05/07/10
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M3G-SERIES
Description
nTotal Dose > 200 krad(Si),
typically usable to > 300 krad(Si)
nSEE Hardened up to 82 MeV.cm2/mg
nInternal EMI filter; Converter Capable of
meeting MIL-STD-461C CE03
nLow Weight, < 110 grams
nMagnetically Coupled Feedback
n18V to 50V DC Input Range
nUp to 40W Output Power
nTriple Output Models Include
+5V and ±12V or ±15V
nMain Output Isolated from Dual Outputs
n High Efficiency - to 80%
n-55°C to +125°C Operating Temperature Range
n100MΩ @ 500VDC Isolation
nUnder-Voltage Lockout
nSynchronization Input and Output
n Short Circuit and Overload Protection
nOutput Over Voltage Limiter
nExternal Inhibit
n> 5,000,000 Hour MTBF
n Standard Microcircuit Drawings Available
Features
28V Input, Triple Output
Applications
n Geostationary Earth Orbit Satellites (GEO)
Non-flight versions of the M3G-Series converters are
available for system development purposes. Variations
in electrical specifications and screening to meet custom
requirements can be accommodated.
The M3G-Series of DC-DC converters are radiation
hardened, high reliability converters designed for
extended operation in hostile environments. Their small
size and low weight make them ideal for applications
such as geostationary earth orbit satellites and deep
space probes. They exhibit a high tolerance to total
ionizing dose, single event effects and environmental
stresses such as temperature extremes, mechanical
shock, and vibration. All components are fully derated
to meet the requirements of MIL-STD-975, MIL-STD-
1547 and GSFC PPL-21 Appendix B.
The converters incorporate a fixed frequency single
ended forward topology with magnetic feedback and
an internal EMI filter that utilizes multilayer ceramic
capacitors that are subjected to extensive lot screening
for optimum reliability. These converters are capable
of meeting the conducted emissions and conducted
susceptibility requirements of MIL-STD-461C without
any additional components. External inhibit and
synchronization input and output allow these converters
to be easily incorporated into larger power systems.
They are enclosed in a hermetic 3" x 2" x 0.475" package
constructed of an Aluminum-Silicon-Carbide (AlSiC)
base and an Alloy 48 ring frame and they weigh less
than 110 grams. The package utilizes rugged ceramic
feed-through copper core pins and is sealed using
parallel seam welding.
n Deep Space Satellites / Probes
n Strategic Weapons and Communication
Systems
M3G
HYBRID-HIGH RELIABILITY
RADIATION HARDENED
DC-DC CONVERTER
Manufactured in a facility fully qualified to MIL-PRF-
38534, these converters are fabricated utilizing DSCC
qualified processes. For available screening options,
refer to device screening table in the data sheet.
PD-94535K
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M3G-SERIES
The M3G-Series converters utilize a single-ended
forward topology with resonant reset. The nominal
switching frequency is 500kHz. Electrical isolation
and tight output regulation are achieved through the
use of a magnetically coupled feedback.
Circuit Description
An internal EMI filter allows the converter to meet the
conducted emissions requirements of MIL-STD-461C
on the input power leads. A two-stage output filter
reduces the typical output ripple to less than 20mV
peak-to-peak.
An under-voltage lockout circuit prohibits the
converter from operating when the line voltage is too
low to maintain the output voltage. The converter will
not start until the line voltage rises to approximately
16.5 volts and will shut down when the input voltage
drops below 15.5 volts. The one volt of hysteresis
reduces the possibility of line noise interfering with
the converter’s start-up and shut down.
An external inhibit port is provided to control converter
operation. The nominal threshold relative to the input
return (pin 2) is 1.4V. If 2.0 volts or greater are applied
to the Inhibit pin (pin 3) then the converter will
operate normally. A voltage of 0.8V or less will cause
the converter to shut-down. The pin may be left
open for normal operation and has a nominal open
circuit voltage of 4.0V.
Design Methodology
The M3G-Series was developed using a proven
conservative design methodology which includes
selecting radiation tolerant and established reliability
components and fully derating to the requirements
of MIL-STD-975 and MIL-STD-1547. Careful sizing
of decoupling capacitors and current limiting
resistors minimizes the possibility of photo-current
burn-out. Heavy derating of the radiation hardened
power MOSFET virtually eliminates the possibility
of SEGR and SEB. A magnetic feedback circuit is
utilized instead of opto-couplers to minimize
temperature, radiation and aging sensitivity. PSPICE
and RadSPICE were used extensively to predict
and optimize circuit performance for both beginning
and end-of-life. Thorough design analyses include
Radiation Susceptibility (TREE ), Worst Case, Stress,
Thermal, Failure Modes and Effects (FMEA) and
Reliability (MTBF).
Synchronization input and output allow multiple
converters to operate at a common switching
frequency. Converters can be synchronized to one
another or to an externally provided clock. This can
be used to eliminate beat frequency noise or to avoid
creating noise at certain frequencies for sensitive
systems.
The main ( +5 volt ) output is regulated by the control
loop and typically exhibits better than 1% regulation.
The auxiliary ( ±12 volt or ±15 volt ) outputs are
maintained through tight coupling in the power
transformer and main output filter inductor and
typically exhibit better than 5% regulation. The main
output and auxiliary outputs are isolated from each
other.
Output power is limited under any load fault condition
to approximately 125% of rated. An overload
condition causes the converter output to behave like
a constant current source with the output voltage
dropping below nominal. The converter will resume
normal operation when the load current is reduced
below the current limit point. This protects the
converter from both overload and short circuit
conditions. The current limit point exhibits a slightly
negative temperature coefficient to reduce the
possibility of thermal runaway.
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M3G-SERIES
1 Meets derating per MIL-STD-975
2For operation at +125°C see table note 14
Electrical Performance Characteristics
For Notes to Specifications, refer to page 5
Limits
Parameter
Group A
Subgroup
Conditions
-55°C ≤ TC ≤ +85°C
VIN = 28V DC ± 5%, CL = 0
unless otherwise specified
Min
Nom
Max
Unit
Input Voltage 1,2,3 Note 2 18 28 50 V
Output Voltage ( Vout )
(main)
M3G280512T (aux.)
M3G280515T (aux.)
(main)
M3G280512T (aux.)
M3G280515T (aux.)
1
2,3
IOUT = 100% rated load, Note 5
4.98
±11.50
±14.60
4.93
±11.30
±14.40
5.00
±11.80
±14.90
5.02
±12.10
±15.20
5.07
±12.30
±15.40
V
Output power ( POUT ) 1,2,3 VIN = 18, 28, 50 Volts, Note 2 0 40 W
Output current ( IOUT )
(main)
M3G280512T (aux.)
M3G280515T (aux.)
1,2,3
VIN = 18, 28, 50 Volts, Notes 2,3,4,5
400
83
67
4000
±833
±667
mA
Line regulation ( VRLINE )
(main)
M3G280512T (aux.)
M3G280515T (aux.)
1,2,3
VIN = 18, 28, 50 Volts
IOUT = 10, 50%, 100% rated
Note 5
-10
-120
-150
10
120
150
mV
Load regulation ( VRLOAD )
(main)
M3G280512T (aux.)
M3G280515T (aux.)
1,2,3
IOUT = 10%, 50%, 100% rated
VIN = 18, 28, 50 Volts
Notes 5,13
-50
-400
-500
50
400
500
mV
Cross regulation ( VRCROSS )
(main)
M3G280512T ( aux.)
M3G280515T (aux.)
1,2,3
VIN = 18, 28, 50 Volts
IOUT = 2.5A to 1A and 2.5 to 4A on main
and ±half rated on aux. outputs
-3.5
-3.0
3.5
3.0
%
IOUT = 0, Pin 3 open
80
Input current ( IIN ) 1,2,3
Pin 3 shorted to pin 2
5.0
mA
Specifications
Input voltage range -0.5Vdc to +80Vdc Input voltage range +18Vdc to +60Vdc
Output power Internally limited Input voltage range1 +18Vdc to +50Vdc
Lead temperature +300°C for 10 seconds Output power 0 to Max. Rated
Operating temperature -55°C to +135°C Operating temperature 2 -55°C to +125°C
Storage temperature -55°C to +135°C Operating temperature 1 -55°C to +70°C
Recommended Operating Conditions Absolute Maximum Ratings
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M3G-SERIES
Electrical Performance Characteristics ( continued )
For Notes to Specifications, refer to page 5
Limits
Parameter
Group A
Subgroup
Conditions
-55°C ≤ TC ≤ +85°C
VIN = 28V DC ± 5%, CL = 0
unless otherwise specified
Min
Nom
Max
Unit
Output ripple ( VRIP )
(main)
M3G280512T (aux.)
M3G280515T (aux.)
1,2,3
VIN = 18, 28, 50 Volts
IOUT = 100% rated load, Notes 5, 6
25
30
30
50
60
75
mV p-p
Switching frequency ( FS ) 1,2,3 Sync. Input (Pin 4) open 450 500 550 KHz
Efficiency ( EFF ) 1,2,3 IOUT = 100% rated load
Note 5
75 79
%
Inhibit Input
open circuit voltage
drive current ( sink )
voltage range
Note 1
3.0
-0.5
5.0
100
50
V
µA
V
Synchronization Input
frequency range
pulse high level
pulse low level
pulse transition time
pulse duty cycle
Ext. Clock on Sync. Input (Pin 4)
Note 1
450
4.0
-0.5
40
20
600
10.0
0.5
80
KHz
V
V
V/µs
%
Current Limit Point
Expressed as a percentage
of full rated output power
1,2
3
Vout = 90% of Nominal, Note 5
135
150 %
Power dissipation, load fault (PD) 1,2,3 Short Circuit, Overload, Note 8
20 W
Output response to
step load changes (VTLD)
4,5,6
Half Load to/from Full Load, Notes 5,9
-300
300
mV pk
Recovery time,
step load changes (TTLD)
4,5,6
Half Load to/from Full Load, Note 5,9,10
200
µs
Output response to
step line changes (VTLN)
18V to/from 50V
IOUT = 100% rated load, Notes 1,5,11
-300
300
mV pk
Recovery time,
step line changes (TTLN)
18V to/from 50V
IOUT = 100% rated load, Notes 1,5,10,11
200
µs
Turn-on Response
Overshoot (VOS)
(main)
(aux.)
Turn-on Delay (TDLY)
4,5,6
No Load, Full Load, Notes 5,12
10% of Nominal
1.0
500
10
5.0
mV
%
ms
Capacitive Load (CL)
(main)
(Each aux. output)
IOUT = 100% rated load, No effect on DC
performance, Notes 1, 5, 7
1000
200
µF
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M3G-SERIES
Electrical Performance Characteristics ( continued )
1. Parameter is tested as part of design characterization or after design changes. Thereafter, parameter shall
be guaranteed to the limits specified.
2. Parameter verified during line and load regulation tests.
3. Although operation with no load is permissible, light loading on the main (+5 volt) output may cause the output
voltage of the auxiliary outputs
(±12 volt or ±15 volt) to drop out of regulation. It is therefore recommended that at least 200 mA or 20 percent
of the total output power, whichever is greater, be taken from the main (+5 volt) output.
4. Although operation with no load is permissible, heavy loading on the main (+5 volt) output may cause the
output voltage of the auxiliary outputs
(±12 volt or ±15 volt) to rise out of regulation. It is therefore recommended that at least 50 mA or 20 percent
of the total output power, whichever is greater, be taken from the auxiliary (±12 volt or ±15 volt) outputs.
5. Unless otherwise specified, “Rated” load is 20W on the main (+5 volt) output and 10 watts each on the auxiliary
(±12 volt or ±15 volt) outputs. Load currents of up to 5A and ±1A on the main and auxiliary outputs respec-
tively are acceptable as long as the total output power does not to exceed 40 watts.
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 interfere with the proper operation of the converter’s
overload protection, causing erratic behavior during turn-on.
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 ³ 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 ³ 100 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 nominal.
13. Load is varied for output under test while the remaining outputs are loaded at 50% of rated. Regulation relative
to output voltage at 50% rated load.
14. Although operation at temperatures between +85°C and +125°C is guaranteed, no parametric limits are
specified.
Notes: Electrical Performance Characteristics
Limits
Parameter
Group A
Subgroup
Conditions
-55°C ≤ TC ≤ +85°C
VIN = 28V DC ± 5%, CL = 0
unless otherwise specified
Min
Nom
Max
Unit
Line Rejection IOUT = 100% rated load
DC to 50KHz, Notes 1,5
40 60 dB
Isolation 1 Input to Output or any pin to case
Except pin 10, test @500VDC
100 MΩ
Device Weight 110 g
MTBF MIL-HDBK-217F2, SF, 35°C 5 x 106 Hrs
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M3G-SERIES
Radiation Performance Characteristics
Test
Conditions
Min
Typ
Unit
Total Ionizing Dose ( Gamma ) MIL-STD-883, Method 1019
Operating bias applied during exposure,
Full Rated Load, VIN = 28V
200
300
KRads (Si)
Dose Rate (Gamma Dot)
Temporary Saturation
Survival
MIL-STD-883, Method 1023
Operating bias applied during exposure,
Full Rated Load, VIN = 28V
1E8
4E10
1E11
Rads (Si)/sec
Neutron Fluence MIL-STD-883, Method 1017 8E12 1E13 Neutrons
/cm2
Single Event Effects
SEU, SEL, SEGR, SEB
Heavy ions (LET)
Operating bias applied during exposure,
Full Rated Load, VIN = 28V
82
MeV•cm2
/mg
Figure 1. Block Diagram - Triple Output
1
3
2
12
11
Vin
INHIBIT
RETURN
+AUX.
OUTPUT
AUX.
RETURN
4
SYNC.
INPUT
10 CASE
GROUND
5
SYNC.
OUTPUT
+
-
LEVEL
TRANSLATOR
& FET DRIVE
BIAS
SUPPLY
UNDER VOLTAGE
LOCKOUT
& INHIBIT
EMI
FILTER
SHORT CIRCUIT
&
OVERLOAD
+10.5V
+5V
+
-
OSCILLATOR
RAMP
GENERATOR SAMPLE
&
HOLD
FEEDBACK
TRIGGER
PWM
EA
+5V+5V
13
-AUX.
OUTPUT
6
+MAIN
MAIN
RETURN
7
International Rectifier currently does not have a DSCC certified Radiation Hardness Assurance Program.
www.irf.com 7
M3G-SERIES
10
10.5
11
11.5
12
12.5
13
13.5
14
±12V Magnitudes ( Volts )
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
±12V Load Current ( Amps each )
5V load = 4A
5V load = 2A
5V load = 0.4A
Figure 2. ±12V Load Regulation vs 5V Load
13
13.5
14
14.5
15
15.5
16
16.5
17
17.5
18
±15V Magnitudes ( Volts )
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
±15V Load Current ( Amps each )
5V load = 4A
5V load = 2A
5V load = 0.4A
Figure 3. ±15V Load Regulation vs 5V Load
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M3G-SERIES
Figure 4. M3G280512T Efficiency vs Line and Load
40
50
60
70
80
90
Efficiency ( % )
0 5 10 15 20 25 30 35 40
Output Power ( Watts )
Vin=18V
Vin=28V
Vin=50V
40
50
60
70
80
90
Efficiency ( % )
0 5 10 15 20 25 30 35 40
Output Power ( Watts )
Vin=18V
Vin=28V
Vin=50V
Figure 5. M3G280515T Efficiency vs Line and Load
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M3G-SERIES
Figure 6. Conducted Emissions, Positive Lead
0
10
20
30
40
50
60
70
80
90
100
dB-uA
1E3 1E4 1E5 1E6 1E7 1E8
Frequency ( Hz )
CEO3 LIMIT
Figure 7. Conducted Emissions, Return Lead
0
10
20
30
40
50
60
70
80
90
100
dB-uA
1E3 1E4 1E5 1E6 1E7 1E8
Frequency ( Hz )
CEO3 LIMIT
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M3G-SERIES
Figure 8. Conducted Emissions, Common Mode
0
10
20
30
40
50
60
70
80
90
100
dB-uA
1E3 1E4 1E5 1E6 1E7 1E8
Frequency ( Hz )
CEO3 LIMIT
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M3G-SERIES
Ensure that flatness of the plate where M3G converter to be mounted is no greater than 0.003” per linear inch.
It is recommended that a thermally conductive gasket is used to promote the thermal transfer and to fill any
voids existing between the two surfaces. IR recommends Sil-Pad 2000 with the thickness of 0.010". The
shape of the gasket should match the footprint of the converter including the mounting flanges. The gasket
is available from IR. The M3G-series converter requires either M3 or 4-40 size screws for attachment
purposes.
The procedure for mounting the converter is as follows:
1. Check the mounting surfaces and remove foreign material, burrs if any or anything that may
interfere with the attachment of the converter.
2. Place the gasket on the surface reserved for the converter and line it up with the mounting holes.
3. Place the converter on the gasket and line both up with mounting holes.
4. Install screws using appropriate washers and tighten by hand (~ 4 in·oz) in the sequence shown below.
Application Note:
A) Attachment of the Converter.
5. Tighten the screws with an appropriate torque driver. Torque the screws up to 6 in·lb in the sequence
shown above.
The following procedure is recommended for mounting the converter for optimum cooling and to circumvent
any potential damage to the converter.
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M3G-SERIES
Mechanical Diagram
Pin Designation (Triple Output)
Pin # Designation Pin # Designation
1 + Input 8 NC
2 Input Return 9 NC
3 Inhibit 10 Case Ground
4 Sync. Input 11 - Aux. Output
5 Sync. Output 12 Aux. Output Return
6 Main Return 13 +Aux. Output
7 + Main Output
3.055 MAX.
0.500 2.00
0.45 1.10
2.5002.30
0.200 Typ.
Non-
cum.
0.30
1.400
Ref.
3.50
Ref.
0.475
MAX.
0.080
Max.
0.260
Pin
Ø0.040
R0.0625
4 places
0.50
0.60
0.20
Tolerance : .XX ±0.01
.XXX ±0.005
1
2
3
4
5
12
13
11
10
9
8
7
6
0.25
2.055
MAX.
FLANGE DETAIL
0.40
0.25
0.14
R0.0625
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M3G-SERIES
Part Numbering
Notes:
c
Best commercial practice.
d
CK is DSCC class K compliant without radiation performance. No Suffix is a radiation rated device but
not available as a DSCC qualified SMD per MIL-PRF-38534.
Main Output
Voltage
Model
Nominal Input
Voltage
28 = 28V
Screening Level
(Please refer to Screening Table)
No Suffix, CK, EM
03R3 = 3.3V
05 = 5V
12 = 12V
15 = 15V
Output
T = Triple
M3G 28 05 15 T /EM
Auxiliary Output
Voltage
05 = ± 5V
12 = ± 12V
15 = ± 15V
Standard Microcircuit IR Standard
Drawing Number Part Number
5962-03226 M3G280512T
5962-03227 M3G280515T
Standard Microcircuit Drawing Equivalence Table
International Rectifier currently does not have a DSCC certified Radiation Hardness Assurance Program.
Device Screening
Requirement MIL-STD-883 Method No Suffix
d
CK
d
EM
Temperature Range -55°C to +85°C -55°C to +85°C -55°C to +85°C
Element Evaluation MIL-PRF-38534 Class K Class K N/A
Non-Destructive Bond Pull 2023 Yes Yes N/A
Internal Visual 2017 Yes Yes
c
Temperature Cycle 1010 Cond C Cond C Cond C
Constant Acceleration 2001, Y1 Axis 3000 Gs 3000 Gs 3000 Gs
PIND 2020 Cond A Cond A N/A
320 hrs @ 125°C 320 hrs @ 125°C 48 hrs @ 125°C
( 2 x 160 hrs ) ( 2 x 160 hrs )
Final Electrical MIL-PRF-38534 -55°C, +25°C, -55°C, +25°C, -55°C, +25°C,
( Group A ) & Specification +85°C +85°C +85°C
PDA MIL-PRF-38534 2% 2% N/A
Seal, Fine and Gross 1014 Cond A, C Cond A, C Cond A
Radiographic 2012 Yes Yes N/A
External Visual 2009 Yes Yes
c
Burn-In 1015
WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, Tel: (310) 252-7105
IR SAN JOSE: 2520Junction Avenue, San Jose, California 95134, Tel: (408) 434-5000
Visit us at www.irf.com for sales contact information.
Data and specifications subject to change without notice. 05/2010
