typical applications 5921rh m.s.kennedy corp. features: satellite system power supplies switching power supply post regulators constant voltage/current regulators microprocessor power supplies rad hard ultra low dropout adjustable positive linear regulator equivalent schematic typical applications description: the msk5921rh is a radiation hardened adjustable linear regulator typically capable of delivering 5.0 amps of output current. the typical dropout is only 0.30 volts with a 3.0a load. an external shutdown function is ideal for power supply sequencing. this device also has latching overload protection that requires no external current sense resistor. the msk5921rh is radiation hardened and specifically designed for space/satellite applications. the device is packaged in a hermetically sealed space efficient 5 pin sip that is electrically isolated from the internal circuitry allowing for direct heat sinking. pin-out information vin gnd vout shutdown adjust total dose hardened to 100 krads(si) (method 1019.7 condition a) ultra low dropout for reduced power consumption external shutdown latching overload protection adjustable output using two external resistors output current limit available in 4 lead form options: straight, up, down and gull wing available as smd 5962r05220 rad certified by dla 1 2 3 4 5 1 8548-16 rev. n 6/14 case=isolated mil-prf-38534 and 38535 certified facility
input voltage range feedback voltage feedback pin current quiescent current line regulation load regulation dropout voltage minimum output current output voltage range output current limit shutdown threshold ripple rejection phase margin gain margin equivalent noise voltage thermal resistance storage temperature range lead temperature range (10 seconds) power dissipation junction temperature absolute maximum ratings +10v 10v 5a -55c to +125c -40c to +85c supply voltage shutdown voltage output current case operating temperature range msk5921k/h rh msk5921rh -65c to +150c 300c see soa curve 150c 1 2 3 4 5 6 7 8 9 10 11 12 13 t st t ld p d t c +v in v sd i out t c unless otherwise specified, v in =5.0v, r1=1.62k, v shutdown =0v and i out =10ma. see figure 2, typical application circuits. guaranteed by design but not tested. typical parameters are representative of actual device performance but are for reference o nly. industrial grade devices shall be tested to subgroups 1 and 4 unless otherwise requested. military grade devices ("h" suffix) shall be 100% tested to subgroups 1,2,3 and 4. subgroup 5 and 6 testing available upon request. subgroup 1,4 t c =+25c subgroup 2,5 t c =+125c subgroup 3,6 t a =-55c output current limit is dependent upon the values of v in and v out . see figure 1 and typical performance curves. continuous operation at or above absolute maximum ratings may adversely effect the device performance and/or life cycle. v in shall be as specified or v in min, whichever is greater. not applicable when v out application notes pin functions vin - this pin provides power to all internal circuitry including bias, start-up, thermal limit and overcurrent latch. input voltage range is 2.9v to 6.5v. gnd - internally connected to ground, this pin should be connected externally by the user to the circuit ground. shutdown - there are two functions to the shut- down pin. it may be used to disable the output voltage or to reset a current latch condition. to activate the shut- down/reset functions the user must apply a voltage greater than 1.6v to the shutdown pin. the voltage ap- plied to the shutdown pin can be greater than the input voltage. the output voltage will turn on when the shut- down pin is pulled below the threshold voltage. if the shut- down pin is not used, it should be connected to ground. it should be noted that with the shutdown pin tied to ground, a current latch condition can only be reset by cycling power off, then on. vout - this is the output pin for the device. adjust - the adjust pin is the inverting input of the internal error amplifier. the non-inverting input is con- nected to an internal 1.265v reference. this error ampli- fier controls the drive to the output transistor to force the adjust pin to 1.265v. an external resistor divider is connected to the output, adjust pin and ground to set the output voltage. current limit and soa the msk5921rh current limit function is directly affected by the input and output voltages. figure 1 illustrates the rela- tionship between vin and icl for various output voltages. it is very important for the user to consult the soa curve when using input voltages which result in current limit conditions beyond 4.5 amps. when using input voltages which result in current limit above 4.5 amps, the user must maintain output current within the soa curve to avoid damage to the device. note that 5 amp maximum is due to current carrying capa- bility of the internal wirebonds. 3 overcurrent latch overcurrent protection is provided by the msk5921rh series through the use of a timed latch off circuit. the internal latch timeout is triggered by an overcurrent con- dition. to allow for start up surge currents, the timeout is approximately 5.5ms at 25c. if the overcurrent con- dition remains at the end of the timeout cycle, the regu- lator will latch off until the latch is reset. reset the latch by pulling the shutdown pin high or cycling vin off then back on. a thermal limit condition will trigger the latch with no time out delay. input power supply bypassing to maximize transient response and minimize power supply transients it is recommended that a 100 f tanta- lum capacitor is connected between vin and ground. a 0.1 f ceramic capacitor should also be used for high frequency bypassing. figure 1 output capacitor selection low esr output capacitors are required to maintain regu- lation and stability. four cwr29fb227 (avx pn tazh227k010l) tantalum capacitors in parallel with ce- ramic decoupling capacitors (0.1 f typical) provides suf- ficient gain and phase margin for most applications. the maximum esr specification for the cwr29fb227 capaci- tor is 180m at 100khz and is sufficient for many appli- cations. msk has found through full wcca that screen- ing for a maximum esr of 57m ensures eol stability criteria to be met for many applications with the most stringent requirements. the typical esr of the tazh227k010l from avx is 49m . analysis of the final design is recommended to ensure stability requirements are met. 8548-16 rev. n 6/14
r sa = -4.0c/w - 0.15c/w application notes cont. 4 to select a heat sink for the msk5921rh, the following formula for convective heat flow may be used. governing equation: t j = p d x (r jc + r cs + r sa ) + t a where t j = junction temperature p d = total power dissipation r jc = junction to case thermal resistance r cs = case to heat sink thermal resistance r sa = heat sink to ambient thermal resistance t a = ambient temperature power dissipation=(v in -v out ) x i out next, the user must select a maximum junction tem- perature. the absolute maximum allowable junction tem- perature is 150c. the equation may now be rearranged to solve for the required heat sink to ambient thermal resistance (r sa ). example: an msk5921rh is connected for v in =+3.3v and v out =+2.5v. i out is a continuous 3a dc level. the am- bient temperature is +25c. the maximum desired junc- tion temperature is +125c. r jc =4.0c/w and r cs =0.15c/w for most thermal greases power dissipation=(3.3v-2.5v) x (3a) =2.4watts solve for r sa: 125c - 25c 2.4w = 36.5c/w in this example, a heat sink with a thermal resistance of no more than 36.5c/w must be used to maintain a junction temperature of no more than 125c. output voltage selection as noted in the above typical applications circuit, the formula for output voltage selection is a good starting point for this output voltage selection is to set r2=1k. by rearranging the formula it is simple to calculate the final r1 value. r1 r2 1+ v out =1.265 v out 1.265 -1 r1=r2 the msk5921rh control circuitry has a thermal shutdown temperature of approximately 150c. this thermal shut- down can be used as a protection feature, but for continu- ous operation, the junction temperature of the pass tran- sistor must be maintained below 150c. proper heat sink selection is essential to maintain these conditions. exceed- ing the thermal limit activates the latch feature of the msk5921rh. toggle the shutdown pin high then low or cycle power to reset the latch. see shutdown pin de- scription and overcurrent latch description for more infor- mation. thermal limiting heat sink selection typical applications circuit radiation performance curves for tid testing have been generated for all radiation testing performed by ms kennedy. these curves show performance trends throughout the tid test process and can be located in the msk5921rh radiation test report. the complete radia- tion test report is available in the rad hard products section on the msk website. total dose radiation test performance http://www.mskennedy.com/store.asp?pid=9951&catid=19680 the msk5921rh sinks increased current during startup to bring up the output voltage. reference the "saturated drive current vs. input voltage" graph in the typical per- formance curves of this data sheet and the "understand- ing startup surge current with ms kennedy's rh1573 based rad hard ldo regulators" application note in the application notes section of the ms kennedy web site for more information. http://www.mskennedy.com/ start up current 8548-16 rev. n 6/14
typical performance curves 5 8548-16 rev. n 6/14
typical performance curves 6 gain and phase response the gain and phase response curves are for the msk typical application circuit and are representative of typical device performance, but are for reference only. the performance should be analyzed for each application to insure individual program requirements are met. external factors such as temperature, input and output voltages, capacitors, etc. all can be major contributors. please consult factory for additional details. 8548-16 rev. n 6/14
mechanical specifications ordering information 7 lead configurations gw= gull wing radiation hardened screening blank= industrial; h=mil-prf-38534 class h; k=mil-prf-38534 class k general part number msk5921 k rh gw the above example is an adjustable class k regulator with gull wing leads. note: see dla smd 5962r05220 for dla part number options. esd triangle indicates pin 1 weight=7.7 grams typical all dimensions are specified in inches 8548-16 rev. n 6/14
mechanical specifications ordering information 8 msk5921 k rh u the above example is an adjustable class k regulator with leads bent up. lead configurations s= straight; u= bent up; d= bent down radiation hardened screening blank= industrial; h=mil-prf-38534 class h; k= mil-prf-38534 class k general part number note: see dla smd 5962r05220 for dla part number options. 8548-16 rev. n 6/14 esd triangle indicates pin 1 weight=7.7 grams typical all dimensions are specified in inches
the information contained herein is believed to be accurate at the time of printing. msk reserves the right to make changes to its products or specifications without notice, however, and assumes no liability for the use of its products. please visit our website for the most recent revision of this datasheet. m.s. kennedy corp. phone (315) 701-6751 fax (315) 701-6752 www.mskennedy.com 9 8548-16 rev. n 6/14 revision history
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