1
SMSA SERIES
5 WATT
MODELS
VDC OUTPUT
DC/DC C
ONVERTERS
28 V
OLT
I
NPUT
SINGLE
5
12
15
DUAL
±12
±15
Size (max.): 1.075 x 1.075 x 0.270 inches
(27.31 x 27.31 x 6.86 mm)
See Figures 23 and 24 for dimensions.
Weight: 15 grams maximum.
Screening: Standard, Class H, or Class K (MIL-PRF-38534)
Radiation hardness levels O, L, and R
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/aero-
space reliability levels and optimum miniaturization. The hermeti-
cally 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.
SCREENING AND REPORTS
SMSA converters offer three screening options – Standard, Class
H, or Class K – and three levels of radiation hardness. See Tables
1 through 3 for more information. Detailed reports on product
performance are also available and are listed in Table 4.
CONVERTER DESIGN
The SMSA converters are switching regulators that use a flyback
converter design with a constant switching frequency of 550 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.
Negative output regulation is maintained by tightly coupled
magnetics. Predictable current limit is accomplished by direct moni-
toring 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 VDC voltage range. An undervoltage lockout
feature keeps the converter shutdown below approximately 13 VDC
to ensure smooth initialization.
IMPROVED DYNAMIC RESPONSE
The SMSA feed-forward compensation system provides excellent
dynamic response and noise rejection. Audio rejection is typically 50
dB. The minimum to maximjm step line transient response is typi-
cally less than 1%.
INHIBIT FUNCTION
SMSA converters provide a TTL open collector-compatible 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 TTL compatible 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.
FEATURES
• Fully qualified to Class H or K
• Radiation hardened
• –55° to +125°C operation
• 16 to 40 VDC input
• Fully isolated
• Optocoupler feedback
• Fixed frequency, 550 kHz typical
• Topology – Single Ended Flyback
• Inhibit function
• Indefinite short circuit protection
• 5 watts output power
• Up to 76% efficiency
RECOMMENDED OPERATING CONDITIONS
TYPICAL CHARACTERISTICS
INHIBIT
ABSOLUTE MAXIMUM RATINGS
Input Voltage
• 16 to 40 V
Output Power
• 5 watts
Lead Soldering Temperature (10 sec per lead)
• 300°C
Storage Temperature Range (Case)
• –65°C to +135°C
2
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
Output Voltage Temperature Coefficient
• 100 ppm/°C typical
Input to Output Capacitance
• 50 pF typical
Isolation
• 100 megohm minimum at 500 V
Audio Rejection
• 50 dB typical
Conversion Frequency
• 550 kHz typical
450 kHz min, 600 kHz max
Inhibit Pin Voltage (unit enabled)
•9 to 11 V
Input Voltage Range
• 16 to 40 VDC continuous
• 50 V for up to 50 msec transient
Case Operating Temperature (Tc)
• –55°C to +125°C full power
• –55°C to +135°C absolute
Derating Output Power/Current (Tc)
• Linearly from 100% at 125°C to 0% at 135°C
Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, radiation level O, unless otherwise specified.
Inhibit TTL Open Collector
• Logic low (output disabled)
Logic low voltage ≤0.8 V max
Inhibit pin current 4 mA max
• Referenced to input common
• Logic high (output enabled)
Open collector
Notes
1. Indefinite short circuit protection not guaranteed above 125°C (case).
2. Recovery time is measured from application of the transient to point at which
VOUT is within 1% of VOUT at final value.
3. Transition time >10µs.
SINGLE OUTPUT MODELS SMSA2805S SMSA2812S SMSA2815S
PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
OUTPUT VOLTAGE Tc = –55°C TO +125°C 4.95 5.00 5.05 11.88 12.00 12.12 14.85 15.00 15.15 VDC
OUTPUT CURRENT
Tc = –55°C TO +125°C VIN = 16 TO 40 VDC 0 — 1000 0 — 417 0 — 333 mA
OUTPUT POWER VIN = 16 TO 40 VDC
Tc = –55°C TO +125°C — — 5 — — 5 — — 5 W
OUTPUT RIPPLE
VOLTAGE 10 kHz - 2 MHz — 150 450 — 125 500 — 150 600 mV p-p
LINE REGULATION VIN = 16 TO 40 VDC
Tc = –55°C TO +125°C — 10 50 — 10 50 — 10 50 mV
LOAD REGULATION NO LOAD TO FULL
Tc = –55°C TO +125°C — 10 50 — 10 50 — 10 50 mV
INPUT VOLTAGE Tc = –55°C TO +125°C
NO LOAD TO FULL CONTINUOUS 16 28 40 16 28 40 16 28 40 VDC
TRANSIENT 50 ms 0 — 50 0 — 50 0 — 50 V
INPUT CURRENT NO LOAD — 35 60 — 35 60 — 35 60
Tc = –55°C TO +125°C FULL LOAD — 250 — — 235 — — 235 — mA
INHIBITED — 3 5 — 3 5 — 3 5
INPUT RIPPLE 10 kHz - 10 MHz — 50 200 — 50 200 — 50 200 mA p-p
CURRENT Tc = –55°C TO +125°C — 60 300 — 60 300 — 60 300
EFFICIENCY 64 69 — 68 74 — 69 74 — %
LOAD FAULT1, 2 POWER DISSIPATION — 1.5 2.0 — 1.2 1.9 — 1.2 1.8 W
SHORT CIRCUIT RECOVERY — 12.5 25 — 1 10 — 1 10 ms
STEP LOAD 50% - 100% - 50%
RESPONSE2, 3 TRANSIENT — 200 500 — 300 750 — 400 1000 mV pk
RECOVERY — 200 500 — 400 1000 — 400 1000 µs
STEP LINE TRANSIENT
RESPONSE2, 3 16 TO 40 VIN — 200 500 — 200 800 — 200 500 mV pk
40 TO 16 VIN — 200 500 — 250 600 — 200 500
RECOVERY
16 TO 40 VIN — 400 1000 — 700 1300 — 500 1300 µs
40 TO 16 VIN — 400 1000 — 700 1300 — 500 1300
START-UP DELAY — 10 75 — 10 75 — 10 75 ms
OVERSHOOT — 0 200 — 0 500 — 0 500 mV pk
3
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, radiation level O, unless otherwise specified.
Notes
1. Up to 4 watts (80% of full power) is available from either output providing the
opposite output is carrying 20% of total power.
2. Shows regulation effect on the minus output during the defined cross loading
conditions, with 80% and 20% referring to the total output power of the
converter. See Figures 15 and 16.
3. Indefinite short circuit protection not guaranteed above 125°C (case).
4. Recovery time is measured from application of the transient to point at which
VOUT is within 1% of VOUT at final value.
5. Transition time >10µs.
DUAL OUTPUT MODELS SMSA2812D SMSA2815D
PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
OUTPUT VOLTAGE +VOUT 11.88 12.00 12.12 14.85 15.00 15.15 VDC
–VOUT 11.76 12.00 12.24 14.70 15.00 15.30
OUTPUT CURRENT1VIN = 16 to 40 VDC
Tc = –55°C to +125°C — ±208 333 — ±167 267 mA
OUTPUT POWER1VIN = 16 to 40 VDC
Tc = –55°C to +125°C — — 5 — — 5 W
OUTPUT RIPPLE VOLT. 10 kHz - 2 MHz — 80 300 — 120 300 mV p-p
LINE REGULATION Tc = –55°C to +125°C
Vin = 16 to 40 VDC +VOUT — 20 100 — 10 50 mV
–VOUT — 40 200 — 40 180
LOAD REGULATION Tc = –55°C to +125°C
NO LOAD TO FULL +VOUT — 10 120 — 10 50 mV
–VOUT — 100 400 — 50 200
CROSS REGULATION2+PO = 20 - 80 %, –PO = 80 - 20% — 3.7 6 — 3 6
–PO = 20 - 80 %, +PO = 80 - 20%
INPUT VOLTAGE NO LOAD TO FULL
Tc = –55°C to +125° CONTINUOUS 16 28 40 16 28 40 VDC
TRANSIENT 50 ms — — 50 — — 50 V
INPUT CURRENT NO LOAD — 40 63 — 38 60
Tc = –55°C to +125°C FULL LOAD — 235 — — 235 — mA
INHIBITED — 3 5 — 3 5
INPUT RIPPLE 10 kHz TO 10 MHz — 50 200 — 50 200
CURRENT Tc = –55°C to +125°C — 60 300 — 60 300 mA p-p
EFFICIENCY 67 73 — 68 73 — %
LOAD FAULT3, 4 POWER DISSIPATION
SHORT CIRCUIT — 1.3 1.7 — 1.3 1.6 W
RECOVERY — 1 30 — 1 50 ms
STEP LOAD 50% - 100% - 50% BALANCED
RESPONSE4, 5 TRANSIENT — 200 550 — 220 600 mV
BOTH OUTPUTS RECOVERY — 200 500 — 200 500 µs
STEP LINE RESP.4, 5
TRANSIENT16 TO 40 VDC — 200 500 — 600 1500
BOTH OUTPUTS 40 TO 16 VDC — 200 500 — 600 1500 mV pk
RECOVERY 16 TO 40 VDC — 300 750 — 500 1200
40 TO 16 VDC — 800 2000 — 500 1200 µs
START-UP DELAY — 10 30 — 10 25 ms
OVERSHOOT — 0 500 — 0 500 mV pk
4
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
Positive
Input
Inhibit
PWM
Control
Negative
Output
Output
Common
Positive
Output
Input
Common
Case
Ground
6
5
7
8
1
2
3
Feedback
Output Filter
Output Filter
Error
Amp
= DUAL OUTPUT
VR
FIGURE 1: SMSA BLOCK DIAGRAM
6
5
7
200 pF
3.9 K
10 K
Inhibit
SMSA
Input
Common
Positive
Input
10 k
Vcc
Typically 1.5 V
when inhibited
12 k
5 k
400
50 k
2N3904
FIGURE 2: INHIBIT INTERFACE
5
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
+
C2
T1
C1
Case
C3
SMSA2815S
Input
Common
Positive
Input Positive
Output
Output Common
To Load
Positive
Input
Input
Common
Positive
Output
Output
Common
From input
power source
EMI Filter
Case
T1
Negative
Output
+
C2
T1
C1
T1
C4
C3
C5
+To Loads
Case
SMSA2815D
Input
Common
Positive
Input Positive
Output
Output Common
Positive
Input
Input
Common
Positive
Output
Output
Common
From input
power source
EMI Filter
Case
FIGURE 3: LOW NOISE OUTPUT FILTER FOR S MSA SINGLE OUTPUT MODEL
FIGURE 4: LOW NOISE OUTPUT FILTER FOR SMSA DUAL OUTPUT MODEL
The filter suggestions in Figures 3 and 4 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, µi= 5000
Dual output: T2 = 10T #28 AWG winding on toroid, µi= 5000
For best results, make interconnections as short as possible.
MODEL NUMBERING KEY
SMD NUMBERS
PIN OUT
6
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
SMSA 28 05 S / K R
Base Model
Radiation Tolerance
Voltage In (28V)
Output Voltage
Environmental Screening
Number of Outputs
(S = single, D = dual)
Pin Single Output Dual Output
1 Positive Output Positive Output
2 Output Common Output Common
3 No connection Negative Output
4 No connection No connection
5 Inhibit Inhibit
6 Positive Input Positive Input
7 Input Common Input Common
8 Case Ground Case Ground
STANDARD MICROCIRCUIT
DRAWING (SMD)
5962-9309202HXC
5962-9309302HXC
5962-9309402HXC
5962-9308902HXC
5962-9309002HXC
SMSA SERIES
SIMILAR PART
SMSA2805S/HO
SMSA2812S/HO
SMSA2815S/HO
SMSA2812D/HO
SMSA2815D/HO
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. SMDs can be downloaded from:
http://dscc.dla.mil/programs/smcr
BOTTOM VIEW
SMSA
876
54321
Squared corner on header and dot
on top of cover indicate pin one.
FIGURE 5: PIN OUT BOTTOM VIEW
See Figures 23 and 24 for dimensions.
7
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
Typical Performance Curves: 25°C Tc, 28 VDC Vin, 100% load, unless otherwise specified.
FIGURE 5FIGURE 7
OUTPUT POWER (Watts)
SMSA2815D EFFICIENCY
EFFICIENCY (%)
30
80
40V
70
60
50
40
123456
16V
28V
100µs/div
16V TO 40V
SMSA2805S STEP LINE RESPONSE
20mV/div.
V
IN
20V/div.
VOUT
OUTPUT POWER (Watts)
SMSA2805S EFFICIENCY
EFFICIENCY (%)
30
80
40V
70
60
50
40
123456
16V
28V
FIGURE 2
OUTPUT POWER (Watts)
SMSA2812S EFFICIENCY
EFFICIENCY (%)
30
80
40V
70
60
50
40
123456
16V
28V
FIGURE 3
FREQUENCY (kHz)
SMSA SERIES AUDIO REJECTION
ATTENUATION (dB)
1000.1 1 10 100
90
80
70
60
50
40
30
20
10
FIGURE 6
FIGURE 4
OUTPUT POWER (Watts)
SMSA2815S EFFICIENCY
EFFICIENCY (%)
30
80
40V
70
60
50
40
123456
16V
28V
FIGURE 11 FIGURE 13
200µs/div
16V TO 40V
SMSA2815D INPUT STEP LINE RESPONSE
100mV/div.
V
IN
20V/div.
+VOUT
–VOUT
200µs/div
10% 90%
SMSA2815D +VO STEP LOAD RESPONSE
200mV/div.
10% to 90%
90% to 10%
–POUT=0.5W
100µs/div
50% 100%
SMSA2805S STEP LOAD RESPONSE
50mV/div.
50% to 100%
100% to 50%
FIGURE 8
100µs/div
10% 100%
SMSA2805S STEP LOAD RESPONSE
50mV/div.
10% to 100%
100% to 10%
FIGURE 9
100µs/div
10% 50%)
SMSA2815D +VO STEP LOAD RESPONSE
100mV/div.
10% to 50%
50% to 10% –P
OUT=2.5W
FIGURE 12
FIGURE 10
1 ms / div
SMSA2805S TURN-ON INTO NO LOAD
1V/div.
V
IN
20V/div.
VOUT
8
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
Typical Performance Curves: 25°C Tc, 28 VDC Vin, 100% load, unless otherwise specified.
FIGURE 17
OUTPUT POWER (Watts)
50 mV DROP
SMSA LOW LINE DROPOUT VS. LOAD
INPUT VOLTAGE (Volts)
12
17
16
15
14
13
123456
2805S
2815S
2812S
500µs/div
SMSA2815D TURN-ON INTO NO LOAD
5V/div.
V
IN
20V/div.
+VOUT
–VOUT
FIGURE 14
OUTPUT LOAD (+VOUT % / –VOUT %)
90–10% LOAD on +V, 10-90% LOAD on –V
SMSA DUAL CROSS REGULATION
–VOUT VOLTAGE CHANGE (%)
–10
0
10
90/10 70/30 50/50 30/70 10/90
–8
–6
–4
–2
2
4
6
8
2815D
2812D
FIGURE 15
OUTPUT POWER (Watts)
50 mV DROP
SMSA LOW LINE DROPOUT VS. LOAD
INPUT VOLTAGE (Volts)
12
17
16
15
14
13
123456
2812D
2815D
FIGURE 18
FIGURE 16
OUTPUT LOAD (%)
COND. A: 50% LOAD +V; 10% to 50% –V
COND. B: 50% LOAD –V; 10% to 50% +V
SMSA DUAL CROSS REGULATION
–VOUT VOLTAGE CHANGE (%)
–5
0
5
10 20 30 40 50
–4
–3
–2
–1
1
2
3
4
2815D
2812D
2812D
COND B
COND A
9
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
CASE C
BOTTOM VIEW
See Figure 24
for pin configurations.
1.075 max
(27.31)
Materials
Header Cold Rolled Steel/Nickel/Gold
Cover Cold Rolled Steel/Nickel
Pins Copper/Nickel/Gold
compression glass seal
Case dimensions in inches (mm)
Tolerance
±0.005 (0.13) for three decimal places
±0.01 (0.3) for two decimal places
unless otherwise specified
1.075 max
(27.31)
CAUTION
Heat from reflow or wave soldering may
damage the device. Solder pins
individually with heat application not
exceeding 300°C for 10 seconds per
pin.
Dot on top of case
indicates pin one
0.000
0.132
(3.35)
0.932
(23.67)
0.000
0.132 (3.35)
876
5432
1
0.332 (8.43)
0.532 (13.51)
0.732 (18.59)
0.932 (23.67)
0.025
(0.64)
dia.
0.000
0.270 max.
(6.86)
SMSA Series
BOTTOM VIEW CASE C1
0.205 ±0.010
(5.21 ±0.25)
Projection Weld Squared corner and dot on
top of case indicate pin one.
FIGURE 24: CASE C1
FIGURE 23: CASE C MAXIMUM DIMENSIONS
Note: Although every effort has been made to render the case drawings at actual size, variations in the printing process may cause some distortion. Please refer
to the numerical dimensions for accuracy.
10
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
ELEMENT EVALUATION STANDARD CLASS CLASS
TEST PERFORMED (O) H K
(COMPONENT LEVEL) M/S P M/S P M/S P
Element Electrical yes no yes yes yes yes
Element Visual no no yes yes yes yes
Internal Visual no no yes no yes no
Temperature Cycling no no no no yes yes
Constant Acceleration no no no no yes yes
Interim Electrical no no no no yes no
Burn-in no no no no yes no
Post Burn-in Electrical no no no no yes no
Steady State Life no no no no yes no
Voltage Conditioning /Aging no no no no no yes
Visual Inspection no no no no no yes
Final Electrical no no yes yes yes yes
Wire Bond Evaluation no no yes yes yes yes
SEM no no no no yes no
SLAM™/C-SAM:
Input capacitors only no no no yes no yes
(Add’l test, not req. by H or K)
Definitions
Element Evaluation: Component testing/screening per MIL-STD-883 as determined by MIL-PRF-38534
SEM: Scanning Electron Microscopy
SLAM™: Scanning Laser Acoustic Microscopy
C-SAM: C - Mode Scanning Acoustic Microscopy
Notes
M/S Active components (Microcircuit and Semiconductor Die)
P Passive components
TABLE 1: ELEMENT EVALUATION
11
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
ENVIRONMENTAL SCREENING
TEST PERFORMED STANDARD CLASS CLASS
(END ITEM LEVEL)(O)HK
Non-destruct bond pull
Method 2023 no no yes
Pre-cap inspection
Method 2017, 2032 yes yes yes
Temperature cycle
Method 1010, Cond. C yes yes yes
Constant acceleration
Method 2001, 3000 g yes yes yes
PIND Test
Method 2020, Cond. B no no yes
Radiography
Method 2012 no no yes
Pre burn-in test yes yes yes
Burn-in, Method 1015, 125°C
96 hours yes no no
160 hours no yes no
2 x 160 hour (includes mid BI test) no no yes
Final electrical test
MIL-PRF-38534, Group A yes yes yes
Hermeticity test
Fine Leak,
Method 1014, Cond. A yes yes yes
Gross Leak,
Method 1014, Cond. C yes yes yes
Final visual inspection
Method 2009 yes yes yes
Test methods are referenced to MIL-STD-883 as determined by MIL-PRF-38534.
TABLE 2: PRODUCT ENVIRONMENTAL SCREENING
12
SMSA SERIES
5 WATT
DC/DC C
ONVERTERS
11915-001-DTS Rev A This revision supercedes all previous releases.
All technical information is believed to be accurate, but no responsibility is assumed
for errors or omissions. Interpoint reserves the right to make changes in products or
specifications without notice. SMSA Series is a trademark of Interpoint. Copyright
© 1997-2001 Interpoint Corporation. All rights reserved.
Contact Information:
Interpoint Headquarters USA
Phone: 1-800-822-8782
+425-882-3100
Email: power@intp.com
www.interpoint.com
Interpoint UK
Phone: +44-1252-815511
Email: poweruk@intp.com
Interpoint France
Phone: +33-134285455
Email: powerfr@intp.com
PRODUCT LEVEL AVAILABILITY ENVIRONMENTAL SCREENING LEVELS
STANDARD CLASS CLASS
RADIATION HARDNESS LEVELS (O) H K
O: Standard, no radiation guarantee
For system evaluation, electrically OO HO Not
and mechanically comparable to available
H and K level.
L: Radiation hardened – Tested lots Not
Up to 50 k Rads (Si) total dose available HL KL
No SEU guarantee
R: Radiation hardened – Tested lots Not
Up to 100 k Rads (Si) total dose available HR KR
SEU guarantee up to 40 MeV
TABLE 4:
REPORTS INCLUDED WITH PURCHASE OF PRODUCT HL, KL, HR, or KR
1. Radiation Susceptibility Analysis
2. Electrical/Thermal Stress Analysis and Derating Report
3. MTBF Report
4. FMEA Report
HO option: Reports 2, 3, and 4 are included with purchase.
OO option: Select reports available as separate purchases.
TABLE 3: RADIATION HARDNESS LEVELS
L and R are referenced to MIL-PRF-38534, appendix G, Radiation Hardness
Assurance (RHA) levels.
