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.

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)

15 for more information.

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.

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.

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.

The SMSA feed-forward compensation system provides excellent

dynamic response and noise rejection. Audio rejection is typically

50 dB (Figure 15 on page 11).

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.

Features

• Radiation tolerant space dc-dc converter

- Single event effects (SEE) LET performance to

- 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)

- 10 mrad(Si)/sec dose rate (Condition D)

• Operating temperature -55°C to +125°C

• Qualified to MIL-PRF-38534 Class H and K

• Input voltage range 16 to 40 volts

• Transient protection 50 volts for 50 ms

• Fully isolated

• Fixed high frequency switching

• Inhibit function

• Indefinite short circuit protection

• High power density, up to 74% typical efficiency

MODELS

SIngLE

DuAL

3.3

±5

5

±12

5.2

±15

12

15

Crane Aerospace & Electronics Power Solutions

SMSA Single and Dual DC-DC Converters

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

Page 1 of 15

28 Volt input – 5 Watt

SMSA Rev AE - 2016.02.01