MCD10073 Rev. 1.0 Page 1 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 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’ 50 A half-bricks
Features
• RoHS lead-free solder and lead-solder-exempted
products are available
• Delivers up to 45 A (150 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: 1.1 oz [31.5 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 45 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 50 A half-bricks. This performance is
accomplished through the use of patented/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.
MCD10073 Rev. 1.0 Page 36 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Electrical Specifications (common to all versions)
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, unless otherwise specified.
Parameter Notes Min Typ Max Units
Absolute Maximum Ratings
Input Voltage Continuous 0 80 VDC
Operating Ambient Temperature -40 85 °C
Storage Temperature -55 125 °C
Input Characteristics
Operating Input Voltage Range 36 48 75 VDC
Input Under Voltage Lockout Non-latching
Turn-on Threshold 33 34 35 VDC
Turn-off Threshold 31 32 33 VDC
Input Voltage Transient 100 ms 100 VDC
Isolation Characteristics
I/O Isolation 2000 VDC
Isolation Capacitance 1.4 nF
Isolation Resistance 10 M
Feature Characteristics
Switching Frequency 415 kHz
Industry-std. equations (3.3-1.5 V) -20 +10 %
Output Voltage Trim Range1 Use trim equation on Page 4
(1.2-1.0 V) -10 +10 %
Remote Sense Compensation1 Percent of VOUT(NOM) +10 %
Output Overvoltage Protection Non-latching 117 128 140 %
Overtemperature Shutdown (PCB) Non-latching 125 °C
Auto-Restart Period Applies to all protection features 100 ms
Turn-On Time See Figs. F, G and H 4 ms
ON/OFF Control (Positive Logic)
Converter Off (logic low) -20 0.8 VDC
Converter On (logic high) 2.4 20 VDC
ON/OFF Control (Negative Logic)
Converter Off (logic high) 2.4 20 VDC
Converter On (logic 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.
MCD10073 Rev. 1.0 Page 3 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Operations
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 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.
Additionally, see the EMC section of this data sheet
for discussion of other external components which
may be required for control of conducted emissions.
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(-). A
typical connection is 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 hardwired directly to
Vin(-) to enable automatic power up of the converter
without the need of an external control signal
The 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 run side by side and
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, which is 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
MCD10073 Rev. 1.0 Page 4 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
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.
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 0.1µF
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 −
−+
=−
− [k]
(For 3.3-1.5 V)
7.2
Δ
84.6
RINCRT −=− [k] (1.2 V)
9
Δ
120
RINCRT −=− [k] (1.0 V)
where,
=−INCRTRRequired value of trim-up resistor [k]
=−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 the 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 −=− [k] (3.3-1.5 V)
15
|Δ|
700
RDECRT −=− [k] (1.2 V)
17
|Δ|
700
RDECRT −=− [k] (1.0 V)
where,
=
−DECRTRRequired value of trim-down resistor [k]
and
Δ
is 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).
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.
MCD10073 Rev. 1.0 Page 5 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
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 typically 34 V for the
converter to turn on. Once the converter has been
turned on, it will shut off when the input voltage drops
typically below 32 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 its nominal value, 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.
Once the output current is brought back into its
specified range, the converter automatically exits the
hiccup mode and continues normal operation.
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 10 A
2.5 V 7 A
2.0-1.5 V 5 A
1.2-1.0 V 3 A
All QM converters are UL approved for a maximum
fuse rating of 15 Amps. To protect a group of modules
with a single fuse, the rating can be increased from
the recommended value 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 an d methods of measurement.
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 requirements. Please contact
Power-One Applications Engineering for details of this
testing.
Fig. E: Location of the thermocouple for thermal testing.
MCD10073 Rev. 1.0 Page 6 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 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 F.
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 Undervoltage 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 G.
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 H.
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 G.
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.
VIN
ON/OFF
STATE
VOUT
t
t0t1t2t3
ON
OFF
Fig. F: Startup scenario #1.
ON/OFF
STATE
VOUT
t0t1t2t3
ON
OFF
VIN
t
Fig. G: Startup scenario #2.
ON/OFF
STATE OFF
ON
VOUT
t0t2t1t5
VIN
t
t4t3
100 ms
Fig. H: Startup scenario #3.
MCD10073 Rev. 1.0 Page 7 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
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
mountings, 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 Fig. E for the
optimum measuring thermocouple location.
Thermal Derating
Load current vs. ambient temperature and airflow
rates are given in Fig. x.1 and Fig x.2 for vertical and
horizontal converter mountings. 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 (45 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
thermocouple location shown in Fig. E 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.
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.
MCD10073 Rev. 1.0 Page 8 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Electrical Specifications: QM48T45033 (3.3 Volt 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 Input Current 45 ADC, 3.3 VDC Out @ 36 VDC In 4.8 ADC
Input Stand-by Current Vin = 48 V, converter disabled 3 mADC
Input No Load Current (0 load on the output) Vin = 48 V, converter enabled 85 mADC
Input Reflected-Ripple Current 25 MHz bandwidth 7.5 mAPK-PK
Input Voltage Ripple Rejection 120 Hz TBD dB
Output Characteristics
Output Voltage Set Point (no load) -40 ºC to 85 ºC 3.267 3.300 3.333 VDC
Output Regulation
Over Line ±2 ±5 mV
Over Load ±2 ±5 mV
Output Voltage Range Over line, load and temperature 3.250 3.350 VDC
Output Ripple and Noise –
25 MHz bandwidth
Full load + 10 µF tantalum + 1 µF
ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 40,000 µF
Output Current Range 0 45 ADC
Current Limit Inception Non-latching 47.25 53 58 ADC
Peak Short-Circuit Current Non-latching, Short = 10 m 55 65 A
RMS Short-Circuit Current Non-latching 12 18 Arms
Dynamic Response
Load Change 25% of Iout Max, di/dt = 1A/s Co = 470 µF tantalum + 1 µF ceramic 160 mV
Settling Time to 1% 100 µs
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 QM48T45033 converter
with B height pins mounted vertically with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
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 QM48T45033 converter
with B height pins mounted horizontally with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
MCD10073 Rev. 1.0 Page 9 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45033 (3.3 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. 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
20.00
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
20.00
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).
MCD10073 Rev. 1.0 Page 10 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45033 (3.3 Volt 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. 3.3V.9: Output voltage response to load current
step-change (22.5 A – 33.75 A – 22.5 A) at Vin = 48 V.
Top trace: output voltage (100 mV/div.). Bottom trace:
load current (10 A/div). Current slew rate: 1 A/µs. Co =
470 µF tantalum + 1 µF ceramic. Time scale: 0.2 ms/div.
Fig. 3.3V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 µF 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 µF
tantalum + 1µF ceramic and Vin = 48 V. Time scale:
1 µs/div.
MCD10073 Rev. 1.0 Page 11 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45033 (3.3 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. 3.3V.11: Test Setup for measuring input reflected ripple currents, ic and is.
Fig. 3.3V.12: Input reflected ripple current, is
(10 mA/div), measured through 10 µH at the source at
full rated load current and Vin = 48 V. Refer to
Fig. 3.3V.11 for test setup. Time scale: 1 µs/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. 3.3V.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. 3.3V.11 for
test setup. Time scale: 1 µs/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.
MCD10073 Rev. 1.0 Page 12 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Electrical Specifications: QM48T45025 (2.5 Volt 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 Input Current 45 ADC, 2.5 VDC Out @ 36 VDC In 3.6 ADC
Input Stand-by Current Vin = 48 V, converter disabled 3 mADC
Input No Load Current (0 load on the output) Vin = 48 V, converter enabled 67 mADC
Input Reflected-Ripple Current 25 MHz bandwidth 7.5 mAPK-PK
Input Voltage Ripple Rejection 120 Hz TBD dB
Output Characteristics
Output Voltage Set Point (no load) -40 ºC to 85 ºC 2.475 2.500 2.525 VDC
Output Regulation
Over Line ±2 ±5 mV
Over Load ±2 ±5 mV
Output Voltage Range Over line, load and temperature 2.462 2.538 VDC
Output Ripple and Noise –
25 MHz bandwidth
Full load + 10 µF tantalum + 1 µF
ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 40,000 µF
Output Current Range 0 45 ADC
Current Limit Inception Non-latching 47.25 53 58 ADC
Peak Short-Circuit Current Non-latching, Short = 10 m. 55 65 A
RMS Short-Circuit Current Non-latching 12 18 Arms
Dynamic Response
Load Change 25% of Iout Max, di/dt = 1A/s Co = 470 F tantalum + 1 F ceramic 160 mV
Settling Time to 1% 100 µs
Efficiency
100% Load 89.0 %
50% Load 91.0 %
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 QM48T45025 converter
with B height pins mounted vertically with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
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. 2.5V.2: Available load current vs. ambient air
temperature and airflow rates for QM48T45025 converter
with B height pins mounted horizontally with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
MCD10073 Rev. 1.0 Page 13 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45025 (2.5 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. 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
20.00
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
20.00
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).
MCD10073 Rev. 1.0 Page 14 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45025 (2.5 Volt 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 (22.5 A – 33.75 A – 22.5 A) at Vin = 48 V.
Top trace: output voltage (100 mV/div.). Bottom trace:
load current (10 A/div). Current slew rate: 1 A/µs. Co =
470 µF tantalum + 1 µF ceramic. Time scale: 0.2 ms/div.
Fig. 2.5V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 µF 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 µF
tantalum + 1 µF ceramic and Vin = 48 V. Time scale:
1 µs/div.
MCD10073 Rev. 1.0 Page 15 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45025 (2.5 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. 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 µH at the source at
full rated load current and Vin = 48 V. Refer to
Fig. 2.5V.11 for test setup. Time scale: 1 µs/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 µs/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.
MCD10073 Rev. 1.0 Page 16 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Electrical Specifications: QM48T45020 (2.0 Volt 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 Input Current 45 ADC, 2.0 VDC Out @ 36 VDC In 2.9 ADC
Input Stand-by Current Vin = 48 V, converter disabled 3 mADC
Input No Load Current (0 load on the output) Vin = 48 V, converter enabled 55 mADC
Input Reflected-Ripple Current 25 MHz bandwidth 7.5 mAPK-PK
Input Voltage Ripple Rejection 120 Hz TBD dB
Output Characteristics
Output Voltage Set Point (no load) -40 ºC to 85 ºC 1.98 2.000 2.02 VDC
Output Regulation
Over Line ±2 ±5 mV
Over Load ±2 ±5 mV
Output Voltage Range Over line, load and temperature 1.97 2.03 VDC
Output Ripple and Noise –
25 MHz bandwidth
Full load + 10 µF tantalum + 1 µF
ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 40,000 µF
Output Current Range 0 45 ADC
Current Limit Inception Non-latching 47.25 53 58 ADC
Peak Short-Circuit Current Non-latching, Short = 10 m 55 65 A
RMS Short-Circuit Current Non-latching 12 18 Arms
Dynamic Response
Load Change 25% of Iout Max, di/dt = 1A/s Co = 470 µF tantalum + 1 µF ceramic 160 mV
Settling Time to 1% 100 µs
Efficiency
100% Load 88.0 %
50% Load 90.0 %
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 QM48T45020 converter
with B height pins mounted vertically with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
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 QM48T45020 converter
with B height pins mounted horizontally with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
MCD10073 Rev. 1.0 Page 17 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45020 (2.0 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. 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
20.00
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
20.00
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).
MCD10073 Rev. 1.0 Page 18 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45020 (2.0 Volt 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 (22.5 A – 33.75 A – 22.5 A) at Vin = 48 V.
Top trace: output voltage (100 mV/div.). Bottom trace:
load current (10 A/div). Current slew rate: 1 A/µs. Co =
470 µF tantalum + 1 µF ceramic. Time scale: 0.2 ms/div.
Fig. 2.0V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 μF 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 µF
tantalum + 1 µF ceramic and Vin = 48 V. Time scale:
1 µs/div.
MCD10073 Rev. 1.0 Page 19 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45020 (2.0 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. 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 µH at the source at
full rated load current and Vin = 48 V. Refer to
Fig. 2.0V.11 for test setup. Time scale: 1 µs/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 µs/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.
MCD10073 Rev. 1.0 Page 20 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Electrical Specifications: QM48T45018 (1.8 Volt 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 Input Current 45 ADC, 1.8 VDC Out @ 36 VDC In 2.7 ADC
Input Stand-by Current Vin = 48 V, converter disabled 3 mADC
Input No Load Current (0 load on the output) Vin = 48 V, converter enabled 50 mADC
Input Reflected-Ripple Current 25 MHz bandwidth 7.5 mAPK-PK
Input Voltage Ripple Rejection 120 Hz TBD dB
Output Characteristics
Output Voltage Set Point (no load) -40 ºC to 85 ºC 1.782 1.800 1.818 VDC
Output Regulation
Over Line ±2 ±4 mV
Over Load ±2 ±5 mV
Output Voltage Range Over line, load and temperature 1.773 1.827 VDC
Output Ripple and Noise –
25 MHz bandwidth
Full load + 10 µF tantalum + 1 µF
ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 40,000 µF
Output Current Range 0 45 ADC
Current Limit Inception Non-latching 47.25 53 58 ADC
Peak Short-Circuit Current Non-latching, Short = 10 m 55 65 A
RMS Short-Circuit Current Non-latching 12 18 Arms
Dynamic Response
Load Change 25% of Iout Max, di/dt = 1A/µs Co = 470 µF tantalum + 1 µF ceramic 160 mV
Settling Time to 1% 150 µs
Efficiency
100% Load 87.0 %
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 QM48T45018 converter
with B height pins mounted vertically with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
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 QM48T45018 converter
with B height pins mounted horizontally with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
MCD10073 Rev. 1.0 Page 21 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45018 (1.8 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. 1.8V.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
3.00
6.00
9.00
12.00
15.00
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
3.00
6.00
9.00
12.00
15.00
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).
MCD10073 Rev. 1.0 Page 22 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45018 (1.8 Volt 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 (22.5 A – 33.75 A – 22.5 A) at Vin = 48 V.
Top trace: output voltage (100 mV/div.). Bottom trace:
load current (10 A/div). Current slew rate: 1 A/µs. Co =
470 µF tantalum + 1 µF ceramic. Time scale: 0.2 ms/div.
Fig. 1.8V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 µF 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 µF
tantalum + 1 µF ceramic and Vin = 48 V. Time scale:
1 µs/div.
MCD10073 Rev. 1.0 Page 23 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45018 (1.8 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. 1.8V.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 µH at the source at
full rated load current and Vin = 48 V. Refer to
Fig. 1.8V.11 for test setup. Time scale: 1 µs/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 µs/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, 1 ms/div) is an
expansion of the on-time portion of the top trace.
MCD10073 Rev. 1.0 Page 24 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Electrical Specifications: QM48T45015 (1.5 Volt 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 Input Current 45 ADC, 1.5 VDC Out @ 36 VDC In 2.3 ADC
Input Stand-by Current Vin = 48 V, converter disabled 3 mADC
Input No Load Current (0 load on the output) Vin = 48 V, converter enabled 42 mADC
Input Reflected-Ripple Current 25 MHz bandwidth 7.5 mAPK-PK
Input Voltage Ripple Rejection 120 Hz TBD dB
Output Characteristics
Output Voltage Set Point (no load) -40 ºC to 85 ºC 1.485 1.500 1.515 VDC
Output Regulation
Over Line ±2 ±4 mV
Over Load ±2 ±4 mV
Output Voltage Range Over line, load and temperature 1.477 1.523 VDC
Output Ripple and Noise –
25 MHz bandwidth
Full load + 10 µF tantalum + 1 µF
ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 40,000 µF
Output Current Range 0 45 ADC
Current Limit Inception Non-latching 47.25 53 58 ADC
Peak Short-Circuit Current Non-latching, Short = 10 m 55 65 A
RMS Short-Circuit Current Non-latching 12 18 Arms
Dynamic Response
Load Change 25% of Iout Max, di/dt = 1A/µs Co = 470 µF tantalum + 1 µF ceramic 160 mV
Settling Time to 1% 150 µs
Efficiency
100% Load 85.5 %
50% Load 88.0 %
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 QM48T45015 converter
with B height pins mounted vertically with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
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 QM48T45015 converter
with B height pins mounted horizontally with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
MCD10073 Rev. 1.0 Page 25 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45015 (1.5 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. 1.5V.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
3.00
6.00
9.00
12.00
15.00
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
3.00
6.00
9.00
12.00
15.00
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).
MCD10073 Rev. 1.0 Page 26 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45015 (1.5 Volt 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 (1 V/div.) Time
scale: 2 ms/div.
Fig. 1.5V.9: Output voltage response to load current
step-change (22.5 A – 33.75 A – 22.5 A) at Vin = 48 V.
Top trace: output voltage (100 mV/div.). Bottom trace:
load current (10 A/div). Current slew rate: 1 A/µs. Co =
470 µF tantalum + 1 µF ceramic. Time scale: 0.2 ms/div.
Fig. 1.5V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 µF 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. 1.5V.10: Output voltage ripple (20 mV/div.) at full
rated load current into a resistive load with Co = 10 µF
tantalum + 1 µF ceramic and Vin = 48 V. Time scale:
1 µs/div.
MCD10073 Rev. 1.0 Page 27 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45015 (1.5 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. 1.5V.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 µH at the source at
full rated load current and Vin = 48 V. Refer to
Fig. 1.5V.11 for test setup. Time scale: 1 µs/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 µs/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.
MCD10073 Rev. 1.0 Page 28 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Electrical Specifications: QM48T45012 (1.2 Volt 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 Input Current 45 ADC, 1.2 VDC Out @ 36 VDC In 1.9 ADC
Input Stand-by Current Vin = 48 V, converter disabled 3 mADC
Input No Load Current (0 load on the output) Vin = 48 V, converter enabled 37 mADC
Input Reflected-Ripple Current 25 MHz bandwidth 7.5 mAPK-PK
Input Voltage Ripple Rejection 120 Hz TBD dB
Output Characteristics
Output Voltage Set Point (no load) -40 ºC to 85 ºC 1.188 1.200 1.212 VDC
Output Regulation
Over Line ±1 ±3 mV
Over Load ±1 ±3 mV
Output Voltage Range Over line, load and temperature 1.182 1.218 VDC
Output Ripple and Noise –
25 MHz bandwidth
Full load + 10 µF tantalum + 1 µF
ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 40,000 µF
Output Current Range 0 45 ADC
Current Limit Inception Non-latching 47.25 53 58 ADC
Peak Short-Circuit Current Non-latching, Short = 10 m 55 65 A
RMS Short-Circuit Current Non-latching 12 18 Arms
Dynamic Response
Load Change 25% of Iout Max, di/dt = 1A/µs Co = 470 µF tantalum + 1 µF ceramic 160 mV
Settling Time to 1% 150 µs
Efficiency
100% Load 83.0 %
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 QM48T45012 converter
with B height pins mounted vertically with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
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. 1.2V.2: Available load current vs. ambient air
temperature and airflow rates for QM48T45012 converter
with B height pins mounted horizontally with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
MCD10073 Rev. 1.0 Page 29 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45012 (1.2 Volt Out)
Load Current [Adc]
0 1020304050
Efficiency
0.60
0.65
0.70
0.75
0.80
0.85
0.90
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
3.00
6.00
9.00
12.00
15.00
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
0.60
0.65
0.70
0.75
0.80
0.85
0.90
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
3.00
6.00
9.00
12.00
15.00
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).
MCD10073 Rev. 1.0 Page 30 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45012 (1.2 Volt 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 (1 V/div.) Time
scale: 2 ms/div.
Fig. 1.2V.9: Output voltage response to load current
step-change (22.5 A – 33.75 A – 22.5 A) at Vin = 48 V.
Top trace: output voltage (100 mV/div.). Bottom trace:
load current (10 A/div). Current slew rate: 1 A/µs. Co =
470 µF tantalum + 1 µF ceramic. Time scale: 0.2 ms/div.
Fig. 1.2V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 µF 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. 1.2V.10: Output voltage ripple (20 mV/div.) at full
rated load current into a resistive load with Co = 10 µF
tantalum + 1 µF ceramic and Vin = 48 V. Time scale:
1 µs/div.
MCD10073 Rev. 1.0 Page 31 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45012 (1.2 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. 1.2V.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 µH at the source at
full rated load current and Vin = 48 V. Refer to
Fig. 1.2V.11 for test setup. Time scale: 1 µs/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
voltage 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 µs/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.
MCD10073 Rev. 1.0 Page 32 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
Electrical Specifications: QM48T45010 (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 Input Current 45 ADC, 1.0 VDC Out @ 36 VDC In 1.6 ADC
Input Stand-by Current Vin = 48 V, converter disabled 3 mADC
Input No Load Current (0 load on the output) Vin = 48 V, converter enabled 35 mADC
Input Reflected-Ripple Current 25 MHz bandwidth 7.5 mAPK-PK
Input Voltage Ripple Rejection 120 Hz TBD dB
Output Characteristics
Output Voltage Set Point (no load) -40 ºC to 85 ºC 0.990 1.000 1.010 VDC
Output Regulation
Over Line ±1 ±3 mV
Over Load ±1 ±3 mV
Output Voltage Range Over line, load and temperature 0.985 1.015 VDC
Output Ripple and Noise –
25 MHz bandwidth
Full load + 10 µF tantalum + 1 µF
ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 40,000 µF
Output Current Range 0 45 ADC
Current Limit Inception Non-latching 47.25 53 58 ADC
Peak Short-Circuit Current Non-latching, Short = 10 m. 55 65 A
RMS Short-Circuit Current Non-latching 12 18 Arms
Dynamic Response
Load Change 25% of Iout Max, di/dt = 1A/µs Co = 470 µF tantalum + 1 µF ceramic 160 mV
Settling Time to 1% 150 µs
Efficiency
100% Load 80.5 %
50% Load 84.5 %
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. 1.0V.1: Available load current vs. ambient air
temperature and airflow rates for QM48T45010 converter
with B height pins mounted vertically with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
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. 1.0V.2: Available load current vs. ambient air
temperature and airflow rates for QM48T45010 converter
with B height pins mounted horizontally with Vin = 48 V, air
flowing from pin 3 to pin 1, and MOSFET temperature ≤
120 °C.
MCD10073 Rev. 1.0 Page 33 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45010 (1.0 Volt Out)
Load Current [Adc]
0 1020304050
Efficiency
0.60
0.65
0.70
0.75
0.80
0.85
0.90
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
Power Dissipation [W]
0
3
6
9
12
15
72 V
48 V
36 V
Fig. 1.0V.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
0.60
0.65
0.70
0.75
0.80
0.85
0.90
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
3.00
6.00
9.00
12.00
15.00
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).
MCD10073 Rev. 1.0 Page 34 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45010 (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 (1V/div.) Time
scale: 2 ms/div.
Fig. 1.0V.9: Output voltage response to load current
step-change (22.5 A – 33.75 A – 22.5 A) at Vin = 48 V.
Top trace: output voltage (100 mV/div.). Bottom trace:
load current (10 A/div). Current slew rate: 1 A/µs. Co =
470 µF tantalum + 1 µF ceramic. Time scale: 0.2 ms/div.
Fig. 1.0V.8: Turn-on transient at full rated load current
(resistive) plus 40,000 µF 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. 1.0V.10: Output voltage ripple (20 mV/div.) at full
rated load current into a resistive load with Co = 10 µF
tantalum + 1 µF ceramic and Vin = 48 V. Time scale:
1 µs/div.
MCD10073 Rev. 1.0 Page 35 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
QM48T45010 (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 µH at the source at
full rated load current and Vin = 48 V. Refer to
Fig. 1.0V.11 for test setup. Time scale: 1 µs/div.
15 60
Iout [Adc]
Vout [Vdc]
0
0
30 45
1.5
1.0
0.5
Fig. 1.0V.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. 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 µs/div.
Fig. 1.0V.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.
Physical Information
MCD10073 Rev. 1.0 Page 36 of 36 www.power-one.com
QM48T45 Family DC-DC Converter Data Sheet
36-75 VDC Input; 1.0-3.3 VDC @ 45 A Output
SIDE VIEW
TOP VIEW
1
2
3
7
8
6
5
4
QM48T Pinout (Through-hole)
Converter Part Numbering/Ordering Information
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 45 033 - N B A 0
Quarter-
Brick
Format
36-75 V
T ⇒
Through-
hole
45 ADC
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 ⇒
Positive
Through
hole
A ⇒ 0.325”
B ⇒ 0.358”
D ⇒ 0.422”
Through
hole
A ⇒ 0.188”
B ⇒ 0.145”
C ⇒ 0.110”
0 ⇒ STD
No Suffix
⇒ RoHS
lead-solder-
exemption
compliant
G ⇒ RoHS
compliant
for all six
substances
The example above describes P/N QM48T45033-NBA0: 36-75 V input, through-hole mounting, 45 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.
Models 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.
Pad/Pin Connections
Pad/Pin # Function
1 Vin (+)
2 ON/OFF
3 Vin (-)
4 Vout (-)
5 SENSE(-)
6 TRIM
7 SENSE(+)
8 Vout (+)
HT
(
Max. Hei
g
ht
)
CL
(
Min. Clea
r
ance
)
Height
Option +0.000 [+0.00]
-0.038 [- 0.97]
+0.016 [+0.41]
-0.000 [- 0.00]
A 0.325 [8.26] 0.030 [0.77]
B 0.358 [9.09] 0.063 [1.60]
D 0.422 [10.72] 0.127 [3.23]
PL
Pin Len
g
th
Pin
Option ±0.005 [±0.13]
A 0.188 [4.77]
B 0.145 [3.68]
C 0.110 [2.79]
QM48T Platform Notes
• 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 Wei
g
ht: 1.1 oz
[
31.5
g]
t
yp
ical
