Crane Aerospace & Electronics Power Solutions
SFMC28-461 EMI Input Filters
0 TO 50 vOlT INPUT - 2.7 AMP
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 volt input, 0 to 50 volt operation
• Up to 2.7 amps throughput current
• Compliant to MIL-STD-461C CE-03
• Compatible with MIL-STD-704 B-E 28 volt power bus
SFCS28-461
INPUT (V)
0 - 50
CURRENT (A)
2.7
DESCRIPTION
The Interpoint® SFMC28-461 Series™ of EMI filters offers up
to 2.7 amps of throughput current in a low profile package.
The FMC-461 filters are manufactured in our fully certified
and qualified MIL-PRF-38534 Class H and K production facility They
are packaged in hermetically sealed steel cases and are ideal for
use in programs requiring high reliability and small size.
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.
F
ilter
d
eSign
SFMC28-461 filters incorporate thick-film hybrid technology and use
only high quality ceramic capacitors for reliable high temperature
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 environmental
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 evaluation (screening
at the component level) of Class H or Class K filters ensures even
greater reliability. See Table 6 on page 8 and Table 7 on page
9 for more information.
S
creening
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 Table 6 on page 8 and Table 7 on page 9 for
more information.
o
perating
t
emperature
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 in Table 4 on page 4.
r
ipple
r
eduction
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 CE03 requirements of MIL-STD-461C.
p
ackaging
SFMC28-461 EMI filters weigh just 48 grams with a small footprint
of 2.100 Inches (53.34 mm) by 1.115 inches (28.32 mm) by 0.400
inches (10.16 mm) which minimizes the board area needed for the
filter.
i
nSertion
l
oSS
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.
Crane Aerospace & Electronics
Power Solutions – Interpoint Products
16706 13th Avenue West, Lynnwood, WA 98037
+1 425-882-3100 • power@craneae.com
www.craneae.com/interpoint
Page 1 of 9
SFMC28-461 Rev AC - 2020.12.14
Crane Aerospace & Electronics Power Solutions
SFMC28-461 EMI Input Filters
0 TO 50 vOlT INPUT - 2.7 AMP
Positive
Input
1
Positive
Output
1
Input
Common
1
3300 pF, 500 V
Output
Common
SFMC-461
Figure 1: SFMC28-461 Schematic
EMI FILTER
Positive
Input
Positive
Output
Case Ground
Input
Common
Output
Common
Optional
Damping
Network
DC-DC CONVERTER
Positive
Input
Case Ground
Input
Common
Output
Common
Positive
Output
RL
Multiple units
allowed up to
rated output
current of filter*
RL
Output impedance of the filter must be less than the combined input impedance of the DC-DC converters.
Figure 2: Connection Diagram
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.
An external RC damping network may need to be added across the output of the FMC-461 to lower it’s impedance in
comparison to the impedance of the converters it will be paired with. See our EMI Conducted Interference application
note or contact our Application Engineers at powerapps@craneae.com or call +1 425.882.3100.
www.craneae.com/interpoint
Page 2 of 9
SFMC28-461 Rev AC - 2020.12.14
Crane Aerospace & Electronics Power Solutions
SFMC28-461 EMI Input Filters
0 TO 50 vOlT INPUT - 2.7 AMP
PIN OUT
Pin
1
2
3
4
5
Designation
Positive Input
Positive Output
Case Ground
Output Common
Input Common
Dotted line outlines flanged package option.
Dot on top of package indicates pin one
1
BOTTOM VIEW
SFMC
NON-FLANGED AND FLANGED
5
2
3
4
t
able
1: p
in
o
ut
See Figure 8 on page 6 and
Figure 9 on page 7 for dimensions.
F
igure
4: p
in
o
ut
MODEl NUMBERING KEY
Base Model
MIL-STD-461 compliant
Package Option
(Non-flanged package has
no designator in this position)
Screening
Radiation Hardness
Assurance (RHA)
F
igure
3: m
odel
n
umbering
k
ey
SFMC28 - 461
F
/ K
H
94010H02HXC
94010H02HZC
94010H02KXC
94010H02KZC
DlA NUMBERS
DLA D
rAwing
(5915)
SFMC28-461
S
iMiLAr
P
Art
SFMC28-461/HH
SFMC28-461F/HH
SFMC28-461/KH
SFMC28-461F/KH
For exact specifications for a DLA product, refer to the DLA
drawing. DLA drawings can be downloaded from:
https://landandmaritimeapps.dla.mil/programs/smcr
Table 2: DLA
d
rawing
c
roSS
r
eFerence
t
o DeterMine the MoDeL nuMber enter one oPtion FroM
eACh CAtegory in the ForM beLow
.
CATEGORY
Base Model and Input voltage
Case Option
1
(Standard, leave blank)
Screening
2
O
H
K
RHA
3
O
H
MODEl NUMBER OPTIONS
OPTIONS
FIll IN FOR
MODEl #
4
SFMC28-461
F (flanged)
___________
SFMC28-461
__________
/
Notes
1. Case Options: For the standard case, Figure 8 on page 6, leave the case option blank. For the flanged case option, Figure 9 on page 7, insert the
letter F in the Case Option position.
2. Screening: A screening level of O is a Space Prototype and is only used with RHA O. See Table 6 on page 8 and Table 7 on page 9 for more
information. “H” indicates Class H and “K” indicates Class K of MIL-PRF-38534.
3. RHA: 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.” RHA O is only available with Screening level O. See Table 7 on page 9 for more information.
4. If ordering by model number add a “-Q” to request solder dipped leads (SFMC28-461/KH-Q).
t
able
3: m
odel
n
umber
o
ptionS
www.craneae.com/interpoint
Page 3 of 9
SFMC28-461 Rev AC - 2020.12.14
Crane Aerospace & Electronics Power Solutions
SFMC28-461 EMI Input Filters
0 TO 50 vOlT INPUT - 2.7 AMP
t
able
4: o
perating
c
onditionS
: 28 V
in
,
unleSS otherwiSe SpeciFied
.
SFMC28-461
PARAMETER
LEAD SOLDERING TEMPERATURE
1
STORAGE TEMPERATURE
1
CASE OPERATING
TEMPERATURE
DERATING OUTPUT POWER/CURRENT
1
ISOLATION, ANY PIN TO CASE
EXCEPT CASE PIN
FULL POWER
ABSOLUTE
1
LINEARLY
@ 500 VDC AT 25°C
CONDITIONS
10 SECONDS MAX.
MIN
—
-65
-55
-55
TYP
—
—
—
—
MAX
300
+150
+125
+135
UNITS
°C
°C
°C
From 100% at 125°C to 0% at 135°C
100
—
—
Megohms
Notes
1. Guaranteed by characterization test and/or analysis. Not a production test.
t
able
5: e
lectrical
c
haracteriSticS
: -55
to
+125°c
caSe
, 28 V
in
,
unleSS otherwiSe SpeciFied
.
MODEL
PARAMETER
INPUT VOLTAGE
NOISE REJECTION
CONDITIONS
CONTINUOUS
500 KHZ
1 MHZ
5 MHZ
DC RESISTANCE (R
DC
)
OUTPUT VOLTAGE
2
CAPACITANCE
T
C
= 25°C
OUTPUT CURRENT
POWER DISSIPATION
1
T
C
= 25°C
STEADY STATE
ANY PIN TO CASE
EXCEPT CASE PIN
STEADY STATE
T
C
= 25°C
—
—
—
MIN
0
55
60
55
—
SFMC28-461
TYP
28
60
—
—
—
V
OUT
= V
IN
- I
IN
(R
DC
)
—
—
—
48,000
2.7
1.5
MAX
50
—
—
—
0.2
Ω
V
pF
A
W
dB
UNITS
V
Notes
1. Guaranteed by characterization test and/or analysis. Not a production test.
2. Typical applications result in Vout within 2% of Vin.
www.craneae.com/interpoint
Page 4 of 9
SFMC28-461 Rev AC - 2020.12.14
Analog electronics
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