Crane Aerospace & Electronics Power Solutions
sMsa single and dual dc/dc converters
28 Volt input – 5 Watt - pending reVision F release
Features
small size, 1.075 inches (27.31 mm) square
•
Qualified to mil-PRF-38534 Class H and K
•
operating temperature -55° to +125°C
•
Radiation hardness assurance (RHa)
to level R 100 kRad(si)
•
input voltage range 16 to 40 VdC
•
Fully isolated, magnetic feedback
•
Fixed high frequency switching
•
inhibit function
•
Transient protection 50 V for 120 ms
VDC O
utput
single
3.3
5
5.2
12
15
dual
±5
±12
±15
models
•
indefinite short circuit protection
•
High power density, 76% efficiency
description
The smsa series™ of high frequency dC/dC converters offers a
new standard of performance for low power, space qualified dC/
dC converters. smsa converters provide up to 5 watts output
power over the full military temperature range of -55°C to +125°C
with up to 76% efficiency. Thick-film hybrid techniques provide
military/aerospace reliability levels and optimum miniaturization.
The hermetically sealed case is only 1.075 by 1.075 inches —
with a height of only 0.270 inches. Power density for the smsa
series converters is 16 watts per cubic inch. The smsa series’
small size, light weight, and hermetically sealed metal packages
make them ideal for use in space, military, aerospace and other
high reliability applications.
negative output regulation is maintained by tightly coupled
magnetics. Predictable current limit is accomplished by direct
monitoring of the output load current, which results in a constant
current output above the overload point. internal input and output
filters eliminate the need for external capacitors.
W
iDe
V
Oltage
r
ange
The smsa converters are designed to provide full power opera-
tion over the full 16 to 40 VdC voltage range. an undervoltage
lockout feature keeps the converter shutdown below approxi-
mately 13 VdC to ensure smooth initialization.
S
Creening
i
mprOVeD
D
ynamiC
r
eSpOnSe
smsa converters offer the following screening options: space
Prototype (o), Class H, or Class K. Radiation tolerant to
Radiation Hardness assurance (RHa) levels of “-” (o), “P” or
“R”, per mil-sTd-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 “Class H and K, Qml screening” tables for
more information.
The smsa feed-forward compensation system provides excellent
dynamic response and noise rejection. audio rejection is typically
50 dB. The minimum to maximum step line transient response is
typically less than 1%.
i
nhibit
F
unCtiOn
C
OnVerter
D
eSign
smsa converters provide an 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.
The converter is inhibited when the 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 4 ma must be sunk from the inhibit
pin at 28 VdC input.
The smsa converters are switching regulators that use a flyback
converter design with a constant switching frequency of 500 kHz.
They are regulated, isolated units using a pulse width modulated
topology and built as high reliability thick-film hybrids. isolation
between input and output circuits is provided with a transformer
in the forward power loop and an optical link in the feedback
control loop. excellent input line transient response and audio
rejection is achieved by an advanced feed-forward compensation
technique.
Crane aerospace & electronics
electronics group (interpoint Brand)
PO Box 97005 • Redmond WA 98073-9705
425.882.3100 • power@crane-eg.com
www.interpoint.com
Page 1 of 14
Rev F - 20090318 - Pending Revision F Release
CRANE [ Crane Aerospace & Electronics. ]
