F
EATURES
• –55°C to +85°C operation
• 0 to 40 VDC volt input
• Up to 40 dB attenuation
110 kHz to 50 MHz
• Transient suppression
• Compliant to
MIL-STD-461C, CE03
EMI I
NPUT
F
ILTERS
28 V
OLT
I
NPUT
FM-461, FMA-461
AND FMB-461
EMI FILTERS
1.75 TO 5 AMP
MODELS
I
NPUT
V
OLTAGE
AND
C
URRENT
Input (V)
0 - 40
0 - 40
0 - 40
Current ( A)
1.75
3.8
5.0
Size (max.): Non-flanged case H3 or H5
2.125 x 1.125 x 0.495* inches (53.98 x 28.58 x 12.57* mm)
Flanged case K4 or K6
2.910 x 1.125 x 0.495* inches (73.91 x 28.58 x 12.57* mm)
See Section B8, cases H3, H5, K4, and K6, for dimensions.
*Height varies depending on model.
Weight:
Maximum – FM-461 38 grams, FMA-461 42 grams, FMB-461 43 grams
Screening: Standard or ES. See Section C2 for screening options, see Section A5
for ordering information.
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.
F
ILTER
O
PERATION
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 performance,
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.
MIL-STD N
OISE
M
ANAGEMENT
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 perform-
ance of a model MHE2805S converter with and without the FM-461
filter is shown in Figures 6 and 7.
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.
B5-3
FM-461 EMI FILTER
1.75 TO 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)
• –55°C to +135°C
Isolation
• 100 megohm minimum at 500 V
• Any pin to case (except case pin)
EMI I
NPUT
F
ILTERS
DERATING
Input Voltage
Derate linearly from 100% at 85°C case to
the 33 VDC at 125°C case
Input Ripple Current
Derate linearly from 100% at 85°C case to
the following at 125°C case
270 mA rms FM-461
400 mA rms FMA-461
480 mA rms FMB-461
DC Input and Output Current
Derate linearly from 100% at 85°C case to
the following at 125°C case
750 mA FM-461
1.7 A FMA-461
1.7 A FMB-461
RECOMMENDED
OPERATING CONDITIONS
Input Voltage Range
• 0 to 40 VDC continuous
Case Operating Temperature (Tc)
• –55°C to +85°C full power
• –55°C to +125°C absolute
Electrical Characteristics: 25°C Tc, nominal Vin, unless otherwise specified.
FM-461
PARAMETER
INPUT VOLTAGE
INPUT CLAMPING
VOLTAGE
INPUT CURRENT
NOISE
REJECTION
DC RESISTANCE
(R
DC
)
CAPACITANCE
OUTPUT VOLTAGE
1
OUTPUT CURRENT
POWER
DISSIPATION
15 kHz - 50 MHz
STEADY STATE
ANY PIN TO CASE
STEADY STATE
STEADY STATE
MAX. CURRENT
—
—
—
—
1.75
1.3
—
—
1900
40
0.38
—
—
0.42
2200
—
0.07
3700
40
0.10
—
—
0.15
4400
—
0.07
6450
40
0.09
—
—
0.10
8000
dB
Ω
pF
VDC
—
—
—
—
5.0
2.5
A
W
CONDITION
CONTINUOUS
–55°C
+25°C
+125°C
DC
RIPPLE
MIN
0
38.9
42.3
44.9
—
—
TYP
28
43.2
47.0
49.9
—
—
MAX
40
47.5
51.7
54.8
1.75
0.67
MIN
0
38.9
42.3
44.9
—
—
FMA-461
TYP
28
43.2
47.0
49.9
—
—
MAX
40
47.5
51.7
54.8
3.8
1.0
MIN
0
38.9
42.3
44.9
—
—
FMB-461
TYP
28
43.2
47.0
49.9
—
—
MAX
40
47.5
51.7
54.8
5.0
1.2
A
A rms
VDC
UNITS
VDC
V
OUT
= V
IN
- I
IN
(R
DC
)
—
—
—
—
3.8
1.6
Note
1. Typical applications result in Vout within 2% of Vin.
469 H
Positive
Input
1000 pF
2.4 H
Positive
Output
x2
0.1 F
0.01 F
0.001 F
50
Input
Common
150
47 pF
Output
Common
4.7 F
FM-461
1000 pF
500 V
F
IGURE
1: S
CHEMATIC
B5-4
EMI I
NPUT
F
ILTERS
>150 H
Positive
Input
1000 pF
x2
x3
0.1 F
0.01 F
2.4 H
FM-461 EMI FILTER
1.75 TO 5 AMP
x2
0.001 F
Positive
Output
50
Input
Common
150
47 pF
x2
4.7 F
Output
Common
FMA-461
1000 pF
500 V
F
IGURE
2: S
CHEMATIC
P6KE47
Positive
Input
0.65
3.5 H
3.5 H
Positive
Output
50
4.7 F
9.4 F
18.8 F
Input
Common
47 pF
500V
Output
Common
FMB-461
3300 pF
500 V
F
IGURE
3: S
CHEMATIC
EMI FILTER
+Vin
+Vout
Case
Output
Input
Common Common
DC/DC CONVERTER
+Vin
+Vout
RL
Case
Output
Input
Common Common
Chassis
ground
Multiple units
allowed up to
rated output
current of filter
RL
The case ground connection should be as low an impedance as possible to minimize EMI. Direct contact of
baseplate to chassis ground provides the lowest impedance.
F
IGURE
4: C
ONNECTION
D
IAGRAM
B5-5
FM-461 EMI FILTER
1.75 YO 5 AMP
EMI I
NPUT
F
ILTERS
PIN OUT
Squared corner and dot on top
of package indicate pin one.
1
Pin
1
2
3
4
5
Designation
Positive Input
Positive Output
Case Ground
Output Common
Input Common
BOTTOM VIEW
FM-461, FMA-461, FMB-461
5
2
3
4
Dotted line outlines flanged package option.
See Section B8, cases H3, H5, K4, and K6, for dimensions.
F
IGURE
5: P
IN
O
UT
MODEL NUMBERING KEY
FMB - 461
Base Model
FM, FMA, or FMB
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
/
ES
Typical Performance Curves: 25°C Tc , nominal Vin, unless otherwise specified.
90
90
CE03 Limit
70
70
CE03 Limit
EMISSION LEVEL (dmA)
50
EMISSION LEVEL (dmA)
.1
1
10
50
50
30
30
10
10
.015
.015
.1
1
10
50
FREQUENCY (MHz)
FREQUENCY (MHz)
MHE Converter Without Filter
F
IGURE
6
MHE Converter With FM-461 EMI Filter
F
IGURE
7
B5-6
26221-001-DTS Rev A
DQ# 14006
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. Copyright © 1990 - 1999 Interpoint. All
rights reserved.
C
ASES
Dot on top of case indicates pin one
CASE H
CASE H
BOTTOM VIEW
See Figures 29 – 34
for pin configurations.
1.125 max
(28.58)
2.125 max
(53.98)
Materials
Header Cold Rolled Steel/Nickel/Gold
cases H1 and H2
Cold Rolled Steel/Nickel/Tin
cases H3, H4, and H5
Cover Kovar/Nickel
cases H1 and H2
Cold Rolled Steel/Nickel/Tin
cases H3, H4, and H5
Pins
#52 alloy
ceramic seal
case H1
case H2 (except MHV Series Single and Dual)
compression glass seal
MHV Series Single and Dual
case H3, H4, H5
Case dimensions in inches (mm)
Tolerance
±0.005
(0.13) for three decimal places
±0.01
(0.3) 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.
F
IGURE
28: C
ASE
H M
AXIMUM
D
IMENSIONS
BOTTOM VIEW CASE H1
FMC EMI Filter: Screening – Standard, ES, or 883
SFMC EMI Filter: Screening – Space Standard, H, or K
Seam Seal
0.040 dia
(1.02)
1.110 (28.19)
0.955 (24.26)
1
0.555 (14.1)
5
0.155 (3.94)
0.000
0.400 max.
(10.16)
0.000
0.25
±0.03
(6.4
±0.8)
0.000
0.245
(6.22)
1.845
(46.86)
2.090
(53.01)
4
2
3
Squared corner and dot on top
of case indicate pin one.
F
IGURE
29: C
ASE
H1
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.
B8-17
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