F
EATURES
• –55°C to +125°C operation
• 50 dB minimum attenuation
at 500 kHz
• Compliant to MIL-STD-461C, CE03
• Compatible with MIL-STD-704E
DC power bus
EMI I
NPUT
F
ILTER
28 V
OLT
I
NPUT
FMH EMI FILTER
1.5 AMP
MODEL
FMH-461
1.5 amp
Size (max.): Non-flanged, case E3
1.460 x 1.130 x 0.330 (37.08 x 28.70 x 8.38 mm)
Flanged, case G3
2.005 x 1.130 x 0.330 inches (50.93 x 28.70 x 8.38 mm)
See Section B8, cases E3 and G3, for dimensions.
Weight:
22 grams typical, 28 grams maximum
Screening: Standard, ES, or 883 (Class H). See Section C2 for screening
options, see Section A5 for ordering information.
DESCRIPTION
Interpoint specifically designed the FMH-461™ EMI filter to reduce
the input line reflected ripple current of the following high frequency
DC/DC converters: MHD, MHF, MHF+, MHV, MSA
1
, and MTR
series converters. It will also reduce EMI for several of Interpoint’s
lower frequency converters: MHE/MLP, MHL, MTO, and MTW
series. The FMH-461 filter is ideal for use in applications which must
meet MIL-STD-461C levels of conducted and radiated emissions.
Throughput current is 1.5 amps. At 16 VDC input (low line), the filter
provides 24 watts of throughput power.
F
ILTER
O
PERATION
FMH-461 filters are rated for full power operation from –55°C to
+125°C baseplate temperature. Operation is offered up to the
absolute maximum of +135°C with derating as defined in
“Recommended Operating Conditions” on the following page. The
maximum DC insertion loss at full load and nominal input voltage
(28 VDC) represents a power loss of less than 2%.
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.
MIL-STD N
OISE
M
ANAGEMENT
When used in conjunction with Interpoint converters, the FMH-461
EMI filter reduces input ripple current by 35 dB or greater at 200 kHz
and by at least 50 dB at 500 kHz (see Figures 5 and 6 and electrical
characteristics table). This attenuation gives the converter/filter
combination performance which exceeds MIL-STD-461C’s CE03
test.
1. MSA models may require an inductor in series with the MSA’s positive input.
2 µH is the suggested value.
B3-17
FMH EMI FILTER
1.5 AMP
ABSOLUTE MAXIMUM RATINGS
Input Voltage
• 0 to 40 VDC continuous
Lead Soldering Temperature (10 sec per lead)
• 300°C
Storage Temperature Range (Case)
• –65°C to +150°C
EMI I
NPUT
F
ILTERS
RECOMMENDED OPERATING CONDITIONS
Input Voltage Range
• 16 to 40 VDC continuous
Case Operating Temperature (Tc)
• –55°C to +125°C full power
Derating DC Input/Output current
• Derate linearly from 100% at 125°C to 0% at
135°C case
TYPICAL CHARACTERISTICS
Capacitance
• 0.024 µF max, any pin to case
Isolation
• 100 megohm minimum at 500 V
• Any pin to case, except case pin
Electrical Characteristics: 25°C Tc, nominal Vin, unless otherwise specified.
PARAMETER
INPUT VOLTAGE
INPUT CURRENT
NOISE REJECTION
DC RESISTANCE (R
DC
)
OUTPUT VOLTAGE
1
OUTPUT CURRENT
INTERNAL POWER
DISSIPATION
CONDITIONS
CONTINUOUS
200 kHz
500 kHz
TC = 25°C
STEADY STATE
RIPPLE
STEADY STATE
MAXIMUM CURRENT
—
—
MIN
0
—
35
50
—
FMH-461
TYP
28
—
40
60
0.20
V
OUT
= V
IN
- I
IN
(R
DC
)
—
—
MAX
40
1.5
—
—
0.35
UNITS
VDC
A
dB
Ω
VDC
A rms
A
W
0.3
1.5
0.8
—
0.5
Notes
1. Typical applications result in Vout within 2% of Vin.
590
Positive
Input
34
H
30
H
Positive
Output
5.1
2
F
1
F
Input
Common
3300 pF
500V
1
F
2
F
6800 pF
500 V
Output
Common
FMH-461
F
IGURE
1: S
CHEMATIC
B3-18
EMI I
NPUT
F
ILTERS
EMI FILTER
+Vin
+Vout
Case
Output
Input
Common Common
DC/DC CONVERTER
+Vin
+Vout
RL
Case
Output
Input
Common Common
FMH EMI FILTER
1.5 AMP
Chassis
ground
Multiple units
allowed up to
rated output
current of filter
RL
The case ground connection between the filter and the converter should be as low an impedance as possible
to minimize EMI. Direct contact of baseplate to chassis ground provides the lowest impedance.
F
IGURE
2: C
ONNECTION
D
IAGRAM
PIN OUT
Dot on top of cover
indicates pin one.
Pin
1
2
3
4
5
Designation
Positive Input
Positive Output
Case Ground
Output Common
Input Common
1
BOTTOM VIEW
FMH
NON-FLANGED
3
AND FLANGED
4
2
5
Dotted line outlines flanged package option.
See Section B8, cases E3 and G3 for dimensions.
F
IGURE
3: P
IN
O
UT
DSCC NUMBER
DSCC D
RAWING
(5915)
95003-01HXC
95003-01HZC
FMH
-461 F
ILTER
MODEL NUMBERING KEY
FMH - 461
Base Model
MIL-STD-461 Reference
Case Option
(Non-flanged case has no designator in
this position)
Screening
(Standard screening has no designator
in this position.)
F
/ 883
S
IMILAR
P
ART
FMH-461/883
FMH-461F/883
For exact specifications for a DSCC product, refer to the
DSCC drawing. See Section A3, “SMD/DSCC Lists”, for
more information.
B3-19
FMH EMI FILTER
1.5 AMP
EMI I
NPUT
F
ILTERS
90
80
A)
70
60
50
40
30
20
10
0
.015
0.1
1
FREQUENCY (MHz)
10
50
CE
03
Typical Performance Curves: 25°C Tc , nominal Vin, unless otherwise specified.
LI
EMISSION LEVEL (dB
M
IT
MHF+2805S Converter Without Filter
F
IGURE
4
90
80
EMISSION LEVEL (dB A)
70
60
50
40
30
20
10
0
.015
0.1
1
FREQUENCY (MHz)
10
50
CE
03
LI
M
IT
MHF+2805S Converter With FMH-461 Filter
F
IGURE
5
20
dB OHMS = 20 LOG ZOUT
10
0
-10
-20
1K
100 K
10 K
FREQUENCY (Hz)
1M
Typical Output Impedance (Z)
With Input Shorted
FMH-461
F
IGURE
6
B3-20
26421-001-DTS Rev A
DQ# 4044
All technical information is believed to be accurate, but no responsibility is
assumed for errors or omissions. Interpoint reserves the right to make changes in
products or specifications without notice. FMH-461 is a trademark of Interpoint.
Copyright © 1992 - 1999 Interpoint. All rights reserved.
C
ASES
Squared corner and dot on top
of case indicate pin one.
Materials
Header Cold Rolled Steel/Nickel/Gold
Cover MHF+ Series and FMH Filter
Kovar/Nickel
SMHF
Cold Rolled Steel/Nickel
Pins
#52 alloy (all cases)
compression glass seal
Case dimensions in inches (mm)
Tolerance
±0.005
(0.13) for three decimal places
±0.01
(0.2) for two decimal places
unless otherwise specified
CAUTION
Heat from reflow or wave soldering may damage
the device. Solder pins individually with heat
application not exceeding 300°C for 10 seconds
per pin.
CASE G
CASE G
BOTTOM VIEW
Flanged package
See Figures 25 - 27
for pin configuration
1.130 max
(28.70)
2.005 max
(50.93)
Flange Thickness:
0.047 (1.19)
F
IGURE
24: C
ASE
G M
AXIMUM
D
IMENSIONS
BOTTOM VIEW CASE G1
Flanged cases: Designator "F" required in Case Option position of model number
MHF+ Series Single and Dual, LIM5050 Module: Screening – Standard, ES, or 883
SMHF Series, SLIM5050 Module: Screening – Space Standard, H, or K
Seam Seal
Projection Weld
Squared corner and dot on top
of case indicate pin one.
0.960
(24.38)
0.030 dia.
(0.76)
1
2
3
4
5
0.128 dia
(3.25)
0.560
(14.22)
8
7
6
0.160
(4.06)
0.000
0.000
0.000
0.330 max.
(8.38)
0.330 max.
(8.38)
0.25 (6.35)
0.25 (6.35)
0.140 (3.56)
0.000
0.205 (5.21)
0.505 (12.83)
0.705 (17.91)
0.905 (22.99)
F
IGURE
25: C
ASE
G1
Note: Although every effort has been made to render the case drawings at actual size, variations in the printing process may cause some distortion. Please refer
to the numerical dimensions for accuracy.
1.105 (28.07)
1.590 (40.39)
B8-15
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