for free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. for small orders, phone 1-800-835-8769. general description the MAX1686 provides power for dual-voltage sub- scriber id module (sim) cards in portable applications such as gsm cellular phones. designed to reside in the portable unit (cellular phone handset), the 1mhz charge pump converts a 2.7v to 4.2v input to regulated 5v out- put. the MAX1686h has a nominal output voltage of 5.0v, while the MAX1686 is set to 4.75v to reduce sim- card current drain. the charge pump has only 45? qui- escent supply current, which reduces to 3? when a 3v-capable sim card is being powered and the charge pump is disabled. an internal input/output shorting switch provides power for 3v sim cards. the MAX1686/MAX1686h require only three external capacitors around their space-saving, thin (1mm) 8-pin ?ax packages. applications gsm cellular phones pcs phones portable pos terminals personal communicators features ? 2.7v to 4.2v input range ? 12ma min charge-pump output current ? 45? quiescent supply current ? 0.1? supply current in shutdown mode ? 5.0v regulated charge-pump output (MAX1686h) 4.75v regulated charge-pump output (MAX1686) ? input-output shorting switch for 3v cards ? small external components (uses a 0.047?, 0.1?, and a 2.2? capacitor) ? output driven to ground in shutdown mode ? super-small 8-pin ?ax package ? soft-start and short-circuit protection MAX1686/MAX1686h 3v to 5v regulating charge pumps for sim cards ________________________________________________________________ maxim integrated products 1 1 2 3 4 8 7 6 5 out cxp cxn pgnd gnd in shdn 3/5 MAX1686 MAX1686h m max top view MAX1686 MAX1686h in cxn cxp gnd pgnd c in input 2.7v to 4.2v output v in or 5v/20ma c x c out shdn 3/5 out typical operating circuit 19-1376; rev 1; 12/98 part MAX1686 eua -40? to +85? temp. range pin-package 8 ?ax pin configuration ordering information MAX1686h eua -40? to +85? 8 ?ax
MAX1686/MAX1686h 3v to 5v regulating charge pumps for sim cards 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = v shdn = 3.3v, 3/ 5 = gnd, c x = 0.22?, c out = 10? (see applications information section to use smaller capacitors), t a = t min to t max , unless otherwise noted. typical values are at t a = +25?.) (note 1) in, out, shdn , 3/ 5 to gnd.....................................-0.3v to +6v cxp to gnd..............................................-0.3v to (v out + 0.3v) cxn to gnd ................................................-0.3v to (v in + 0.3v) pgnd to gnd ......................................................-0.3v to + 0.3v out short circuit to gnd ..........................................continuous in-to-out current...............................................................50ma continuous power dissipation (t a = +70? ) 8-pin ?ax (derate 4.1mw/? above +70?) .............330mw operating temperature range MAX1686eua/MAX1686heua........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +165? lead temperature (soldering, 10sec) .............................+300? parameter conditions min typ max units input voltage range 2.7 4.2 v input undervoltage-lockout threshold voltage 0.8 1.2 1.6 v quiescent supply current charge pump enabled, no load, 3/ 5 = gnd ? charge pump disabled, no load, 3/ 5 = in shutdown supply current v in = 3.6v, shdn = gnd 0.1 5 v out output voltage 4.55 4.75 5.25 v 3/ 5 = v in = 3.0v 2.5 5 out short-circuit current 3/ 5 = gnd or in 20 100 200 ma logic input low voltage shdn , 3/ 5 0.5 v in 0.3 v in v logic input high voltage shdn , 3/ 5 0.7 v in 0.5 v in v logic input leakage current shdn , 3/ 5 = gnd or in 0.1 1 ? 4.75 5.00 5.25 out discharge switch on-resistance 3/ 5 = gnd or in, shdn = gnd 80 200 in-to-out switch on-resistance t a = +25? 800 1000 1200 ? note 1: electrical specifications are measured by pulse testing and are guaranteed for a junction temperature within the operating temperature range, unless otherwise noted. limits are 100% production tested at t a = +25?. limits over the entire operat- ing temperature range are guaranteed through correlation using statistical quality control (sqc) methods and are not pro- duction tested. stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. t a = +25? 45 100 310 charge-pump frequency t a = -40? to +85? 700 1300 khz t a = -40? to +85? 150 3/ 5 = in v in MAX1686 MAX1686h v in = 2.7v to 4.2v, load = 0 to 12ma
MAX1686/MAX1686h 3v to 5v regulating charge pumps for sim cards _______________________________________________________________________________________ 3 0 0.1 100 10 1 efficiency vs. load current (5v mode) 30 10 70 50 90 40 20 80 60 MAX1686-01 load current (ma) efficiency (%) v in = 3.6v v in = 2 .7v v in = 3.3v 0 0 efficiency vs. input voltage (5v mode) MAX1686-toc2 input voltage (v) efficiency (%) 10 20 30 40 50 60 70 80 90 123 45 6 i load = 10ma i load = 1ma 1000 0.1 02 146 no-load input current vs. input voltage (3v mode) 1 10 100 MAX1686-03 input voltage (v) input current ( m a) 35 10,000 1 02 146 no-load input current vs. input voltage (5v mode) 10 100 1000 MAX1686-04 input voltage (v) input current ( m a) 35 0 2 1 4 3 5 6 023 1 456 output voltage vs. input voltage (3v mode) MAX1686-07 input voltage (v) output voltage (v) no load 3.20 3.24 3.22 3.28 3.26 3.30 3.34 3.32 0 5 10 15 20 25 output voltage vs. load current (3v mode) MAX1686-05 load current (ma) output voltage (v) 4.70 0.1 100 10 1 MAX1686 output voltage vs. load current (5v mode) 4.73 4.71 4.77 4.75 4.80 4.74 4.72 4.78 4.79 4.76 MAX1686-06 load current (ma) output voltage (v) v in = 2.7v v in = 3 .3v v in = 3.6v 0 2 1 4 3 5 6 023 1 456 output voltage vs. input voltage (5v mode) MAX1686-08 input voltage (v) output voltage (v) no load MAX1686 MAX1686h 2.5 m s/div output waveform (i load = 10ma) MAX1686-09 v out (20mv/div) 5v mode, ac coupled, c out = 10 m f ?? 0.1 m f typical operating characteristics (see typical operating circuit , c in = 0.47?, c x = 0.22?, c out = 10?, v in = 3.3v, t a = +25?, unless otherwise noted.)
MAX1686/MAX1686h 3v to 5v regulating charge pumps for sim cards 4 _______________________________________________________________________________________ typical operating characteristics (continued) (see typical operating circuit , c in = 0.47?, c x = 0.22?, c out = 10?, v in = 3.3v, t a = +25?, unless otherwise noted.) 25?/div output waveform (i load = 1ma) MAX1686-10 v out (20mv/div) 5v mode, ac coupled, c out = 10 m f ?? 0.1 m f 2.5ms/div line-transient response MAX1686-11 v in (500mv/div) v in = 2.8v to 3.3v, i load = 10ma, 5v mode, ac coupled v out (50mv/div) 2.5ms/div load-transient response MAX1686-12 i load (10ma/div) i load = 0 to 10ma, 5v mode, ac coupled v out (50mv/div) 250 m s/div start-up waveform (3v mode, r l = 500 w ) MAX1686-13 shdn (5v/div) v out (1v/div) 0v 1ms/div shutdown waveform (3v mode, no load) MAX1686-16 shdn (5v/div) v out (1v/div) r l = 500 w 0v 250 m s/div start-up waveform (5v mode, r l = 500 w ) MAX1686-14 shdn (5v/div) v out (1v/div) 0v 250 m s/div 3v mode to 5v mode waveform (r l = 500 w ) MAX1686-15 3/5 (5v/div) v out (1v/div) 0v 1ms/div shutdown waveform (5v mode, no load) MAX1686-17 shdn (5v/div) v out (1v/div) 0v 500 m s/div 5v mode to 3v mode waveform (no load) MAX1686-18 3/5 (5v/div) v out (1v/div) 0v
MAX1686/MAX1686h 3v to 5v regulating charge pumps for sim cards _______________________________________________________________________________________ 5 name function 1 3/ 5 3v/5v select input. when low, the output is regulated at 4.75v for MAX1686, 5.00v for MAX1686h. when high, the output is shorted to the input. 2 shdn active-low shutdown input. shdn = gnd is off. output is actively pulled low in shutdown. pin 3 in supply input pin. can range from 2.7v to 4.2v. bypass to ground with a ceramic capacitor. 4 gnd ground pin 8 out power output. bypass to gnd with an output filter capacitor. 7 cxp positive terminal of the charge-pump transfer capacitor 6 cxn negative terminal of the charge-pump transfer capacitor 5 pgnd power ground. connect to gnd through a short trace. pin description _______________detailed description the MAX1686/MAX1686h charge pumps provide two modes of operation: 3v mode or 5v mode. the devices consist of an error amplifier, a 1.23v bandgap refer- ence, an internal resistive feedback network, a 1mhz oscillator, high-current mosfet drivers and switches, and a power-management block as shown in the functional diagram (figure 1). in 3v mode (3/ 5 = in), the input is connected to the output through a 2.5 switch. in 5v mode (3/ 5 = gnd), the MAX1686? output voltage is regulated at 4.75v (5.00v for the MAX1686h) with a 2.7v to 4.2v input and can deliver more than 12ma of load current. designed specifically for compact applications, these regulators require only three small external capacitors. the skip mode control scheme provides high efficiency over a wide output current range. the devices offer a shutdown feature which actively discharges the output to ground and reduces the supply current to less than MAX1686 MAX1686h c x power management dis ss osc cxp cxn en shdn 3/5 1.23v gnd pgnd in s1 s2 pwrok out figure 1. functional diagram
MAX1686/MAX1686h 3v to 5v regulating charge pumps for sim cards 6 _______________________________________________________________________________________ 1?. other features include soft-start, undervoltage lockout, and short-circuit protection. charge-pump control figure 2 shows an idealized, unregulated charge-pump voltage doubler. the oscillator runs at a 50% duty cycle. during one half of the period, the transfer capac- itor (c x ) charges to the input voltage. during the other half, the doubler stacks the voltage across c x and the input voltage, and transfers the sum of the two voltages to the output filter capacitor (c out ). the MAX1686 uses skip mode control to regulate its output voltage and to achieve good efficiency over a large output current range. when the comparator detects that the output voltage is too low, the 1mhz oscillator is enabled and c x is switched. when the output voltage is above regu- lation, the oscillator is disabled and c x is connected at the input. soft-start in the 5v mode (3/ 5 = gnd), the start-up current is lim- ited by the soft-start control to typically 200ma, inde- pendent of the load. until the output voltage reaches v in / 2, the input is connected to the output through a 50 series p-channel mosfet and the charge pump is disabled. for v in / 2 < v out < 4.75v (5.00v for MAX1686h) and for a maximum of 2ms the charge pump is active, but r on of the switch s2 is limited to 50 . this limits typical current surges associated with charge pumps at start-up. when soft-start is complete, v out > 4.75v (5.00v for MAX1686h) or 2ms (whichever occurs first), switch s2? on-resistance is decreased to minimize losses. in 3v mode (3/ 5 = in), the start-up current is limited by the 50 series p-channel mosfet connected between in and out until the output voltage reaches v in / 2. for v out > v in / 2, r on is reduced to 2.5 . with a 500 load the device turns on in less than 1.5ms (see typical operating characteristics for graphs of start-up waveforms). shutdown mode driving shdn low places the device in shutdown mode, which disables the oscillator, the control logic, and the reference. placing the device in shutdown mode reduces the no-load supply current to less than 1 a; the output is actively discharged through the internal n- channel fet and disconnected from the input. in normal operation, shdn is driven high or connected to in. applications information capacitor selection the MAX1686 requires only three external capacitors. the capacitor values are closely linked to the output current capability, noise, and switching frequency. the 1mhz oscillator frequency minimizes capacitor size compared to lower-frequency charge pumps. generally, the transfer capacitor (c x ) will be the smallest, the input capacitor (c in ) will be twice the size of c x , and the output capacitor (c out ) can be from 10 to 50 times c x . the suggested capacitor values are c in = 0.1?, c x = 0.047?, and c out = 2.2? as shown in figure 3. for input voltages as low as 2.7v, the following values are recommended: c in = 0.47?, c x = 0.22?, and c out = 10?. table 1 lists the perfor- c x osc cxp cxn gnd in s1 s2 out c in c out figure 2. unregulated voltage doubler MAX1686 in 38 2 1 45 6 7 cxn cxp gnd pgnd c in 0.1 m f 3v 5v input 2.85v to 4.2v output v in or 4.75v at 20ma c x 0.047 m f c out 2.2 m f (ceramic) shdn 3/5 out figure 3. standard application circuit
MAX1686/MAX1686h 3v to 5v regulating charge pumps for sim cards _______________________________________________________________________________________ 7 mance with different input voltages and an additional small 0.1? capacitor at the output. the extra 0.1? capacitor improves start-up capability under full load and reduces output ripple for high input voltages. table 2 lists the recommended capacitor manufacturers. low- esr capacitors, such as surface-mount ceramics, decrease noise and give the best efficiency. capaci- tance and esr variation over temperature need to be taken into consideration for best performance in applica- tions with large operating temperature ranges. for applications where the minimum input voltage is 3v or greater, the flying capacitor, c x , can be decreased to 0.1?. this provides two benefits: the inrush surge current at start-up is reduced, and the output ripple voltage (especially at high input voltages) is also reduced. layout considerations high switching frequencies and large peak currents make pc board layout an important part of design. all capacitors should be soldered close to the ic. con- nect ground and power ground through a short, low- impedance trace. keep the extra copper on the board and integrate it into ground as a pseudo-ground plane. on multilayer boards, route the star ground using com- ponent-side copper fill, then connect it to the internal ground plane using vias. ensure that the load is con- nected directly across the output filter capacitor. 2.7 1 30 84.3 2.7 10 30 86.2 3.3 1 60 69.5 3.3 10 60 70.5 3.6 1 80 63.2 3.6 10 80 63.8 4.2 1 120 52.3 4.2 10 120 52.1 table 2. recommended surface-mount capacitor manufacturers value (?) description mfr. phone number 1 to 47 595d-series tantalum sprague (603) 224-1961 4.7 to 47 tps-series tantalum avx (803) 946-0690 1 to10 267 series tantalum matsuo (714) 969-2491 0.047 to 2.2 x7r ceramic tdk (847) 390-4373 avx (803) 946-0690 input voltage (v) load current (ma) v out ripple (mv) efficiency (%) table 1. ripple and efficiency vs. input voltage and load current chip information transistor count: 840
MAX1686/MAX1686h 3v to 5v regulating charge pumps for sim cards maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 1998 maxim integrated products printed usa is a registered trademark of maxim integrated products. maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 1998 maxim integrated products printed usa is a registered trademark of maxim integrated products. package information 8lumaxd.eps
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