MCD10085 Rev. 1.1, 08-Jul-10 Page 1 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
The new 25A SemiQ™ Family of DC-DC converters provide
a high-efficiency single output in a size that is only 60% of
industry-standard quarter-bricks, while preserving the same
pinout and functionality.
The 25A SQM48 Series converters of the SemiQ™ Family
provide thermal performance in high temperature environ-
ments that exceeds most competitors' 25 A quarter-bricks.
This is accomplished through the use of patent pending cir-
cuit, packaging and processing techniques to achieve ultra-
high efficiency, excellent thermal management and a very
low body profile.
Low body profile and the preclusion of heatsinks minimize
airflow shadowing, thus enhancing cooling for downstream
devices. The use of 100% automation for assembly, coupled
with advanced electric and thermal design, results in a prod-
uct with extremely high reliability.
Operating from a 36-75 V input, the 25A SQM48 Series
converters provide any standard output voltage from 2.5 V
down to 1.2 V. Outputs can be trimmed from –20% to +10%
of the nominal output voltage (±10% for output voltage 1.2
V), thus providing outstanding design flexibility.
With a standard pinout and trim equations, the SQM48
Series converters are perfect drop-in replacements for exist-
ing 25 A quarter-brick designs. Inclusion of this converter in
new designs can result in significant board space and cost
savings. The device is also available in a surface mount
package.
In both cases the designer can expect reliability improve-
ment over other available converters because of the SQM48
Series’ optimized thermal efficiency.
Applications
Telecommunications
Data communications
Wireless
Servers
SQM48T and SQM48S Converters
Features
RoHS lead-free solder and lead-solder-exempted
products are available
Delivers up to 25 A (62.5 W)
Industry-standard quarter-brick pinout
Extremely small footprint: 0.896” x 2.30” (2.06 in2),
40% smaller than conventional quarter-bricks
Higher current capability at elevated temperatures
than most competitors' 25 A quarter-bricks
On-board input differential LC-filter for the lowest input
ripple current in industry
Outputs available in 2.5, 2.0, 1.8, 1.5, and 1.2 V
High efficiency – no heatsink required
Start-up into pre-biased output
No minimum load required
Available in through-hole and SM packages
Low profile: 0.28” (7.1 mm)
Light weight: 0.66 oz (18.5 g)
Meets Basic Insulation requirements of EN60950
Withstands 100 V input transient for 100 ms
Fixed-frequency operation
Fully protected
Remote output sense
Output voltage trim range: +10%/20% with Industry-
standard trim equations (except 1.2 V output)
High reliability: MTBF of 3.4 million hours, calculated
per Telcordia TR-332, Method I Case 1
Positive or negative logic ON/OFF option
UL 60950 recognized in US and Canada and DEMKO
certified per IEC/EN 60950 (pending)
Meets conducted emissions requirements of FCC
Class B and EN 55022 Class B with external filter
All materials meet UL94, V-0 flammability rating
MCD10085 Rev. 1.1, 08-Jul-10 Page 2 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Electrical Specifications (common to all versions)
Conditions: TA=25ºC, 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
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 160 pF
Isolation Resistance 10 M
FEATURE CHARACTERISTICS
Switching Frequency 435 kHz
Output Voltage Trim Range1 Industry-std. equations (2.5 - 1.5 V) -20 +10 %
Use trim equation on Page 4 (1.2 V) -10 +10 %
Remote Sense Compensation1 Percent of VOUT(NOM) +10 %
Output Over-Voltage Protection Non-latching 117 122 127 %
Over-Temperature Shutdown (PCB) Non-latching 125 °C
Auto-Restart Period Applies to all protection features 100 ms
Turn-On Time 3 ms
ON/OFF Control (Positive Logic)
Converter Off -20 0.8 Vdc
Converter On 2.4 20 Vdc
ON/OFF Control (Negative Logic)
Converter Off 2.4 20 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 insure specified operation of over-voltage protection circuitry.
MCD10085 Rev. 1.1, 08-Jul-10 Page 3 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Operation
Input and Output Impedance
These power converters have been designed to be stable
with no external capacitors when used in low inductance in-
put and output circuits.
However, 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 addi-
tion of a 33 µF electrolytic capacitor with an ESR < 1
across the input helps ensure stability of the converter. In
many applications, the user has to use decoupling capacit-
ance at the load. The power converter will exhibit stable op-
eration with external load capacitance up to 20,000 µF on
2.5 – 1.2 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 con-
trol options available, positive logic and negative logic and
both are referenced to Vin(-). Typical connections are shown
in Fig. A.
Rload
Vin
CONTROL
INPUT
Vin (+)
Vin (-)
ON/OFF
Vout (+)
Vout (-)
TRIM
SENSE (+)
SENSE (-)
(Top View)
Converter
Semi
Q
TM
Family
Fig. A: Circuit configuration for ON/OFF function.
The positive logic version turns on when the ON/OFF pin is
at logic high and turns off when at logic low. The converter is
on when the ON/OFF pin is left open.
The negative logic version turns on when the pin is at logic
low and turns off when the pin is at 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 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 vol-
tage of 0.8 V. An external voltage source of ±20 V max.
may be connected directly to the ON/OFF input, in which
case it should be capable of sourcing or sinking (depending
on the signal polarity) up to 1 mA. See the Start-up Informa-
tion 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 con-
verter 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 (+)
Vin (-)
ON/OFF
Vout (+)
Vout (+)
TRIM
SENSE (+)
SENSE (-)
(Top View)
Converter
SemiQ
TM
Family
Fig. B: Remote sense circuit configuration.
If remote sensing is not required, 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 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 insure optimum performance. When wiring
discretely, twisted pair wires should be used to connect the
sense lines to the load to reduce susceptibility to noise.
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 capabili-
ty of the converter, equal to the product of the nominal out-
put voltage and the allowable output current for the given
conditions.
When using remote sense, the output voltage at the conver-
ter 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
MCD10085 Rev. 1.1, 08-Jul-10 Page 4 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
actual output power remains at or below the maximum al-
lowable 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 relative to the rated
output voltage by the addition of an externally connected
resistor.
The TRIM pin should be left open if trimming is not being
used. To minimize noise pickup, a 0.1 µF capacitor is con-
nected internally between the TRIM and SENSE(-) pins.
To increase the output voltage, refer to Fig. C. A trim resis-
tor, 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] (2.5 –1.5V)
7.2
Δ
84.6
RINCRT [k] (1.2 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 previous
the section for a complete discussion of this requirement.
Rload
Vin
Vin (+)
Vin (-)
ON/OFF
Vout (+)
Vout (-)
TRIM
SENSE (+)
SENSE (-)
R
T-IN CR
(Top View)
Converter
SemiQ
TM
Family
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] (2.5 – 1.5 V)
15
Δ
700
RDECRT [k] (1.2 V)
where,
DECRTRRequired value of trim-down resistor [k]
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.
Rload
Vin
Vin (+)
Vin (-)
ON/OFF
Vout (+)
Vout (-)
TRIM
SENSE (+)
SENSE (-)
R
T-DEC R
(Top View)
Converter
SemiQ
TM
Family
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 over-voltage protec-
tion (OVP) circuit. The designer should ensure that the dif-
ference 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 sens-
ing and/or output trim.
MCD10085 Rev. 1.1, 08-Jul-10 Page 5 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
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 cir-
cuit conditions. Upon sensing an overcurrent condition, the
converter will switch to constant current operation and there-
by begin to reduce output voltage. When the output voltage
drops below 40-50% of the nominal value of output voltage,
the converter will shut down (Fig. x.11).
Once the converter has shut down, it will attempt to restart
nominally every 100 ms with a typical 1-2% duty cycle
(Fig. x.12). The attempted restart will continue indefinitely
until the overload or short circuit conditions are removed or
the output voltage rises above 40-50% 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 refer-
ence, 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 con-
dition to protect itself from overheating caused by operation
outside the thermal derating curves, or operation in abnor-
mal conditions such as system fan failure. After the conver-
ter has cooled to a safe operating temperature, it will auto-
matically restart.
Safety Requirements
The converters meet North American and International safe-
ty regulatory requirements per UL60950 and EN60950
(pending). 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 be-
low provides the recommended fuse rating for use with this
family of products.
Output Voltage Fuse Rating
2.5 V 4-
A
2.0 - 1.5 V 3-
A
1.2 V 2.5-
A
Modules are UL approved for maximum fuse rating of 15-A.
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 characte-
ristics 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 distur-
bance characteristics - Limits and methods of measurement.
Effective internal LC differential filter significantly reduces
input reflected ripple current (Fig. x.9), and improves EMC.
With the addition of a simple external filter, all versions of the
SQM48 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 EN 55022 and
Class B per FCC Title 47CFR, Part 15-J. Please contact
di/dt 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, start-up 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.
MCD10085 Rev. 1.1, 08-Jul-10 Page 6 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
The following pages contain specific plots or waveforms as-
sociated 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, comprising two-ounce cop-
per, were used to provide traces for connectivity to the con-
verter.
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 pur-
poses.
All measurements requiring airflow were made in vertical
and horizontal wind tunnel facilities using Infrared (IR) ther-
mography and thermocouples for thermometry.
Ensuring components on the converter do not exceed their
ratings is important to maintaining high reliability. If one an-
ticipates 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. Thermo-
graphic imaging is preferable; if this capability is not availa-
ble, then thermocouples may be used. Power-One recom-
mends the use of AWG #40 gauge thermocouples to ensure
measurement accuracy. Careful routing of the thermocouple
leads will further minimize measurement error. Refer to Fig-
ure H for optimum measuring thermocouple location.
Thermal Derating
Load current vs. ambient temperature and airflow rates are
given in Fig. x.1 for through-hole version. Ambient tempera-
ture was varied between 25 °C and 85 °C, with airflow rates
from 30 to 500 LFM (0.15 to 2.5 m/s), and vertical converter
mounting.
For each set of conditions, the maximum load current was
defined as the lowest of:
(i) The output current at which either any FET junction tem-
perature did not exceed a maximum specified temperature
(120°C) as indicated by the thermographic image, or
(ii) The nominal rating of the converter (25 A on 2.5 – 1.2 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 oper-
ate inside the derating curves.
Efficiency
Efficiency vs. load current plot is shown in Fig. x.2 for am-
bient temperature of 25 ºC, airflow rate of 300 LFM (1.5 m/s),
vertical converter mounting, and input voltages of 36 V, 48 V
and 72 V.
Start-up
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.3 and Fig. x.4, respectively.
Ripple and Noise
Fig. x.7 shows the output voltage ripple waveform, measured
at full rated load current with a 10 µF tantalum and 1 µF ce-
ramic capacitor across the output. Note that all output vol-
tage waveforms are measured across a 1 F ceramic capa-
citor.
The input reflected ripple current waveforms are obtained
using the test setup shown in Fig x.8. The corresponding
waveforms are shown in Fig. x.9 and Fig. x.10.
MCD10085 Rev. 1.1, 08-Jul-10 Page 7 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Start-up Information (using negative ON/OFF)
Scenario #1: Initial Start-up 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 start-up time (t3- t1) is typically
3 ms.
Scenario #2: Initial Start-up 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 start-up time (t3- t1) is typically
3 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 start-up 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 start-up
time (t5- t2) is typically 103 ms. For (t2- t1) > 100 ms, start-up will
be typically 3 ms after release of ON/OFF pin.
Fig. E: Start-up scenario #1.
ON/OFF
STATE
VOUT
t0t1t2t3
ON
OFF
VIN
t
Fig. F: Start-up scenario #2.
ON/OFF
STATE OFF
ON
VOUT
t0t2t1t5
VIN
t
t4t3
100 ms
Fig. G: Start-up scenario #3.
VIN
ON/OFF
STATE
VOUT
t
t0t1t2t3
ON
OFF
MCD10085 Rev. 1.1, 08-Jul-10 Page 8 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Electrical Specifications: SQM48T/S25025 (2.5 Volts Out)
Conditions: TA=25ºC, 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 25 Adc, 2.5 Vdc Out @ 36 Vdc In 2.0 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 25MHz bandwidth 6 mAPK-PK
Input Voltage Ripple Rejection 120Hz TBD dB
OUTPUT CHARACTERISTICS
Output Voltage Set Point (no load) -40ºC to 85ºC 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 - 25MHz bandwidth Full load + 10 F tantalum + 1 F ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 20,000 F
Output Current Range 0 25 Adc
Current Limit Inception Non-latching 26.5 30 32 Adc
Peak Short-Circuit Current Non-latching. Short=10m. 35 46 A
RMS Short-Circuit Current Non-latching 6.7 Arms
DYNAMIC RESPONSE
Load Change 20% of Iout Max, di/dt = 0.1 A/S Co = 1 F ceramic 80 mV
di/dt = 5 A/S Co = 450 F tant. + 1 F ceramic 140 mV
Setting Time to 1% 100 µs
EFFICIENCY
100% Load 85.5 %
50% Load 89 %
Ambient Temperature [°C]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
5
10
15
20
25
30
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)
30 LFM (0.15 m/s)
Fig. 2.5V.1: Available load current vs. ambient air temperature
and airflow rates for SQM48T25025 converter with D height
pins mounted vertically with air flowing from pin 3 to pin 1,
MOSFET temperature 120 C, Vin = 48 V.
Load Current [Adc]
0 5 10 15 20 25 30
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 2.5V.2: Efficiency vs. load current and input voltage for
SQM48T/S25025 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.
MCD10085 Rev. 1.1, 08-Jul-10 Page 9 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25025 (2.5 Volts Out)
Fig. 2.5V.3: Turn-on transient at full rated load current (resis-
tive) 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: 1 ms/div.
Fig. 2.5V.5: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 0.1 A/s. Co = 1 F ceramic. Time scale: 0.2
ms/div.
Fig. 2.5V.4: Turn-on transient at full rated load current (resis-
tive) plus 20,000 F at Vin = 48 V, triggered via ON/OFF pin.
Top trace: ON/OFF signal (5 V/div.). Bottom trace: output vol-
tage (1 V/div.). Time scale: 2 ms/div.
Fig. 2.5V.6: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 5 A/s. Co = 450 F tantalum + 1 F ceramic.
Time scale: 0.2 ms/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 10 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25025 (2.5 Volts Out)
Fig. 2.5V.7: Output voltage ripple (20 mV/div.) at full rated load
current into a resistive load with Co = 10 F tantalum + 1uF ce-
ramic and Vin = 48 V. Time scale: 1 s/div.
Fig. 2.5V.9: 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.8 for test setup. Time scale: 1 s/div.
Vout
Vsource
isic
1 F
ceramic
capacitor
10 H
source
inductance SemiQTM Family
DC/DC
Converter
33 F
ESR <1
electrolytic
capacitor
Fig. 2.5V.8: Test setup for measuring input reflected ripple cur-
rents, ic and is.
Fig. 2.5V.10: 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.8 for test setup. Time scale:
1s/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 11 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25025 (2.5 Volts Out)
520
3.0
Iout [Adc]
Vout [Vdc]
0
0
2.5
1.0
0.5
10 15
2.0
1.5
25 30
Fig. 2.5V.11: Output voltage vs. load current showing current
limit point and converter shutdown point. Input voltage has al-
most no effect on current limit characteristic.
Fig. 2.5V.12: Load current (top trace, 20 A/div., 20 ms/div.) in-
to 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 por-
tion of the top trace.
MCD10085 Rev. 1.1, 08-Jul-10 Page 12 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Electrical Specifications: SQM48T/S25020 (2.0 Volts Out)
Conditions: TA=25ºC, 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 25 Adc, 2.0 Vdc Out @ 36 Vdc In 1.65 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 32 mAdc
Input Reflected-Ripple Current 25MHz bandwidth 6 mAPK-PK
Input Voltage Ripple Rejection 120Hz TBD dB
OUTPUT CHARACTERISTICS
Output Voltage Set Point (no load) -40ºC to 85ºC 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 1.970 2.030 Vdc
Output Ripple and Noise - 25MHz bandwidth Full load + 10 F tantalum + 1 F ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 20,000 F
Output Current Range 0 25 Adc
Current Limit Inception Non-latching 26.5 30 32 Adc
Peak Short-Circuit Current Non-latching. Short=10m. 35 46 A
RMS Short-Circuit Current Non-latching 6.7 Arms
DYNAMIC RESPONSE
Load Change 20% of Iout Max, di/dt = 0.1 A/S Co = 1 F ceramic 80 mV
di/dt = 5 A/S Co = 450 F tant. + 1 F ceramic 140 mV
Setting Time to 1% 100 µs
EFFICIENCY
100% Load 84 %
50% Load 88 %
Ambient Temperature [°C]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
5
10
15
20
25
30
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)
30 LFM (0.15 m/s)
Fig. 2.0V.1: Available load current vs. ambient air temperature
and airflow rates for SQM48T25020 converter with D height
pins mounted vertically with air flowing from pin 3 to pin 1,
MOSFET temperature 120 C, Vin = 48 V.
Load Current [Adc]
0 5 10 15 20 25 30
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 2.0V.2: Efficiency vs. load current and input voltage for
SQM48T/S25020 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.
MCD10085 Rev. 1.1, 08-Jul-10 Page 13 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25020 (2.0 Volts Out)
Fig. 2.0V.3: Turn-on transient at full rated load current (resis-
tive) 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: 1 ms/div.
Fig. 2.0V.5: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 0.1 A/s. Co = 1 F ceramic. Time scale: 0.2
ms/div.
Fig. 2.0V.4: Turn-on transient at full rated load current (resis-
tive) plus 20,000 F at Vin = 48 V, triggered via ON/OFF pin.
Top trace: ON/OFF signal (5 V/div.). Bottom trace: output vol-
tage (1 V/div.). Time scale: 1 ms/div.
Fig. 2.0V.6: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 5 A/s. Co = 450 F tantalum + 1 F ceramic.
Time scale: 0.2 ms/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 14 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25020 (2.0 Volts Out)
Fig. 2.0V.7: Output voltage ripple (20 mV/div.) at full rated load
current into a resistive load with Co = 10 F tantalum + 1uF ce-
ramic and Vin = 48 V. Time scale: 1 s/div.
Fig. 2.0V.9: 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.8 for test setup. Time scale: 1 s/div.
Vout
Vsource
isic
1 F
ceramic
capacitor
10 H
source
inductance SemiQTM Family
DC/DC
Converter
33 F
ESR <1
electrolytic
capacitor
Fig. 2.0V.8: Test setup for measuring input reflected ripple cur-
rents, ic and is.
Fig. 2.0V.10: 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.8 for test setup. Time scale:
1s/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 15 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25020 (2.0 Volts Out)
530
3.0
Iout [Adc]
Vout [Vdc]
0
0
2.5
1.0
0.5
10 15
2.0
1.5
20 25
Fig. 2.0V.11: Output voltage vs. load current showing current
limit point and converter shutdown point. Input voltage has al-
most no effect on current limit characteristic.
Fig. 2.0V.12: Load current (top trace, 20 A/div., 20 ms/div.) in-
to 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 por-
tion of the top trace.
.
MCD10085 Rev. 1.1, 08-Jul-10 Page 16 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Electrical Specifications: SQM48T/S25018 (1.8 Volts Out)
Conditions: TA=25ºC, 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 25 Adc, 1.8 Vdc Out @ 36 Vdc In 1.45 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 30 mAdc
Input Reflected-Ripple Current 25MHz bandwidth 6 mAPK-PK
Input Voltage Ripple Rejection 120Hz TBD dB
OUTPUT CHARACTERISTICS
Output Voltage Set Point (no load) -40ºC to 85ºC 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 - 25MHz bandwidth Full load + 10 F tantalum + 1 F ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 20,000 F
Output Current Range 0 25 Adc
Current Limit Inception Non-latching 26.5 30 32 Adc
Peak Short-Circuit Current Non-latching. Short=10m. 35 46 A
RMS Short-Circuit Current Non-latching 6.7 Arms
DYNAMIC RESPONSE
Load Change 20% of Iout Max, di/dt = 0.1 A/S Co = 1 F ceramic 80 mV
di/dt = 5 A/S Co = 450 F tant. + 1 F ceramic 140 mV
Setting Time to 1% 100 µs
EFFICIENCY
100% Load 83 %
50% Load 87 %
Ambient Temperature [°C]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
5
10
15
20
25
30
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)
30 LFM (0.15 m/s)
Fig. 1.8V.1: Available load current vs. ambient air temperature
and airflow rates for SQM48T25018 converter with D height
pins mounted vertically with air flowing from pin 3 to pin 1,
MOSFET temperature 120C, Vin = 48 V.
Load Current [Adc]
0 5 10 15 20 25 30
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 1.8V.2: Efficiency vs. load current and input voltage for
SQM48T/S25018 converter mounted vertically with air flowing
from pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta =
25C.
MCD10085 Rev. 1.1, 08-Jul-10 Page 17 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25018 (1.8 Volts Out)
Fig. 1.8V.3: Turn-on transient at full rated load current (resis-
tive) 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: 1 ms/div.
Fig. 1.8V.5: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 0.1 A/s. Co = 1 F ceramic. Time scale: 0.2
ms/div.
Fig. 1.8V.4: Turn-on transient at full rated load current (resis-
tive) plus 20,000 F at Vin = 48 V, triggered via ON/OFF pin.
Top trace: ON/OFF signal (5 V/div.). Bottom trace: output vol-
tage (1 V/div.). Time scale: 1 ms/div.
Fig. 1.8V.6: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 5 A/s. Co = 450 F tantalum + 1 F ceramic.
Time scale: 0.2 ms/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 18 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25018 (1.8 Volts Out)
Fig. 1.8V.7: Output voltage ripple (20 mV/div.) at full rated load
current into a resistive load with Co = 10 F tantalum + 1uF ce-
ramic and Vin = 48 V. Time scale: 1 s/div.
Fig. 1.8V.9: 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.8 for test setup. Time scale: 1 s/div.
Vout
Vsource
isic
1 F
ceramic
capacitor
10 H
source
inductance SemiQTM Family
DC/DC
Converter
33 F
ESR <1
electrolytic
capacitor
Fig. 1.8V.8: Test setup for measuring input reflected ripple cur-
rents, ic and is.
Fig. 1.8V.10: 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.8 for test setup. Time scale:
1s/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 19 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25018 (1.8 Volts Out)
530
2.0
Iout [Adc]
Vout [Vdc]
0
0
1.5
1.0
0.5
10 15 20 25
Fig. 1.8V.11: Output voltage vs. load current showing current
limit point and converter shutdown point. Input voltage has al-
most no effect on current limit characteristic.
Fig. 1.8V.12: Load current (top trace, 20 A/div., 20 ms/div.) in-
to 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 por-
tion of the top trace.
MCD10085 Rev. 1.1, 08-Jul-10 Page 20 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Electrical Specifications: SQM48T/S25015 (1.5 Volts Out)
Conditions: TA=25ºC, 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 25 Adc, 1.5 Vdc Out @ 36 Vdc In 1.25 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 26 mAdc
Input Reflected-Ripple Current 25MHz bandwidth 6 mAPK-PK
Input Voltage Ripple Rejection 120Hz TBD dB
OUTPUT CHARACTERISTICS
Output Voltage Set Point (no load) -40ºC to 85ºC 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 - 25MHz bandwidth Full load + 10 F tantalum + 1 F ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 20,000 F
Output Current Range 0 25 Adc
Current Limit Inception Non-latching 26.5 30 32 Adc
Peak Short-Circuit Current Non-latching. Short=10m. 35 46 A
RMS Short-Circuit Current Non-latching 6.7 Arms
DYNAMIC RESPONSE
Load Change 20% of Iout Max, di/dt = 0.1 A/S Co = 1 F ceramic 80 mV
di/dt = 5 A/S Co = 450 F tant. + 1 F ceramic 140 mV
Setting Time to 1% 100 µs
EFFICIENCY
100% Load 81.5 %
50% Load 86 %
Ambient Temperature [°C]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
5
10
15
20
25
30
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)
30 LFM (0.15 m/s)
Fig. 1.5V.1: Available load current vs. ambient air temperature
and airflow rates for SQM48T25015 converter with D height
pins mounted vertically with air flowing from pin 3 to pin 1,
MOSFET temperature 120 C, Vin = 48 V.
Load Current [Adc]
0 5 10 15 20 25 30
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 1.5V.2: Efficiency vs. load current and input voltage for
SQM48T/S25015 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.
MCD10085 Rev. 1.1, 08-Jul-10 Page 21 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25015 (1.5 Volts Out)
Fig. 1.5V.3: Turn-on transient at full rated load current (resis-
tive) 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: 1 ms/div.
Fig. 1.5V.5: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 0.1 A/s. Co = 1 F ceramic. Time scale: 0.2
ms/div.
Fig. 1.5V.4: Turn-on transient at full rated load current (resis-
tive) plus 20,000 F at Vin = 48 V, triggered via ON/OFF pin.
Top trace: ON/OFF signal (5 V/div.). Bottom trace: output vol-
tage (0.5 V/div.). Time scale: 1 ms/div.
Fig. 1.5V.6: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 5 A/s. Co = 450 F tantalum + 1 F ceramic.
Time scale: 0.2 ms/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 22 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25015 (1.5 Volts Out)
Fig. 1.5V.7: Output voltage ripple (20 mV/div.) at full rated load
current into a resistive load with Co = 10 F tantalum + 1uF ce-
ramic and Vin = 48 V. Time scale: 1 s/div.
Fig. 1.5V.9: 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.8 for test setup. Time scale: 1 s/div.
Vout
Vsource
isic
1 F
ceramic
capacitor
10 H
source
inductance SemiQTM Family
DC/DC
Converter
33 F
ESR <1
electrolytic
capacitor
Fig. 1.5V.8: Test setup for measuring input reflected ripple cur-
rents, ic and is.
Fig. 1.5V.10: 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.8 for test setup. Time scale:
1s/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 23 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25015 (1.5 Volts Out)
530
2.0
Iout [Adc]
Vout [Vdc]
0
0
1.5
1.0
0.5
10 15 20 25
Fig. 1.5V.11: Output voltage vs. load current showing current
limit point and converter shutdown point. Input voltage has al-
most no effect on current limit characteristic.
Fig. 1.5V.12: Load current (top trace, 20 A/div., 20 ms/div.) in-
to 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 por-
tion of the top trace.
MCD10085 Rev. 1.1, 08-Jul-10 Page 24 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Electrical Specifications: SQM48T/S25012 (1.2 Volts Out)
Conditions: TA=25ºC, 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 25 Adc, 1.2 Vdc Out @ 36 Vdc In 1 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 24 mAdc
Input Reflected-Ripple Current 25MHz bandwidth 6 mAPK-PK
Input Voltage Ripple Rejection 120Hz TBD dB
OUTPUT CHARACTERISTICS
Output Voltage Set Point (no load) -40ºC to 85ºC 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 - 25MHz bandwidth Full load + 10 F tantalum + 1 F ceramic 30 50 mVPK-PK
External Load Capacitance Plus full load (resistive) 20,000 F
Output Current Range 0 25 Adc
Current Limit Inception Non-latching 26.5 30 32 Adc
Peak Short-Circuit Current Non-latching. Short=10m. 35 46 A
RMS Short-Circuit Current Non-latching 6.7 Arms
DYNAMIC RESPONSE
Load Change 20% of Iout Max, di/dt = 0.1 A/S Co = 1 F ceramic 80 mV
di/dt = 5 A/S Co = 450 F tant. + 1 F ceramic 140 mV
Setting Time to 1% 100 µs
EFFICIENCY
100% Load 79 %
50% Load 84 %
Ambient Temperature [°C]
20 30 40 50 60 70 80 90
Load Current [Adc]
0
5
10
15
20
25
30
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)
30 LFM (0.15 m/s)
Fig. 1.2V.1: Available load current vs. ambient air temperature
and airflow rates for SQM48T25012 converter with D height
pins mounted vertically with air flowing from pin 3 to pin 1,
MOSFET temperature 120 C, Vin = 48 V.
Load Current [Adc]
0 5 10 15 20 25 30
Efficiency
0.65
0.70
0.75
0.80
0.85
0.90
0.95
72 V
48 V
36 V
Fig. 1.2V.2: Efficiency vs. load current and input voltage for
SQM48T/S25012 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.
MCD10085 Rev. 1.1, 08-Jul-10 Page 25 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25012 (1.2 Volts Out)
Fig. 1.2V.3: Turn-on transient at full rated load current (resis-
tive) 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: 1 ms/div.
Fig. 1.2V.5: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 0.1 A/s. Co = 1 F ceramic. Time scale: 0.2
ms/div.
Fig. 1.2V.4: Turn-on transient at full rated load current (resis-
tive) plus 20,000 F at Vin = 48 V, triggered via ON/OFF pin.
Top trace: ON/OFF signal (5 V/div.). Bottom trace: output vol-
tage (0.5 V/div.). Time scale: 1 ms/div.
Fig. 1.2V.6: Output voltage response to load current step-
change (5 A – 10 A – 5 A) at Vin = 48 V. Top trace: output vol-
tage (100 mV/div.). Bottom trace: load current (5 A/div.). Cur-
rent slew rate: 5 A/s. Co = 450 F tantalum + 1 F ceramic.
Time scale: 0.2 ms/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 26 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25012 (1.2 Volts Out)
Fig. 1.2V.7: Output voltage ripple (20 mV/div.) at full rated load
current into a resistive load with Co = 10 F tantalum + 1uF ce-
ramic and Vin = 48 V. Time scale: 1 s/div.
Fig. 1.2V.9: 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.8 for test setup. Time scale: 1 s/div.
Vout
Vsource
isic
1 F
ceramic
capacitor
10 H
source
inductance SemiQTM Family
DC/DC
Converter
33 F
ESR <1
electrolytic
capacitor
Fig. 1.2V.8: Test setup for measuring input reflected ripple cur-
rents, ic and is.
Fig. 1.2V.10: 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.8 for test setup. Time scale:
1s/div.
MCD10085 Rev. 1.1, 08-Jul-10 Page 27 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
SQM48T/S25012 (1.2 Volts Out)
530
Iout [Adc]
Vout [Vdc]
0
0
10 15
1.5
1.0
0.5
20 25
Fig. 1.2V.11: Output voltage vs. load current showing current
limit point and converter shutdown point. Input voltage has al-
most no effect on current limit characteristic.
Fig. 1.2V.12: Load current (top trace, 20 A/div., 20 ms/div.) in-
to 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 por-
tion of the top trace..
MCD10085 Rev. 1.1, 08-Jul-10 Page 28 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Physical Information
SIDE VIEW
TOP VIEW
3
2
1
4
5
6
7
8
SQM48S Pinout (Surface Mount)
SIDE VIEW
TOP VIEW
1
2
3
7
8
6
5
4
SQM48T Pinout (Through-hole)
Pad/Pin Connections
Pad/Pin # Function
1 Vin (+)
2 ON/OFF
3 Vin (-)
4 Vout (-)
5 SENSE(-)
6 TRIM
7 SENSE(+)
8 Vout (+)
Height
Option
HT
(Max. Height)
CL
(Min. Clearance)
+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]
C 0.522 [13.26] 0.227 [5.77]
D 0.422 [10.72] 0.127 [3.23]
E 0.304 [7.72] 0.009 [0.23]
Pin
Option
PL
Pin Length
±0.005 [±0.13]
A 0.188 [4.77]
B 0.145 [3.68]
C 0.110 [2.79]
SQM48S Platform Notes
All dimensions are in inches [mm]
Connector Material: Copper
Connector Finish: Gold over Nickel
Converter Weight: 0.66 oz [18.5 g]
Recommended Surface-Mount Pads:
Min. 0.080” X 0.112” [2.03 x 2.84]
Max. 0.092” X 0.124” [2.34 x 3.15]
SQM48T 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
Converter Weight: 0.66 oz [18.5 g]
MCD10085 Rev. 1.1, 08-Jul-10 Page 29 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
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 Environmental
SQM 48 S 25 018 - N B A 0
1/8th
Brick
Format
36-75 V
S
Surface
Mount
25 A
(1.2 – 2.5 V)
012 1.2 V
015 1.5 V
018 1.8 V
020 2.0 V
025 2.5 V
N
Negative
P
Positive
SMT
S 0.295”
SMT
0 0.00”
0 STD
No Suffix
Character
RoHS lead-
solder-exempt
compliant
G RoHS com-
pliant for all six
substances
Product
Series
Input
Voltage
Mounting
Scheme
Rated Load
Current
Output
Voltage ON/OFF
Logic
Maximum
Height
[HT]
Pin
Length
[PL]
Special
Features Environmental
SQM 48 T 25 018 - N B A 0
1/8th
Brick
Format
36-75 V
T
Through-
hole
25 A
(1.2 – 2.5 V)
012 1.2 V
015 1.5 V
018 1.8 V
020 2.0 V
025 2.5 V
N
Negative
P
Positive
Through
hole
A 0.325”
B 0.358”
C 0.522”
D 0.422”
E 0.304”
Through
hole
A 0.188”
B 0.145”
C 0.110”
0 STD
No Suffix
Character
RoHS lead-
solder-exempt
compliant
G RoHS com-
pliant for all six
substances
The example above describes P/N SQM48T25018-NBA0: 36-75 V input, through-hole mounting, 25 A @ 1.8 V output, negative ON/OFF logic, a
maximum height of 0.358”, a through the board pin length of 0.188”, and RoHS lead-solder-exempt compliancy. Please consult factory regarding availability
of a specific version.
Model numbers highlighted in yellow or shaded are not recommended for new designs.
MCD10085 Rev. 1.1, 08-Jul-10 Page 30 of 30 www.power-one.com
SQM48 Series Data Sheet
SemiQTM Family 25A DC-DC Converters
Fig. H: Location of the thermocouple for thermal testing.
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.
