
trIM taBLes
trIm DOwn
Singles
RtrIm should be connected between the trim pin and positive sense pin.
Duals
RtrIm should be connected between the trim B pin and positive Vout B
pin. This only trims output B, output A can use the sense pin to trim up
only. See page 2 for instructions on trimming up output A.
Triples
RtrIm should be connected between the trim a pin and positive Vout
a pin to adjust the Main output.
RtrIm should be connected between the trim B pin and positive Vout
B pin to adjust the Auxiliary outputs.
RtrIm = K ( Vout - Vmin )
Vnom - Vout
Vout = Desired Voltage; K/Vmin/Vnom from table below.
VnOM
K
VMIn
% OF VnOM
3.3
3500
3.18
96
5.0
4520
4.16
83
7.0
8020
5.47
78
8.7
9040
6.13
70
12
11030
7.05
58
15
12900
7.65
51
1
2
3
4
5
14
13
12
11
10
9
8
SMRT Single
Sense
Trim
1
2
3
4
5
14
13
12
11
10
9
8
SMRT Dual
Vout B
Trim B
1
2
3
4
5
14
13
12
11
10
9
8
SMRT Triple
Vout A
Trim A
Trim B
+Vout B
trIm up
Singles
RtrIm should be connected between the trim pin and sense return pin.
Duals
RtrIm should be connected between the trim B pin and Vout B return pin.
This only trims output B, output A can use the sense pin to trim up only.
Triples
RtrIm should be connected between the trim a pin and Vout a return pin
to adjust the Main outputs.
RtrIm should be connected between the trim B pin and Vout B return pin
to adjust the Auxiliary outputs.
RtrIm = K ( Vmax - Vout )
Vout - Vnom
Vout = Desired Voltage; K/Vmax/Vnom from table below.
VnOM
K
VMAX
% OF VnOM
3.3
3000
3.70
112
5.0
3000
6.26
125
7.0
5300
8.27
118
8.7
5300
10.46
149
12
5300
14.69
122
15
5300
18.54
124
1
2
3
4
5
14
13
12
11
10
9
8
SMRT Single
Sense Return
Trim
1
2
3
4
5
14
13
12
11
10
9
8
SMRT Dual
Vout B Return
Trim B
1
2
3
4
5
14
13
12
11
10
9
8
SMRT Triple
Vout A Return
Trim A
Trim B
Vout B Return
FIgure 1: trIm DOwn DIagramS
FIgure 2: trIm up DIagramS
note: Do not exceed maximum power rating when trimming up.
note: Do not exceed maximum current rating when trimming down,
Crane Aerospace & Electronics Power Solutions
www.craneae.com/interpoint
Page 4 of 22
sMrt28 single, Dual and triple space Dc/Dc converters
28 VOLt Input – 35 Watt – space quaLIFIeD
SMRT28 Rev F - 2011.01.24