Description

designed to reduce the reflected input ripple current of

Interpoint high frequency dc-dc converters. FMD filters minimize

electromagnetic interference (EMI) for the MOR, MFL, MTR,

MHV, MHF+, MHF, MTO and MHE Series of converters. These

filters are intended for use in 28 volt applications which must

meet MIL-STD-461C CE03 levels of conducted emissions. One

filter can be used with multiple converters up to the rated output

current of the filter.

Switching dc-dc converters naturally generate two noise

components on the power input line: differential noise and

common mode noise. Input ripple current refers to both of these

components. Differential noise occurs between the positive

input and input common. Most Interpoint converters have an

input filter that reduces differential noise which is sufficient for

many applications. Common mode noise occurs across stray

capacitances between the converter’s power train components

and the baseplate (bottom of the package) of the converter. See

“Figure 1: FMD28-461 Block Diagram” on page 2

Where low noise currents are required to meet CE03 of

MIL-STD-461C a power line filters reduces the common mode

and differential noise generated by the converters. FMD28-461

filters reduce input ripple current by a minimum of 50 dB at 500

kHz when used in conjunction with Interpoint dc-dc converters.

Place the filter as close as possible to the converter for optimum

performance. The baseplates of the filter and the converter

should be connected with the shortest and widest possible

conductors. See “Figure 2: Connection Diagram” on page 2.

A transient of 100 V for up to 100 ms with a 0.5 ohm source

impedance will not damage the filter.

The FMD28-461 Series filters are rated for full power operation

from -55°C to +125°C case temperature. Current is derated

linearly to zero at +135°C case temperature.

The maximum dc insertion loss at full load and nominal input

voltage represents a power loss of less than 1.3%.

FMD28-461 filters are sealed in metal hermetic, down-leaded

packages, “Figure 6: Case J4 - FMD28-461” on page 6. Also

available in a side-leaded package, “Figure 7: Case U - FMD28-

461SL” on page 7.

Features

attenuation to 50 dB at 500 kHz

• Operating temperature -55° to +125°C

• Nominal 28 V input, 0 to 50 V operation

• Transient rating to 100 V for 100 ms

• Up to 7 A throughput current

• Compliant to MIL-STD-461C, CE03

• Compatible with MIL-STD-704 A-E 28 VDC power bus

Crane Aerospace & Electronics Power Solutions

FMD28-461 eMi input Filters

Page 1 of 8

FMD28 Rev AA - 2014.02.06

28 Volt input – 7 aMp

Crane Aerospace & Electronics

Power Solutions – Interpoint Products

10301 Willows Road NE, Redmond, WA 98052

+1.425.882.3100 • power@crane-eg.com

www.craneae.com/interpoint