Description

The SFMC28-461™ EMI filters provide an off-the-shelf filtering

solution compliant to MIL-PRF-38534, Class H or Class K,

for use in your space system. SFMC28-461 filters reduce

the input line reflected ripple current of our switching DC/DC

converters. Use an SFMC28-461 filter with our SMTR, SMHF

and SMSA series of DC/DC converters to meet MIL-STD-461C

levels of conducted emission (CE01, CE03). The SFMC filters

are designed exclusively with passive components providing

maximum tolerance for space environments.

The SFMC28-461 EMI filters offer environmental screening

levels to Space Prototype (O), Class H, or Class K requirements.

Radiation tolerant to Radiation Hardness Assurance (RHA) levels

of “-” (O) or “H”, per MIL-PRF-38534. Interpoint model numbers

use an “O” in the RHA designator position to indicate the “-”

(dash) Radiation Hardness Assurance level of MIL-PRF-38534,

which is defined as “no RHA”. See Screening Tables 1, 2 and 3

for more information.

The SFMC28-461 EMI filter, when used with Interpoint’s

converters, reduces reflected input ripple current by a minimum

of 55 dB at 500 kHz and 60 dB at 1 MHz. The filter and converter

combination performance exceeds the CEO3 requirements of

MIL-STD-461C.

The maximum DC insertion loss for the SFMC28-461 filter (at

a load of 22 watts) represents a power loss of less than 2% at

nominal input voltage.

SFMC28-461 filters incorporate thick-film hybrid technology and

use only high quality ceramic capacitors for reliable high temper-

ature operation.

All SFMC28-461 filters are built to the same assembly drawing

regardless of environmental screening or radiation tolerance

level. Filters designated level OO, indicating standard environ-

mental screening, are electrically comparable to filters designated

level KH, the highest environmental screening level. This ensures

consistency between your prototype or test system using level

OO filters and your flight system using filters with higher levels of

environmental screening and radiation tolerance. Element evalu-

ation (screening at the component level) of Class H or Class K

filters ensures even greater reliability. Refer to Table 1, 2 and 3

for more information.

The filter operates at full load over the temperature range of

-55°C to +125°C case. Above +125°C, the current must be

derated as specified on page two.

SFMC28-461 EMI filters are encased in high-reliability, hermet-

ically-sealed metal packages and weigh just 48 grams. A small

footprint of 2.100 Inches (53.34 mm) by 1.115 inches (28.32 mm)

by 0.400 inches (10.16 mm) minimizes the board area needed

for the filter.

and

Input (V)

28

Current (A)

2.7

Features

Attenuation 60 dB at 500 kHz, typical

Operating temperature -55° to +125°C

•

Qualified to MIL-PRF-38534 Class H and K

•

Passive components used for maximum tolerance

•

in space environments

Nominal 28 V input, 0 V to 50 V operation

•

Up to 2.7 A throughput current

•

Compliant to MIL-STD-461C CE-03

•

Compatible with MIL-STD-704 B-E 28 VDC power bus

•

Crane Aerospace & Electronics Power Solutions

sFMc28-461 eMi input Filters

Crane Aerospace & Electronics

Electronics Group (Interpoint Brand)

POBox97005•RedmondWA98073-9705

425.882.3100•power@crane-eg.com

www.interpoint.com

Page 1 of 11

SFMC28-461 Rev E - 20100628

28 Volt input – 2.7 aMp