Product Plan

Power Management Group
RADIATION HARDENED
ISOLATED DC/DC CONVERTERS
SA50-28-5/15T
50 Watts Total Power
+5Vdc±15Vdc Triple Output
Microsemi Power Management Group (PMG)
multiple decades of fault free heritage complex custom
(radiation hardened) switching power design and systems
are now complimented with the introduction of “SA Series”
Standard Radiation Hardened DC/DC converter modules
Standard Product Offering

+28 Vdc Satellite Input Interface

100kRad (Si) TID; Single Event Effect rated

Surface Mount Construction (non-hybrid)

50W total power, high efficiencies 83%+

Patented Magnetic Feedback

Isolated Synchronization Input

Primary referenced ON – OFF command

Over-current Protection

Input Under-voltage lockout

MIL-STD-1547B design de-rating criteria

100% Space level Environmental Screening

Standard Mounting 2.05” x 3.05” x 0.475”

Single, Dual & Triple Output Options

SEE > 80 MeV•cm2 /mg
SA50-28-5/15T Rev A
Application Scenarios
Power Systems & Devices
Typical Threat
Environments
Military Surveillance & Navigation
Communications Satellites
(GEO) (MEO) (LEO)
Deep Space Probes
EPS, Payload & Subsystems
• Primary
- Total Dose
- SEE
- Dose-Rate-Upset
• Secondary
- Displacement Damage
Commercial Communications
Monitoring Satellites
Launch Vehicles
• Primary
- SEE
- Total Dose (NWE)
• Secondary
- Total Dose (natural)
- Displacement Damage
Tactical Military Systems
Including Avionics
• Primary
- Dose-rate (upset &
Latch up)
- SEE (for avionics)
• Secondary
- Total dose
- Neutron irradiation
ICBM & Strategic Interceptor
• Primary
- Neutron Irradiation
- Dose-Rate
- upset/Survivability
• Secondary
- Total Ionizing Dose
Microsemi Corp.
Page 1 of 14
Radiation Performance Rating
Magnetics are designed, manufactured and screened in
accordance
with
MIL-STD-981.
Group
B
and
All bipolar microcircuits contained within the SA50 series
Qualification test per MIL-STD-981 can be performed if
design are characterized for enhanced low dose rate
required by the customer at additional charge. Part De-
sensitivity (ELDRS), with data constructed at a dose rate
rating is in accordance with MIL-STD-1547B and MIL-
of 0.01 rad (Si)/s or less with assessments in both a
STD-975M. The enclosure is of machined Aluminum
biased and unbiased state
construction. The finish is conductive Alodyne per MILC-5541, Type 3.
Test
Total Ionizing Dose
Min
Typ
Unit
100
300
kRads (Si)
(Gamma)
Note: The product may be upgraded to meet TOR2006(8583)-5236
Single Event Effects
SEU, SEL, SEGR, SEB
LET
requirements
at
customer’s
the
request.
82
MeV•cm2 /mg
(129Xe)
Workmanship is in accordance with the highest industry
standards, including ANSI/STD-001 Class 3.
Qualification and Acceptance Testing
Qualification and inspection/testing minimally include;
Alternate Version (-P)
Random Vibration, Mechanical Shock, Thermal Vacuum,
Thermal Cycling, EMI, and Burn-in testing with periodic
The SA50 series alternate version is offered for
corresponding performance measurements as required.
prototypes
All converter modules are pre-screened according to
Selective component alternatives are employed within
specific in-line acceptance testing. These processes
the design, specifically by utilizing “B” level or lower
include multiple cycles of High and Low temperature
component substitutions. The part substitutions do not
cycling, Random vibration, with Pre and Post Electrical
impact electrical performance characteristics.
and
less
stringent
flight
applications.
Performance Verification prior to delivery.
Parts, Materials and Processes
Internal
electronic
components
are
selected
and
screened in accordance with GSFC EEE-INST-002
(Instruction for EEE Parts Selection, Screening, and
Qualification).
SA50-28-5/15T Rev A
Microsemi Corp.
Page 2 of 14
Ratings
Absolute Maximum Ratings
VIN range
Output power
Lead temperature
Operating temperature
Storage temperature
Shock
Constant Acceleration
-0.5Vdc to +60Vdc
50 Watts
+300°C for 10 Sec.
-55°C to +125°C
-55°C to +125°C
1500 gpk, 0.5 msec
½ sine
50 g
Random Vibration
24.06 grms , 50-2000 Hz
Recommended Operating Conditions
VIN range
+17Vdc to +50Vdc
Output power
2 watts to Max. Rated
Operating temperature c
-55°C to +125°C
Operating temperature a,b
-55°C to +70°C
a Meets derating per MIL-STD-975M
b Meets derating per MIL-STD-1547B
c For operation at +125°C see table Note 15
Electrical Specifications
Group A
Subgroup
1 25°C
2 -55°C
3 85°C
Conditions
-55°C ≤ TCASE ≤ +85°C
VIN = 28V DC ± 5%, CL = 0
unless otherwise specified
Input Voltage
Output Voltage ( VOUT )
(main)
(aux.)
(main)
(aux.)
1,2,3
Note 2
1
IOUT = 100% rated load, Note 5
2,3
IOUT = 100% rated load, Note 5
Output Power (POUT)
1,2,3
VIN = 17, 28, 50 Volts, Notes 2,4
5
50
W
1,2,3
VIN = 17, 28, 50 Volts, Notes 2,3,4,5
400
100
4000
1000
mA
1,2,3
VIN = 17, 28, 50 Volts
IOUT =10%, 50%, 100% rated, Notes 5, 14
-10
-150
10
150
mV
1,2,3
VIN = 17, 28, 50 Volts
IOUT =10%, 50%, 100% rated, Note 5, 13
-50
-500
50
500
mV
-3.00
3.00
%
Parameter
Output current (IOUT)
(main)
(aux.)
Line regulation ( VRLINE )
(main)
(aux.)
Load regulation ( VRLOAD)
(main)
(aux.)
Limits
Unit
Min
17
Nom
28
Max
50
5.08
14.46
5.05
14.25
5.10
14.75
5.10
14.75
5.12
15.05
5.15
15.25
V
V
V
Cross regulation (VRCROSS)
(aux.)
SA50-28-5/15T Rev A
1,2,3
VIN = 17, 28, 50 Volts
IOUT = 2.5A to 1A and 2.5A to 4A on main
and ±half rated on aux. outputs
Microsemi Corp.
Page 3 of 14
Group A
Subgroup
1 25°C
2 -55°C
3 85°C
Conditions
-55°C ≤ TCASE ≤ +85°C
VIN = 28V DC ± 5%, CL = 0
unless otherwise specified
1,2,3
IOUT = 0, Pin 3 open
Pin 3 shorted to pin 2
Nom
100
2.0
Max
150
5.0
1,2,3
VIN = 17, 28, 50 Volts
IOUT = 100% rated load, Notes 5, 6
25
37.5
50
75
mV p-p
Switching frequency (FS)
1,2,3
Sync. Input (Pin 4) open
200
220
240
kHz
Efficiency ( EFF )
1,2,3
IOUT = 100% rated load, Note 5
80
83
Note 1
4.5
1000
Input current (IIN)
Output ripple (VRIP)
(main)
(aux.)
Inhibit Input
ON voltage (or Open Collector)
OFF drive current (sink)
OFF voltage
Min
Ext. Clock on Sync. Input (Pin 4)
Note 1
Current Limit Point
Expressed as a % of full rated
output current
1,2,3
VOUT = 90% of Nominal, Note 5
Power dissipation,
load fault (PD)
1,2,3
Short Circuit, Overload, Note 8
Output response to
step load changes (VTLD)
4,5,6
Recovery time,
step load changes (TTLD)
4,5,6
Half Load to/from Full Load, Notes 5,9
17V to/from 50V
IOUT = 100% rated load, Notes 1, 5,11
Recovery time,
step line changes (TTLN)
17V to/from 50V
IOUT = 100% rated load, Notes 1, 5,11
4,5,6
Capacitive Load (CL)
(main)
(Each aux. output)
No Load, Full Load
Notes 5,12
1
80
105
135
%
18
W
300
mV pk
200
μSec
300
mV pk
200
μs
500
750
5.0
mV
mV
mSec
1000
200
μF
μF
-300
50
-300
50
1.0
DC to 50KHz, Notes 1, 5
IOUT = 100% rated load
40
Input (Pins 1,2,3) to Outputs
Any Pin to Case (except pin 6)
Sync and Sync Rtn to any pin and case
100
60
SA50-28-5/15T Rev A
dB
MΩ
110
MIL-HDBK-217F2, SF, 35°C
Microsemi Corp.
V
μA
V
kHz
V
V
V/μs
%
Device Weight
MTBF
%
300
10.0
0.5
IOUT = 100% rated load, No effect on DC
performance, Notes 1, 5, 7
Line Rejection
mA
250
4.0
-0.5
200
10
Half Load to/from Full Load, Note 5,9,10
Output response
to step line changes (VTLN)
Isolation
Unit
2
Synchronization Input
frequency range
pulse high level
pulse low level
pulse transition rate
pulse duty cycle
Turn-on Response
Overshoot (VOS) (main)
Overshoot (VOS) (aux.)
Turn-on Delay (TDLY)
Limits
8.22E+06
g
Hrs
Page 4 of 14
Test
Total Ionizing Dose
(Gamma)
Dose Rate (Gamma Dot)
Temporary Saturation Survival
Radiation Tests
Conditions
MIL-STD-883, Method 1019
Operating bias applied during exposure,
MIL-STD-883, Method 1023
Operating bias applied during exposure,
Full Rated Load, VIN = 28V
1E8
4E10
1E11
MIL-STD-883, Method 1017
8E12
1E13
Heavy ions (LET)
Operating bias applied during exposure,
82
86
Neutron Fluence
Single Event Effects SEU, SEL,
SEGR, SEB
Min
Typ
Unit
100
300
KRads (Si)
Rads (Si)
/sec
Neutrons
/cm2
MeV•cm2
/mg
Notes: Electrical Performance Characteristics
1. Parameter guaranteed by design.
2. Parameter verified during line and load regulation tests. Regulation is specified for 10% to 100% loading on all outputs.
3. Auxiliary output regulation is not maintained if main output load is less than 10%.
4. Auxiliary outputs require at least 10% loading for specified regulation. Voltage may increase at lighter loads and is ultimately limited by overvoltage zener diodes.
5.Unless otherwise specified, “Rated” load is 20W on the main (+5 volt) output and 15 watts each on the auxiliary (±15 volt) outputs. Load currents of up to 5A and
6. Guaranteed for a D.C. to 20MHz bandwidth. Tested using a 20kHz to 10MHz bandwidth.
7. Capacitive load may be any value from 0 to the maximum limit without compromising dc performance. A capacitive load in excess of the maximum limit may
8. Overload power dissipation is defined as the device power dissipation with the load set such that VOUT = 90% of nominal.
9. Load step transition time ≥ 10 μs.
10. Recovery time is measured from the initiation of the transient to where VOUT has returned to within ±1% of its steady state value.
11. Line step transition time ≥ 100 μs.
12. Turn-on delay time from either a step application of input power or a logic low to a logic high transition on the inhibit pin (pin 3) to the point where VOUT = 90% of
13. Load Regulation relative to output voltage at 50% rated load.
14. Line Regulation relative to output voltage at 28Vdc input.
15. For operation at temperatures between +85°C and +125°C, derate power linearly from 50 watts to zero. Parameter limits are not guaranteed.
Pin Designation
Pin #
1
2
3
4
5
6
Designation
+28V IN
+28V RTN
ON/OFF
SYNC
SYNC RTN
CHASSIS
Pin #
7
8
9
10
11
12
Designation
15V B RTN
+15V B
15V A RTN
+15V A
+5V
5V RTN
Place a low ESR ceramic capacitor and a Tantalum capacitor within one inch of the SA50 module’s input terminals. The suggested
minimum values are 4.7uF and 25uF respectively.
SA50-28-5/15T Rev A
Microsemi Corp.
Page 5 of 14
The Power Supply can sustain short circuit operation indefinitely. When short circuited, the Power Supply output cycles at
approximately 2% duty cycle. Short circuit operation begins when the Power Supply output voltage falls below approximately 60% of
its nominal value.
Output ripple is measured as shown:
SA50-28-5/15T Rev A
Microsemi Corp.
Page 6 of 14
Theory of Operation for the SA50 28 Series
Input voltage is applied to the input EMI filter. This filter consists of differential and common mode components that
attenuate the internal converter switching noise. Additional external filtering is required to ensure compliance to MIL-STD461 levels.
Internal controller bias is supplied during power up and in over-current scenarios via Darlington startup transistors off the
input line. The controller power supply ramps up to the turn on point where it starts to supply drive to the main power
converter MOSFET Q1. Under normal load conditions the output voltage will come up and a “Bootstrap” voltage is fed
back to stabilize the Bias supply eliminating power loss in the start-up transistors.
SA50-28-5/15T Rev A
Microsemi Corp.
Page 7 of 14
Main power conversion occurs in the forward converter Q1 and associated Transformer. The secondary windings develop
the required output voltages in parallel. A coupled inductor promotes good output cross regulation. Elimination of
secondary side post regulators promotes high efficiency performance.
Output voltages are regulated on the main output secondary side. A TL1431 reference develops a current mode error
signal which is chopped by the main forward transformer voltage and the summed with the primary side converter current
in a patented magnetic feedback approach. The combined “V + I” error signal is applied to the primary controller’s ramp
control input to complete the regulation loop.
The primary ON OFF command disables internal switch-mode action when pulled low.
The SYNC input is fully transformer isolated to allow operation from primary or secondary referenced sync drives.
SA50-28-5/15T Rev A
Microsemi Corp.
Page 8 of 14
APPLICATION DATA
Under voltage Operation:
The Input Under-voltage protection feature prevents operation at an undesirably low input voltage. The outputs are guaranteed to turn on at the
specified minimum input voltage and guaranteed to be disabled below 70% of the specified minimum input
Inhibit feature:
An external inhibit port is provided to control converter operation. The inhibit circuit is referenced to the DC Input return. The interface is as shown
below.
The
inhibit signal may be an open-collector or TTL type. Interface must sink 1 mA minimun to inhibit the output.
Inhibit Pin
Power Supply Output
Open
> 4.5 volt
Short
< 3.0 volt
ON
ON
OFF
OFF
I1
1K
I n h ib it (3 )
V in _ R TN (2 )
Sync Input:
The Power Supply’s internal clock may be synchronized to an external signal. For enhanced system configuration flexibility and noise immunity,
the sync input circuit is magnetically isolated from all other circuits and chassis. The interface is shown below. The circuit operates from the
rising (leading) edge of the sync waveform, that generates a short synchronization pulse to the PWM controller. Note that the sync circuit DC
input resistance is 500 Ohms. Specifically, the circuit driving the sync input needs to deliver a minimum of 5 mA of current into the input for a
minimum of 50 ns, resulting in a minimum reflected voltage of 4 volts. Higher voltage drives are acceptable up to 10 volts, delivering
approximately proportional higher current levels. Maintenance of high level voltage drive beyond 50 ns is not essential for correct synchronization
function.
12
27.4
Magnitude (p-p)
min. 4.0 volt
max. 10.0 volt
Duty Cycle
min. 10%
max. 90%
511
SY NC (4)
R1
P1
Rate of Rise
min. 200 V/µsec
Frequency
min. 500kHz
max. 600kHz
S1
SY NC RTN (5)
sy nc_pulse
27.4
SA50-28-5/15T Rev A
Microsemi Corp.
Page 9 of 14
Wire current: -:E1#P / mA
Typical Sync Operation
input current
10
8
6
4
input voltage
2
-0
E1-P / V
4
3
2
1
sync_pulse / V
0
Sync pulse
beta = 17
5
4
3
2
1
-0
4
4.5
5
5.5
6
6.5
Time/uSecs
7
7.5
8
8.5
500nSecs/div
Short Circuit/ Over current limit protection:
The output current is limited by the built in current limit circuit, to protect the Power Supply and the load from overstress.
The weighted sum of main and auxiliary output currents is controlled. The maximum current of any one of the outputs can be calculated
using the following relationship:
5.5×I15A + 5.5× I15B + 2 × I5 = 27 amps
Where,
I15A is the 15V A output current in amperes
I15B is the 15V B output current in amperes
I5 is the 5V output current in amperes
For example, if all outputs are fully loaded and the 5V output load impedance is further reduced to the current limit threshold, the
resulting maximum 5V output load current is:
(27 amp - 5.5×1amp - 5.5×1amp) ×1/2 = 8 amps
The converter continues to regulate its output voltage under this loading condition. If the load impedances of any of the outputs are
further decreased, the converter turns off and attempts to restart after a delay.
SA50-28-5/15T Rev A
Microsemi Corp.
Page 10 of 14
Dual Output Configuration
The SA50-120 Triple configurations are readily configurable as Dual Output supplies.
For balanced output Dual Supply configuration, connect Pins 8 & 9 together to form the Dual Output Common potential. Pin 7 is now the
negative (–) Dual output and Pin 10 is the positive (+) Dual output. In this configuration it is important to preload the unused 5V output
with 12 ohms, representing a 10% of rated load on that output. This assures proper regulation and cross regulation of the dual outputs
over their full load ranges.
For an unbalanced Dual Supply configuration, connect the auxiliary outputs in parallel (Pin 10 to Pin 8 and Pin 9 to Pin 7). Since the
Auxiliary and Main outputs are internally isolated, it is allowable to connect either the main output as the high side dual supply
(Connect Pin 12 to Pin 10 for the Common output) or the Auxiliary output as the high side dual supply (Connect Pin 11 to Pin 9 for the
common output). Again please ensure that the main output load is at least 10% of rated.
Following the above guidelines, the regulation and cross regulation performance of the triple applies to the dual configurations in
general.
Model Numbering Scheme
PMG-28 Series Available Data Items:
Analyses & Reports:
1: Mechanical Analysis
2: Stress Analysis
3: Thermal Analysis
4: Radiation Analysis
5: Worse Case Analysis
6: FEMA
7: First Article Qualification Test Report
8: EMI Test Report
SA50-28-5/15T Rev A
Microsemi Corp.
Page 11 of 14
SA50 Mechanical Installation Application Note
1
Mechanical interface
The surface on which an SA50 power supply is mounted is recommended to be flat to .005 in or
less, with a surface roughness of 32 microinches or less. The mounting hole pattern and housing
footprint for SA50 power supplies is shown in Figure 1.
Figure 1: Mounting hole pattern and housing footprint
2
Mounting fasteners
The fasteners recommended for mounting of SA50 power supplies are 4-40 size fasteners, made
from A-286 steel, used with NAS620C4 washers. Representative fasteners include NAS1101,
NAS1352, or equivalent. The recommended torque is 6-8 in-lb.
SA50-28-5/15T Rev A
Microsemi Corp.
Page 12 of 14
90.0%
Efficiency
25°C 28 volt
85.0%
Main output swept
from 10% to 100%
Aux load each 0.1 amp
80.0%
Aux load each 0.2 amp
Efficiency
Aux load each 0.3 amp
Aux load each 0.4 amp
75.0%
Aux load each 0.5 amp
Aux load each 0.6 amp
Aux load each 0.7 amp
70.0%
Aux load each 0.8 amp
Aux load each 0.9 amp
Aux load each 1.0 amp
65.0%
60.0%
0 watt
10 watt
20 watt
30 watt
40 watt
50 watt
60 watt
Total output
85.0%
Efficiency
25°C 28 volt
84.0%
Main output swept
from 10% to 100% load
Aux load each 0.1 amp
Aux load each 0.2 amp
83.0%
Efficiency
Aux load each 0.3 amp
Aux load each 0.4 amp
Aux load each 0.5 amp
Aux load each 0.6 amp
82.0%
Aux load each 0.7 amp
Aux load each 0.8 amp
Aux load each 0.9 amp
Aux load each 1.0 amp
81.0%
80.0%
0.0 amp
0.5 amp
1.0 amp
1.5 amp
2.0 amp
2.5 amp
3.0 amp
3.5 amp
4.0 amp
4.5 amp
Main output load
SA50-28-5/15T Rev A
Microsemi Corp.
Page 13 of 14
Package Outline
Contact:
Kent Brooten
Sales Manager
Power Management Group
Phone: 714-994-6500, ext. 215 (USA)
E-mail: [email protected]
Web: www.microsemi.com
Address:
Microsemi Corporation PMG
14930 East Alondra Blvd
La Mirada, CA 90638-5752
Phone: 714-994-6500
Information furnished by Microsemi is believed to be accurate and reliable. However, no responsibility is assumed by Microsemi for its
use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by
implication or otherwise under any patent or patent rights of Microsemi Corporation.
SA50-28-5/15T Rev A
Microsemi Corp.
Page 14 of 14