for technical support and more information, see inside back cover or visit www.ti.com/powertrends standard application for stby* pin: open = output enabled ground = output disabled. pin-out information pin function 1 vid0 2 vid1 3 vid2 4vid3 5 stby* - stand-by 6 do not connect 7v in 8v in 9v in pin function 10 v in 11 v in 12 remote sense gnd (4) 13 gnd 14gnd 15 gnd 16 gnd 17 gnd 18 gnd description the PT7708 is a next generation big hammer, a high-performance integrated switching regulator (isr), which is made available in power trends aluminum 27-pin sip p ack- age. the PT7708 improves on the popular pt7706 with 20a of output current and short circuit protection. the PT7708 is suitable for exist- ing 5v system designs that require power for the latest high-speed, low- voltage ps, and bus drivers. the PT7708 output is program- mable from 1.3v to 2.05v with a 4-bit input, which is compatible with the intel pentium ? processor. a differ- ential remote sense is also provided to compensate for voltage drop be tween the isr and load. only 33 0f of output capacitance are required for proper operation. c in = required 1500f electrolytic c out = required 330f electrolytic l1 = optional 1h input choke pin function 19 gnd 20 v out 21 v out 22 v out 23 v out 24v out 25 v out 26 remote sense v out 27 sync out c in + c out + load v in vid0 vid1 vid2 vid3 v out gnd gnd sync out stby* l1 1h remote sense ( ) remote sense (+) programming pins PT7708 4321 26 20-25 12 5 13-19 27 7-11 vo vin gnd sns(+) sns(-) synch out stby vid3 - vid0 PT7708?3.3v 20 amp programmable next generation ?big hammer? slts083 (revised 6/30/2000) specifications characteristics PT7708 series (t a = 25c unless noted) symbols conditions min typ max units output current i o t a = +60c, 200 lfm, pkg n 0.1 (1) 19 a t a = +25c, natural convection 0.1 (1) 20 input voltage range v in 0.1a i o 20a 3.1 3.6 v output voltage tolerance ? v o v in = +3.3v, i o = 20a v o -0.03 v o +0.03 v 0c t a +65c line regulation reg line 3.1v v in 3.6v, i o = 20a 10 mv load regulation reg load v in = +3.3v, 0.1 i o 20a 10 mv v o ripple/noise v n v in = +3.3v, i o = 20a 50 mv transient response t tr i o step between 10a and 20a 50 sec with c out = 330f v os v o over/undershoot 100 mv efficiency v in = +3.3v, i o = 10a v o = 1.8v 85 % v o = 1.5v 82 v in = +3.3v, i o = 20a v o = 1.8v 78 % v o = 1.5v 74 switching frequency ? o 3.1v v in 3.6v 300 350 400 khz 0.1a i o 20a absolute maximum t a over v in and i o ranges C40 (2) +85 (3) c operating temperature range storage temperature t s C40 +125 c mechanical shock per mil-std-883d, method 2002.3 1 msec, half sine, mounted to a fixture 500 gs mechanical vibration per mil-std-883d, method 2007.2, 10 gs 20-2000 hz, soldered in a pc board weight vertical/horizontal 31/41 grams notes: (1) isr-will operate down to no load with reduced specifications. (2) for operation below 0c, cin and cout must have stable characteristics. use either low esr tantalum or oscon? capacitors. (3) see safe operating area curves or contact the factory for the appropriate derating. (4) if the remote sense ground is not used, pin 12 must be connected to pin 13 for optimum output voltage accuracy. external capacitors: the PT7708 requires a minimum output capacitance of 330f for proper operation. the PT7708 also requires an input capacitance of 1500f, which must be rated for a minimum of 1.4arms of ripple current. for transient or dynamic load applications, additional capacitance may be required. for more information refer to the application note regarding capacitor selection for this product. input filter: an input filter inductor is optional for most applications. the inductor must be sized to handle 20adc with a typical value of 1h.
typical characteristics for technical support and more information, see inside back cover or visit www.ti.com/powertrends programming information vid3 vid2 vid1 vid0 vout 1 1 1 1 1.30v 1 1 1 0 1.35v 1 1 0 1 1.40v 1 1 0 0 1.45v 1 0 1 1 1.50v 1 0 1 0 1.55v 1 0 0 1 1.60v 1 0 0 0 1.65v 0 1 1 1 1.70v 0 1 1 0 1.75v 0 1 0 1 1.80v 0 1 0 0 1.85v 0 0 1 1 1.90v 0 0 1 0 1.95v 0 0 0 1 2.00v 0 0 0 0 2.05v features ? single-device: +3.3v input ? 4-bit programmable: 1.3v to 2.05v@20a ? high efficiency ? differential remote sense ? short-circuit protection ? parallelable with pt7742 20a current booster safe operating area (see note b) ordering information PT7708 ? ? ? ? ? = 1.3 to 2.05 volts (for dimensions and pc board layout, see package styles 800 and 810.) pt series suffix (pt1234 x ) case/pin configuration vertical through-hole n horizontal through-hole a horizontal surface mount c logic 0 = pin 12 potential (remote sense gnd) logic 1 = open circuit (no pull-up resistors) vid3 may not be changed while the unit is operating. characteristic data, v in =3.3v (see note a) PT7708?3.3v 20 amp programmable next generation ?big hammer? power dissipation vs output current efficiency vs output current ripple vs output current note a: all data in the above graphs has been developed from actual products tested at 25c. the data is considered typical for the isr note b: soa curves represent operating conditions at which internal components are at or below manufacturers maximum rated operating t emperatures. PT7708, v in =3.3v, vo =1.8v 50 60 70 80 90 0 4 8 121620 iout (a) efficiency - % 1.8 1.5 v out 0 10 20 30 40 0 4 8 121620 iout (a) ripple - mv 1.5 1.8 v out 0 2 4 6 8 10 12 0 4 8 121620 iout (a) pd - watts 1.5 1.8 v out 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 0.0 4.0 8.0 12.0 16.0 20.0 iout (a) ambient temperature ( c) 200lfm 120lfm 60lfm nat conv airflow
application notes for technical support and more information, see inside back cover or visit www.ti.com/powertrends PT7708/pt7709, pt7742/pt7743 capacitor recommendations for the PT7708/09 regulators and pt7742/43 current boosters input capacitors the recommended input capacitance is determined by 1.4 ampere minimum ripple current rating and 1500f minimum capacitance. capacitors listed below must be rated for a minimum of 2x the input voltage with +5v operation. ripple current and 100m ? equivalent series resistance (esr) values are the major considerations along with temperature when selecting the proper capacitor. output capacitors the minimum required output capacitance is 330f with a maximum esr less than or equal to 100m ? . failure to observe this requirement may lead to regulator instability or oscillation. electrolytic capacitors have poor ripple per- formance at frequencies greater than 400khz, but excellent low frequency transient response. above the ripple fre- quency ceramic decoupling capacitors are necessary to improve the transient response and reduce any microproces- sor high frequency noise components apparent during higher current excursions. preferred low esr type capaci- tor part numbers are identified in the table 1 below. note: (n/r) is not recommended for this application, due to extremely low equivalent series resistance (esr) table 1 capacitors characteristic data tantalum characteristics tantalum capacitors with a minimum 10v rating are recommended on the output bus, but only the avx tps series, sprague 594/595 series, or kemet t495/t510 series. the avx tps series, sprague series or kemet series capacitors are specified over other types due to their higher surge current, excellent power dissipation and ripple current ratings. as an ex ample, the taj series by avx is not recommended. this series exhibits considerably higher esr, reduced power dissipation and lower ripple current capability. the taj series is a less reliable compared to the tps series when determining power dissipation capability. capacitor table table 1 identifies the characteristics of capacitors from a number of vendors with acceptable esr and ripple current (rms) ratings. the suggested minimum quantities per regu- lator for both the input and output buses are identified. this is not an extensive capacitor list. the table below is a selection guide for input and output capacitors. other capacitor vendors are available with comparable rms ripple current rating and esr (equivalent series resistance at 100khz). these critical parameters are necessary to insure both optimum regulator performance and long capacitor life. r o t i c a p a cr o t i c a p a c r o t i c a p a c r o t i c a p a cr o t i c a p a c / r o d n e v/ r o d n e v / r o d n e v / r o d n e v/ r o d n e v s e i r e ss e i r e s s e i r e s s e i r e ss e i r e s s c i t s i r e t c a r a h c r o t i c a p a cs c i t s i r e t c a r a h c r o t i c a p a c s c i t s i r e t c a r a h c r o t i c a p a c s c i t s i r e t c a r a h c r o t i c a p a cs c i t s i r e t c a r a h c r o t i c a p a cy t i t n a u qy t i t n a u q y t i t n a u q y t i t n a u qy t i t n a u q g n i k r o wg n i k r o w g n i k r o w g n i k r o wg n i k r o w e g a t l o ve g a t l o v e g a t l o v e g a t l o ve g a t l o v ) f ( e u l a v) f ( e u l a v ) f ( e u l a v ) f ( e u l a v) f ( e u l a vt n e l a v i u q e ) r s e (t n e l a v i u q e ) r s e ( t n e l a v i u q e ) r s e ( t n e l a v i u q e ) r s e (t n e l a v i u q e ) r s e ( e c n a t s i s e r s e i r e se c n a t s i s e r s e i r e s e c n a t s i s e r s e i r e s e c n a t s i s e r s e i r e se c n a t s i s e r s e i r e s m u m i x a m c 5 0 1m u m i x a m c 5 0 1 m u m i x a m c 5 0 1 m u m i x a m c 5 0 1m u m i x a m c 5 0 1 e l p p i re l p p i r e l p p i r e l p p i re l p p i r ) s m r i ( t n e r r u c) s m r i ( t n e r r u c ) s m r i ( t n e r r u c ) s m r i ( t n e r r u c) s m r i ( t n e r r u c l a c i s y h pl a c i s y h p l a c i s y h p l a c i s y h pl a c i s y h p ) m m ( e z i s) m m ( e z i s ) m m ( e z i s ) m m ( e z i s) m m ( e z i s t u p n it u p n i t u p n i t u p n it u p n i s u bs u b s u b s u bs u b t u p t u ot u p t u o t u p t u o t u p t u ot u p t u o s u bs u b s u b s u bs u b r e b m u n r o d n e vr e b m u n r o d n e v r e b m u n r o d n e v r e b m u n r o d n e vr e b m u n r o d n e v c i n o s a n a p c f g t m e c a f r u s a f v 6 1 v 5 3 v 0 1 v 6 1 0 0 2 2 0 3 3 0 8 6 0 0 8 1 8 3 0 . 0 ? 5 6 0 . 0 ? ? 0 9 0 . 0 ? 2 3 0 . 0 a m 0 0 0 2 a m 5 0 2 1 a m 5 5 7 a m 0 0 0 2 5 . 6 1 x 8 1 5 . 6 1 x 5 . 2 1 5 . 2 1 x 0 1 5 1 x 8 1 1 1 1 1 1 1 n 2 2 2 c 1 c f v e e q l 1 3 3 v 1 c f v e e 1 8 6 a 1 a f u e e a 2 8 1 c 1 a f u e e d e t i n u n o c - i m e h c s e i r e s v f l v 5 2 v 6 1 v 6 1 0 3 3 0 0 2 2 0 7 4 4 8 0 . 0 ? 8 3 0 . 0 ? 4 8 0 . 0 ? 2 4 0 = 2 / ? a m 5 2 8 a m 0 3 6 1 2 x a m 5 2 8 6 1 x 0 1 0 2 x 6 1 6 1 x 0 1 1 1 1 1 l l 6 1 x 0 1 m 1 3 3 b v 5 2 v x l l l 0 2 x 6 1 m 2 2 2 b v 6 1 v x l l l 6 1 x 0 1 m 1 7 4 b v 6 1 v x l n o c i h c i n s e i r e s l p s e i r e s m p v 0 1 v 0 1 v 5 2 0 8 6 0 0 8 1 0 3 3 0 9 0 . 0 ? 4 4 0 . 0 ? 5 9 0 . 0 ? a m 0 7 7 a m 0 2 4 1 a m 0 5 7 5 1 x 0 1 5 1 x 6 1 5 1 x 0 1 1 1 1 1 6 h h m 1 8 6 a 1 l p u 6 h h m 2 8 1 a 1 l p u 6 h p m 1 3 3 e 1 l p u s s n o c s o v s v 0 1 v 0 1 0 3 3 0 3 3 6 0 0 . 0 = 4 / w 5 2 0 . 0 ? 5 0 0 . 0 = 4 / 0 2 0 . 0 ? a m 0 0 8 9 > a m 0 0 8 9 > 5 . 0 1 x 0 1 6 . 2 1 x 3 . 0 1 4 4 r / n ) e t o n ( m 0 3 3 s s 0 1 g t m e c a v f u s ( m 0 3 3 v s 0 1 x v a m u l a t a n a t s e i r e s - s p t v 0 1 v 0 1 0 3 3 0 3 3 0 2 = 5 / 0 0 1 . 0 ? 0 6 0 . 0 ? a m 0 0 5 3 a m 6 2 8 1 x l 3 . 7 x w 3 . 4 h 1 . 4 5 5 1 1 0 0 1 0 r 0 1 0 m 7 3 3 v s p t 0 6 0 0 r 0 1 0 m 7 3 3 v s p t e u g a r p s m u l a t n a t d 4 9 5 / d 5 9 5 v 0 1 v 0 1 0 3 3 0 8 6 1 1 0 . 0 = 4 / w 5 4 0 . 0 ? 0 9 0 . 0 ? a m 0 0 5 4 > a m 0 6 6 1 > x l 3 . 7 x w 7 . 5 h 0 . 4 5 2 1 1 t 2 r 0 1 0 0 x 7 3 3 d 4 9 5 t n u o m e c a f r u s t 2 r 0 1 0 0 x 7 8 6 d 5 9 5 t e m e k m u l a t n a t 5 9 4 t / 0 1 5 t s e i r e s v 0 1 v 0 1 0 3 3 0 2 2 5 3 0 . 0 ? 0 7 0 . 0 ? 5 3 0 . 0 = 2 / ? a m 0 0 0 2 a m 0 0 0 2 > l 3 . 7 x w 3 . 4 h 0 . 4 x 5 6 1 2 s a 0 1 0 m 7 3 3 x 0 1 5 s a 0 1 0 m 7 2 2 x 5 9 4 t t n u o m e c a f r u s p a c s o p o y n a s b p t v 0 10 2 20 4 0 . 0 ? a m 0 0 0 3x l 2 . 7 x w 3 . 4 h 1 . 3 62 m 0 2 2 b p t 0 1 t n u o m e c a f r u s
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