F

EATURES

• –55°C to +125°C operation

• Up to 60 dB attenuation

at 500 kHz.

• Compliant to

MIL-STD-461C, CE03

• Compatible with

MIL-STD-704E

DC power bus

EMI I

NPUT

F

ILTERS

28 & 270 V

OLT

I

NPUT

FMD/FME EMI FILTER

0.7 TO 15 AMP

MODELS

I

NPUT

V

OLTAGE

AND

C

URRENT

Input (V)

28

28

270

270

Current ( A)

7.0

15.0

0.7

1.5

Size (max.): Case U2, FME all models; Case U1, FMD28-461SL and FMD270-461SL

3.005 x 1.505 x 0.400 inches (76.33 x 38.23 x 11.16 mm)

[FME models, shown in Case U2 (flanged, short leads). Also available:

Flanged – leads bent down (case V); Tabbed – leads bent up (case W), short

leads (case Y), and leads bent down (case Z).See Section B8, cases U2, V, W,

Y, and Z for dimensions and options.]

Case J4, FMD28-461

2.720 x 1.350 x 0.505 inches (69.09 x 34.29 x 12.83 mm)

See Section B8, cases J4, U1, U2, V, W, Y, and Z for dimensions.

Weight:

77 grams typical cases U1, U2, V, W, Y, and Z; 55 grams typical case J4

Screening: Standard, ES, or 883 (Class H).

See Section C2 for screening options, see Section A5 for ordering information.

DESCRIPTION

The FMD Series™ and FME Series™ EMI filters are specifically

designed to reduce the reflected input ripple current of Interpoint’s

high frequency DC/DC converters. FMD/FME filters minimize elec-

tromagnetic interference (EMI) for the MHE, MHL, MLP, MRH, MTO,

MHF, MHF+, MHV, MHD, MTR, MFL, MHP, and MFLHP Series.

These filters are intended for use in 28 or 270 volt applications

which must meet MIL-STD-461C, CE03 levels of conducted emis-

sions. One filter can be used with multiple converters up to the rated

output current of the filter.

best connection, mount the filter’s and converter’s baseplates on or

above a small ground plane. See Figure 5.

T

RANSIENTS

The transients listed below will not damage the filter but will be

passed on to the converter:

• All filters: ±600 volts (50 ohm source

impedance) for up to 10 µs.

• 28 volt filter: ±100 volts (0.5 ohm source

impedance) for up to 100 ms.

• 270 volt filter: ±500 volts (independent of

source impedance) for up to 100 ms.

I

NPUT

R

IPPLE AND

EMI

Switching DC/DC converters naturally generate two noise compo-

nents 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.

Where low noise currents are required to meet CE03 of MIL-STD-

461, a power line filter is needed. The FMD/FME Series of EMI

power line filters reduces the common mode and differential noise

generated by the converters. FMD/FME-461 filters reduce input

ripple current by as much as 60 dB at 500 kHz and 55 dB at 1 MHz

when used in conjunction with Interpoint’s DC/DC converters. See

Figures 8 and 9.

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. For the

O

PERATION OVER

T

EMPERATURE

All FMD/FME-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.

I

NSERTION

L

OSS

The maximum dc insertion loss at full load and nominal input voltage

represents a power loss of less than 4%.

P

ACKAGING

FMD/FME-461 filters are sealed in metal hermetic side-leaded

packages. See Section B8, cases U1, U2, V, W, Y, and Z.

Additionally the FMD28-461 filter is available in a metal hermetic

down-leaded package (see Section B8, case J4).

L

AYOUT

R

EQUIREMENTS

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

through a low impedance connection to minimize EMI.

B3-7