the msk 5046rh series are high efficiency, 4 amp, radiation hardened switching regulators. the output voltage is configured for 1.5v, 2.5v, 3.0v, 3.3v or 5.0v internally with a tolerance of 1% at 1.5 amps. the operating frequency of the msk 5046rh is 300khz. a low quiescent current and greater than tbd operating efficiency keep the total internal power dissipation of the msk 5046rh down to an absolute minimum. the device is packaged in a hermetic power package for high reliability applications, and is available fully compliant to mil-prf-38534 class h or k. 4707 dey road liverpool, n.y. 13088 m.s.kennedy corp. (315) 701-6751 features: 5046rh series iso-9001 certified by dscc radiation hardened high efficiency, 4 amp switching regulators up to 92% conversion efficiency for 5v version 4 amp output current 3.1v to 18v input range with startup bias 12v to 18v input range with uvlo (vbias=v in ) preset 1.5v, 2.5v, 3.0v, 3.3v or 5.0v output versions custom output voltages available 300khz switching frequency hermetic package with three lead form options -55c to +125c operating temperature range total dose rated to tbdk rad description: equivalent schematic mil-prf-38534 certified typical applications pin-out information step-down switching regulator microprocessor, fpga power source high efficiency low voltage subsystem power supply comp enable vboot vbias vin vin 1 2 3 4 5 6 12 11 10 9 8 7 sense vout vout vout return return preliminary rev. b 11/03 1
t st t ld t c t j storage temperature range lead temperature range (10 seconds) case operating temperature msk5046rh series msk5046rh k/h/e series junction temperature absolute maximum ratings -65c to +150c 300c -40c to +85c -55c to +125c +150c input voltage enable output current thermal resistance (@ 125c) -0.3v, +20v -0.3v, 10.5v 4.0 amps 10c/w electrical specifications preliminary rev. b 11/03 2 notes: 1 2 3 4 5 6 8 9 10 11 12 13 v in =12v, vbias=12v, i out =1.5a unless otherwise specified. guaranteed by design but not tested. typical parameters are representative of actual device performance but are for reference o nly. all output parameters are tested using a low duty cycle pulse to maintain t j = t c . industrial grade and 'e' suffix devices shall be tested to subgroup 1 unless otherwise specified. military grade devices ('h' and 'k' suffix) shall be 100% tested to subgroups 1,2,3 and 4. subgroup 1 subgroup 2 subgroup 3 alternate output voltages are available. please contact the factory. vboot is measured with a 40ma load on the vboot pin. the device can operate with input voltages as high as 18v, but efficiency is best at lower inputs. with vbias connected to a separate source, v in min. is approximately 3.1v. contact factory for post radiation limits. includes vbias power consumption. t a =t c =+25c t a =t c =+125c t a =t c =-55c
application notes bootstrapping: the msk 5046rh's vboot output can be used to supply bias voltage once the device is operating. use a diode to "or" the startup bias supply with the vboot output if the startup supply voltage is less than vboot. use a switching scheme if vboot is less than or equal to vstartup. additional bypass capacitance is required on the vbias input pin when bootstrapping the msk 5046rh. since the bootstrap voltage is stepped up from the output voltage, it will vary with load. any voltage drop between the output and the sense pin will increase the bootstrap voltage. direct biasing of the vbias input may be more efficient due to the additional conversion involved in bootstrapping. preliminary rev. b 11/03 3 input capacitor selection: the msk 5046rh should have an external high frequency ceramic capacitor (0.1uf) between vin and gnd. connect a low-esr bulk capacitor directly to the input pin of the msk 5046rh. select the bulk input filter capacitor according to input ripple-current requirements and voltage rating, rather than capacitor value. electrolytic capacitors that have low enough esr to meet the ripple-current requirement invariably have more than adequate capacitance values. aluminum-electrolytic ca- pacitors are preferred over tantalum types, which could cause power-up surge-current failure when connecting to robust ac adapters or low-impedance batteries. input bias and uvlo: the vbias pin of the msk 5046rh provides bias to the con- trol circuitry. the vbias pin can be connected directly to the input bus for 12v to 16v operation or it can be biased sepa- rately with a 12v to 16v source to extend the input range of the device refer to the paragraph titled "input voltage range". the msk 5046rh's built in under voltage lockout feature prevents damage to downstream devices in the event of a drop in bias voltage. under voltage lockout occurs at bias voltages of approximately 10.3v rising and 9.5v falling. the internal bias draws approximately 40ma under normal opera- tion. input voltage range the msk 5046rh's input range of 12v to 16v can be fur- ther extended down to 3.1v by using a separate bias supply. in this configuration very efficient low v to low v conversion can be achieved. output capacitor selection: sense: enable function: the enable pin of the msk 5046rh is designed for open collector drive. leaving the pin open will allow for normal operation. pulling the pin low will shut the de- vice down. it is very important that the dc voltage returned to the sense pin from the output be as noise and oscillation free as possible. this voltage helps to determine the final output and therefore must be a clean voltage. excessive noise or oscillation can cause the device to have an incor- rect output voltage. proper pc board layout techniques can help to achieve a noise free voltage at the sense pin. compensation: w hen driving large capacitive loads it may be neces- sary to connect a 10 to 20nf ceramic capacitor between the v sense pin and the comp pin. this will add a zero/ pole pair to the overall loop transfer function to prevent oscillation and improve bandwidth. the msk 5046rh has an internal 0.1f ceramic ca- pacitor between vout and return. an additional 1f of ceramic capacitance on the output will help suppress the high frequency switching noise. use between 100 and 300f of low esr bulk capacitance for optimum performance. larger output capacitance may require ad- ditional loop compensation, refer to the paragraph titled "compensation".
application notes cont'd typical bootstrapped application preliminary rev. b 11/03 4
typical performance curves preliminary rev. b 11/03 5 note: overall efficiency curves include vbias power consumption.
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. contact msk for mil-prf-38534 class h, class k and appendix g (radiation) status. mechanical specifications m.s. kennedy corp. 4707 dey road, liverpool, new york 13088 phone (315) 701-6751 fax (315) 701-6752 www.mskennedy.com preliminary rev. b 11/03 the above example is a +3.3v, military regulator with leads bent up. esd triangle indicates pin 1. note: all dimensions are 0.010 inches unless otherwise labeled. ordering information 6 msk5046-3.3 h rh u lead configurations s= straight; u= bent up; d= bent down radiation hardened screening blank= industrial; e=extended reliability h=mil-prf-38534 class h; k= mil-prf-38534 class k output voltage 1.5=+1.5v; 2.5=+2.5v; 3.0=+3.0v; 3.3=+3.3v; 5.0=+5.0v general part number
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