PD-94533O
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. 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 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.
70V Input, Triple Output
M3G
Features
n
Total Dose > 200 krad(Si),
typically usable to > 300 krad(Si)
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
SEE Hardened up to 82 MeV
.
cm
2
/mg
Low Input & Output Noise
Low Weight, < 110 grams
Magnetically Coupled Feedback
60V to 120V DC Input Range
Up to 40W Output Power
Triple Output Models Include
+5V and
±
12V or
±
15V
Main Output Isolated from Dual Outputs
High Efficiency - to 82%
-55°C to +125°C Operating Temperature Range
100M
Ω
@ 500VDC Isolation
Under-Voltage Lockout
Synchronization Input and Output
Short Circuit and Overload Protection
Output Over Voltage Limiter
External Inhibit
> 5,000,000 Hour MTBF
Applications
n
n
n
Geostationary Earth Orbit Satellites (GEO)
Deep Space Satellites / Probes
Strategic Weapons and Communication
Systems
www.irf.com
1
09/12/12
M3G-SERIES
(70V Input, Triple 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 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.
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.
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 54 volts. The four 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.
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
www.irf.com
M3G-SERIES
(70V Input, Triple Output)
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
Recommended Operating Conditions
Input voltage range
Input voltage range
Output power
1
+60Vdc to +120Vdc
+60Vdc to +100Vdc
0 to Max. Rated
2
1
Operating temperature
Operating temperature
2
-55°C to +125°C
-55°C to +70°C
Meets derating per MIL-STD-975
For operation at +125°C see table note 15
Electrical Performance Characteristics
Group A
Subgroup
1,2,3
1
2,3
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 70V DC ± 5%, C
L
= 0
unless otherwise specified
Note 2
I
OUT
= 100% rated load, Note 5
Limits
Min
60
4.98
±11.50
±14.60
4.93
±11.30
±14.40
V
IN
= 60, 70, 100 Volts, Note 2
V
IN
= 60, 70, 100 Volts, Notes 2,3,4,5
0
400
83
67
-10
-120
-150
-50
-400
-500
-3.5
-3.0
35
2.0
Nom
70
5.00
±11.80
±14.90
Max
100
5.02
±12.10
±15.20
5.07
±12.30
±15.40
40
4000
±833
±667
10
120
150
50
400
500
3.5
3.0
50
5.0
Unit
V
Parameter
Input Voltage
Output Voltage ( Vout )
(main)
M3G700512T (aux.)
M3G700515T (aux.)
(main)
M3G700512T (aux.)
M3G700515T (aux.)
Output power ( P
OUT
)
Output current ( I
OUT
)
(main)
M3G700512T (aux.)
M3G700515T (aux.)
Line regulation ( VR
LINE
)
(main)
M3G700512T (aux.)
M3G700515T (aux.)
Load regulation ( VR
LOAD
)
(main)
M3G700512T (aux.)
M3G700515T (aux.)
Cross regulation ( VR
CROSS
)
M3G700512T (aux.)
M3G700515T (aux.)
Input current ( I
IN
)
V
1,2,3
1,2,3
W
mA
1,2,3
V
IN
= 60, 70, 100 Volts
I
OUT
=10%, 50%, 100% rated
Note 5, 14
I
OUT
= 10%, 50%, 100% rated
V
IN
= 60, 70, 100 Volts
Notes 5,13
V
IN
= 60, 70, 100 Volts
I
OUT
= 2.5A to 1A and 2.5A to 4A on main
and ±half rated on aux. outputs
I
OUT
= 0, Pin 3 open
Pin 3 shorted to pin 2
mV
1,2,3
mV
1,2,3
1,2,3
%
mA
For Notes to Specifications, refer to page 5
www.irf.com
3
M3G-SERIES
(70V Input, Triple Output)
Electrical Performance Characteristics
Group A
Subgroup
1,2,3
( continued )
Limits
Min
Nom
25
30
30
450
78
500
82
Max
50
60
75
550
Unit
Parameter
Output ripple ( V
RIP
)
(main)
700512T (aux.)
700515T (aux.)
Switching frequency ( F
S
)
Efficiency ( E
FF
)
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 output power
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
)
( main )
( aux. )
Turn-on Delay (T
DLY
)
Capacitive Load (CL)
(main)
(Each aux. output)
Line Rejection
Isolation
Device Weight
MTBF
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 70V DC ± 5%, C
L
= 0
unless otherwise specified
V
IN
= 60, 70, 100 Volts
I
OUT
= 100% rated load, Notes 5, 6
Sync. Input (Pin 4) open
I
OUT
= 100% rated load
Note 5
Note 1
mV p-p
KHz
%
1,2,3
1,2,3
3.0
-0.5
5.0
100
50
600
10.0
0.5
80
135
18
V
µA
V
KHz
V
V
V/µs
%
%
W
mV pk
µs
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
4,5,6
V
out
= 90% of Nominal, Note 5
Short Circuit, Overload, Note 8
Half Load to/from Full Load, Notes 5,9
Half Load to/from Full Load, Note 5,9,10
60V to/from 100V
I
OUT
= 100% rated load, Notes1, 5,11
60V to/from 100V
I
OUT
= 100% rated load, Notes 1. 5,10,11
-300
50
300
200
-300
50
300
200
500
750
mV pk
µs
mV
mV
ms
µF
4,5,6
No Load, Full Load
Notes 5,12
1.0
I
OUT
= 100% rated load, No effect on DC
performance, Notes 1, 5, 7
DC to 50KHz, Notes 1, 5
I
OUT
= 100% rated load
40
100
60
5.0
1000
200
dB
MΩ
110
g
Hrs
1
Input to Output or Any Pin to Case
except pin 10, test @ 500VDC
MIL-HDBK-217F2, SF, 35°C
5 x 10
6
For Notes to Specifications, refer to page 5
4
www.irf.com
M3G-SERIES
(70V Input, Triple Output)
Notes: Electrical Performance Characteristics
1.
2.
3.
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.
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.
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.
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 respectively are acceptable as long as the total output power does not to exceed 40 watts.
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.
Load Regulation relative to output voltage at 50% rated load.
Line Regulation relative to output voltage at 70Vdc input.
Although operation at temperatures between +85°C and +125°C is guaranteed, no parametric limits are
specified.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
www.irf.com
5
京公网安备 11010802033920号
EEWORLD
