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 Aerospace & Electronics Power Solutions
sMsa single and dual dc/dc converters
28 Volt input – 5 Watt - pending reVision F release
Operating COnditiOns and
CharaCteristiCs
input Voltage range
•
16 to 40 VdC continuous
•
50 V for up to 50 msec transient
inhibit
output power
•
5 watts
lead soldering temperature (10 sec per lead)
•
300°C
storage temperature range (case)
•
-65°C to +135°C
•
active low (output disabled)
-
Active low voltage ≤0.8 V max
- inhibit pin current 4 ma max
- Referenced to input common
•
active high (output enabled)
- open collector
- open pin voltage, 9 - 11 Volts
meChaniCal and envirOnmental
size (maximum)
•
1.075 x 1.075 x 0.270 inches (27.31 x 27.31 x 6.86 mm)
•
see case C1 for dimensions.
Weight (maximum)
•
15 grams typical
input to output capacitance
•
50 pF typical
output Voltage temperature coefficient
•
100 ppm/°C typical
derating output power/current (tc)
•
linearly from 100% at 125°C to 0% at 135°C
case operating temperature (tc)
•
-55°C to +125°C full power
•
-55°C to +135°C absolute
isolation
•
100 megohm minimum at 500 VdC
•
any pin to case, except case pin
•
audio Rejection
•
50 dB typical
conversion Frequency
•
500 kHz typical
•
450 kHz min, 600 kHz max
screening
space Prototype (o), Class H, or Class K are radiation tolerant to
Radiation Hardness assurance (RHa) levels of “-” (o) 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, mil-PRF-38534 screening” tables for more
information. available configurations: oo, HP, KP, HR, KR
SMSA SINGLE AND DUAL
Positive 6
Input
Input Filter
Output Filter
1 Positive
Output
Inhibit 5
PWM
Control
Input 7
Common
Case 8
Ground
Feedback
Error
Amp
VRef
2
Output
Common
Output Filter
= DUAL OUTPUT
3
Negative
Output
F
igure
1: SmSa b
lOCk
D
iagram
www.interpoint.com
Page 2 of 14
Rev F - 20090318 - Pending Revision F Release
Crane Aerospace & Electronics Power Solutions
sMsa single and dual dc/dc converters
28 Volt input – 5 Watt - pending reVision F release
PIN OUT
Pin
1
2
3
4
5
6
7
8
single output
Positive output
output Common
no connection
no connection
inhibit
Positive input
input Common
Case ground
dual output
Positive output
output Common
negative output
no connection
inhibit
Positive input
input Common
Case ground
Squared corner on header and dot
on top of cover indicate pin one.
1
2
3
4
5
BOTTOM VIEW
SMSA
8
7
6
see case C1 for dimensions.
F
igure
2: p
in
O
ut
b
OttOm
V
ieW
www.interpoint.com
Page 3 of 14
Rev F - 20090318 - Pending Revision F Release
Crane Aerospace & Electronics Power Solutions
sMsa single and dual dc/dc converters
28 Volt input – 5 Watt - pending reVision F release
Positive
6
Input
SMSA
12 k V
5kV
Inhibit
200 pF
10 K
3.9 K
5
400 V
50 k V
2N3904
10 k V
7
Vcc
Typically 1.5 V
when inhibited
Input
Common
F
igure
3: i
nhibit
i
nterFaCe
EMI Filter
Positive
Input
Input
Common
Positive
Output
Output
Common
SMSA2815S
Positive
Input
Input
Common
Positive
Output
Output Common
T1
C2
+
C3 To Load
From input
power source
Case
Case
C1
T1
F
igure
4: l
OW
n
OiSe
O
utput
F
ilter FOr
SmSa S
ingle
O
utput
m
ODel
emi Filter
Positive
input
input
Common
Positive
output
output
Common
smsa2815d
Positive
input
input
Common
Positive
output
output Common
negative
output
Case
C1
T1
C2
C4
+
C3
To loads
+
C5
From input
power source
Case
T1
F
igure
5: l
OW
n
OiSe
O
utput
F
ilter FOr
SmSa D
ual
O
utput
m
ODel
The filter suggestions in Figures 4 and 5 will further reduce the output ripple for systems requiring very low output noise.
C1 = 0.27 µF ceramic capacitor, 500V
C2 = C4 = 6.8 µF tantalum capacitor
C3 = C5 = 0.27 µF ceramic capacitor
Single output: T1 = 15T #28 AWG winding on toroid, µ
i
= 5000
Dual output: T2 = 10T #28 AWG winding on toroid, µ
i
= 5000
For best results, make interconnections as short as possible.
www.interpoint.com
Page 4 of 14
Rev F - 20090318 - Pending Revision F Release
Crane Aerospace & Electronics Power Solutions
sMsa single and dual dc/dc converters
28 Volt input – 5 Watt - pending reVision F release
mOdel numbering key
Base Model
SMSA
28 05 S / K R
smd numbers
sTandaRd miCRo-CiRCuiT
DRAWinG (SMD)
5962R0621001KxC
5962R9309202KxC
in PRoCess
5962R9309302KxC
5962R9309402KxC
5962R9308902KxC
5962R9309002KxC
smsa seRies
similaR PaRT
smsa283R3s/KR
smsa2805s/KR
smsa285R2s/KR
smsa2812s/KR
smsa2815s/KR
smsa2812d/KR
smsa2815d/KR
Number of Outputs
(S = single, D = dual)
Environmental Screening
Voltage In (28V)
Output Voltage
Radiation Hardness
Assurance (RHA)
The smd number shown is for Class H screening and no Radiation
Hardness assurance (RHa) level. see the smd for the numbers for other
screening and radiation levels. For exact specifications for an smd
product, refer to the smd drawing. Call your interpoint representative for
status on the smsa smd releases which are “in process.” smds can be
downloaded from:
http://www.dscc.dla.mil/programs/smcr
mOdel seleCtiOn
smsa28
Base model
V
out
value
number of outputs
/
screening
RHa
Choose one from each of the following rows
V
out
value
number of outputs
screening
Radiation hardness assurance (RHa)
for singles: 3R3, 5, 5R2, 12, 15 for duals: 5, 12, 15
“R” = decimal point, 3R3 = 3.3VdC
s (single) or d (dual)
o* - space prototype, H, K
o* - space prototype, P, R
*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”
www.interpoint.com
Page 5 of 14
Rev F - 20090318 - Pending Revision F Release
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