FEATURES
• –55°C to +125°C operation
• 16 to 40 VDC input
• Surface mountable
• Will withstand solder reflow
• Transient protection up to 80V/120 ms,
meets MIL-STD-704A requirements
• Inhibit function
• Fully isolated
• Ultra-wide bandwidth magnetic feedback
• Up to 82% efficiency
MSM SERIES
5 WATT
DC/DC CONVERTERS
28 VOLT NPUT
I
MODELS
VDC OUTPUT
SINGLES
DUALS
12
3.3
5
15
12
15
• Indefinite short circuit protection
• Undervoltage shutdown below 10 Vin
Size (max.): 2.01 x 2.01 x 0.312 inches (51.1 x 51.1 x 7.9 mm)
Weight: 20 grams maximum
DESCRIPTION
The converter is inhibited when the TTL compatible low (≤0.8 V) 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 V. In the inhibit mode, a
maximum of 0.5 mA must be sunk from the inhibit pin.
The MSM Series™ of DC/DC converters delivers up to 5 watts in a
surface mountable package. The use of commercially available
discrete components, printed wiring board construction, and surface
mount technology keep costs low. Mature design technology and
severe derating maintain high-reliability, providing full power opera-
tion over the full military temperature range of –55 to +125°C.
Output voltages of 3.3, 5, 5.2, 12, 15, 12, or 15 operate from an
input range of 16 to 40 VDC. Operation below 16 volts is possible at
reduced power while still maintaining output regulation. The
converters are rated for input transients up to 80 V for up to 120
milliseconds which meets the requirements for MIL-STD-704A.
PROTECTION FEATURES
Undervoltage lockout prevents the MSM Series converters from
operating below approximately 10 VDC input. This circuitry can
prevent system shutdown problems in starting “constant power”
devices at low input voltages. All models include a soft-start function
to prevent large current draw and minimize overshoot under all load
and line conditions. The MSM Series of converters also provide
short circuit and overload protection. Short circuit internal dissipation
is lower than the internal dissipation which occurs during full load
conditions.
CONVERTER DESIGN
The converters incorporate a flyback topology with a constant
frequency to minimize EMI and noise. The pulse-width-modulator is
constructed of discrete devices to allow to the use of mature tech-
nologies and assure operation over the full temperature range. A
proprietary magnetic isolator, designed with feed-forward and load
correction, provides nearly instantaneous output control for good
output regulation.
SURFACE MOUNTABLE PACKAGING
The MSM Series of DC/DC converters can be surface mounted or
hand-soldered. Maximum reflow temperature for surface mounting
the MSM converter is 230°C for a maximum of 30 seconds. SN60,
62, or 63 are the recommended types of solder. Hand soldering
should not exceed 300°C for 10 seconds per pin.
INHIBIT FUNCTION
MSM Series converters provide a TTL open collector-compatible
inhibit feature that can be used to disable internal switching and
inhibit the unit’s output. Inhibiting in this manner results in low
standby current, and no generation of switching noise.
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CRANE [ Crane Aerospace & Electronics. ]
