Active surge protection filter module for 28v military applications

-June 18, 2013

Here is a part of ultra-reliable, mission critical power systems that is often understated, but is nonetheless a key component to a robust design----the surge protection filter.



XP Power developed the DSF226 filter and surge protection module specifically designed for use in 28 VDC input defense applications. The encapsulated metal cased unit is capable of delivering up to 200 Watt output and meets the DEF STAN 61-5 part 6 issue 6 load dump requirement. The module also meets the internationally recognized immunity and emission standards MIL-STD 1275A-D, DEF STAN 59-411 & MIL-STD 461C. Providing active surge protection, the unit allows for the full 200 W output to be supplied over the entire 15 – 33 VDC including accommodating transients down to 10 VDC for up to 1 s. The output tracks the input voltage and is clamped at < 36 VDC.


I would want this in my battle vehicle!


The DSF226 can operate from -46 degrees C to + 100 degrees C. A thermal warning output can be used to control the end-application or disable the filter output.


Thermal Warning output


The TW output is an open collector transistor rated at 100 VDC, with a maximum sink current of 10 mA, referenced to –V in/-V out. The signal output is low when the maximum baseplate temperature is exceeded. This signal indicates an over temperature condition so that action can be taken by the end application such as shutting down non critical loads or individual downstream DC/DC converters. If connected to the DIS pin of the DSF226 this will disable the filter output and perform as a thermal shut down for the system. The TW output will automatically return to a high signal level once the filter base plate has cooled to a temperature of less than 100°C.


Input transient handling capability


±250 V for 70 μs 15 mJ, 100 V for 50 ms 0.5 Ω per MIL-STD-1275A/B/C/D ±200 V for 100 ns, pulse train, 174 V+Vin for 350 ms per DEF-STAN 61-5 part 6 issue 6 10V for 1 s.




MIL-STD-810F method 514.5C-17. Minimum integrity test for military equipment (1 Hr/axis, 3 axes). Vibration 5-33 Hz, 0.5 mm displacement


EMC immunity


MIL-STD-1275A-D, MIL-STD-461E/F (CS101, CS114, CS115 & CS116) MIL-STD-704A, DEF-STAN 61-5 part 6 issue 6


EMC emissions


MIL-STD 461E/F CE101, CE102 & DEF STAN 59-411 DCE01/DCE02 with external components. (See application notes and longform datasheet)


The filter is ideal for use in combination with XP Power’s MTC family of military-specification DC/DC converters, QSB and ICH series of power bricks. The DSF226 could also be combined with XP Power’s J series of 24V 4:1 input converters for multiple output COTS defense applications.


The DSF226 is priced at $187 in 500 pc quantities and is available direct from XP Power.

For more information visit the XP Power website

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