SQE48T40025-NDA0G - Power-One

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 1 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

Applications

 Telecommunications

 Data communications

 Wireless communications

 Servers, workstations

Benefits

 High efficiency – no heat sink required

 Higher current capability at elevated temperatures

than competitors‟ 40A quarter-bricks

 Industry-standard 1/8th brick footprint: 0.896” x

2.30” (2.06 in2), 38% smaller than conventional

quarter-bricks

Features

 RoHS lead-free solder and lead-solder-exempted

products are available

 Delivers up to 40A

 Industry-standard quarter-brick pinout

 On-board input differential LC-filter

 Start-up into pre-biased load

 No minimum load required

 Weight: 0.88 oz [25.1 g]

 Meets Basic Insulation requirements of EN60950

 Withstands 100 V input transient for 100 ms

 Fixed-frequency operation

 Fully protected

 Remote output sense

 Positive or negative logic ON/OFF option

 Low height of 0.374” (9.5mm)

 Output voltage trim range: +10%/−20% with

industry-standard trim equations

 High reliability: MTBF = 15.4 million hours,

calculated per Telcordia SR-332, Method I Case 1

 UL60950 recognized in US and Canada and

DEMKO certified per IEC/EN60950 (pending)

 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 high performance 40A SQE48T40025 eighth-brick DC-DC converter provides a high efficiency single output,

in a physical package that is only 62% the size of the industry-standard quarter-brick. Specifically designed for

operation in systems that have limited airflow and increased ambient temperatures, the SQE48T40025 converter

utilize the same pinout and functionality of the industry-standard quarter-bricks.

The SQE48T40025 converter provides thermal performance in high temperature environments that exceeds most

40A quarter-bricks in the market. This performance is accomplished through the use of patented/patent-pending

circuits, packaging, and processing techniques to achieve ultra-high efficiency, excellent thermal management,

and a low-body profile.

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 36-75V input, the SQE48T40025 converter provides a 2.5V output voltage that can be trimmed

from –20% to +10% of the nominal output voltage, thus providing outstanding design flexibility.

With standard pinout and trim equations, the SQE48T40025 converter is a perfect drop-in replacement for existing

40A quarter-brick designs. Inclusion of this converter in a new design can result in significant board space and

cost savings. The designer can expect reliability improvement over other available converters because of the

SQE48T40025‟s optimized thermal efficiency.

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 2 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

Electrical Specifications

Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, Cin=33 µF, unless otherwise specified.

Parameter

Notes

Min

Typ

Max

Units

Absolute Maximum Ratings

Input Voltage

Continuous

-0.3

VDC

Operating Ambient Temperature

-40

°C

Operating Altitude

Iout = 40A

3000

Iout ≤ 32A

3001

10000

Storage Temperature

-55

125

°C

Isolation Characteristics

Standard Product: Option 0 (refer to Converter Part Numbering/Ordering Information)

I/O Isolation

2250

VDC

Isolation Capacitance

160

Isolation Resistance

MΩ

Option K (refer to Converter Part Numbering/Ordering Information)

I/O Isolation

1500

VDC

Isolation Capacitance

200

1500

Isolation Resistance

MΩ

Feature Characteristics

Switching Frequency

440

kHz

Output Voltage Trim Range1

Industry-std. equations

-20

+10

Remote Sense Compensation1

Percent of VOUT(NOM)

+10

Output Overvoltage Protection

Non-latching

117

122

130

Overtemperature Shutdown (PCB)

Non-latching

125

°C

Operating Humidity

Non-condensing

Storage Humidity

Non-condensing

Peak Back-drive Output Current

(Sinking current from external source)

during startup into pre-biased output

Peak amplitude

ADC

Peak duration

µs

Back-drive Output Current (Sinking Current

from external source)

Converter OFF;

external voltage 5 VDC

mADC

Auto-Restart Period

Applies to all protection features

200

Turn-On Time

See Figures E, F, and G

ON/OFF Control (Positive Logic)

Converter Off (logic low)

-20

0.8

VDC

Converter On (logic high)

2.4

VDC

ON/OFF Control (Negative Logic)

Converter Off (logic high)

2.4

VDC

Converter On (logic low)

-20

0.8

VDC

Additional Notes:

1 Vout can be increased up to 10% via the sense leads or 10% via the trim function. However, the total output voltage trim from all sources

should not exceed 10% of VOUT(NOM), in order to ensure specified operation of overvoltage protection circuitry.

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 3 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

Electrical Specifications (continued)

Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, unless otherwise specified.

Parameter

Notes

Min

Typ

Max

Units

Input Characteristics

Operating Input Voltage Range

VDC

Input Undervoltage Lockout

Turn-on Threshold

35.5

VDC

Turn-off Threshold

32.5

34.5

VDC

Lockout Hysteresis Voltage

1.0

2.0

VDC

Input Voltage Transient

100 ms

100

VDC

Input Voltage Transient Rate

V/ms

Input Current Transient Rate

0.1

A2s

Required Input Capacitance

ESR < 1Ω

µF

Maximum Input Current

40 ADC Out @ 36 VDC In

VOUT = 2.5 VDC

2.4

ADC

Input Stand-by Current

Vin = 48V, converter disabled

3.5

Input No Load Current (0A load on the output)

Vin = 48V, converter enabled

VOUT = 2.5 VDC

Input Reflected-Ripple Current, is

Vin = 48V, 25 MHz bandwidth

VOUT = 2.5 VDC

mAPK-PK

Input Voltage Ripple Rejection

120 Hz, VOUT = 2.5 VDC

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 4 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

Electrical Specifications (continued)

Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, unless otherwise specified.

Parameter

Notes

Min

Typ

Max

Units

Output Characteristics

External Load Capacitance

Plus full load (resistive)

10,000

µF

Output Current Range

ADC

Current Limit Inception

Non-latching

ADC

Peak Short-Circuit Current

Non-latching, Short = 10 mΩ

RMS Short-Circuit Current

Non-latching

Arms

Output Voltage Set Point (no load)2

-1

%Vout

Output Regulation

Over Line

±2

±5

Over Load

±2

±5

Output Voltage Range

Over line, load and temperature2

-3.0

+3.0

%Vout

Output Ripple and Noise – 25 MHz bandwidth

Full load + 10 µF tantalum + 1 µF ceramic

VOUT = 2.5 VDC

mVPK-PK

Dynamic Response

Load Change 50%-75%-50% of Iout Max,

di/dt = 0.1 A/μs

Co = 1 µF ceramic (Figure 8)

di/dt = 2.5 A/μs

Co = 470 µF POS + 1 µF ceramic

Settling Time to 1% of Vout

µs

Efficiency

100% Load

VOUT = 2.5 VDC

89.0

50% Load

VOUT = 2.5 VDC

92.5

Mechanical

Weight

25.1g

Vibration IEC Class 3M5

Freq. Velocity IEC 68-2-6

5-9Hz 5mm/s

Freq. Accelerat. IEC 68-2-6

9-200Hz 1g

Shocks IEC Class 3M5

Accelerat. IEC 68-2-29

10g

MIL-STD-202F

Method 213B Cond. F

Reliability

MTBF

Telcordia SR-332, Method I Case 1

50% electrical stress, 40°C ambient

15.4

MHrs

Additional Notes:

2 Operating ambient temperature range of -40 ºC to 85 ºC for converter.

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 5 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A 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.

However, in some applications, the inductance

associated with the distribution from the power

source to the input of the converter can affect the

stability of the converter. A 33 µF electrolytic

capacitor with an ESR < 1 Ω across the input is

required to ensure proper operation of the converter

over wide range of input source impedance and

transients.

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 10,000 µF.

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 and

negative logic, with both referenced to Vin(-). A

typical connection is shown in Fig. A.

Rload

Vin

CONTROL

INPUT

Vin (+)

Vin (-)

ON/OFF

Vout (+)

Vout (-)

TRIM

SENSE (+)

SENSE (-)

(Top View)

SQE48 Converter

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 the pin is at a

logic low. The converter is on when the ON/OFF pin

is left open. See the Electrical Specifications for logic

high/low definitions.

The negative logic version turns on when the pin is

at a logic low and turns off when the pin is at a logic

high. The ON/OFF pin can be hard wired directly to

Vin(-) to enable automatic power up of the converter

without the need of an external control signal.

The ON/OFF pin is internally pulled up to 5 V

through a resistor. A properly de-bounced

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

Rload

Vin

Vin (+)

Vin (-)

ON/OFF

Vout (+)

Vout (-)

TRIM

SENSE (+)

SENSE (-)

(Top View)

SQE48 Converter

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 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

current (originally obtained from the derating curves)

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 6 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

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%, 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 connected internally between the TRIM

and SENSE(-) pins.

To increase the output voltage, refer to Fig. C. A trim

resistor, RT-INCR, should be connected between the

TRIM (Pin 6) and SENSE(+) (Pin 7), with a value of:

10.22

1.225Δ

626Δ)V5.11(100

RNOMO

INCRT 







[kΩ],

where,

INCRTR

Required value of trim-up resistor kΩ]

NOMOV

Nominal value of output voltage [V]

100X

V)V(V

Δ NOM- O

NOM-OREQ-O 



[%]

REQOV

Desired (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)

SQE48 Converter

Fig. C: Configuration for increasing output voltage.

To decrease the output voltage (Fig. D), a trim

resistor, RT-DECR, should be connected between the

TRIM (Pin 6) and SENSE(-) (Pin 5), with a value of:

10.22

|Δ|511

RDECRT 

[kΩ]

where,

DECRTR

Required value of trim-down resistor [kΩ]

and

is 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 (-) RT-DECR

(Top View)

SQE48 Converter

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.

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 7 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A 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 33 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.

If the converter is equipped with the special OCP

version designated by the suffix K in the part

number, the converter will shut down in

approximately 15ms after entering the constant

current mode of operation. The standard version

(suffix 0) will continue operating in the constant

current mode until the output voltage drops below

60% at which point the converter will shut down as

shown in Figure 14.

Once the converter has shut down, it will attempt to

restart nominally every 200 ms with a typical 3-5%

duty cycle as shown in Figure 15. 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.

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 200 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. Converter with the non-

latching option will automatically restart after it has

cooled to a safe operating temperature.

Safety Requirements

The converters meet North American and

International safety regulatory requirements per

UL60950 and EN60950. Basic Insulation is provided

between input and output.

The converters have no internal fuse. If required, the

external fuse needs to be provided to protect the

converter from catastrophic failure. Refer to the

“Input Fuse Selection for DC/DC converters”

application note on www.power-one-com for proper

selection of the input fuse. Both input traces and the

chassis ground trace (if applicable) must be capable

of conducting a current of 1.5 times the value of the

fuse without opening. The fuse must not be placed

in the grounded input line.

Abnormal and component failure tests were

conducted with the input protected by a TBD fuse. If

a fuse rated greater than TBD A is used, additional

testing may be required. To protect a group of

converters 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 and 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, the

SQE48T40025 converter passes the requirements of

Class B conducted emissions per EN55022 and FCC

requirements. Contact Power-One Applications

Engineering for details of this testing.

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 8 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

Startup Information (using negative ON/OFF)

Scenario #1: Initial Startup From Bulk Supply

ON/OFF function enabled, converter started via application

of VIN. See Figure E.

Time

Comments

ON/OFF pin is ON; system front-end power is

toggled on, VIN to converter begins to rise.

VIN crosses undervoltage Lockout protection

circuit threshold; converter enabled.

Converter begins to respond to turn-on

command (converter turn-on delay).

Converter VOUT reaches 100% of nominal value.

For this example, the total converter startup time (t3- t1) is

typically 3 ms.

Scenario #2: Initial Startup Using ON/OFF Pin

With VIN previously powered, converter started via

ON/OFF pin. See Figure F.

Time

Comments

VINPUT at nominal value.

Arbitrary time when ON/OFF pin is enabled

(converter enabled).

End of converter turn-on delay.

Converter VOUT reaches 100% of nominal value.

For this example, the total converter startup 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

VIN and VOUT are at nominal values; ON/OFF pin

ON.

ON/OFF pin arbitrarily disabled; converter

output falls to zero; turn-on inhibit delay period

(200 ms typical) is initiated, and ON/OFF pin

action is internally inhibited.

ON/OFF pin is externally re-enabled.

If (t2- t1) ≤ 200 ms, external action of

ON/OFF pin is locked out by startup inhibit

timer.

If (t2- t1) > 200 ms, ON/OFF pin action is

internally enabled.

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.

End of converter turn-on delay.

Converter VOUT reaches 100% of nominal value.

For the condition, (t2- t1) ≤ 200 ms, the total converter

startup time (t5- t2) is typically 203 ms. For (t2- t1) > 200 ms,

startup will be typically 3 ms after release of ON/OFF pin.

VIN

ON/OFF

STATE

VOUT

t0t1t2t3

OFF

Fig. E: Startup scenario #1.

ON/OFF

STATE

VOUT

t0t1t2t3

OFF

VIN

Fig. F: Startup scenario #2.

Fig. G: Startup scenario #3.

ON/OFF

STATE

OFF

OUT

200 ms

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 9 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A 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

mounting, efficiency, startup and shutdown

parameters, output ripple and noise, transient

response to load step-change, overload, and short

circuit.

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. H for the

optimum measuring thermocouple locations.

Thermal Derating

Load current vs. ambient temperature and airflow

rates are given in Figure 1. 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 temperature

of 120 °C as indicated by the thermographic image, or

(ii) The temperature of the transformer does not

exceed 120 °C, or

(iii) The nominal rating of the converter (40 A at

2.5 V).

During normal operation, derating curves with

maximum FET temperature less or equal to 120 °C

should not be exceeded. Temperature at both

thermocouple locations shown in Fig. H should not

exceed 120 °C in order to operate inside the derating

curves.

Fig. H: Locations of the thermocouple for thermal testing.

Efficiency

Figure 2 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 Figure 3.

Power Dissipation

Figure 4 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 Figure 5.

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 Figure 6 and Figure 7,

respectively.

Ripple and Noise

Figure 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.

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 10 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

The input reflected-ripple current waveforms are

obtained using the test setup shown in Figure 11. The corresponding waveforms are shown in Figure 12 and

Figure 13.

Ambient Temperature [°C]

20 30 40 50 60 70 80 90

Load Current [Adc]

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)

Figure 1. Available load current vs. ambient air temperature and airflow rates for SQE48T40025 converter mounted vertically with air

flowing from pin 3 to pin 1, MOSFET temperature  120 C, Vin = 48 V.

Note: NC – Natural convection

Load Current [Adc]

0 8 16 24 32 40 48

Efficiency

0.75

0.80

0.85

0.90

0.95

72 V

48 V

36 V

Figure 2. Efficiency vs. load current and input voltage for

SQE48T40025 converter mounted vertically with air flowing

from pin 3 to pin 1 at 300 LFM (1.5 m/s) and Ta=25C.

Load Current [Adc]

0 8 16 24 32 40 48

Efficiency

0.75

0.80

0.85

0.90

0.95

70 C

55 C

40 C

Figure 3. Efficiency vs. load current and ambient temperature

for SQE48T40025 converter mounted vertically with Vin=48V

and air flowing from pin 3 to pin 1 at 200LFM (1.0m/s).

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 11 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

Load Current [Adc]

0 5 10 15 20 25 30 35 40 45

Power Dissipation [W]

0.00

3.00

6.00

9.00

12.00

72 V

48 V

36 V

Figure 4. Power dissipation vs. load current and input

voltage for SQE48T40025 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 8 16 24 32 40 48

Power Dissipation [W]

0.00

3.00

6.00

9.00

12.00

15.00

18.00

70 C

55 C

40 C

Figure 5. Power dissipation vs. load current and ambient

temperature for SQE48T40025 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).

Figure 6. 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 (1.0 V/div.). Time scale: 5 ms/div.

Figure 7. Turn-on transient at full rated load current

(resistive) plus 10,000 µF at Vin = 48 V, triggered via ON/OFF

pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: Output

voltage (1.0 V/div.). Time scale: 5 ms/div.

Figure 8. Output voltage response to load current step-

change (20 A – 30 A – 20 A) at Vin = 48 V. Top trace: output

voltage (20 mV/div.). Bottom trace: load current (10 A/div.).

Current slew rate: 0.1 A/µs. Co = 1 µF ceramic.

Time scale: 0.2ms/div.

Figure 9. Output voltage response to load current step-

change (20 A – 30 A –20A) at Vin = 48 V. Top trace: output

voltage (100 mV/div.). Bottom trace: load current (10 A/div.).

Current slew rate: 2.5 A/µs. Co = 470 µF POS + 1 µF ceramic.

Time scale: 0.2 ms/div.

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 12 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

Figure 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.

Vout

Vsource

iSiC

1 F

ceramic

capacitor

10 H

source

inductance DC-DC

Converter

33 F

ESR < 1

electrolytic

capacitor



SQE48

Figure 11. Test setup for measuring input reflected ripple

currents, ic and is.

Figure 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 Figure 11 for test setup. Time

scale: 1 µs/div.

Figure 13. Input reflected ripple-current, ic (100 mA/div.),

measured at input terminals at full rated load current and Vin

= 48 V. Refer to Figure 11 for test setup. Time scale: 1 µs/div.

Figure 14. Output voltage vs. load current showing current

limit point and converter shutdown point. Input voltage has

almost no effect on current limit characteristic.

Figure 15. Load current (top trace, 50 A/div., 50 ms/div.) into

a 10 mΩ short circuit during restart, at Vin = 48 V. Bottom

trace (50 A/div., 1 ms/div.) is an expansion of the on-time

portion of the top trace.

ZD-01723 Rev 1.2, 04-Jan-10 www.power-one.com Page 13 of 13

SQE48T40025 DC-DC Converter Data Sheet

36-75 VDC Input; 2.5 VDC @ 40A Output

Physical Information

SQE48T Pinout (Through-hole)

MAXIMUM MODULE

HEIGHT

0.407 [10.34]

ALL DIMENSIONS ARE IN INCHES

DIMENSIONS IN BRACKETS [ ] ARE IN MILLIMETERS

CODE CLEARENCE OFF

USER BOARD

0.035 [0.89]

CL -0.00

+0.41+0.016

-0.000 PIN INTERCONNECT

LENGTH

+0.000

-0.038 -0.97

+0.00

0.145 [3.68]

0.188 [4.77]

+0.005

-0.005 +0.13

-0.13

FUNCTION

PAD/PIN CONNECTIONS

PIN #

1SQE48T Platform Notes:

- All dimensions are in inches [mm]

- Pins 1-3 and 5-7 are Ø0.040" [1.02]

with Ø0.078 [1.98] shoulder

- Pins 4 and 8 are Ø.062" [1.57]

without shoulder

- Pin Material: CDA 145

- Connector Finish: Tin over Nickel

Vin (+)

ON/OFF

Vin (-)

Vout (-)

SENSE (-)

TRIM

SENSE (+)

Vout (+)

TOP VIEW

SIDE VIEW

Converter Part Numbering/Ordering Information

Product

Series

Input

Voltage

Mounting

Scheme

Rated

Current

Output

Voltage

ON/OFF

Logic

Maximum

Height [HT]

Pin Length

[PL]

Special

Features

RoHS

SQE

025

One-

Eighth

Brick

Format

36-75 V

T 

Through-

hole

40 

40 ADC

025 

2.5 V

N 

Negative

P 

Positive

D  0.374”

Through

hole

A  0.188”

B  0.145”

0 

2250VDC

isolation, no

CM cap

K 

1500VDC

isolation, CM

cap, and

special OCP

No Suffix 

RoHS

lead-solder-

exemption

compliant

G  RoHS

compliant for all

six substances

The example above describes P/N SQE48T40025-NDAKG: 36-75 V input, through-hole, 40A @ 2.5V output, negative ON/OFF logic,

maximum height of 0.374”, 0.188” pins, 1500VDC isolation, common mode capacitor, special OCP, and RoHS compliant for all 6 substances.

Consult factory for availability of other options.

Notes:

1. 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.

2. 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

Vin (+)

ON/OFF

Vin (-)

Vout (-)

SENSE(-)

TRIM

SENSE(+)

Vout (+)

Height

Option

(Max. Height)

(Min. Clearance)

+0.000 [+0.00]

-0.038 [- 0.97]

+0.016 [+0.41]

-0.000 [- 0.00]

0.374 [9.5]

0.045 [1.14]

Option

Pin Length

±0.005 [±0.13]

0.188 [4.78]

0.145 [3.68]

SQE48T 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 Alloy 360

 Pin Finish: Tin over Nickel