PD-94532I
M3G-SERIES
HYBRID - HIGH RELIABILITY
RADIATION HARDENED
DC-DC CONVERTER
Description
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. By using two stage filtering these
converters produce low input and output noise. 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.
Manufactured in a facility fully qualified to MIL-PRF-
38534, these converters are fabricated utlizing DSCC
qualified processes. For available screening options,
refer to device screening table in the data sheet.
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.
70V Input, Single/Dual Output
M3G
Features
n
Total Dose > 200KRad(Si),
typically usable to > 300KRad(Si)
n
SEE Hardened to LET up to 82 MeV
.
cm
2
/mg
n
Low Weight, < 110 grams
n
Low Input & Output Noise
n
Magnetically Coupled Feedback
n
60V to 120V DC Input Range
n
Up to 40W Output Power
n
Single and Dual Output Models Include
3.3, 5, 12, 15,
±
5,
±
12 and
±
15V
n
High Efficiency - to 82%
n
-55°C to +125°C Operating Temperature Range
n
100M
Ω
@ 500V DC Isolation
n
Under-Voltage Lockout
n
Short Circuit and Overload Protection
n
Output Over Voltage Limiter
n
Remote Sense on Single Output Models
n
Adjustable Output Voltage for Duals
n
Synchronization Input and Output
n
External Inhibit
n
> 5,000,000 Hour MTBF
Applications
n
n
n
Geostationary Earth Orbit Satellites (GEO)
Deep Space Satellites / Probes
Strategic Weapons and Communication
Systems
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1
05/07/10
M3G-SERIES
Circuit Description
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.
An internal EMI filter reduces the conducted
emissions to less than 5mA rms on the input power
leads. A two-stage output filter reduces the typical
output ripple to less than 20mV peak-to-peak.
Output current 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.
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
58 volts and will shut down when the input voltage
drops below 54 volts. The four volts 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.
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.
Remote sense is provided on the single output
models to compensate for voltage drops in the
interconnects between the converter and the load.
The output voltage of dual output models can be
adjusted by a single external resistor.
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).
2
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M3G-SERIES
Specifications
Absolute Maximum Ratings
Input voltage range
Output power
Lead temperature
Operating temperature
Storage temperature
-0.5Vdc to +150Vdc
Internally limited
+300°C for 10 seconds
-55°C to +135°C
-55°C to +135°C
1
2
Recommended Operating Conditions
Input voltage range
Input voltage range
Output power
1
Operating temperature
1
Operating temperature
2
+60Vdc to +120Vdc
+60Vdc to +100Vdc
0 to Max. Rated
-55°C to +125°C
-55°C to +70°C
Meets derating per MIL-STD-975
For operation at +125°C see table note 13
Electrical Performance Characteristics
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 70V DC ± 5%, C
L
= 0
unless otherwise specified
Limits
Parameter
Input Voltage
Output Voltage (Vout)
M3G7003R3S
M3G7005S
M3G7012S
M3G7015S
M3G7005D
M3G7012D
M3G7015D
M3G7003R3S
M3G7005S
M3G7012S
M3G7015S
M3G7005D
M3G7012D
M3G7015D
Output power ( P
OUT
)
M3G7003R3S
All Others
Output current ( I
OUT
)
M3G7003R3S
M3G7005S
M3G7012S
M3G7015S
M3G7005D
M3G7012D
M3G7015D
Line regulation ( VR
LINE
)
Load regulation ( VR
LOAD
)
Group A
Subgroup
Min
60
Nom
70
3.30
5.00
12.00
15.00
±5.00
±12.00
±15.00
Max
100
3.32
5.02
12.05
15.06
±5.02
±12.05
±15.06
3.36
5.07
12.16
15.20
±5.07
±12.16
±15.20
30
40
9.1
8.0
3.34
2.67
6.4
2.67
2.14
10
0.5
Unit
V
1
1
1
1
1
1
1
2,3
2,3
2,3
2,3
2,3
2,3
2,3
1,2,3
I
OUT
= 100% rated load
Note 4
3.28
4.98
11.95
14.94
±4.98
±11.95
±14.94
3.24
4.93
11.84
14.80
±4.93
±11.84
±14.80
0
0
0
0
0
0
0
0
0
-10
-0.5
V
I
OUT
= 100% rated load
Note 4
V
IN
= 60, 70, 100 Volts, Note 2
W
1,2,3
V
IN
= 60, 70, 100 Volts, Note 2
Either Output, Note 3
Either Output, Note 3
Either Output, Note 3
1,2,3
1,2,3
V
IN
= 60, 70, 100 Volts
I
OUT
= 0, 50%, 100% rated, Note 4
I
OUT
= 0, 50%, 100% rated, Note 4
V
IN
= 60, 70, 100 Volts
A
mV
%
Cross regulation ( VR
CROSS
)
M3G7005D
M3G7012D
M3G7015D
1,2,3
Duals only, Note 5
V
IN
= 60, 70, 100 Volts
-5.0
-3.0
-3.0
5.0
3.0
3.0
%
For Notes to Specifications, refer to page 5
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3
M3G-SERIES
Electrical Performance Characteristics
Group A
Subgroup
1,2,3
( continued )
Limits
Min
Nom
30
2.0
15
20
25
25
20
30
30
450
70
77
78
79
77
78
79
3.0
-0.5
500
75
81
82
83
81
82
83
5.0
100
50
600
10.0
0.5
80
145
20
-300
50
-300
300
200
300
Max
50
5.0
35
50
60
80
50
60
60
550
Unit
mA
Parameter
Input current (I
IN
)
Output ripple ( V
RIP
)
M3G7003R3S
M3G7005S
M3G7012S
M3G7015S
M3G7005D
M3G7012D
M3G7015D
Switching frequency ( F
S
)
Efficiency ( E
FF
)
M3G7003R3S
M3G7005S
M3G7012S
M3G7015S
M3G7005D
M3G7012D
M3G7015D
Inhibit Input
open circuit voltage
drive current ( sink )
voltage range
Synchronization Input
frequency range
pulse high level
pulse low level
pulse transition time
pulse duty cycle
Current Limit Point
Expressed as a percentage
of full rated load current
Power dissipation, load fault (P
D
)
Output response to
step load changes (V
TLD
)
Recovery time,
step line changes (T
TLN
)
Output response to
step line changes (V
TLN
)
Turn-on Response
Overshoot (V
OS
)
Turn-on Delay (T
DLY
)
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 70V DC ± 5%, C
L
= 0
unless otherwise specified
I
OUT
= 0, Pin 3 open
Pin 3 shorted to pin 2
1,2,3
V
IN
= 60, 70, 100 Volts
I
OUT
= 100% rated load
Notes 4, 6
mV p-p
1,2,3
1,2,3
Sync. Input (Pin 4) open
I
OUT
= 100% rated load
Note 4
KHz
%
Note 1
V
µA
V
KHz
V
V
V/µs
%
%
W
mV pk
µs
mV pk
Ext. Clock on Sync. Input (Pin 4)
Note 1
450
4.0
-0.5
40
20
1,2,3
1,2,3
4,5,6
V
out
= 90% of Nominal, Note 4
Short Circuit, Overload, Note 8
Half Load to/from Full Load, Notes 4,9
60V to/from 100V
I
OUT
= 100% rated load, Notes 1,4,10,11
60V to/from 100V
I
OUT
= 100% rated load, Notes 1, 4,11
4,5,6
No Load, Full Load
Notes 4,12
1.0
10
5.0
%
ms
For Notes to Specifications, refer to page 5
4
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M3G-SERIES
Electrical Performance Characteristics
Group A
Subgroup
( continued )
Limits
Min
Nom
Max
2200
1000
180
120
500
90
60
40
100
110
60
Unit
Parameter
Capacitive Load (CL)
M3G7003R3S
M3G7005S
M3G7012S
M3G7015S
M3G7005D
M3G7012D
M3G7015D
Line Rejection
Isolation
Device Weight
MTBF
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 70V DC ± 5%, C
L
= 0
unless otherwise specified
I
OUT
= 100% rated load
No effect on DC performance
Notes 1, 4, 7
Each output on duals
µF
I
OUT
= 100% rated load
DC to 50KHz, Notes 1, 4
1
Input to Output or Any Pin to Case
except pin 6, test @ 500VDC
dB
MΩ
g
Hrs
MIL-HDBK-217F2, SF, 35°C
5 x 10
6
Notes: Electrical Performance Characteristics
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Parameter is tested as part of design characterization or after design changes. Thereafter, parameter shall
be guaranteed to the limits specified.
Parameter verified during line and load regulation tests.
Output load current must be distributed such that at least 20% of the total load current is being provided by
one of the outputs.
Load current split equally between outputs on dual output models.
Cross regulation is measured with 20% rated load on output under test while changing the load on the
other output from 20% to 80% of rated.
Guaranteed for a D.C. to 20MHz bandwidth. Tested using a 20KHz to 10MHz bandwidth.
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.
Overload power dissipation is defined as the device power dissipation with the load set such that V
OUT
=
90% of nominal.
Load step transition time
³
10
µs.
Recovery time is measured from the initiation of the transient to where V
OUT
has returned to within ±1% of
its steady state value.
Line step transition time
³
100
µs.
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 V
OUT
= 90% of nominal.
Although operation at temperatures between +85°C and +125°C is guaranteed, no parametric limits are
specified.
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