www.irf.com 1 hybrid-high reliability radiation hardened dc-dc converter M3G2803R312T description total dose > 200 krad(si), typically usable to > 300 krad(si) see hardened to let up to 82 mev . cm 2 /mg internal emi filter, converter capable of meeting mil-std-461c ceo3 low weight, < 110 grams magnetically coupled feedback 18v to 50v dc input range up to 33w output power main output isolated from dual outputs high efficiency - to 80% -55c to +125c operating temperature range 100m ? @ 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 features 28v input, triple output 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. applications 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. deep space satellites / probes strategic weapons and communication systems the converters incorporate a fixed frequency single ended forward topology with magnetic feedback and an internal emi filter. 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. m3g pd-95890d
2 www.irf.com M3G2803R312T 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. circuit description 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 16.5v and will shut down when the input voltage drops to 15.5v. 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 2.0v 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 (+3.3v) output is regulated by the control loop and typically exhibits better than 1% regulation. the auxiliary (12v) 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 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.
www.irf.com 3 M3G2803R312T for notes to specifications, refer to page 5 specifications 1 meets derating per mil-std-975 2 for operation at +125c see table note 14 electrical performance characteristics conditions -55c t c +85c group a v in = 28v dc 5%, c l = 0 parameter subgroup unless otherwiese specified min. nom. max. unit input voltage 1,2,3 note 2 18 28 50 v i out = 100% rated load, note 5 1 (main) 3.28 3.3 3.32 (aux.) 11.60 12.00 12.40 v 2,3 (main) 3.24 3.36 (aux.) 11.40 12.60 output power ( p out ) 1,2,3 v in = 18, 28, 50 volts, note 2 0 33.2 w v in = 18, 28, 50 volts, notes 2,3,4,5 output current ( i out ) 1,2,3 (main) 400 4000 (aux.) 83 833 v in = 18, 28, 50 volts line regulation ( vr line ) 1,2,3 i out = 10, 50, 100% rated load, note 5 (main) -10 10 (aux.) -120 120 v in = 18, 28, 50 volts load regulation ( vr load ) 1,2,3 i out = 10, 50, 100% rated load, notes 5,13 (main) -30 30 (aux.) -400 400 v in = 18, 28, 50 volts cross regulation ( vr cross ) 1,2,3 i out = 2.5a to 1.0a and 2.5 to 4.0a -3.5 3.5 % on main and half rated on aux. outputs i out = 0, pin 3 open 80 pin 3 shorted to pin 2 5.0 v in = 18, 28, 50 volts output ripple ( v rip ) 1,2,3 i out = 10, 50, 100% rated load, notes 5, 6 (main) 20 30 (aux.) 30 60 output voltage ( v out ) mv p-p input current ( i in ) 1,2,3 limits ma ma mv mv input voltage range -0.5vdc to +80vdc input voltage range +18vdc to +60vdc output power internally limited in p ut volta g e ran g e 1 +18vdc to +50vdc lead temperature +300c for 10 seconds output power 0 to max. rated operating temperature -55c to +135c o p eratin g tem p erature 2 -55c to +125c storage temperature -55c to +135c o p eratin g tem p erature 1 -55c to +70c recommended operating conditions absolute maximum ratings
4 www.irf.com M3G2803R312T for notes to specifications, refer to page 5 electrical performance characteristics ( continued ) conditions -55c t c +85c group a v in = 28v dc 5%, c l = 0 parameter subgroup unless otherwise specified min. nom. max. unit switching frequency ( f s ) 1,2,3 sync. input (pin 4) open 450 500 550 khz efficiency ( e ff ) 1,2,3 i out = 100 % rated load , note 5 72 75 % inhibit input open circuit voltage 3.0 5.0 v drive current ( sink ) note 1 100 a voltage range -0.5 50 v synchronization input frequency range 1,2,3 450 600 khz pulse high level 4.0 10 v pulse low level ext. clock on sync. input (pin 4), note 1 -0.5 0.5 v pulse transition time 40 v/ s pulse duty cycle 20 80 % current limit point expressed as a percentage 1,2 v out = 90% of nominal, note 5 135 of full rated output power 3150 power dissipation, load fault ( p d ) 1,2,3 short circuit, overload, note 8 20 w output response to step load changes ( v tld ) 4,5,6 half load to/from full load, notes 5, 9 -300 300 mv pk recovery time, step load changes ( t tld ) 4,5,6 half load to/from full load, notes 5, 9, 10 100 s output response to 18v to/from 50v step line changes ( v tln ) i out = 100% rated load, notes 1, 5, 10, 11 -300 300 mv pk recovery time, 18v to/from 50v step line changes ( t tln ) i out = 100% rated load, notes 1, 5, 10, 11 100 s turn-on response no load, full load, notes 5, 12 overshoot ( v os ) (main) 500 4,5,6 (aux.) 750 turn-on delay ( t dly ) 1.0 5.0 ms capacitive load ( c l ) i out = 100% rated load, 1,2,3 no effect on dc performance, notes 1,5,7 (main) 1000 (each aux.output) 200 i out = 100% rated load, dc to 50khz, notes 1, 5 input to output or any pin to case except pin 10, test @ 500vdc device weight 110 g mtbf mil-hdbk-217f2, sf, 35c 5 x 10 6 hrs % isolation 1 100 ? line rejection 40 limits db mv f 60
www.irf.com 5 M3G2803R312T notes: electrical performance characteristics 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 output may cause the output voltage of the auxiliary outputs to drop out of regulation. it is therefore recommended that at least 200ma or 20 percent of the total output power, whichever is greater, be taken from the main output. 4. although operation with no load is permissible, heavy loading on the main output may cause the output voltage of the auxiliary outputs to rise out of regulation. it is therefore recommended that at least 50ma or 20 percent of the total output power, whichever is greater, be taken from the auxiliary (12 volts) output. 5. unless otherwise specified, ?rated? load is 13.2w on the main output and 10w each on the auxiliary outputs. 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 v out = 90% of nominal. 9. load step transition time 10 s. 10. recovery time is measured from the initiation of the transient to where v out has returned to within 1% of its steady state value. 11. line step transition time 100 s. 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 v out = 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 +85c and +125c, is guaranteed, no parametric limits are specified.
6 www.irf.com M3G2803R312T figure 1. block diagram 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
www.irf.com 7 M3G2803R312T figure 2. conducted emissions, positive lead figure 3. 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 0 10 20 30 40 50 60 70 80 90 100 db-ua 1e3 1e4 1e5 1e6 1e7 1e8 frequency ( hz ) ceo3 limit
8 www.irf.com M3G2803R312T figure 4. 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 radiation performance characteristics test inspection method min typ unit mil-prf-883, method 1019 total ionizing dose (gamma) operating bias applied during exposure, full rated load, v in = 28v 200 300 krads(si) dose rate (gamma dot) mil-std-883, method 1023 temporary saturation operating bias applied during exposure, 1e8 rads(si)/sec survival full rated load, v in = 28v 4e10 1e11 neutron fluence mil-std-883, method 1017 8e12 1e13 neutrons/cm 2 heavy ions (let) single event effects operating bias applied during exposure, mev cm 2 /mg seu, sel, segr, seb full rated load, v in = 28v >82
www.irf.com 9 M3G2803R312T mechanical diagram pin designation pin # designation pin # designation 1 + input 8 n/c 2 input return 9 n/c 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 2.500 2.30 0.200 typ. non- cum. 0.30 1.400 ref. 3.50 ref. 0.475 max. 0.080 max. 0.260 pin ?0.040 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 r 0 . 0 6 2 5
10 www.irf.com M3G2803R312T device screening requirement mil-std-883 method no suffix ck em temperature range -55c to +85c -55c to +85c -55c to +85c 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 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 @ 125c 320 hrs @ 125c 48 hrs @ 125c ( 2 x 160 hrs ) ( 2 x 160 hrs ) final electrical mil-prf-38534 -55c, +25c, -55c, +25c, -55c, +25c, ( group a ) & specification +85c +85c +85c 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 burn-in 1015 notes: best commercial practice. ck is dscc class k com p liant without radiation p erformance. no suffix is a radiation rated device but not available as a dscc qualified smd per mil-prf-38534. international rectifier currently does not have a dscc certified radiation hardness assurance program. part numbering model screening level (please refer to screening table) no suffix, ck, em output t = triple m3g 28 03r3 12 t /em 03r3 = 3.3v main output voltage nominal input voltage 28 = 28v auxiliary output voltage 12 = 12v 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. 03/2010
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