PD-94534Q
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.
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.
Manufactured in a facility fully qualified to MIL-PRF-
38534, these converters are fabricated utilizing DLA Land
and Maritime 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.
28V Input, Single/Dual Output
M3G
Features
n
Total Dose > 200 KRad(Si),
typically usable to > 300 KRad(Si)
n
SEE Hardened to LET up to 82 MeV
.
cm
2
/mg
n
Internal EMI filter; Converter Capable of
meeting MIL-STD-461C CE03
n
Low Weight, < 110 grams
n
Magnetically Coupled Feedback
n
18V to 50V DC Input Range
n
Up to 40W Output Power
n
Single and Dual Output Models Include
3.3, 5, 5.2, 12, 15,
±
5,
±
7,
±
12 and
±
15V
n
High Efficiency - to 82%
n
-55°C to +125°C Operating Temperature Range
n
100M
Ω
@ 500VDC Isolation
n
Under-Voltage Lockout
n
Short Circuit and Overload Protection
n
Remote Sense on Single Output Models
n
Adjustable Output Voltage for Duals
n
Synchronization Input and Output
n
Output Over Voltage Limiter
n
External Inhibit
n
> 5,000,000 Hour MTBF
n
Standard Microcircuit Drawings Available
Applications
n
n
n
Geostationary Earth Orbit Satellites (GEO)
Deep Space Satellites / Probes
Strategic Weapons and Communication System
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1
09/11/12
M3G-SERIES
(28V Input, Single/Dual Output)
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. Voltage
feed-forward with duty factor limiting provides high
line rejection and protection against output over
voltage in the event of an internal control loop failure.
This mechanism limits the maximum output voltage
to approximately 20% over the nominal regardless of
the line voltage.
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.
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
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.
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 except for the
CDR type ceramic capacitors, a capacitor with 50V
rating is used for in-circuit voltage stress of less than
10V. 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
(28V Input, Single/Dual Output)
Specifications
Absolute Maximum Ratings
Input voltage range
Output power
Lead temperature
Operating temperature
Storage temperature
-0.5Vdc to +80Vdc
Internally limited
+300°C for 10 seconds
-55°C to +135°C
-55°C to +135°C
1
Recommended Operating Conditions
Input voltage range
Input voltage range
1
Output power
Operating temperature
1
Operating temperature
2
2
+18Vdc to +60Vdc
+18Vdc to +50Vdc
0 to Max. Rated
-55°C to +125°C
-55°C to +70°C
Electrical Performance Characteristics
Parameter
Group A
Subgroup
Meets derating per MIL-STD-975
For operation at +125°C see table note 13
Limits
Unit
Min
18
Nom
28
3.30
5.00
5.20
12.00
15.00
±5.00
±7.00
±12.00
±15.00
Max
50
3.32
5.02
5.23
12.05
15.06
±5.02
±7.03
±12.05
±15.06
3.36
5.07
5.27
12.16
15.20
±5.07
±7.10
±12.16
±15.20
30
40
9.10
8.00
7.70
3.34
2.67
6.40
4.57
2.67
2.14
10
0.5
V
V
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 28V DC ± 5%, C
L
= 0
unless otherwise specified
Input Voltage
Output Voltage ( Vout )
M3G2803R3S
M3G2805S
M3G2805R2S
M3G2812S
M3G2815S
M3G2805D
M3G2807D
M3G2812D
M3G2815D
M3G2803R3S
M3G2805S
M3G2805R2S
M3G2812S
M3G2815S
M3G2805D
M3G2807D
M3G2812D
M3G2815D
Output power ( P
OUT
)
M3G2803R3S
All Others
Output current ( I
OUT
)
M3G2803R3S
M3G2805S
M3G2805R2S
M3G2812S
M3G2815S
M3G2805D
M3G2807D
M3G2812D
M3G2815D
Line regulation ( VR
LINE
)
Load regulation ( VR
LOAD
)
Cross regulation ( VR
CROSS
)
M3G2805D
M3G2807D
M3G2812D
M3G2815D
1
1
1
1
1
1
1
1
1
2,3
2,3
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
5.17
11.95
14.94
±4.98
±6.97
±11.95
±14.94
3.24
4.93
5.13
11.84
14.80
±4.93
±6.90
±11.84
±14.80
0
0
0
0
0
0
0
0
0
0
0
-10
-0.5
I
OUT
= 100% rated load
Note 4
V
IN
= 18, 28, 50 Volts, Note 2
W
1,2,3
V
IN
= 18, 28, 50 Volts, Note 2
A
Either Output, Note 3
Either Output, Note 3
Either Output, Note 3
Either Output, Note 3
1,2,3
1,2,3
V
IN
= 18, 28, 50 Volts
I
OUT
= 0, 50%, 100% rated, Note 4
I
OUT
= 0, 50%, 100% rated, Note 4
V
IN
= 18, 28, 50 Volts
Duals only, Note 5
V
IN
= 18, 28, 50 Volts
mV
%
1,2,3
-5.0
-5.0
-3.0
-3.0
5.0
5.0
3.0
3.0
%
For Notes to Specifications, refer to page 5
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3
M3G-SERIES
(28V Input, Single/Dual Output)
Electrical Performance Characteristics
Parameter
Group A
Subgroup
1,2,3
( continued )
Limits
Unit
Min
Nom
40
2.0
450
500
15
20
25
25
25
20
25
30
30
68
75
75
75
77
75
75
76
77
3.0
-0.5
72
77
77
78
80
78
78
79
80
5.0
100
50
600
10.0
0.5
80
125
135
Max
80
5.0
550
35
50
50
60
80
50
55
60
60
KHz
mA
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 28V DC ± 5%, C
L
= 0
unless otherwise specified
I
OUT
= 0, Pin 3 open
Pin 3 shorted to pin 2
Input current ( I
IN
)
Switching frequency ( F
S
)
Output ripple ( V
RIP
)
M3G2803R3S
M3G2805S
M3G2805R2S
M3G2812S
M3G2815S
M3G2805D
M3G2807D
M3G2812D
M3G2815D
Efficiency ( E
FF
)
M3G2803R3S
M3G2805S
M3G2805R2S
M3G2812S
M3G2815S
M3G2805D
M3G2807D
M3G2812D
M3G2815D
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 load changes (T
TLD
)
Output response to
step line changes (V
TLN
)
Recovery time,
step line changes (T
TLN
)
Turn-on Response
Overshoot (V
OS
)
Turn-on Delay (T
DLY
)
1,2,3
1,2,3
Sync. Input (Pin 4) open
I
OUT
= 100% rated load
Notes 4, 6
mV p-p
1
I
OUT
= 100% rated load
Note 4
%
Note 1
V
µA
V
KHz
V
V
V/µs
%
%
Ext. Clock on Sync. Input (Pin 4)
Note 1
450
4.0
-0.5
40
20
1,2,3
V
out
= 90% of Nominal,
Note 4
Short Circuit, Overload, Note 8
Half Load to/from Full Load,
Notes 4, 9
Half Load to/from Full Load,
Notes 4, 9,10
18V to/from 50V
I
OUT
= 100% rated load, Notes 1,4,11
18V to/from 50V
I
OUT
= 100% rated load, Notes 1,4,10,11
-300
-300
1,2,3
4,5,6
4,5,6
14
20
300
W
mV pk
µs
50
200
300
50
200
10
5.0
mV pk
µs
%
ms
4,5,6
No Load, Full Load
Notes 4,12
1.0
For Notes to Specifications, refer to page 5
4
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M3G-SERIES
(28V Input, Single/Dual Output)
Electrical Performance Characteristics
Parameter
Capacitive Load (CL)
M3G2803R3S
M3G2805S
M3G2805R2S
M3G2812S
M3G2815S
M3G2805D
M3G2807D
M3G2812D
M3G2815D
Line Rejection
Isolation
Device Weight
MTBF
1
Group A
Subgroup
( continued )
Limits
Unit
Min
Nom
Max
2200
1000
1000
180
120
500
300
90
60
40
100
110
60
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 28V 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
Input to Output or Any Pin to Case
except pin 6, test @ 500VDC
MIL-HDBK-217F2, SF, 35°C
dB
MΩ
g
Hrs
5.0 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.
Limit represents 80% of total rated output current. To achieve rated output power, the remaining 20% of
the total rated output current must be provided by the other output.
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
≥
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
≥
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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