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FM/A/B Rev C 20100212

Crane Aerospace & Electronics

Electronics Group (Interpoint Brand)

PO Box 97005 • Redmond WA 98073-9705

425.882.3100 • power@crane-eg.com

www.interpoint.com

Description

The FM-461, FMA-461, and FMB-461 EMI filter modules have

been specifically designed to reduce the input line reflected ripple

current of Interpoint’s MTO, MTW, MHE, MLP, and MFW Series

of DC/DC converters. They are intended for use in applications of

high frequency (100 kHz) switch-mode DC/DC converters which

must meet MIL-STD-461C levels of conducted power line noise.

These filters are built using thick-film hybrid technology and are

sealed in metal packages for military, aerospace, and other high-

reliability applications. See Section B8, cases H3, H5, K4, and

K6 for dimensions. See Section C2 for screening options.

When used in conjunction with Interpoint’s DC/DC converters

(see connection diagram, Figure 2), the input ripple current will

be reduced by 40 dB within the frequency band of 100 kHz to 50

MHz. This gives the filter/converter combination a performance

which exceeds the CE03 test limit of MIL-STD-461C. The CE03

performance of a model MHE2805S converter with and without

the FM-461 filter is shown in Figures 6 and 7.

A fast-reacting (1 picosecond) transient suppressor clamps

the input voltage at approximately 47 V, protecting the DC/DC

converter from line induced transients.

The filters are rated to operate, with no degradation of perfor-

mance, over the temperature range of –55°C to +85°C (as

measured at the baseplate). Above 85°C, input voltage and

current must be derated as specified in “Derating” on the

following page. The maximum power dissipation of the filters at

maximum input current represents a power loss of less than 3%

at typical input voltage.

The case of the filter must be connected to the case of the

converter through a low impedance connection to minimize EMI.

Size (max.): Non-flanged case

H3 - FM-461 2.110 x 1.120 x 0.417 inches (53.59 x 28.45 x 10.59 mm)

H5 - FMA/FMB 2.110 x 1.120 x 0.495 inches (53.59 x 28.45 x 12.57* mm)

Flanged case

K4 - FM-461 2.910 x 1.115 x 0.417 inches (73.91 x 28.32 x 10.59* mm)

K6 - FMA/FMB 2.910 x 1.115 x 0.495 inches (73.91 x 28.32 x 12.57 mm)

Weight:

Maximum – FM-461 38 grams, FMA-461 42 grams, FMB-461 43 grams

Screening: Standard or ES. See screening table for more information.

MODELS

aND

0 - 40

0 - 40

0 - 40

1.75

3.8

5.0

FM-461, FMA-461

AND FMB-461

1.75 To 5 AMP

NOT RECOMMENDED FOR NEW DESIGNS

Features

Attenuation 40 dB from 110 kHz to 50 MHz

Operating temperature -55° to +85°C

•

Nominal 28 V input, 0 V to 40 V operation

•

1.75 to 5 A throughput current

•

Transient suppression

•

Compliant to MIL-STD-461C CE-03

•