Crane Aerospace & Electronics Power Solutions
sMsa single and dual dc-dc converter
16 to 40 Volt input - 5 Watt
Features
•
Radiation tolerant space dc-dc converter
- 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)
•
Operating temperature -55°C to +125°C
•
Input voltage range 16 to 40 volts
•
Fully isolated
- 10 mrad(Si)/sec dose rate (Condition D)
MODELS
o
utput
v
oltage
(v)
- Single event effects (SEE) LET performance to
86 MeV cm
2
/mg
•
Qualified to MIL-PRF-38534 Class H and K
•
Transient protection 50 volts for 50 ms
•
Fixed high frequency switching
•
Inhibit function
•
Indefinite short circuit protection
SIngLE
3.3
5
5.2
12
15
DuAL
±5
±12
±15
•
High power density, up to 74% typical efficiency
description
The Interpoint® SMSA Series™ of DC-DC converters offers
up to 5 watts of power in a radiation tolerant design. The low
profile SMSA converters are manufactured in our fully certified
and qualified MIL-PRF-38534 Class K production facility and
packaged in hermetically sealed steel cases. They are ideal
for use in programs requiring high reliability, small size, and
high levels of radiation hardness assurance. 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.
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 cm
2
/mg. See Table 10 on page
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.
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.
W
iDe
v
oltage
r
ange
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.
S
creening
S
pan
v
oltage on
D
ualS
c
onverter
D
eSign
Dual outputs may be spanned to increase the output voltage by
configuring the converter as a single output. The positive output
is used as one rail and the negative output is used as the other
rail. As an example the positive and negative 15 volt dual can
be configured as a single 30 volt output. This can be used as a
positive 30 volt output or a negative 30 volt output. In all cases
Output Common of the converter is not connected.
If the dual is configured as a positive 30 volt output the negative
output would be used as system ground and the positive output
would be used as the positive 30 volt output. If the dual is
configured as a negative 30 volt output the positive output would
be used as system ground and the negative output would be
used as the negative 30 volt output.
The maximum capacitance when using a span voltage on a dual
is half the value specified for each output.
SMSA Rev AF - 2018.02.02
Page 1 of 15
Crane Aerospace & Electronics Power Solutions
sMsa single and dual dc-dc converter
16 to 40 Volt input - 5 Watt
D
ynaMic
r
eSponSe
The SMSA feed-forward compensation system provides excellent
dynamic response and audio rejection. Audio rejection is typically
50 dB (Figure 16 on page 11).
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.
i
nhiBit
F
unction
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.
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
Positive
6
Input
SMSA
12 K
5K
400
Ω
Inhibit
200 pF
10 K
3.9 K
5
50 K
2N3904
10 K
7
Vcc
Typically 1.5 V
when inhibited
Input
Common
F
igure
2: i
nhiBit
i
nterFace
www.craneae.com/interpoint
SMSA Rev AF - 2018.02.02
Page 2 of 15
Crane Aerospace & Electronics Power Solutions
sMsa single and dual dc-dc converter
16 to 40 Volt input - 5 Watt
Model nuMbering key
Base Model
SMSA
28 05 S / K R
S
tandard
M
icrocircuit
d
rawing
(SMd)
5962R0621001KXC
5962R9309202KXC
5962R1421601KXC
5962R9309302KXC
5962R9309402KXC
5962R0052202KXC
5962R9308902KXC
5962R9309002KXC
sMd nuMbers
SMSa S
iMilar
P
art
SMSA283R3S/KR
SMSA2805S/KR
SMSA285R2S/KR
SMSA2812S/KR
SMSA2815S/KR
SMSA2805D/KR
SMSA2812D/KR
SMSA2815D/KR
Number of Outputs
(S = single, D = dual)
Environmental Screening
Voltage In (28V)
Output Voltage
Radiation Hardness
Assurance (RHA)
F
igure
6: M
oDel
n
uMBering
k
ey
The SMD number shown is for Class K screening and
radiation hardness assurance (RHA) level R. See the SMD
for the numbers for other screening and radiation levels. For
exact specifications for an SMD product, refer to the SMD
drawing. SMDs can be downloaded from:
https://landandmaritimeapps.dla.mil/programs/smcr
t
aBle
3: SMD n
uMBer
c
roSS
r
eFerence
o
n
the lineS below
,
enter one Selection froM each category to deterMine the Model nuMber
.
Model nuMber options
output Voltage
1
3R3, 05, 5R2, 12, 15
category
base Model and
input Voltage
number of
outputs
2
S
D
screening
3
O
H
K
rHa
4
O
P
L
R
options
Fill in For Model #
5
SMSA28
05, 12, 15
_____
SMSA28
__________
/
_______
notes
1. An R indicates a decimal point. 3R3 is 3.3 volts out. The values of 3.3 and 5.2 are only available in single output models.
2. number of Outputs: S is a single output and D is a dual output.
3. Screening: A screening level of O is a space prototype and is only used with RHA O. See Table 9 on page 14 and Table 10 on page 15 for
more information.
4. RHA: 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.” RHA O is only available with screening level O. See Table 10 on page 15 for more information.
5. If ordering by model number add suffix “-Q” to request solder dipped leads (SMSA2805S/KR-Q). Available only for Class H or Class K.
t
aBle
4: M
oDel
n
uMBer
o
ptionS
www.craneae.com/interpoint
SMSA Rev AF - 2018.02.02
Page 5 of 15
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