Trim Ran
g
e
1
Industr
y
-std. e
q
uations
(
3.3 - 1.5 V
)
-20 +10 %
Use trim e
q
uation on Pa
g
e 4
(
1.2 - 1.0 V
)
-10 +10 %
Remote Sense Com
p
ensation
1
Percent of VOUT
(
NOM
)
+10 %
Out
p
ut Overvolta
g
e Protection Non-latchin
g
117 128 140 %
Overtem
p
erature Shutdown
(
PCB
)
Non-latchin
g
125 °C
Auto-Restart Period A
pp
lies to all
p
rotection features 100 ms
Turn-On Time 4 ms
ON/OFF Control
(
Positive Lo
g
ic
)
Converter Off
(
lo
g
ic low
)
-20 0.8 VDC
Converter On
(
lo
g
ic hi
g
h
)
2.4 20 VDC
ON/OFF Control
(
Ne
g
ative Lo
g
ic
)
Converter Off
(
lo
g
ic hi
g
h
)
2.4 20 VDC
Converter On
(
lo
g
ic low
)
-20 0.8 VDC
Additional Notes:
1. Vout can be increased up to 10% via the sense leads or up to 10% via the trim function. However, total output voltage trim from all sources
should not exceed 10% of VOUT(NOM), in order to ensure specified operation of overvoltage protection circuitry.
MCD10048 Rev. 1.0 Page 3 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Operation
Input and Output Impedance
These power converters have been designed to be stable
with no external capacitors when used in low inductance
input and output circuits.
In many applications, the inductance associated with the
distribution from the power source to the input of the
converter can affect the stability of the converter. The
addition of a 33 µF electrolytic capacitor with an ESR < 1 Ω
across the input helps to ensure stability of the converter. In
many applications, the user has to use decoupling
capacitance at the load. The power converter will exhibit
stable operation with external load capacitance up to 40,000
µF on 3.3 – 1.0 V outputs.
ON/OFF (Pin 2)
The ON/OFF pin is used to turn the power converter on or
off remotely via a system signal. There are two remote
control options available, positive logic and negative logic
with both referenced to Vin(-). Typical connections are
shown in Fig. A.
Rload
CONTROL
INPUT
Vin (+)
Vin (-)
ON/ OFF
Vout (+)
Vout (-)
TRIM
SENSE (+)
SENSE (-)
(Top View)
Converter
QmaXTM Series
Vin
Fig. A: Circuit configuration for ON/OFF function.
The positive logic version turns on when the ON/OFF pin is
at a logic high and turns off when at a logic low. The
converter is on when the ON/OFF pin is left open. See the
Electrical Specifications for logic high/low definitions.
The negative logic version turns on when the pin is at a logic
low and turns off when the pin is at a logic high. The
ON/OFF pin can be hard wired directly to Vin(-) to enable
automatic power up of the converter without the need of an
external control signal.
ON/OFF pin is internally pulled up to 5 V through a resistor.
A properly debounced mechanical switch, open-collector
transistor, or FET can be used to drive the input of the
ON/OFF pin. The device must be capable of sinking up to
0.2 mA at a low level voltage of ≤ 0.8 V. An external voltage
source (±20 V maximum) may be connected directly to the
ON/OFF input, in which case it must be capable of sourcing
or sinking up to 1 mA depending on the signal polarity. See
the Startup Information section for system timing waveforms
associated with use of the ON/OFF pin.
Remote Sense (Pins 5 and 7)
The remote sense feature of the converter compensates for
voltage drops occurring between the output pins of the
converter and the load. The SENSE(-) (Pin 5) and SENSE(+)
(Pin 7) pins should be connected at the load or at the point
where regulation is required (see Fig. B).
100
10
Rw
Rw
Rload
Vin (+)
Vin (-)
ON/ OFF
Vout (+)
Vout (-)
TRIM
SENSE (+)
SENSE (-)
(Top View)
Converter
QmaXTM Series
Vin
Fig. B: Remote sense circuit configuration.
CAUTION
If remote sensing is not utilized, the SENSE(-) pin must be connected
to the Vout(-) pin (Pin 4), and the SENSE(+) pin must be connected to
the Vout(+) pin (Pin 8) to ensure the converter will regulate at the
specified output voltage. If these connections are not made, the
converter will deliver an output voltage that is slightly higher than the
specified data sheet value.
Because the sense leads carry minimal current, large traces
on the end-user board are not required. However, sense
traces should be located close to a ground plane to minimize
system noise and ensure optimum performance.
The converter’s output overvoltage protection (OVP) senses
the voltage across Vout(+) and Vout(-), and not across the
sense lines, so the resistance (and resulting voltage drop)
between the output pins of the converter and the load should
be minimized to prevent unwanted triggering of the OVP.
When utilizing the remote sense feature, care must be taken
not to exceed the maximum allowable output power
capability of the converter, equal to the product of the
nominal output voltage and the allowable output current for
the given conditions.
When using remote sense, the output voltage at the
converter can be increased by as much as 10% above the
nominal rating in order to maintain the required voltage
across the load. Therefore, the designer must, if necessary,
decrease the maximum current (originally obtained from the
derating curves) by the same percentage to ensure the
converter’s actual output power remains at or below the
maximum allowable output power.
MCD10048 Rev. 1.0 Page 4 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Output Voltage Adjust /TRIM (Pin 6)
The output voltage can be adjusted up 10% or down 20% for
Vout 1.5 V, and ±10% for Vout = 1.2 V and 1.0 V relative
to the rated output voltage by the addition of an externally
connected resistor. For 3.3 V output voltage, trim up to 10%
is guaranteed only at Vin 40 V, and it is marginal (8% to
10%) at Vin = 36 V.
The TRIM pin should be left open if trimming is not being
used. To minimize noise pickup, a 0.1 µF capacitor is
connected internally between the TRIM and SENSE(-) pins.
To increase the output voltage, refer to Fig. C. A trim
resistor, RT-INCR, should be connected between the TRIM
(Pin 6) and SENSE(+) (Pin 7), with a value of:
10.22
1.225Δ
626Δ)V5.11(100
RNOMO
INCRT −
−+
=−
− [kΩ](3.3-1.5 V)
7.2
Δ
84.6
RINCRT −=− [kΩ] (1.2V)
9
Δ
120
RINCRT −=− [kΩ] (1.0 V)
where,
=−INCRTRRequired value of trim-up resistor [kΩ]
=−NOMOVNominal value of output voltage [V]
100X
V
)V(V
Δ
NOM- O
NOM-OREQ-O −
= [%]
=−REQOVDesired (trimmed) output voltage [V].
When trimming up, care must be taken not to exceed the
converter‘s maximum allowable output power. See previous
section for a complete discussion of this requirement.
Rload
Vin
Vin (+)
Vin (-)
ON/ OFF
Vout (+)
Vout (-)
TRIM
SENSE (+)
SENSE (-)
RT- INCR
(Top View)
Converter
Series
QmaXTM
Fig. C: Configuration for increasing output voltage.
To decrease the output voltage (Fig. D), a trim resistor,
RT-DECR, should be connected between the TRIM (Pin 6) and
SENSE(-) (Pin 5), with a value of:
10.22
|Δ|
511
RDECRT −=− [kΩ] (For 3.3 - 1.5 V)
15
|Δ|
700
RDECRT −=− [kΩ] (1.2 V)
17
|Δ|
700
RDECRT −=− [kΩ] (1.0 V)
where,
=
−DECRTRRequired value of trim-down resistor [kΩ]
and
Δ
is as defined above.
Note: The above equations for calculation of trim resistor
values match those typically used in conventional industry-
standard quarter-bricks (except for 1.2 V and 1.0 V outputs).
Converters with output voltages 1.2 V and 1.0 V are
available with alternative trim feature to provide the
customers with the flexibility of second sourcing.
For 1.2 V and 1.0 V only, “T” version converter with a
character “T” in the part number uses the following trim
equations:
Δ
485
RINCRT =− [kΩ] (1.2 V)
2
Δ
323
RINCRT −=− [kΩ] (1.0 V)
10.22
|Δ|
511
RDECRT −=− [kΩ] (For 1.2 V and 1.0 V)
For 1.2 V only, “U” version converter with a character “U” in
the part number uses the following trim equations:
Δ
100
RINCRT =− [kΩ]
2
|Δ|
100
RDECRT −=− [kΩ]
MCD10048 Rev. 1.0 Page 5 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Rload
Vin (+)
Vin (-)
ON/ OFF
Vout (+)
Vout (-)
TRIM
SENSE (+)
SENSE (-)
RT- DECR
(Top View )
Converter
Series
TM
QmaX
Vin
Fig. D: Configuration for decreasing output voltage.
Trimming/sensing beyond 110% of the rated output voltage
is not an acceptable design practice, as this condition could
cause unwanted triggering of the output overvoltage
protection (OVP) circuit. The designer should ensure that the
difference between the voltages across the converter’s
output pins and its sense pins does not exceed 10% of
VOUT(NOM), or:
X NOM-O SENSESENSEOUTOUT 10%V)](V)([V)](V)([V ≤−−+−−−+ [V]
This equation is applicable for any condition of output
sensing and/or output trim.
Protection Features
Input Undervoltage Lockout
Input undervoltage lockout is standard with this converter.
The converter will shut down when the input voltage drops
below a pre-determined voltage.
The input voltage must be at least 35 V for the converter to
turn on. Once the converter has been turned on, it will shut
off when the input voltage drops below 31 V. This feature is
beneficial in preventing deep discharging of batteries used in
telecom applications.
Output Overcurrent Protection (OCP)
The converter is protected against overcurrent or short
circuit conditions. Upon sensing an overcurrent condition,
the converter will switch to constant current operation and
thereby begin to reduce output voltage. When the output
voltage drops below 60% of the nominal value of output
voltage, the converter will shut down.
Once the converter has shut down, it will attempt to restart
nominally every 100 ms with a typical 1-2% duty cycle. The
attempted restart will continue indefinitely until the overload
or short circuit conditions are removed or the output voltage
rises above 60% of its nominal value.
Output Overvoltage Protection (OVP)
The converter will shut down if the output voltage across
Vout(+) (Pin 8) and Vout(-) (Pin 4) exceeds the threshold of
the OVP circuitry. The OVP circuitry contains its own
reference, independent of the output voltage regulation loop.
Once the converter has shut down, it will attempt to restart
every 100 ms until the OVP condition is removed.
Overtemperature Protection (OTP)
The converter will shut down under an overtemperature
condition to protect itself from overheating caused by
operation outside the thermal derating curves, or operation
in abnormal conditions such as system fan failure. After the
converter has cooled to a safe operating temperature, it will
automatically restart.
Safety Requirements
The converters meet North American and International
safety regulatory requirements per UL60950 and EN60950.
Basic Insulation is provided between input and output.
To comply with safety agencies’ requirements, an input line
fuse must be used external to the converter. The Table
below provides the recommended fuse rating for use with
this family of products.
Output Voltage Fuse Rating
3.3 V 7.5
A
2.5 -1.8 V 5
A
1.5 - 1.0 V 3
A
Modules are UL approved for maximum fuse rating of
15 Amps. To protect a group of modules with a single fuse,
the rating can be increased from the recommended values
above.
Electromagnetic Compatibility (EMC)
EMC requirements must be met at the end-product system
level, as no specific standards dedicated to EMC
characteristics of board mounted component dc-dc
converters exist. However, Power-One tests its converters to
several system level standards, primary of which is the more
stringent EN55022, Information technology equipment -
Radio disturbance characteristics - Limits and methods of
measurement.
MCD10048 Rev. 1.0 Page 6 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
An effective internal LC differential filter significantly reduces
input reflected ripple current, and improves EMC.
With the addition of a simple external filter, all versions of the
QmaX™ Series of converters pass the requirements of
Class B conducted emissions per EN55022 and FCC, and
meet at a minimum, Class A radiated emissions per
EN55022 and Class B per FCC Title 47CFR, Part 15-J.
Please contact Power-One Applications Engineering for
details of this testing.
Characterization
General Information
The converter has been characterized for many operational
aspects, to include thermal derating (maximum load current
as a function of ambient temperature and airflow) for vertical
and horizontal mounting, efficiency, startup and shutdown
parameters, output ripple and noise, transient response to
load step-change, overload, and short circuit.
The figures are numbered as Fig. x.y, where x indicates the
different output voltages, and y associates with specific plots
(y = 1 for the vertical thermal derating, …). For example,
Fig. x.1 will refer to the vertical thermal derating for all the
output voltages in general.
The following pages contain specific plots or waveforms
associated with the converter. Additional comments for
specific data are provided below.
Test Conditions
All data presented were taken with the converter soldered to
a test board, specifically a 0.060” thick printed wiring board
(PWB) with four layers. The top and bottom layers were not
metalized. The two inner layers, comprised of two-ounce
copper, were used to provide traces for connectivity to the
converter.
The lack of metalization on the outer layers as well as the
limited thermal connection ensured that heat transfer from
the converter to the PWB was minimized. This provides a
worst-case but consistent scenario for thermal derating
purposes.
All measurements requiring airflow were made in the vertical
and horizontal wind tunnel using Infrared (IR) thermography
and thermocouples for thermometry.
Ensuring components on the converter do not exceed their
ratings is important to maintaining high reliability. If one
anticipates operating the converter at or close to the
maximum loads specified in the derating curves, it is prudent
to check actual operating temperatures in the application.
Thermographic imaging is preferable; if this capability is not
available, then thermocouples may be used. The use of
AWG #40 gauge thermocouples is recommended to ensure
measurement accuracy. Careful routing of the thermocouple
leads will further minimize measurement error. Refer to
Figure H for optimum measuring thermocouple location.
Thermal Derating
Load current vs. ambient temperature and airflow rates are
given in Figs. x.1 and x.2 for vertical and horizontal converter
mounting. Ambient temperature was varied between 25 °C
and 85 °C, with airflow rates from 30 to 500 LFM (0.15 to
2.5 m/s).
For each set of conditions, the maximum load current was
defined as the lowest of:
(i) The output current at which any FET junction temperature
does not exceed a maximum specified temperature (120 °C)
as indicated by the thermographic image, or
(ii) The nominal rating of the converter (40 A on 3.3 – 1.0 V).
During normal operation, derating curves with maximum FET
temperature less or equal to 120 °C should not be exceeded.
Temperature on the PCB at the thermocouple location
shown in Fig. H should not exceed 118 °C in order to
operate inside the derating curves.
Efficiency
Fig. x.3 shows the efficiency vs. load current plot for ambient
temperature of 25 ºC, airflow rate of 300 LFM (1.5 m/s) with
vertical mounting and input voltages of 36 V, 48 V and 72 V.
Also, a plot of efficiency vs. load current, as a function of
ambient temperature with Vin = 48 V, airflow rate of 200 LFM
(1 m/s) with vertical mounting is shown in Fig. x.4.
Power Dissipation
Fig. x.5 shows the power dissipation vs. load current plot for
Ta = 25 ºC, airflow rate of 300 LFM (1.5 m/s) with vertical
mounting and input voltages of 36 V, 48 V and 72 V. Also, a
plot of power dissipation vs. load current, as a function of
ambient temperature with Vin = 48 V, airflow rate of 200 LFM
(1 m/s) with vertical mounting is shown in Fig. x.6.
Startup
Output voltage waveforms, during the turn-on transient using
the ON/OFF pin for full rated load currents (resistive load)
are shown without and with external load capacitance in
Fig. x.7 and Fig. x.8, respectively.
MCD10048 Rev. 1.0 Page 7 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Ripple and Noise
Fig. x.10 shows the output voltage ripple waveform,
measured at full rated load current with a 10 µF tantalum
and 1 µF ceramic capacitor across the output. Note that all
output voltage waveforms are measured across a 1 µF
ceramic capacitor.
The input reflected ripple current waveforms are obtained
using the test setup shown in Fig x.11. The corresponding
waveforms are shown in Fig. x.12 and Fig. x.13.
Fig. H: Location of the thermocouple for thermal testing.
MCD10048 Rev. 1.0 Page 8 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Startup Information (using negative ON/OFF)
Scenario #1: Initial Startup From Bulk Supply
ON/OFF function enabled, converter started via application of VIN.
See Figure E.
Time Comments
t0 ON/OFF pin is ON; system front end power is toggled
on, VIN to converter begins to rise.
t1 V
IN crosses Under-Voltage Lockout protection circuit
threshold; converter enabled.
t2 Converter begins to respond to turn-on command
(converter turn-on delay).
t3 Converter VOUT reaches 100% of nominal value.
For this example, the total converter startup time (t3- t1) is typically
4 ms.
Scenario #2: Initial Startup Using ON/OFF Pin
With VIN previously powered, converter started via ON/OFF pin.
See Figure F.
Time Comments
t0 V
INPUT at nominal value.
t1 Arbitrary time when ON/OFF pin is enabled (converter
enabled).
t2 End of converter turn-on delay.
t3 Converter VOUT reaches 100% of nominal value.
For this example, the total converter startup time (t3- t1) is typically
4 ms.
Scenario #3: Turn-off and Restart Using ON/OFF Pin
With VIN previously powered, converter is disabled and then
enabled via ON/OFF pin. See Figure G.
Time Comments
t0 V
IN and VOUT are at nominal values; ON/OFF pin ON.
t1 ON/OFF pin arbitrarily disabled; converter output falls
to zero; turn-on inhibit delay period (100 ms typical) is
initiated, and ON/OFF pin action is internally inhibited.
t2 ON/OFF pin is externally re-enabled.
If (t2- t1) ≤ 100 ms, external action of ON/OFF pin
is locked out by startup inhibit timer.
If (t2- t1) > 100 ms, ON/OFF pin action is internally
enabled.
t3 Turn-on inhibit delay period ends. If ON/OFF pin is ON,
converter begins turn-on; if off, converter awaits
ON/OFF pin ON signal; see Figure F.
t4 End of converter turn-on delay.
t5 Converter VOUT reaches 100% of nominal value.
For the condition, (t2- t1) ≤ 100 ms, the total converter startup time
(t5- t2) is typically 104 ms. For (t2- t1) > 100 ms, startup will be
typically 4 ms after release of ON/OFF pin.
Fig. E: Startup scenario #1.
ON/OFF
STATE
VOUT
t0t1t2t3
ON
OFF
VIN
t
Fig. F: Startup scenario #2.
ON/OFF
STATE OFF
ON
VOUT
t0t2t1t5
VIN
t
t4t3
100 ms
Fig. G: Startup scenario #3.
.
VIN
ON/OFF
STATE
VOUT
t
t0t1t2t3
ON
OFF
MCD10048 Rev. 1.0 Page 9 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Electrical Specifications: QM48T40033 (3.3 Volts Out)
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, Vout = 3.3 VDC unless otherwise specified.
Parameter Notes Min Typ Max Units
Input Characteristics
Maximum In
p
ut Current 40 ADC
,
3.3 VDC Out
@
36 VDC In 4.1 ADC
In
p
ut Stand-b
y
Current Vin = 48 V
,
converter disabled 3 mADC
In
p
ut No Load Current
(
0 load on the out
p
ut
)
Vin = 48 V
,
converter enabled 63 mADC
In
p
ut Reflected-Ri
pp
le Current 25 MHz bandwidth 7.5 mAPK-PK
In
p
ut Volta
g
e Ri
pp
le Re
j
ection 120 Hz TBD dB
Output Characteristics
Out
p
ut Volta
g
e Set Point
(
no load
)
-40 ºC to 85 ºC 3.267 3.300 3.333 VDC
Out
p
ut Re
g
ulation
Over Line ±2 ±5 mV
Over Load ±2 ±5 mV
Out
p
ut Volta
g
e Ran
g
e Over line
,
load and tem
p
erature 3.250 3.350 VDC
Out
p
ut Ri
pp
le and Noise
–
25 MHz bandwidth Full load + 10
F tantalum + 1
F ceramic 30 50 mVPK-PK
External Load Ca
p
acitance Plus full load
(
resistive
)
40
,
000
F
Out
p
ut Current Ran
g
e 0 40 ADC
Current Limit Ince
p
tion Non-latchin
g
42 47 52 ADC
Peak Short-Circuit Current Non-latchin
g
,
Short = 10 m 50 60 A
RMS Short-Circuit Current Non-latchin
g
10 15 Arms
Dynamic Response
Load Chan
g
e 25% of Iout Max
,
di/dt = 1 A/
s Co = 470
F tantalum + 1
F ceramic 120 mV
Settin
g
Time to 1% 80
µ
s
Efficiency
100% Load 90.5 %
50% Load 92.5 %
Ambient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 3.3V.1: Available load current vs. ambient air temperature
and airflow rates for QM48T40033 converter with B height pins
mounted vertically with air flowing from pin 3 to pin 1, MOSFET
temperature ≤ 120 °C, Vin = 48 V.
Note: NC – Natural convection
A
mbient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 3.3V.2: Available load current vs. ambient air temperature
and airflow rates for QM48T40033 converter with B height pins
mounted horizontally with air flowing from pin 3 to pin 1,
MOSFET temperature ≤ 120 °C, Vin = 48 V.
MCD10048 Rev. 1.0 Page 10 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40033 (3.3 Volts Out)
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 3.3V.3: Efficiency vs. load current and input voltage for
converter mounted vertically with air flowing from pin 3 to pin 1
at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
72 V
48 V
36 V
Fig. 3.3V.5: Power dissipation vs. load current and input
voltage for converter mounted vertically with air flowing from
pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
70 C
55 C
40 C
Fig. 3.3V.4: Efficiency vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
70 C
55 C
40 C
Fig. 3.3V.6: Power dissipation vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
MCD10048 Rev. 1.0 Page 11 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40033 (3.3 Volts Out)
Fig. 3.3V.7: Turn-on transient at full rated load current
(resistive) with no output capacitor at Vin = 48 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom
trace: output voltage (1 V/div.) Time scale: 2 ms/div.
Fig. 3.3V9: Output voltage response to load current
step-change (20 A – 30 A – 20 A) at Vin = 48 V. Top trace:
output voltage (100 mV/div.). Bottom trace: load current
(10 A/div). Current slew rate: 1 A/s. Co = 470 F tantalum + 1
F ceramic. Time scale: 0.2 ms/div.
Fig. 3.3V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 F at Vin = 48 V, triggered via ON/OFF
pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output
voltage (1 V/div.). Time scale: 2 ms/div.
Fig. 3.3V.10: Output voltage ripple (20 mV/div.) at full rated
load current into a resistive load with Co = 10 F tantalum +
1 F ceramic and Vin = 48 V. Time scale: 1 s/div.
MCD10048 Rev. 1.0 Page 12 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40033 (3.3 Volts Out)
Vout
Vsource
iSiC
1 μF
ceramic
capacitor
10 μH
source
inductance
DC-DC
Converter
33 μF
ESR < 1
electrolytic
capacitor
Series
QmaXTM
Fig. 3.3V.11: Test setup for measuring input reflected ripple currents, ic and is.
Fig. 3.3V12: Input reflected ripple current, is (10 mA/div),
measured through 10 H at the source at full rated load
current and Vin = 48 V. Refer to Fig. 3.3V.11 for test setup.
Time scale: 1 s/div.
Iout [Adc]
15 60
4.0
Vout [Vdc]
0
0
2.0
1.0
30 45
3.0
Fig. 3.3V.14: Output voltage vs. load current showing
current limit point and converter shutdown point. Input
voltage has almost no effect on current limit characteristic.
Fig. 3.3V13: Input reflected ripple current, ic (100 mA/div),
measured at input terminals at full rated load current and Vin
= 48 V. Refer to Fig. 3.3V.11 for test setup. Time scale:
1 s/div.
Fig. 3.3V.15: Load current (top trace, 20 A/div, 20 ms/div)
into a 10 m short circuit during restart, at Vin = 48 V.
Bottom trace (20 A/div, 1 ms/div) is an expansion of the
on-time portion of the top trace.
MCD10048 Rev. 1.0 Page 13 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Electrical Specifications: QM48T40025 (2.5 Volts Out)
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, Vout = 2.5 VDC unless otherwise specified.
Parameter Notes Min Typ Max Units
Input Characteristics
Maximum In
p
ut Current 40 ADC
,
2.5 VDC Out
@
36 VDC In 3.2 ADC
In
p
ut Stand-b
y
Current Vin = 48 V
,
converter disabled 3 mADC
In
p
ut No Load Current
(
0 load on the out
p
ut
)
Vin = 48 V
,
converter enabled 50 mADC
In
p
ut Reflected-Ri
pp
le Current 25 MHz bandwidth 10 mAPK-PK
In
p
ut Volta
g
e Ri
pp
le Re
j
ection 120 Hz TBD dB
Output Characteristics
Out
p
ut Volta
g
e Set Point
(
no load
)
-40 ºC to 85 ºC 2.475 2.500 2.525 VDC
Out
p
ut Re
g
ulation
Over Line ±2 ±5 mV
Over Load ±2 ±5 mV
Out
p
ut Volta
g
e Ran
g
e Over line
,
load and tem
p
erature 2.462 2.538 VDC
Out
p
ut Ri
pp
le and Noise
–
25 MHz bandwidth Full load + 10
F tantalum + 1
F ceramic 30 50 mVPK-PK
External Load Ca
p
acitance Plus full load
(
resistive
)
40
,
000
F
Out
p
ut Current Ran
g
e 0 40 ADC
Current Limit Ince
p
tion Non-latchin
g
42 47 52 ADC
Peak Short-Circuit Current Non-latchin
g
,
Short = 10 m 50 60 A
RMS Short-Circuit Current Non-latchin
g
10 15 Arms
Dynamic Response
Load Chan
g
e 25% of Iout Max
,
di/dt = 1 A/
s Co = 470
F tantalum + 1
F ceramic 120 mV
Settin
g
Time to 1% 100
µ
s
Efficiency
100% Load 89 %
50% Load 91 %
Ambient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 2.5V.1: Available load current vs. ambient air temperature
and airflow rates for QM48T40025 converter with B height pins
mounted vertically with air flowing from pin 3 to pin 1, MOSFET
temperature ≤ 120 °C, Vin = 48 V.
A
mbient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 2.5V.2: Available load current vs. ambient air temperature
and airflow rates for QM48T40025 converter with B height pins
mounted horizontally with air flowing from pin 3 to pin 1,
MOSFET temperature ≤ 120 °C, Vin = 48 V.
Note: NC – Natural convection
MCD10048 Rev. 1.0 Page 14 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40025 (2.5 Volts Out)
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 2.5V.3: Efficiency vs. load current and input voltage for
converter mounted vertically with air flowing from pin 3 to pin 1
at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
72 V
48 V
36 V
Fig. 2.5V.5: Power dissipation vs. load current and input
voltage for converter mounted vertically with air flowing from
pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
70 C
55 C
40 C
Fig. 2.5V.4: Efficiency vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
70 C
55 C
40 C
Fig. 2.5V.6: Power dissipation vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
MCD10048 Rev. 1.0 Page 15 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40025 (2.5 Volts Out)
Fig. 2.5V.7: Turn-on transient at full rated load current
(resistive) with no output capacitor at Vin = 48 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom
trace: output voltage (1 V/div.) Time scale: 2 ms/div.
Fig. 2.5V.9: Output voltage response to load current
step-change (20 A – 30 A – 20 A) at Vin = 48 V. Top trace:
output voltage (100 mV/div.). Bottom trace: load current
(10 A/div). Current slew rate: 1 A/s. Co = 470 F tantalum +
1 F ceramic. Time scale: 0.2 ms/div.
Fig. 2.5V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 F at Vin = 48 V, triggered via ON/OFF
pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output
voltage (1 V/div.). Time scale: 2 ms/div.
Fig. 2.5V.10: Output voltage ripple (20 mV/div.) at full rated load
current into a resistive load with Co = 10 F tantalum + 1 F
ceramic and Vin = 48 V. Time scale: 1 s/div.
MCD10048 Rev. 1.0 Page 16 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40025 (2.5 Volts Out)
Vout
Vsource
iSiC
1 μF
ceramic
capacitor
10 μH
source
inductance
DC-DC
Converter
33 μF
ESR < 1
electrolytic
capacitor
Series
QmaXTM
Fig. 2.5V.11: Test Setup for measuring input reflected ripple currents, ic and is.
Fig. 2.5V.12: Input reflected ripple current, is (10 mA/div),
measured through 10 H at the source at full rated load
current and Vin = 48 V. Refer to Fig. 2.5V.11 for test setup.
Time scale: 1 s/div.
15 60
3.0
Iout [Adc]
Vout [Vdc]
0
0
2.5
1.0
0.5
30 45
2.0
1.5
Fig. 2.5V.14: Output voltage vs. load current showing
current limit point and converter shutdown point. Input
voltage has almost no effect on current limit characteristic.
Fig. 2.5V.13: Input reflected ripple current, ic (100 mA/div),
measured at input terminals at full rated load current and Vin
= 48 V. Refer to Fig. 2.5V.11 for test setup. Time scale:
1 s/div.
Fig. 2.5V.15: Load current (top trace, 20 A/div, 20 ms/div)
into a 10 m short circuit during restart, at Vin = 48 V.
Bottom trace (20 A/div, 1 ms/div) is an expansion of the
on-time portion of the top trace.
MCD10048 Rev. 1.0 Page 17 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Electrical Specifications: QM48T40020 (2.0 Volts Out)
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, Vout = 2.0 VDC unless otherwise specified.
Parameter Notes Min Typ Max Units
Input Characteristics
Maximum In
p
ut Current 40 ADC
,
2.0 VDC Out
@
36 VDC In 2.6 ADC
In
p
ut Stand-b
y
Current Vin = 48 V
,
converter disabled 3 mADC
In
p
ut No Load Current
(
0 load on the out
p
ut
)
Vin = 48 V
,
converter enabled 40 mADC
In
p
ut Reflected-Ri
pp
le Current 25 MHz bandwidth 7.5 mAPK-PK
In
p
ut Volta
g
e Ri
pp
le Re
j
ection 120 Hz TBD dB
Output Characteristics
Out
p
ut Volta
g
e Set Point
(
no load
)
-40 ºC to 85 ºC 1.98 2.000 2.02 VDC
Out
p
ut Re
g
ulation
Over Line ±2 ±5 mV
Over Load ±2 ±5 mV
Out
p
ut Volta
g
e Ran
g
e Over line
,
load and tem
p
erature 1.970 2.030 VDC
Out
p
ut Ri
pp
le and Noise
–
25 MHz bandwidth Full load + 10
F tantalum + 1
F ceramic 30 50 mVPK-PK
External Load Ca
p
acitance Plus full load
(
resistive
)
40
,
000
F
Out
p
ut Current Ran
g
e 0 40 ADC
Current Limit Ince
p
tion Non-latchin
g
42 47 52 ADC
Peak Short-Circuit Current Non-latchin
g
,
Short = 10 m 50 60 A
RMS Short-Circuit Current Non-latchin
g
10 15 Arms
Dynamic Response
Load Chan
g
e 25% of Iout Max
,
di/dt = 1 A/
s Co = 470
F tantalum + 1
F ceramic 120 mV
Settin
g
Time to 1% 110
µ
s
Efficiency
100% Load 88 %
50% Load 90 %
Ambient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 2.0V.1: Available load current vs. ambient air temperature
and airflow rates for QM48T40020 converter with B height pins
mounted vertically with air flowing from pin 3 to pin 1, MOSFET
temperature ≤ 120 °C, Vin = 48 V.
Note: NC – Natural convection
A
mbient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 2.0V.2: Available load current vs. ambient air temperature
and airflow rates for QM48T40020 converter with B height pins
mounted horizontally with air flowing from pin 3 to pin 1,
MOSFET temperature ≤ 120 °C, Vin = 48 V.
MCD10048 Rev. 1.0 Page 18 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40020 (2.0 Volts Out)
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 2.0V.3: Efficiency vs. load current and input voltage for
converter mounted vertically with air flowing from pin 3 to pin 1
at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
72 V
48 V
36 V
Fig. 2.0V.5: Power dissipation vs. load current and input
voltage for converter mounted vertically with air flowing from
pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
70 C
55 C
40 C
Fig. 2.0V.4: Efficiency vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
70 C
55 C
40 C
Fig. 2.0V.6: Power dissipation vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
MCD10048 Rev. 1.0 Page 19 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40020 (2.0 Volts Out)
Fig. 2.0V.7: Turn-on transient at full rated load current
(resistive) with no output capacitor at Vin = 48 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom
trace: output voltage (1 V/div.) Time scale: 2 ms/div.
Fig. 2.0V.9: Output voltage response to load current step-
change (20 A – 30 A – 20 A) at Vin = 48 V. Top trace: output
voltage (100 mV/div.). Bottom trace: load current (10 A/div).
Current slew rate: 1 A/s. Co = 470 F tantalum + 1 F
ceramic. Time scale: 0.2 ms/div.
Fig. 2.0V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 F at Vin = 48 V, triggered via ON/OFF
pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output
voltage (1 V/div.). Time scale: 2 ms/div.
Fig. 2.0V.10: Output voltage ripple (20 mV/div.) at full rated
load current into a resistive load with Co = 10 F tantalum +
1 F ceramic and Vin = 48 V. Time scale: 1 s/div.
MCD10048 Rev. 1.0 Page 20 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40020 (2.0 Volts Out)
Vout
Vsource
iSiC
1 μF
ceramic
capacitor
10 μH
source
inductance
DC-DC
Converter
33 μF
ESR < 1
electrolytic
capacitor
Series
QmaXTM
Fig. 2.0V.11: Test Setup for measuring input reflected ripple currents, ic and is.
Fig. 2.0V.12: Input reflected ripple current, is (10 mA/div),
measured through 10 H at the source at full rated load current
and Vin = 48 V. Refer to Fig. 2.0V.11 for test setup. Time scale:
1 s/div.
15 60
3.0
Iout [Adc]
Vout [Vdc]
0
0
2.5
1.0
0.5
30 45
2.0
1.5
Fig. 2.0V.14: Output voltage vs. load current showing
current limit point and converter shutdown point. Input
voltage has almost no effect on current limit characteristic.
Fig. 2.0V.13: Input reflected ripple current, ic (100 mA/div),
measured at input terminals at full rated load current and Vin
= 48 V. Refer to Fig. 2.0V.11 for test setup. Time scale:
1 s/div.
Fig. 2.0V.15: Load current (top trace, 20 A/div, 20 ms/div)
into a 10 m short circuit during restart, at Vin = 48 V.
Bottom trace (20 A/div, 1 ms/div) is an expansion of the
on-time portion of the top trace.
MCD10048 Rev. 1.0 Page 21 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Electrical Specifications: QM48T40018 (1.8 Volts Out)
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, Vout = 1.8 VDC unless otherwise specified.
Parameter Notes Min Typ Max Units
Input Characteristics
Maximum In
p
ut Current 40 ADC
,
1.8 VDC Out
@
36 VDC In 2.4 ADC
In
p
ut Stand-b
y
Current Vin = 48 V
,
converter disabled 3 mADC
In
p
ut No Load Current
(
0 load on the out
p
ut
)
Vin = 48 V
,
converter enabled 38 mADC
In
p
ut Reflected-Ri
pp
le Current 25 MHz bandwidth 10 mAPK-PK
In
p
ut Volta
g
e Ri
pp
le Re
j
ection 120 Hz TBD dB
Output Characteristics
Out
p
ut Volta
g
e Set Point
(
no load
)
-40 ºC to 85 ºC 1.782 1.800 1.818 VDC
Out
p
ut Re
g
ulation
Over Line ±2 ±4 mV
Over Load ±2 ±5 mV
Out
p
ut Volta
g
e Ran
g
e Over line
,
load and tem
p
erature 1.773 1.827 VDC
Out
p
ut Ri
pp
le and Noise
–
25 MHz bandwidth Full load + 10
F tantalum + 1
F ceramic 30 50 mVPK-PK
External Load Ca
p
acitance Plus full load
(
resistive
)
40
,
000
F
Out
p
ut Current Ran
g
e 0 40 ADC
Current Limit Ince
p
tion Non-latchin
g
42 47 52 ADC
Peak Short-Circuit Current Non-latchin
g
,
Short = 10 m 50 60 A
RMS Short-Circuit Current Non-latchin
g
10 15 Arms
Dynamic Response
Load Chan
g
e 25% of Iout Max
,
di/dt = 1 A/
s Co = 470
F tantalum + 1
F ceramic 120 mV
Settin
g
Time to 1% 120
µ
s
Efficiency
100% Load 87 %
50% Load 89.5 %
Ambient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 1.8V.1: Available load current vs. ambient air temperature
and airflow rates for QM48T40018 converter with B height pins
mounted vertically with air flowing from pin 3 to pin 1, MOSFET
temperature ≤ 120 °C, Vin = 48 V.
Note: NC – Natural convection
A
mbient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 1.8V.2: Available load current vs. ambient air temperature
and airflow rates for QM48T40018 converter with B height pins
mounted horizontally with air flowing from pin 3 to pin 1,
MOSFET temperature ≤ 120 °C, Vin = 48 V.
MCD10048 Rev. 1.0 Page 22 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40018 (1.8 Volts Out)
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 1.8V.3: Efficiency vs. load current and input voltage for
converter mounted vertically with air flowing from pin 3 to pin 1
at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
72 V
48 V
36 V
Fig. 1.8V.5: Power dissipation vs. load current and input
voltage for converter mounted vertically with air flowing from
pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
70 C
55 C
40 C
Fig. 1.8V.4: Efficiency vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM (1.0
m/s).
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
70 C
55 C
40 C
Fig. 1.8V.6: Power dissipation vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
MCD10048 Rev. 1.0 Page 23 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40018 (1.8 Volts Out)
Fig. 1.8V.7: Turn-on transient at full rated load current
(resistive) with no output capacitor at Vin = 48 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom
trace: output voltage (1 V/div.) Time scale: 2 ms/div.
Fig. 1.8V.9: Output voltage response to load current
step-change (20 A – 30 A – 20 A) at Vin = 48 V. Top trace:
output voltage (100 mV/div.). Bottom trace: load current (10
A/div). Current slew rate: 1 A/s. Co = 470 F tantalum + 1 F
ceramic. Time scale: 0.2 ms/div.
Fig. 1.8V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 F at Vin = 48 V, triggered via ON/OFF
pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output
voltage (1 V/div.). Time scale: 2 ms/div.
Fig. 1.8V.10: Output voltage ripple (20 mV/div.) at full rated
load current into a resistive load with Co = 10 F tantalum +
1 F ceramic and Vin = 48 V. Time scale: 1 s/div.
MCD10048 Rev. 1.0 Page 24 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40018 (1.8 Volts Out)
Vout
Vsource
iSiC
1 μF
ceramic
capacitor
10 μH
source
inductance
DC-DC
Converter
33 μF
ESR < 1
electrolytic
capacitor
Series
QmaXTM
Fig. 1.8V.11: Test Setup for measuring input reflected ripple currents, ic and is.
Fig. 1.8V.12: Input reflected ripple current, is (10 mA/div),
measured through 10 H at the source at full rated load current
and Vin = 48 V. Refer to Fig. 1.8V.11 for test setup. Time scale:
1 s/div.
15 60
3.0
Iout [Adc]
Vout [Vdc]
0
0
2.5
1.0
0.5
30 45
2.0
1.5
Fig. 1.8V.14: Output voltage vs. load current showing current
limit point and converter shutdown point. Input voltage has
almost no effect on current limit characteristic.
Fig. 1.8V.13: Input reflected ripple current, ic (100 mA/div),
measured at input terminals at full rated load current and Vin =
48 V. Refer to Fig. 1.8V.11 for test setup. Time scale: 1 s/div.
Fig. 1.8V.15: Load current (top trace, 20 A/div, 20 ms/div) into
a 10 m short circuit during restart, at Vin = 48 V. Bottom trace
(20 A/div, 2 ms/div) is an expansion of the on-time portion of
the top trace.
MCD10048 Rev. 1.0 Page 25 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Electrical Specifications: QM48T40015 (1.5 Volts Out)
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, Vout = 1.5 VDC unless otherwise specified.
Parameter Notes Min Typ Max Units
Input Characteristics
Maximum In
p
ut Current 40 ADC
,
1.5 VDC Out
@
36 VDC In 2 ADC
In
p
ut Stand-b
y
Current Vin = 48 V
,
converter disabled 3 mADC
In
p
ut No Load Current
(
0 load on the out
p
ut
)
Vin = 48 V
,
converter enabled 32 mADC
In
p
ut Reflected-Ri
pp
le Current 25 MHz bandwidth 7.5 mAPK-PK
In
p
ut Volta
g
e Ri
pp
le Re
j
ection 120 Hz TBD dB
Output Characteristics
Out
p
ut Volta
g
e Set Point
(
no load
)
-40 ºC to 85 ºC 1.485 1.500 1.515 VDC
Out
p
ut Re
g
ulation
Over Line ±2 ±4 mV
Over Load ±2 ±4 mV
Out
p
ut Volta
g
e Ran
g
e Over line
,
load and tem
p
erature 1.477 1.523 VDC
Out
p
ut Ri
pp
le and Noise
–
25 MHz bandwidth Full load + 10
F tantalum + 1
F ceramic 30 50 mVPK-PK
External Load Ca
p
acitance Plus full load
(
resistive
)
40
,
000
F
Out
p
ut Current Ran
g
e 0 40 ADC
Current Limit Ince
p
tion Non-latchin
g
42 47 52 ADC
Peak Short-Circuit Current Non-latchin
g
,
Short = 10 m 50 60 A
RMS Short-Circuit Current Non-latchin
g
10 15 Arms
Dynamic Response
Load Chan
g
e 25% of Iout Max
,
di/dt = 1 A/
s Co = 470
F tantalum + 1
F ceramic 120 mV
Settin
g
Time to 1% 150
µ
s
Efficiency
100% Load 85.5 %
50% Load 88 %
Ambient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 1.5V.1: Available load current vs. ambient air temperature
and airflow rates for QM48T40015 converter with B height pins
mounted vertically with air flowing from pin 3 to pin 1, MOSFET
temperature ≤ 120 °C, Vin = 48 V.
Note: NC – Natural convection
A
mbient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 1.5V.2: Available load current vs. ambient air temperature
and airflow rates for QM48T40015 converter with B height pins
mounted horizontally with air flowing from pin 3 to pin 1,
MOSFET temperature ≤ 120 °C, Vin = 48 V.
MCD10048 Rev. 1.0 Page 26 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40015 (1.5 Volts Out)
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 1.5V.3: Efficiency vs. load current and input voltage for
converter mounted vertically with air flowing from pin 3 to pin 1
at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
72 V
48 V
36 V
Fig. 1.5V.5: Power dissipation vs. load current and input
voltage for converter mounted vertically with air flowing from
pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
70 C
55 C
40 C
Fig. 1.5V.4: Efficiency vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
70 C
55 C
40 C
Fig. 1.5V.6: Power dissipation vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
MCD10048 Rev. 1.0 Page 27 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40015 (1.5 Volts Out)
Fig. 1.5V.7: Turn-on transient at full rated load current
(resistive) with no output capacitor at Vin = 48 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom
trace: output voltage (0.5 V/div.) Time scale: 2 ms/div.
Fig. 1.5V.9: Output voltage response to load current
step-change (20 A – 30 A – 20 A) at Vin = 48 V. Top trace:
output voltage (100 mV/div.). Bottom trace: load current
(10 A/div). Current slew rate: 1 A/s. Co = 470 F tantalum +
1 F ceramic. Time scale: 0.2 ms/div.
Fig. 1.5V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 F at Vin = 48 V, triggered via ON/OFF
pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output
voltage (0.5 V/div.). Time scale: 2 ms/div.
Fig. 1.5V.10: Output voltage ripple (20 mV/div.) at full rated
load current into a resistive load with Co = 10 F tantalum +
1 F ceramic and Vin = 48 V. Time scale: 1 s/div.
MCD10048 Rev. 1.0 Page 28 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40015 (1.5 Volts Out)
Vout
Vsource
iSiC
1 μF
ceramic
capacitor
10 μH
source
inductance
DC-DC
Converter
33 μF
ESR < 1
electrolytic
capacitor
Series
QmaXTM
Fig. 1.5V.11: Test setup for measuring input reflected ripple currents, ic and is.
Fig. 1.5V.12: Input reflected ripple current, is (10 mA/div),
measured through 10 H at the source at full rated load
current and Vin = 48 V. Refer to Fig. 1.5V.11 for test setup.
Time scale: 1 s/div.
15 60
2.0
Iout [Adc]
Vout [Vdc]
0
0
1.5
1.0
0.5
30 45
Fig. 1.5V.14: Output voltage vs. load current showing
current limit point and converter shutdown point. Input
voltage has almost no effect on current limit characteristic.
Fig. 1.5V.13: Input reflected ripple current, ic (100 mA/div),
measured at input terminals at full rated load current and Vin
= 48 V. Refer to Fig. 1.5V.11 for test setup. Time scale:
1 s/div.
Fig. 1.5V.15: Load current (top trace, 20 A/div, 20 ms/div)
into a 10 m short circuit during restart, at Vin = 48 V.
Bottom trace (20 A/div, 1 ms/div) is an expansion of the
on-time portion of the top trace.
MCD10048 Rev. 1.0 Page 29 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Electrical Specifications: QM48T40012 (1.2 Volts Out)
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, Vout = 1.2 VDC unless otherwise specified.
Parameter Notes Min Typ Max Units
Input Characteristics
Maximum In
p
ut Current 40 ADC
,
1.2 VDC Out
@
36 VDC In 1.7 ADC
In
p
ut Stand-b
y
Current Vin = 48 V
,
converter disabled 3 mADC
In
p
ut No Load Current
(
0 load on the out
p
ut
)
Vin = 48 V
,
converter enabled 28 mADC
In
p
ut Reflected-Ri
pp
le Current 25 MHz bandwidth 7.5 mAPK-PK
In
p
ut Volta
g
e Ri
pp
le Re
j
ection 120 Hz TBD dB
Output Characteristics
Out
p
ut Volta
g
e Set Point
(
no load
)
-40 ºC to 85 ºC 1.188 1.200 1.212 VDC
Out
p
ut Re
g
ulation
Over Line ±1 ±3 mV
Over Load ±1 ±3 mV
Out
p
ut Volta
g
e Ran
g
e Over line
,
load and tem
p
erature 1.182 1.218 VDC
Out
p
ut Ri
pp
le and Noise
–
25 MHz bandwidth Full load + 10
F tantalum + 1
F ceramic 30 50 mVPK-PK
External Load Ca
p
acitance Plus full load
(
resistive
)
40
,
000
F
Out
p
ut Current Ran
g
e 0 40 ADC
Current Limit Ince
p
tion Non-latchin
g
42 47 52 ADC
Peak Short-Circuit Current Non-latchin
g
,
Short = 10 m 50 60 A
RMS Short-Circuit Current Non-latchin
g
10 15 Arms
Dynamic Response
Load Chan
g
e 25% of Iout Max
,
di/dt = 1 A/
s Co = 470
F tantalum + 1
F ceramic 120 mV
Settin
g
Time to 1% 250
µ
s
Efficiency
100% Load 83 %
50% Load 86.5 %
Ambient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 1.2V.1: Available load current vs. ambient air temperature
and airflow rates for QM48T40012 converter with B height pins
mounted vertically with air flowing from pin 3 to pin 1, MOSFET
temperature ≤ 120 °C, Vin = 48 V.
A
mbient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 1.2V.2: Available load current vs. ambient air temperature
and airflow rates for QM48T40012 converter with B height pins
mounted horizontally with air flowing from pin 3 to pin 1,
MOSFET temperature ≤ 120 °C, Vin = 48 V.
Note: NC – Natural convection
MCD10048 Rev. 1.0 Page 30 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40012 (1.2 Volts Out)
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 1.2V.3: Efficiency vs. load current and input voltage for
converter mounted vertically with air flowing from pin 3 to pin 1
at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
72 V
48 V
36 V
Fig. 1.2V.5: Power dissipation vs. load current and input
voltage for converter mounted vertically with air flowing from
pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
70 C
55 C
40 C
Fig. 1.2V.4: Efficiency vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
70 C
55 C
40 C
Fig. 1.2V.6: Power dissipation vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
MCD10048 Rev. 1.0 Page 31 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40012 (1.2 Volts Out)
Fig. 1.2V.7: Turn-on transient at full rated load current
(resistive) with no output capacitor at Vin = 48 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom
trace: output voltage (0.5 V/div.) Time scale: 2 ms/div.
Fig. 1.2V.9: Output voltage response to load current step-
change (20 A – 30 A – 20 A) at Vin = 48 V. Top trace: output
voltage (100 mV/div.). Bottom trace: load current (10 A/div).
Current slew rate: 1 A/s. Co = 470 F tantalum + 1 F
ceramic. Time scale: 0.2 ms/div.
Fig. 1.2V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 F at Vin = 48 V, triggered via ON/OFF
pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output
voltage (0.5 V/div.). Time scale: 2 ms/div.
Fig. 1.2V.10: Output voltage ripple (20 mV/div.) at full rated
load current into a resistive load with Co = 10 F tantalum +
1 F ceramic and Vin = 48 V. Time scale: 1 s/div.
MCD10048 Rev. 1.0 Page 32 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40012 (1.2 Volts Out)
Vout
Vsource
iSiC
1 μF
ceramic
capacitor
10 μH
source
inductance
DC-DC
Converter
33 μF
ESR < 1
electrolytic
capacitor
Series
QmaXTM
Fig. 1.2V.11: Test setup for measuring input reflected ripple currents, ic and is.
Fig. 1.2V.12: Input reflected ripple current, is (10 mA/div),
measured through 10 H at the source at full rated load
current and Vin = 48 V. Refer to Fig. 1.2V.11 for test setup.
Time scale: 1 s/div.
15 60
Iout [Adc]
Vout [Vdc]
0
0
30 45
1.5
1.0
0.5
Fig. 1.2V.14: Output voltage vs. load current showing
current limit point and converter shutdown point. Input volt-
age has almost no effect on current limit characteristic.
Fig. 1.2V.13: Input reflected ripple current, ic (100 mA/div),
measured at input terminals at full rated load current and Vin
= 48 V. Refer to Fig. 1.2V.11 for test setup. Time scale:
1 s/div.
Fig. 1.2V.15: Load current (top trace, 20 A/div, 20 ms/div)
into a 10 m short circuit during restart, at Vin = 48 V.
Bottom trace (20 A/div, 1 ms/div) is an expansion of the on-
time portion of the top trace.
MCD10048 Rev. 1.0 Page 33 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Electrical Specifications: QM48T40010 (1.0 Volt Out)
Conditions: TA = 25 ºC, Airflow=300 LFM (1.5 m/s), Vin = 48 VDC, Vout = 1.0 VDC unless otherwise specified.
Parameter Notes Min Typ Max Units
Input Characteristics
Maximum In
p
ut Current 40 ADC
,
1.0 VDC Out
@
36 VDC In 1.4 ADC
In
p
ut Stand-b
y
Current Vin = 48 V
,
converter disabled 3 mADC
In
p
ut No Load Current
(
0 load on the out
p
ut
)
Vin = 48 V
,
converter enabled 27 mADC
In
p
ut Reflected-Ri
pp
le Current 25 MHz bandwidth 7.5 mAPK-PK
In
p
ut Volta
g
e Ri
pp
le Re
j
ection 120 Hz TBD dB
Output Characteristics
Out
p
ut Volta
g
e Set Point
(
no load
)
-40 ºC to 85 ºC 0.990 1.000 1.010 VDC
Out
p
ut Re
g
ulation
Over Line ±1 ±3 mV
Over Load ±1 ±3 mV
Out
p
ut Volta
g
e Ran
g
e Over line
,
load and tem
p
erature 0.985 1.015 VDC
Out
p
ut Ri
pp
le and Noise
–
25 MHz bandwidth Full load + 10
F tantalum + 1
F ceramic 30 50 mVPK-PK
External Load Ca
p
acitance Plus full load
(
resistive
)
40
,
000
F
Out
p
ut Current Ran
g
e 0 40 ADC
Current Limit Ince
p
tion Non-latchin
g
42 47 52 ADC
Peak Short-Circuit Current Non-latchin
g
,
Short = 10 m 50 60 A
RMS Short-Circuit Current Non-latchin
g
10 15 Arms
Dynamic Response
Load Chan
g
e 25% of Iout Max
,
di/dt = 1 A/
s Co = 470
F tantalum + 1
F ceramic 120 mV
Settin
g
Time to 1% 280
µ
s
Efficiency
100% Load 81 %
50% Load 85 %
Ambient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 1.0V.1: Available load current vs. ambient air temperature
and airflow rates for QM48T40010 converter with B height pins
mounted vertically with air flowing from pin 3 to pin 1, MOSFET
temperature ≤ 120 °C, Vin = 48 V.
A
mbient Tem
p
erature
[
°C
]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
10
20
30
40
50
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
NC - 30 LFM (0.15 m/s)
Fig. 1.0V.2: Available load current vs. ambient air temperature
and airflow rates for QM48T40010 converter with B height pins
mounted horizontally with air flowing from pin 3 to pin 1,
MOSFET temperature ≤ 120 °C, Vin = 48 V.
Note: NC – Natural convection
MCD10048 Rev. 1.0 Page 34 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40010 (1.0 Volt Out)
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 1.0V.3: Efficiency vs. load current and input voltage for
converter mounted vertically with air flowing from pin 3 to pin 1
at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
72 V
48 V
36 V
Fig. 1.0V.5: Power dissipation vs. load current and input volt-
age for converter mounted vertically with air flowing from pin 3
to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25 °C.
Load Current [Adc]
0 1020304050
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
70 C
55 C
40 C
Fig. 1.0V.4: Efficiency vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
Load Current [Adc]
0 1020304050
P
ower
Di
ss
i
pa
ti
on
[W]
0.00
4.00
8.00
12.00
16.00
70 C
55 C
40 C
Fig. 1.0V.6: Power dissipation vs. load current and ambient
temperature for converter mounted vertically with Vin = 48 V
and air flowing from pin 3 to pin 1 at a rate of 200 LFM
(1.0 m/s).
MCD10048 Rev. 1.0 Page 35 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40010 (1.0 Volt Out)
Fig. 1.0V.7: Turn-on transient at full rated load current
(resistive) with no output capacitor at Vin = 48 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom
trace: output voltage (0.5 V/div.) Time scale: 2 ms/div.
Fig. 1.0V.9: Output voltage response to load current
step-change (20 A – 30 A – 20 A) at Vin = 48 V. Top trace:
output voltage (100 mV/div.). Bottom trace: load current (10
A/div). Current slew rate: 1 A/s. Co = 470 F tantalum + 1 F
ceramic. Time scale: 0.2 ms/div.
Fig. 1.0V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 F at Vin = 48 V, triggered via ON/OFF
pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output
voltage (0.5 V/div.). Time scale: 2 ms/div.
Fig. 1.0V.10: Output voltage ripple (20 mV/div.) at full rated
load current into a resistive load with Co = 10 F tantalum +
1 F ceramic and Vin = 48 V. Time scale: 1 s/div.
MCD10048 Rev. 1.0 Page 36 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
QM48T40010 (1.0 Volt Out)
Vout
Vsource
iSiC
1 μF
ceramic
capacitor
10 μH
source
inductance
DC-DC
Converter
33 μF
ESR < 1
electrolytic
capacitor
Series
QmaXTM
Fig. 1.0V.11: Test Setup for measuring input reflected ripple currents, ic and is.
Fig. 1.0V.12: Input reflected ripple current, is (10 mA/div),
measured through 10 H at the source at full rated load
current and Vin = 48 V. Refer to Fig. 1.0V.11 for test setup.
Time scale: 1 s/div.
15 60
Iout [Adc]
Vout [Vdc]
0
0
30 45
1.5
1.0
0.5
Fig. 1.0V14: Output voltage vs. load current showing current
limit point and converter shutdown point. Input voltage has
almost no effect on current limit characteristic.
Fig. 1.0V.13: Input reflected ripple current, ic (100 mA/div),
measured at input terminals at full rated load current and Vin
= 48 V. Refer to Fig. 1.0V.11 for test setup. Time scale:
1 s/div.
Fig. 1.0V15: Load current (top trace, 20 A/div, 20 ms/div)
into a 10 m short circuit during restart, at Vin = 48 V.
Bottom trace (20 A/div, 1 ms/div) is an expansion of the
on-time portion of the top trace.
MCD10048 Rev. 1.0 Page 37 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Physical Information
SIDE VIEW
TOP VIEW
1
2
3
7
8
6
5
4
Pin Connections
Pin # Function
1 Vin (+)
2 ON/OFF
3 Vin (-)
4 Vout (-)
5 SENSE(-)
6 TRIM
7 SENSE(+)
8 Vout (+)
HT
(Maximum
Height)
CL
(Minimum Clearance)
PL
(Pin Length)
Height
Option +0.000 [+0.00]
-0.038 [-0.97]
+0.016 [+0.41]
-0.000 [-0.00]
Pin
Option
±0.005 [±0.13]
A 0.325 [8.26] 0.030 [0.77] A 0.188 [4.77]
B 0.358 [9.09] 0.063 [1.60] B 0.145 [3.68]
D 0.422 [10.72] 0.127 [3.23] C 0.110 [2.79]
•
All dimensions are in inches [mm]
• Pins 1-3 and 5-7 are Ø 0.040” [1.02]
with Ø 0.078” [1.98] shoulder
• Pins 4 and 8 are Ø 0.062” [1.57]
without shoulder
• Pin Material: Brass
• Pin Finish: Tin/Lead over Nickel or
Matte Tin over Nickel for “G” version
• Converter Weight: 1.06 oz [30 g]
MCD10048 Rev. 1.0 Page 38 of 38 www.power-one.com
QM48T40 DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 40 A Output
Converter Part Numbering Scheme
Product
Series
Input
Voltage
Mounting
Scheme
Rated Load
Current
Output
Voltage ON/OFF
Logic
Maximum
Height (HT)
Pin
Length
(PL)
Special
Features
Environ-
mental
QM 48 T 40 033 - N B A 0
Quarter-
Brick
Format
36-75 V Through-
hole
40 A
(1.0- 3.3 V)
010 ⇒ 1.0 V
012 ⇒ 1.2 V
015 ⇒ 1.5 V
018 ⇒ 1.8 V
020 ⇒ 2.0 V
025 ⇒ 2.5 V
033 ⇒ 3.3 V
N ⇒
Negative
P ⇒
Postive
A ⇒ 0.325”
B ⇒ 0.358”
D ⇒ 0.422”
A ⇒ 0.188”
B ⇒ 0.145”
C ⇒ 0.110”
0 ⇒ STD
U ⇒ Special
Trim2
(For 1.2 V
only)
T ⇒ Special
Trim2
(For 1.2 V &
1.0 V only)
No Suffix ⇒
RoHS
lead-solder-
exemption
compliant
G ⇒ RoHS
compliant for
all six sub-
stances
1. The example above describes P/N QM48T40033-NBA0: 36-75 V input, through-hole mounting, 40 A @ 3.3 V output, negative ON/OFF logic, a
maximum height of 0.358”, a through the board pin length of 0.188”, and Eutectic Tin/Lead solder. Please consult factory for the complete list of available
options.
2. For definitions, operation, and associated trim equations for all trim options, please refer to Trim Feature for Isolated dc-dc converters Application Note.
Model numbers highlighted in yellow or shaded are not recommended for new designs.
NUCLEAR AND MEDICAL APPLICATIONS - Power-One products are not designed, intended for use in, or authorized for use as critical components in life
support systems, equipment used in hazardous environments, or nuclear control systems without the express written consent of the respective divisional
president of Power-One, Inc.
TECHNICAL REVISIONS - The appearance of products, including safety agency certifications pictured on labels, may change depending on the date
manufactured. Specifications are subject to change without notice.