Crane Aerospace & Electronics Power Solutions
SMSA Single and Dual DC-DC Converters
28 Volt input – 5 Watt
Features
• Radiation tolerant space dc-dc converter
-- Single event effects (SEE) LET performance to
86 MeV cm2/mg
-- Total ionizing dose (TID) guaranteed per MIL-STD-883
method 1019, radiation hardness assurance (RHA)
P = 30 krad(Si), L = 50 krad(Si), R = 100 krad(Si)
-- 50 - 300 rad(Si)/sec dose rate (Condition A)
MODELS
-- 10 mrad(Si)/sec dose rate (Condition D)
Output Voltage (V)
• Operating temperature -55°C to +125°C
Single
Dual
3.3
±5
5
±12
• Fully isolated
5.2
±15
• Inhibit function
15
• Qualified to MIL-PRF-38534 Class H and K
• Input voltage range 16 to 40 volts
• Transient protection 50 volts for 50 ms
12
• Fixed high frequency switching
• Indefinite short circuit protection
• High power density, up to 74% typical efficiency
description
The Interpoint® SMSA Series™ of high frequency, space
qualified, dc-dc converters provide up to 5 watts output power
over the full military temperature range of -55°C to +125°C
with up to 74% efficiency. Thick-film hybrid techniques provide
military/aerospace reliability levels and optimum miniaturization.
The hermetically sealed case is 1.075 by 1.075 inches with
a height of 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.
Screening
SMSA converters offer screening to space prototype (O), Class H
or K, radiation hardness assurance (RHA) levels P - 30 krad(Si),
L - 50 krad(Si) or R - 100 krad(Si). Single event effects (SEE)
LET performance to 86 MeV cm2/mg. See Table 10 on page
15 for more information.
Converter Design
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. 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.
On dual output models negative output regulation is maintained
by tightly coupled magnetics.
Crane Aerospace & Electronics
Power Solutions – Interpoint Products
10301 Willows Rd. NE, Redmond, WA 98052
+1 425-882-3100 • power@crane-eg.com
www.craneae.com/interpoint
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.
Wide Voltage Range
The SMSA converters are designed to provide full power
operation over the full 16 to 40 volt range. An undervoltage
lockout feature keeps the converter shutdown below
approximately 13 volts to ensure smooth initialization.
Dynamic Response
The SMSA feed-forward compensation system rovides excellent
p
dynamic response and noise rejection. Audio rejection is typically
50 dB (Figure 15 on page 11).
Inhibit Function
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 an active 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 volts. In the
inhibit mode, a maximum of 4 mA must be sunk from the inhibit
pin at 28 volt input.
Page 1 of 15
SMSA Rev AE - 2016.02.01
