Crane Aerospace & Electronics Power Solutions
SMTR Single, Dual and Triple DC/DC Converters
28 VOlT INPuT – 30 WaTT – PENDINg REVISION F RElEaSE
W
iDe
v
oltage
r
ange
SMTR converters are designed to provide full power operation
over a full 16 to 40 VDC voltage range. Operation below 16 volts,
including MIL-STD-704D emergency power conditions is possible
with derated power.
i
nhibit
F
unction
i
mproveD
D
ynamic
r
eSponSe
The SMTR Series feed-forward compensation system provides
excellent dynamic response and noise rejection. Audio rejection
is typically 50 dB (for Triple output models). The min. to max.
step line transient response is typically less than 4%.
SMTR converters provide an inhibit terminal that can be used to
disable internal switching, resulting in no output and very low
quiescent input current. The converter is inhibited when an active
low (≤0.8V) is applied to the inhibit pin. The unit is enabled when
the pin, which is internally connected to a pull-up resistor, is left
unconnected or is connected to an open-collector gate. The open
circuit output voltage associated with the inhibit pin is 9 to 11
VDC. In the inhibit mode, a maximum of 8 mA must be sunk from
the inhibit pin.
TRIM aND REMOTE SENSE (aVaIlablE ON SINglE OuTPuT MODElS ONly)
SMTR SINGLE OUTPUT CONVERTER
1
+VIN
OUTPUT
COMMON
SENSE
RETURN
SENSE
10
INPUT
COMMON
POSITIVE
OUTPUT
4
1
3
6
1
RT
5
10
RL
SENSE
INPUT
COMMON
POSITIVE
OUTPUT
SMTR SINGLE OUTPUT CONVERTER
1
+VIN
OUTPUT
COMMON
SENSE
RETURN
4
2
3
6
2
RL
5
EXTERNAL TRIM CONNECTION
1 Make connections at converter.
REMOTE SENSE CONNECTION
2 Make connections at load.
F
igure
1: t
rim
C
OnneCtiOn
1, 2, 3
F
igure
2: r
emOte
S
enSe
2, 3
Trim Formulas
Vout = desired output voltage; Rt = trim resistor
3.3V: Rt = 1300 * Vout – 4304
1.2475
5V: Rt = 1300 * Vout – 6512
1.2475
12V: Rt = 1300 * Vout – 15631
1.2475
15V: Rt = 1300 * Vout – 19498
1.2475
notes for Remote Sense and Trim
1. When trimming output voltage and/or remote sensing, the
total output voltage increase must be less than 0.6 volts at the
converters pins to maintain specified performance.
2. If neither voltage trim nor remote sense will be used, connect pin 3
to pin 4 and pin 5 to pin 6 or the output voltage will increase by 1.2
volts.
3. CAUTIOn: The converter will be permanently damaged if the posi-
tive remote sense (pin 6) is shorted to ground. Damage may also
result if the output common or positive output is disconnected from
the load with the remote sense leads connected to the load.
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Rev F - 20090324 - Pending Revision F Release
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