M-FIAM5 Vicor Corporation, M-FIAM5 Datasheet - Page 4

• Manufacturer Part Number: M-FIAM5
• Description: Military 28Vin Filter Input Attenuator Module
• Manufacturer: Vicor Corporation

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Addendum A
MIL-STD-704E Transient / Overvoltage Protection
The standard (COTS) 24V input 2nd Generation Converter Modules may be used in Military 28 volt applications. The
M-FIAM5 provides compliance to MIL-STD-461E conducted emissions and susceptibility standards. Additional circuitry,
as illustrated in the accompanying schematic (see Fig. 1), provides compliance to the MIL-STD-704E transient
overvoltage specification. The 24V input modules employ undervoltage and overvoltage protection. These converters,
shut down if the input falls below 18V or rises to 36V or above.18V is consistent with the MIL-STD-704E specification,
but the standard also requires uninterrupted performance in the event of an input voltage transient to 50V for a period
of 12.5 millisec. The above referenced circuit clamps the input voltage, in the event that it exceeds 32V, as illustrated in
figure 2. This performance prevents the converter from shutting down, thus meeting the transient overvoltage
specification of MIL- STD-704E.
Figure 1– Transient / Overvoltage protection circuit.
Figure 2– Overvoltage clamping
Input
+28V
15v, 1N5245B
2.0k
+28v
rtn
R1
D1
50
28
27
Volts
C1
4.7uf, 63v
R2
2.0k
R3
64.9k
R5
10K
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R4
64.9k
2
3
8
+
–
4
LM258N
615001
R6
10K
1
U1A
32
1.0k
R7
U2
LM4040CIZ-5.0
2
R8
24.3k
3
MFIAM5
5
6
8
4
+
–
R9
14.0k
C2
.1ufd
12.5 Millisec Max
7
U1B
LM258N
C3
Cbulk
880 Uf d
R10
1.0K
Vicor FIAM & Mods
Vc
1
4
3
2
Vout
Q1
IRFP3710
ND PN
Rev. 1.7
Transient Surpressor Circuit
C1
C2
C3
D1
Q1
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
U1
U2
Vin
Vout
4.7uF, 63V
0.1uF
880uF, 100V
1N5245B
IRFP3710ND
2.0K
2.0K
64.5K
64.5K
10K
10K
1K
24.3K
14K
1K
LM258N
LM4040CIZ-5.0
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