1 ltc1517-5 typical applicatio n u micropower, regulated 5v charge pump in a 5-pin sot-23 package n ultralow power: i cc = 6 m a typ n short-circuit/thermal protected n 5v 4% regulated output n v in range: 2.7v to 5v n output current: 10ma (v in 3 2.7v) 20ma (v in 3 3v) n no inductors n ultrasmall application circuit (0.045in 2 ) n 800khz switching frequency n available in 5-pin sot-23 features descriptio n u the ltc ? 1517-5 is a micropower charge pump dc/dc converter that produces a regulated 5v output. the input voltage range is 2.7v to 5v. extremely low operating current (typically 6 m a with no load) and low external parts count (one 0.1 m f flying capacitor and two small bypass capacitors at v in and v out ) make the part ideally suited for small, light load battery-powered applications. the total printed circuit board area of the application circuit shown below is only 0.045in 2 . the part operates as a burst mode tm switched-capacitor voltage doubler to produce a regulated output. the part has thermal shutdown capability and can survive a continuous short circuit from v out to gnd. the device is available in a 5-pin sot-23 package. , ltc and lt are registered trademarks of linear technology corporation. burst mode is a trademark of linear technology corporation. output current (ma) 0 output voltage (v) 5.0 5.1 80 1517 ta02 4.9 4.8 20 40 60 5.2 v in = 3.3v v in = 3v v in = 2.7v t a = 25 c c1 = 0.1 f c out = 6.8 f typical output voltage vs output current 3.3 f 1517 ta01 123 4 5 0.1 f 6.8 f v out = 5v 4% i out = 10ma (v in 3 2.7v) i out = 20ma (v in 3 3v) v in 2.7v to 5v v in gnd ltc1517-5 v out c1 + c1 n cellular telephones n battery-operated equipment n local power supplies n handheld instruments n pcmcia supplies applicatio n s u
2 ltc1517-5 absolute m axi m u m ratings w ww u package/order i n for m atio n w u u order part number (note 1) v in to gnd ................................................... C 0.3v to 6v v out to gnd ................................................C 0.3v to 6v v out short-circuit duration ............................. indefinite operating temperature range: commercial ............................................ 0 c to 70 c extended (note 2).............................. C 40 c to 85 c storage temperature range ................. C 65 c to 150 c lead temperature (soldering, 10 sec).................. 300 c s5 part marking t jmax = 125 c, q ja = 256 c/ w c1 5 c1 + 1 2 3 v in top view s5 package 5-lead plastic sot-23 v out gnd 4 consult factory for industrial and military grade parts and for -3 and -3.3 version availability. symbol parameter conditions min typ max units v in operating input voltage l 2.7 5 v v out output voltage 2.7v v in 5v, i out 10ma l 4.8 5.0 5.2 v 3v v in 5v, i out 20ma l 4.8 5.0 5.2 v i cc input supply current 2.7v v in 5v, i out = 0 l 615 m a v out ripple v in = 3v, i out = 20ma, c out = 6.8 m f75mv p-p f osc oscillator frequency 800 khz t on v out turn-on time v in = 3v 1 ms v in = 2.7v to 5v, c1 = 0.1 m f, c in = 3.3 m f, c out = 6.8 m f, t min to t max , unless otherwise noted. electrical characteristics the l denotes specifications that apply over the full operating temperature range. note 1: absolute maximum ratings are those values beyond which the life of the device may be impaired. note 2: extended grade parts are 100% tested at t a = 25 c. performance at C 40 c and 85 c is assured by design, characterization and correlation with statistical process controls. ltc1517cs5-5 ltc1517es5-5 ltcx lttf
3 ltc1517-5 typical perfor m a n ce characteristics uw output ripple vs input voltage input voltage (v) 2.5 output voltage (v) 5.05 5.10 5.15 4.5 1517-5 g01 5.00 4.95 4.90 3.0 3.5 4.0 5.0 i out = 10ma c out = 10 m f t a = 70 c t a = 25 c t a = 0 c output voltage vs input voltage input voltage (v) 2.5 v ripple p-p (mv) 150 200 250 4.5 1517-5 g03 100 50 0 3.0 3.5 4.0 5.0 i out = 10ma c1 = 0.1 m f t a = 25 c c out = 6.8 m f c out = 10 m f c out = 22 m f c out = 3.3 m f input voltage (v) 2.5 efficiency (%) 70 80 90 4.5 1517-5 g02 60 50 40 3.0 3.5 4.0 5.0 i out = 10ma t a = 25 c efficiency vs input voltage no load input current vs input voltage input voltage (v) 2.5 input current ( m a) 7 8 9 4.5 1517-5 g04 6 5 4 3.0 3.5 4.0 5.0 i out = 0ma t a = 70 c t a = 25 c t a = 0 c output current (ma) 50 60 70 80 90 efficiency (%) 100 1517-5 g05 0.01 0.1 1 10 v in = 3v shdn = 0v t a = 25 c efficiency vs output current load transient response i out 0ma to 10ma 10ma/div v out ac coupled 50mv/div v in = 3v 500 m s/div 1517-5 g06 c out = 6.8 m f
4 ltc1517-5 si plified w block diagra w 1517 bd c1 0.1 f v in charge pump ltc1517-5 v out 3.75m 1.25m c out c in c1 + c1 800khz osc thermal shdn 1.25v ref + v in (pin 1): charge pump input voltage. may be between 2.7v and 5v. v in should be bypassed with a 3 3.3 m f low esr capacitor as close as possible to the pin for best performance. gnd (pin 2): ground. should be tied to a ground plane for best performance. pi n fu n ctio n s uuu v out (pin 3): regulated output voltage. v out should be bypassed with a 3 3.3 m f low esr capacitor as close as possible to the pin for best performance. c1 + (pin 4): charge pump flying capacitor positive terminal. c1 C (pin 5): charge pump flying capacitor negative terminal.
5 ltc1517-5 applicatio n s i n for m atio n wu u u operation the ltc1517-5 uses a switched-capacitor charge pump to boost v in to a 5v 4% regulated output. the part achieves regulation by sensing the output voltage through an internal resistor divider and enabling the charge pump when the divided output droops below the comparators lower trip point (set by v ref ). when the charge pump is enabled, a 2-phase nonoverlapping clock controls the internal charge pump switches. flying capacitor c1 is charged to v in on phase one of the clock. on phase two of the clock, c1 is stacked in series with v in and connected to v out through an internal switch. this sequence of charging and discharging the flying capacitor occurs at a free running frequency of 800khz (typ) and continues until the divided output voltage reaches the upper trip point of the comparator. once the output is back in regulation, the charge pump is disabled. this method of bursting the charge pump on and off enables the ltc1517-5 to achieve high efficiency at extremely low output loads. capacitor selection for best performance, it is recommended that low esr capacitors be used for both c in and c out to reduce noise and ripple. the c in and c out capacitors should be either ceramic or tantalum and should be 3.3 m f or greater. ceramic capacitors will provide the smallest size and lowest esr for a given capacitance. if the input source impedance is very low (< 0.5 w ), c in may not be needed. ceramic capacitors are recommended for the flying ca- pacitor c1 with values of 0.1 m f or 0.22 m f. smaller value flying capacitors may be used in low i out applications. output ripple normal ltc1517-5 operation produces voltage ripple on the v out pin. output voltage ripple is required for the part to regulate. low frequency ripple exists due to the hyster- esis in the sense comparator and propagation delays in the charge pump enable/disable circuits. high frequency ripple is also present mainly from the esr (equivalent series resistance) in the output capacitor. typical output ripple with v in = 3v under maximum load is 100mv peak-to-peak with a low esr (< 0.5 w ) 3.3 m f output capacitor (minimum recommended c out ). for applications requiring v in to exceed 3.3v or for applications requiring < 100mv of peak-to-peak ripple, a 6.8 m f to 10 m f c out capacitor is recommended. slight further decreases in output ripple can be achieved by using c out capacitors larger than 10 m f. short-circuit/thermal protection during short-circuit conditions, the ltc1517-5 will draw between 50ma and 200ma from v in , causing a rise in junction temperature. on-chip thermal shutdown circuitry disables the charge pump once the junction temperature exceeds approximately 160 c. the charge pump is reenabled once the junction temperature drops to approxi- mately 145 c. the ltc1517-5 will cycle in and out of thermal shutdown indefinitely without latchup or damage until the v out short is removed.
6 ltc1517-5 typical applicatio n s u 1 f 1517 ta04a 123 4 5 0.1 f 3.3 f 1 f 1 f 1 f 470 w 470 w v out = 5v i out = 1ma (v in 3 3.3v) i out = 10ma (v in 3 3.6v) v ripple < 2mv p-p v in 3.3v to 5v v in gnd ltc1517-5 v out c1 + c1 q2 q1, q2: 2n3904 q1 a b 50mv/div ac coupled v out 2mv/div ac coupled 50 m s/div v in = 3.3v i out = 1ma 1517-5 ta04b low noise boosted 5v supply generating 5v and a negative supply 3.3 f 1517 ta05 123 4 5 0.1 f 0.1 f * ** 3.3k v out = 5v 4% i out = 10ma (2.7v v in 5v) i out = 20ma (3v v in 5v) ? out = 1.4v to 3.5v ? out = 0ma to 5ma v in 2.7v to 5v v in gnd ltc1517-5 v out c1 + c1 8.2k 470 w 3.3 f central semiconductor cmpsh-35 dual schottky optional circuitry for maintaining v out with low v out loads q1, q2: 2n3904 * ** 3.3 f q2 q1 a b
7 ltc1517-5 dimensions in inches (millimeters) unless otherwise noted. package descriptio n u s5 package 5-lead plastic sot-23 (ltc dwg # 05-08-1633) 0.95 (0.037) ref 1.50 ?1.75 (0.059 ?0.069) 0.10 ?0.60 (0.004 ?0.024) ref 0.35 ?0.50 (0.014 ?0.020) five places (note 2) s5 sot-23 0797 2.80 ?3.00 (0.110 ?0.118) (note 3) 1.90 (0.074) ref 0.90 ?1.45 (0.035 ?0.057) 0.90 ?1.30 (0.035 ?0.051) 0.00 ?0.15 (0.00 ?0.006) 0.09 ?0.20 (0.004 ?0.008) (note 2) 2.60 ?3.00 (0.102 ?0.118) note: 1. dimensions are in millimeters 2. dimensions are inclusive of plating 3. dimensions are exclusive of mold flash and metal burr 4. mold flash shall not exceed 0.254mm 5. package eiaj reference is sc-74a (eiaj) information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
8 ltc1517-5 15175fs, sn15175a lt/tp 0298 4k ? printed in usa ? linear technology corporation 1997 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 l (408) 432-1900 fax: (408) 434-0507 l telex: 499-3977 l www.linear-tech.com 3.3v to 1.9v, 6a power supply ltc1517-5 ltc1430cs g1 pv cc1 pgnd gnd sense fb sense + shdn g2 pv cc2 v cc i fb i max freqset comp ss 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 c3 0.22 f 5 1 2 34 c6 to c9* 330 f 6.3v 4 c15 10 f 10v c13 390pf c14 0.012 f c12 0.1 f c16 0.018 f v out 1.9v 6a c4 0.1 f 5v c5 1 f d1 bat54 d2 mbrs120 r5 4.99k 1% r6 10k 1% l1 2.4 h, 8a sumida cdrh127-2r4 c11 1 f q1 si4410 q2 si4410 r2 24k r4 5.2k c10 0.1 f c1 y5v ceramic 3.3 f v in 3.3v c2 y5v ceramic 10 f + c17 to c21 * 330 f 6.3v 5 *avx tps tantalum 1517 ta03 + r1 100 r3 1k on off + typical applicatio n u part number description comments ltc1514-x step-up/step-down switched-capacitor dc/dc converter with 3.3v or 5v output up to 50ma low battery comparator ltc1515 series step-up/step-down switched-capacitor dc/dc converter with reset fixed or adjustable output up to 50ma ltc1516 micropower regulated 5v charge pump dc/dc converter 20ma for v in 3 2v, 50ma for v in 3 3v ltc1522 micropower regulated 5v charge pump dc/dc converter same as ltc1517-5 with shutdown, available in msop related parts
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