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? 2006 california micro devices corp. all rights reserved. 03/20/06 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 1 cm3702 low noise charge pump/lin ear regulator led driver features ? low noise regulator with integrated charge pump voltage-booster ? 5v output with input vo ltage as low as 3.0v ? charge pump can also power external ldo ? low noise in 20hz to 20khz audio band ? up to 200ma continuous output current ? low operating and shutdown currents ? stable with low-esr cera mic or tantalum capaci- tors ? 10-lead msop package ? lead-free version available applications ? backlight white leds in wireless handsets and lcd modules ? 3.3v to 5v conversion in pcmcia cards, pci express cards, other applications needing 5v ? 5v analog supply for audio codec in notebook computers, pdas, mp3 players, etc. product description the cm3702 low-noise charge pump ldo regulator is designed to provide accurate and "clean" power to a subsystem, e.g an led driver, audio codec or flash memory. the 5v output provides up to 100ma continu- ous current for input voltages from 3.0v to 5.5v, and up to 200ma for a narrower range. this is accom- plished with an integrated charge pump that boosts the input voltage before feeding it to an internal ldo linear regulator. the charge pump is designed to maintain a nominal 0.8v differential between the input and output of the ldo regulator. this allows the ldo regulator to operate with good power supply ripple rejection across the audio band while mainta ining good power effi- ciency. the charge pump works with two external capacitors and operates at 250khz, well outside the audible frequency band. in addition, separate analog and digital ground pins are provided for the charge pump and the rest of the circuitry to eliminate ground noise feed-through from the charge pump to the regu- lated output. the cm3702 is fully protecte d, offering both overload current limiting and high temperature thermal shut- down. (cont?d next page) typical application sim plified block diagram cm3702 4 3 2 1 6 7 8 9 msop-10 5 10 v in c i 10 f** c s 3 f + + c byp 0.1 f + v out c out 0.1 f + c p + enable ** this can be pre-existing system capacitance. 1 f charge pump cs cp- cp+ c p c s cs dgnd v in en_chip en_ldo v ref ldo byp gnd v out 1 2 3 7 6 54 8 9 10 enable charge pump control circuit enable ldo
? 2006 california micro devices corp. all rights reserved. 2 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 03/20/06 cm3702 product description (cont?d) two enable inputs provide flexibility in powering down the device. for maximum power saving in shutdown, both the charge pump and ldo regulator should be disabled. for applications that require the 5v output to be re-established with minimum delay after shutdown, the charge pump can be left enabled while the regula- tor is disabled. this avoids the delay that may other- wise be required for the charge pump to reach full operating voltage after being disabled. the cmos ldo regulator features low quiescent current even at full load, making it very su itable for po wer sensitive applications. a bandgap reference bypass pin is provided to further minimize noise by connecti ng an external capacitor between this pin and ground. another, external, regula- tor can be connected to the charge pump output pin cs, if required. the cm3702 is available in a 10-lead msop package, with optional lead-free finishing and is ideal for space critical applications. package / pinout diagram note: this drawing is not to scale. cm3702-50ms/mr 10 lead msop package 10-lead msop-10 1 2 3 4 10 9 8 7 dgnd v in cs gnd cp- cp+ v out en_chip top view 56 byp en_ldo 3702 50/50s pin descriptions lead(s) name description 1 dgnd ground for the charge pump circuit. this should be connected to the system (noisy) ground. 2v in input power source for the device. since the charge pump draws current in pulses at the 250khz internal clock frequency, a low-esr input decoupling capacitor is usually required close to this pin to ensure low noise operation. 3 cs charge pump output which is connected to the external reservoir capacitor c s . this should be a low-esr capacitor. when the voltage on this pin reaches about 5.8v then the charge pump pauses until the voltage on this pin drops to about 5.7v. this gives rise to at least 100mv of 'rip- ple' (the frequency and amplitude of this ripple depends upon values of c p and c s and also the esr of c s ). 4 gnd ground reference for all internal circuits exce pt the charge pump. this pin should be connected to a "clean" low-noise analog ground 5 byp bypass input connected to the internal volt age reference of the ldo regulator. an external bypass capacitor c byp of 0.1uf may be added to minimize internal voltage reference noise and maximize power supply ripple rejection.
? 2006 california micro devices corp. all rights reserved. 03/20/06 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 3 cm3702 ordering information note 1: parts are shipped in tape & reel form unless otherwise specified. 6, 7 en_ldo, en_chip en_ldo (pin 6) and en_chip (pin 7) are active -high ttl-level logic inputs to enable the linear regulator and charge pump according to the following truth table: 8v out the regulated output. an output capacitor ma y be added to improve noise and load-transient response. when the ldo regulator is disabled, an internal pull-down with a nominal resistance of 500 ohms is activated to discharge the v out rail to gnd 9, 10 cp+, cp- cp+ (pin 9) and cp- (pin 10) are us ed to connect the external "flying" capacitor c p to the charge pump. the charge stored in c p is transferred to the reservoir capacitor c s at the 250khz inter- nal clock rate. pin descriptions (cont?d) en_chip (pin 7) en_ldo (pin 6) charge pump regulator 1 1 enabled enabled 1 0 enabled disabled 0 1 disabled disabled 0 0 disabled disabled part numbering information leads package standard finish lead-free finish ordering part number 1 part marking ordering part number 1 part marking 10 msop-10 cm3702-50ms 3702 50s CM3702-50MR 3702 50
? 2006 california micro devices corp. all rights reserved. 4 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 03/20/06 cm3702 specifications absolute maximum ratings parameter rating units esd protection (hbm) 2000 v v en logic input voltage (v in + 0.5) to (gnd - 0.5) v v in, v out pin voltages +5.5 to (gnd - 0.5) v storage temperature range -40 to +150 c operating temperature range ambient junction 0 to +70 0 to +170 c c standard operat ing conditions parameter value units input voltage range (v in ) 3.0 to 5.5 v ambient operating temperature 0 to +70 c ja of msop package on pcb 200 (approx.) c/w output load current (i out ) 0 to 200 ma c byp 0 to 0.1 f c out 0 to 100 f
? 2006 california micro devices corp. all rights reserved. 03/20/06 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 5 cm3702 specifications (cont?d) note 1: unless otherwise noted, electrical oper ating characteristics are specified with t a = 0 to 70c, v in = 5.0v, i out =100ma, c out =10 f, c p = 1 f, c s = 2.2 f. note 2: these parameters are guarant eed by design and characterization. electrical operat ing characteristics (see note 1) symbol parameter conditions min typ max units v cp charge pump output voltage v in = 4v, v out = 5v, 1ma < i out < 100ma 5.5 5.8 7 v v out regulator output voltage v in = 4.0v, 1ma < i out < 100ma 4.85 5.15 v v r load load regulation i out = 1ma to 100ma 0.2 % v r line line regulation vary v in from 3.0v to 5.0v 0.02 % r dischg v out discharge resistance ldo regulator disabled, en_ldo grounded, v in = 5v 500 i gnd ldo regulator ground current via the gnd pin shutdown (en_ldo grounded) 1 10 a regulator enabled, i out = 0ma 180 a regulator enabled, i out = 100ma 180 a i dgnd charge pump shutdown current via dgnd pin en_chip grounded, v in = 5v 1 10 a psrr power supply ripple rejection i out = 100ma, c byp =0.1 f, note 2 f = 100hz f = 10khz 42 42 db db e no output voltage noise bw=22hz-22khz, c out = 10 f, c byp = 0.1 f, i out = 100ma, note 2 35 vrms bw=22hz-22khz, c p = 1 f, c s =3 f, c out = c byp = 0.1 f, i out = 100ma, note 2 38 vrms v ih en_chip, en_ldo input high threshold v in = 5.0v 2.0 v v il en_chip, en_ldo input low threshold v in = 5.0v 0.5 v i lim overload current limit ldo only, note 2 200 300 ma i sc output short circuit current ldo only, note 2 50 ma t jsd thermal shutdown junction temperature note 2 170 c t hys thermal shutdown hysteresis note 2 25 c
? 2006 california micro devices corp. all rights reserved. 6 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 03/20/06 cm3702 performance information figure 1. cm3702 noise spectrum ( t a = 25c, c p =0.47 f, c s = 1.5 f, c o = c byp = 0.1 f, i out =100ma ) figure 2. cm3702 psrr (upper curve with v in = 3.3v, lower curve with v in = 5v, i out = 100ma both cases) p 1.00e-08 1.00e-07 1.00e-06 1.00e-05 1.00e-04 1.00e-03 10 100 1000 10000 100000 frequency [hz] voltage [v] noise loor cs=1.uf note: noise peaks may appear for different values of c p , c s & i out , and are due to the ripple frequency of the charge pump (see later). 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 10 100 1000 10000 100000 frequency [hz] psrr [db] measuredyorcingv in voltageto3.3v.0vdc,thensweeping100mvaconv in .c out =10 f, c byp = 0.1 f.
? 2006 california micro devices corp. all rights reserved. 03/20/06 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 7 cm3702 performance information (cont?d) typical dc characteristics (t a =25c, c p =1.0 f, c s =10 f, c byp =0.1 f, c out =10 f unless otherwise noted) figure 3. v out vs. i out (v in = 5v) figure 4. v out vs. v in figure 5. cs pin vs. v in figure 6. dropout voltage (ldo only) figure 7. v en threshold vs. v in figure 8. i in vs. v in figure 9. i in vs. i out figure 10. overcurrent characteristic (ldo only) 4.9 4.92 4.94 4.96 4.98 5 5.02 5.04 5.06 5.08 5.1 0 20 40 60 80 100 i_out [ma] v_out [v] 4.9 4.92 4.94 4.96 4.98 5 5.02 5.04 5.06 5.08 5.1 3 3.5 4 4.5 5 5.5 v_in [v] v_out [v] i_out=0ma i_out=100ma 5 5.25 5.5 5.75 6 6.25 6.5 6.75 7 3 3.5 4 4.5 5 5.5 v_in [v] cs pin [v] at t=150'c, t=85'c and t=25'c 0 100 200 300 400 0 102030405060708090100 i_out [ma] v do [mv] t a =150c t a =25c t a =85c 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 3 3.5 4 4.5 5 5.5 v_in [v] v_en [v] 0 50 100 150 200 250 300 33.544.555.5 v_in [v] i_in [ a] 0 50 100 150 200 250 020406080100 i_out [ma] i_in [ma] v_in=3.1v v_in=5v 0 1 2 3 4 5 6 0 0.1 0.2 0.3 0.4 0.5 i_out [a] v_out [v]
? 2006 california micro devices corp. all rights reserved. 8 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 03/20/06 cm3702 performance information (cont?d) transient characteristics (t a =25c, c p =1.0 f, c s =10 f, c byp =0.1 f, c out =10 f unless otherwise noted) figure 11. load regulation (0ma to 100ma) figure 12. load regulation (2ma to 100ma) figure 13. line regulation figure 14. cold start / power-up figure 15. ldo power-up figure 16. ldo power-down
? 2006 california micro devices corp. all rights reserved. 03/20/06 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 9 cm3702 performance information (cont?d) transient characteristics (t a =25c, v in =5v, c p =1.0 f, c s =10 f, c byp =0.1 f, c out =10 f unless otherwise noted) figure 17. v out with v in = 5v figure 18. v out with v in =3.0v, i out =100ma figure 19. bypass pin voltage figure 20. i in leakage current (pins 6,7=0v) figure 21. undervoltage lockout 4.90 4.95 5.00 5.05 5.10 -50 -25 0 25 50 75 100 125 150 temperature ['c] voltage [v] i_out=0 i_out=30ma i_out=75ma i_out=100ma i_out=150ma 4.8 4.85 4.9 4.95 5 5.05 5.1 -50 -25 0 25 50 75 100 125 temperature ['c] v_out voltage [v] 1.6 1.605 1.61 1.615 1.62 1.625 1.63 1.635 1.64 1.645 1.65 -50 -25 0 25 50 75 100 125 150 temperature ['c] voltage [v] 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 -50 -25 0 25 50 75 100 125 150 temperature ['c] current [ a] 0 0.5 1 1.5 2 2.5 3 -50 -25 0 25 50 75 100 125 150 temperature ['c] v_in voltage [v]
? 2006 california micro devices corp. all rights reserved. 10 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 03/20/06 cm3702 application information ripple frequency the charge pump internal oscillation frequency is about 250khz. however, this is the continuous, free- running frequency, which is us ually only seen while the charge pump is powering up. after the charge pump output voltage (cs) reaches approximately 5.8v, the charge pump pauses until the cs voltage drops to approximately 5.7v. then the charge pump restarts and runs until the cs voltage is greater than approxi- mately 5.8v, when it pauses again, and this process repeats. this gives rise to a sawtooth 'ripple' waveform on cs which can have a much lower frequency than 250khz. this mode of operation is necessary to con- serve power - if it were not done this way then a much larger package with heatsink would be required. the frequency of this 'ripple' is affected by v in , i out , c s capacitor value and c p capacitor value. guidelines for choosing values for external capacitors (1) to find c p : specify value of v in , and highest value of i out : if v in = 3.3v +/- 5%, then minimum value of c p (f) = i out (ma) / 85. if v in = 5.0v +/- 10%, then minimum value of c p (f) = i out (ma) / 700 (2) c i , the v in decoupling capacitor, should typically be much greater than c p to prevent voltage droop during c p charging. excessive glitches on v in will affect the output voltage v out . typically c i is 10x greater than c p . but usually there are already some capacitors on this supply, so adding extra capacitors is not necessary - simply move an already-present low-esr capacitor close to the cm3702. this is especially important for v in = 5v. (3) choose value of c s . c s should be small to ensure that the ripple frequency is high, but c s should be at least 2x greater than c p otherwise the ripple amplitude will be very high. reducing the value of c s will increase the ripple frequency. examples of cs ripple frequencies (c s =10 f, t a =25c) are shown in following tables: (4) c o , the optional v out decoupling capacitor, helps minimize noise and improve load regulation. 0.1f - 100f is recommended. (5) c byp , the optional bypass capacitor helps reduce noise in the ldo. 0.1f is recommended. after choosing external component values, check in- system performance (at min/max v in , max tempera- ture, and min/max i out ). see the troubleshooting guide on next page for tips if there are problems. charge pump noise the charge pump is 'digital' in operation and can pro- duce digital noise at both the free-running frequency and at the ripple frequency. to minimize noise, pcb grounding is important! this part requires short, low-impedance ground connec- tions for dgnd (pin 1), gnd (pin 4), the v in decou- pling capacitor (pin 2), the c s capacitor (pin 3), the bypass decoupling capacitor (pin 5) and the v out decoupling capacitor (pin 8) . all decoupling capacitors and the c s capacitor should be low-esr ceramics. the c p capacitor does not need to be low-esr. c p = 0.47 f v in i out cs frequency 3.14 15ma 46khz 3.60 15ma 35khz 4.50 70ma 76khz 5.50 70ma 56khz c p = 1.0 f v in i out cs frequency 3.14 100ma 250khz 3.60 100ma 110khz 4.50 100ma 67khz 5.50 100ma 49khz
? 2006 california micro devices corp. all rights reserved. 03/20/06 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 11 cm3702 efficiency the power efficiency in % of the combined charge pump and ldo is approximately: 100 x (v out ) / (v in x 2) power dissipation the dissipation of the part is approximately: ((v in x 2) - v out ) x i out the msop-10 package heats at a rate of about 200c/ w ( ja ). note that th is value is approximate because it depends upon the copper tracks and ground planes on the pcb. if v in = 5v and i out = 100ma then the power dissipation will be approxima tely 500mw. multiplying this by the ja of 200, the part's internal temperature will be about 100c higher than the ambient tempera- ture. if the ambient temperature is 70c then the inter- nal temperature will be appr oximately 170c which will typically trigger the overtemperature circuit and depower the part. internal temperature = ambient temperature + ( ja x power dissipation ) (must be less than 170c) how to reduce the power dissipation of the part and how to get more than 100ma if v in = 5v typ., then the charge pump / ldo combina- tion is capable of providing more than 100ma. the only problem is power dissipation. if the input voltage is lowered using an external diode then the output current can be increased without caus- ing the part to over heat. the circuit below illustrates an example of how to increase the output current. using this circuit, i out can be 200ma if v in = 4.75v, and yet the part will not overheat even if v in = 5.25v, i out =200ma and the ambient temperature is 85c. warnings the charge pump output cs (pin 3) must not be shorted to gnd or held belo w its internally-set voltage while the part is powered. th is usually results in the destruction of the part. with v in = 5v, the maximum current that can be con- tinuously drawn from cs is approximately 100ma dc. never short c p + (pin 9) to c p - (pin 10). this will cause large currents to flow from v in to dgnd through the part, usually causing its de struction. this will happen even if en_chip and en_ldo are off. troubleshooting guide 1) is the output voltage is drooping under heavy loads? perhaps the charge pump cannot provide the neces- sary current. try increasing the value of c p . if that does not work then is v in too low? is v in dropping dur- ing the c p charging cycle? if v in is not suitably decou- pled and drops below 3.0v then the available current will be very low. 2) is the output voltage oscillating between 5v and 0v? the part may be reaching its overtemperature limit. reduce current consumption, reduce ja or add an external diode on the input to reduce v in . 3. is the part too noisy? try increasing value (or reduc- ing esr) of c s , c i , c o , c byp . at minimum current the charge pump ripple freq uency will be low. if v out noise is at the charge pump ripple frequency then change values of c p and c s . reducing the input voltage v in will reduce the charge pump ripple frequency noise on v out . 4. will the part power up? pin 6 must be high to power up. even if pin 7 is high, pin 6 must also be high to power up. 5. can the cold start power-up time be reduced? yes, by reducing the value of the byp capacitor. cm3702 4 3 2 1 6 7 8 9 msop-10 5 10 5v c i 10 f c s 3 f + + c byp 0.1 f + v out c o 0.1 f + c p + enable 1 f pacdn042 10%
? 2006 california micro devices corp. all rights reserved. 12 490 n. mccarthy blvd., milpitas, ca 95035-5112 tel: 408.263.3214 fax: 408.263.7846 www.cmd.com 03/20/06 cm3702 mechanical detailsmechanical details msop-10 mechanical specifications cm3702-50ms/mr is packaged in 10-pin msop pack- age. dimensions are presented below. for complete information on the msop-10 package, see the california micro devices msop package infor- mation document. package dimensions for msop-10 package dimensions package msop pins 10 dimensions millimeters inches min max min max a 0.75 0.95 0.028 0.038 a1 0.05 0.15 0.002 0.006 b 0.17 0.27 0.007 0.011 c 0.18 0.007 d 2.90 3.10 0.114 0.122 e 2.90 3.10 0.114 0.122 e 0.50 bsc 0.0197 bsc h 4.90 bsc 0.193 bsc l 0.40 0.70 0.0137 0.029 # per tape and reel 4000 controlling dimension: millimeters mechanical package diagrams e d h 1234 10 9 8 7 l end view c e b a a1 seating plane side view top view 6 5 pin 1 marking

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