for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. general description the ultra-small max1682/max1683 monolithic, cmos charge-pump voltage doublers accept input voltages ranging from +2.0v to +5.5v. their high voltage-con- version efficiency (over 98%) and low operating current (110? for max1682) make these devices ideal for both battery-powered and board-level voltage-doubler applications. oscillator control circuitry and four power mosfet switches are included on-chip. the max1682 operates at 12khz, and the max1683 operates at 35khz. a typi- cal application includes generating a 6v supply to power an lcd display in a hand-held pda. both parts are available in a 5-pin sot23 package and can deliver 30ma with a typical voltage drop of 600mv. ________________________applications small lcd panels cell phones handy-terminals pdas ____________________________features ? 5-pin sot23 package ? +2.0v to +5.5v input voltage range ? 98% voltage-conversion efficiency ? 110 a quiescent current (max1682) ? requires only two capacitors ? up to 45ma output current max1682/max1683 switched-capacitor voltage doublers ________________________________________________________________ maxim integrated products 1 out in c1- 15 c1+ gnd max1682 max1683 sot23-5 top view 2 34 pin configuration voltage doubler c1+ c1- in out gnd input supply voltage output voltage 2 x v in max1682 max1683 1 3 c1 c2 54 2 v in typical operating circuit 19-1305; rev 3; 11/10 part max1682 euk+t -40? to +85? temp range pin- package 5 sot23-5 ordering information note: these parts are available in tape-and-reel only. minimum order quantity is 2500 pieces. + denotes a lead(pb)-free/rohs-compliant package. t = tape and reel. max1683 euk+t -40? to +85? 5 sot23-5 sot top mark accl accm
max1682/max1683 switched-capacitor voltage doublers 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = +5.0v, capacitor values from table 2, t a = 0? to +85?, unless otherwise noted. typical values are at t a = +25?.) electrical characteristics (v in = +5.0v, capacitor values from table 2, t a = -40? to +85?, unless otherwise noted.) (note 3) 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. note 2: once started, the max1682/max1683 typically operate down to 1v. note 3: specifications at -40? to +85? are guaranteed by design. in to gnd .................................................................+6v to -0.3v out to gnd .......................................................+12v, v in - 0.3v out output current............................................................50ma output short-circuit duration .................................1sec (note 1) continuous power dissipation (t a = +70?) sot23-5 (derate 7.1mw/? above +70?)...................571mw operating temperature range max1682euk/max1683euk ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +160? lead temperature (soldering, 10sec) .............................+300? soldering temperature (reflow) .......................................+260? (note 2) t a = +25? t a = +25? i out = 0ma, t a = +25? conditions v 1 minimum operating voltage ? 230 310 110 145 no-load supply current 8.4 12 15.6 khz 24.5 35 45.5 oscillator frequency % 98 99.9 voltage conversion efficiency units min typ max parameter note 1: avoid shorting out to gnd, as it may damage the device. for temperatures above +85?, shorting out to gnd even instantaneously will damage the device. max1682 max1683 r load = 10k t a = +25? t a = 0? to +85? v 2.1 1.8 5.5 2.0 1.7 5.5 supply voltage range max1682 max1683 t a = +25? t a = 0? to +85? i out = 5ma 20 50 65 output resistance i out = 0ma i out = 5ma max1683 max1682 r load = 10k max1683 max1682 conditions % 97 voltage conversion efficiency 65 output resistance khz 17.5 57.8 oscillator frequency 6.6 18.6 v 2.3 5.5 supply voltage range ? 350 160 no-load supply current units min typ max parameter
max1682/max1683 switched-capacitor voltage doublers _______________________________________________________________________________________ 3 10 30 20 60 50 40 80 70 90 1.0 2.5 3.0 1.5 2.0 3.5 4.0 4.5 5.0 5.5 output resistance vs. supply voltage max1682/83 toc1 v in (v) output resistance ( ) max1683, c1 = c2 = 3.3 f max1683, c1 = c2 = 10 f max1682, c1 = c2 = 10 f 0 5 10 15 20 25 30 35 40 -40 0 -20 20 40 60 80 max1682 output resistance vs. temperature max1682/83 toc02 temperature (?) output resistance ( ) i load = 5ma v in = 5v v in = 3.3v v in = 2v 0 5 10 15 20 25 30 35 40 -40 0 -20 20406080 max1683 output resistance vs. temperature max1682/83 toc03 temperature (?) output resistance ( ) i load = 5ma v in = 5v v in = 3.3v v in = 2v 0 40 20 80 60 100 120 01520 5 10 253035 max1682 output resistance vs. capacitance max1682/83 toc4 capacitance ( f) output resistance ( ) v in = 5v v in = 3.3v v in = 2v 0 200 100 400 300 600 500 700 900 800 1000 01015 5 2025303540 max1683 output voltage ripple vs. output current max1682/83 toc07 i out (ma) v ripple (mv) c1 = c2 =1 f c1 = c2 = 3.3 f c1 = c2 = 10 f 0 15 10 5 25 20 45 40 35 30 50 0 5 10 15 20 25 30 35 max1683 output resistance vs. capitance max1682/83 toc05 capacitance ( f) output resistance ( ) v in = 2v v in = 3.3v v in = 5v 0 200 100 400 300 500 600 700 800 01015 5 2025303540 max1682 output voltage ripple vs. output current max1682/83 toc06 i out (ma) v ripple (mv) c1 = c2 = 3.3 f c1 = c2 = 10 f c1 = c2 = 33 f 0 50 100 150 200 250 300 1.0 2.0 1.5 2.5 3.0 3.5 4.0 4.5 5.0 5.5 supply current vs. supply voltage max1682/83 toc09 supply voltage (v) supply current ( a) max1683 max1682 typical operating characteristics (typical operating circuit, v in = +5v, c1 = c2 = 10? for the max1682 and 3.3? for the max1683, t a = +25?, unless otherwise noted.)
max1682/max1683 switched-capacitor voltage doublers 4 _______________________________________________________________________________________ typical operating characteristics (continued) (typical operating circuit, v in = +5v, c1 = c2 = 10? for the max1682 and 3.3? for the max1683, t a = +25?, unless otherwise noted.) 11.0 11.5 12.0 12.5 -40 0 20 -20 406080 max1682 oscillator frequency vs. temperature max1682/83 toc10 temperature (?) oscillator frequency (khz) v in = 5v v in = 3.3v v in = 2v 28 32 30 36 34 38 40 -40 0 20 -20 406080 max1683 oscillator frequency vs. temperature max1682/83 toc11 temperature (?) oscillator frequency (khz) v in = 5v v in = 3.3v v in = 2v 0 2 1 4 3 6 5 7 9 8 10 0 101520 5 253035 45 40 50 max1682 output voltage vs. output current max1682/83 toc12 output current (ma) output voltage (v) v in = 5v v in = 3.3v v in = 2v 0 2 1 4 3 6 5 7 9 8 10 0 101520 5 253035 45 40 50 max1683 output voltage vs. output current max1682/83 toc13 output current (ma) output voltage (v) v in = 5v v in = 3.3v v in = 2v 20 s/div v out 20mv/div i load = 5ma, v in = 5v, c1 = c2 = 10 f max1682 output ripple max1682toc16 80 86 84 82 88 90 92 94 96 98 100 010 5 15202530 max1682 efficiency vs. load current max1682/83 toc14 load current (ma) efficiency (%) v in = 5v v in = 3.3v v in = 2v 80 86 84 82 88 90 92 94 96 98 100 010 5 15202530 max1683 efficiency vs. load current max1682/83 toc15 load current (ma) efficiency (%) v in = 5v v in = 3.3v v in = 2v max1683 output ripple max1682toc17 i load = 5ma, v in = 5v, c1 = 3.3 f, c2 = 10 f 20 s/div v out 20mv/div 0 0.5 1.0 1.5 2.0 2.5 700 30 10 100 70 300 7 3 1 0.7 0.3 start-up voltage vs. resistive load max1682toc18 r load (k ) v start (v) max1682 max1683
_______________detailed description the max1682/max1683 capacitive charge pumps double the voltage applied to their input. figure 1 shows a simplified functional diagram of an ideal volt- age doubler. during the first half-cycle, switches s1 and s2 close, and capacitor c1 charges to v in . during the second half cycle, s1 and s2 open, s3 and s4 close, and c1 is level shifted upward by v in volts. this connects c1 to the reservoir capacitor c2, allowing energy to be delivered to the output as necessary. the actual voltage is slightly lower than 2 x v in , since switches s1?4 have resistance and the load drains charge from c2. charge-pump output the max1682/max1683 have a finite output resistance of about 20 (table 2). as the load current increases, the devices?output voltage (v out ) droops. the droop equals the current drawn from v out times the circuit? output impedance (r s ), as follows: v droop = i out x r s v out = 2 x v in - v droop efficiency considerations the power efficiency of a switched-capacitor voltage converter is affected by three factors: the internal losses in the converter ic, the resistive losses of the capacitors, and the conversion losses during charge transfer between the capacitors. the total power loss is: the internal losses are associated with the ic? internal functions, such as driving the switches, oscillator, etc. these losses are affected by operating conditions such as input voltage, temperature, and frequency. the next two losses are associated with the voltage converter circuit? output resistance. switch losses occur because of the on-resistance of the mosfet switches in the ic. charge-pump capacitor losses occur because of their esr. the relationship between these losses and the output resistance is as follows: where f osc is the oscillator frequency. the first term is the effective resistance from an ideal switched- capacitor circuit (figures 2a and 2b). pp ixr r fxc r esr esr pump capacitor losses switch losses out out out osc switches c c += ? () ++ + 2 1 2 1 1 24 pp p p loss internal losses pump capacitor losses conversion losses = + + max1682/max1683 switched-capacitor voltage doublers _______________________________________________________________________________________ 5 _____________________pin description name function 1 gnd ground 2 out doubled output voltage. connect c2 between out and gnd. pin 3 c1- negative terminal of the flying capacitor 4 in input supply 5 c1+ positive terminal of the flying capacitor figure 2a. switched-capacitor model v+ c1 f c2 r l v out figure 1. simplified functional diagram of ideal voltage doubler s1 v in s3 s2 v in v out s4 c1 c2 figure 2b. equivalent circuit r equiv = r equiv v out r l 1 v+ f c1 c2
max1682/max1683 conversion losses occur during the charge transfer between c1 and c2 when there is a voltage difference between them. the power loss is: where v ripple is the peak-to-peak output voltage ripple determined by the output capacitor and load current (see output capacitor section). choose capacitor val- ues that decrease the output resistance (see flying capacitor section). applications information flying capacitor (c1) to maintain the lowest output resistance, use capaci- tors with low esr. suitable capacitor manufacturers are listed in table 1. the charge-pump output resistance is a function of c1 and c2? esr and the internal switch resistance, as shown in the equation for r out in the efficiency considerations section. minimizing the charge-pump capacitor? esr mini- mizes the total resistance. suggested values are listed in tables 2 and 3. using a larger flying capacitor reduces the output impedance and improves efficiency (see the efficiency considerations section). above a certain point, increas- ing c1? capacitance has a negligible effect because the output resistance becomes dominated by the inter- nal switch resistance and capacitor esr (see the output resistance vs. capacitance graph in the typical operating characteristics ). table 2 lists the most desirable capacitor values?hose that produce a low output resistance. but when space is a constraint, it may be necessary to sacrifice low output resistance for the sake of small capacitor size. table 3 demonstrates how the capacitor affects output resistance. output capacitor (c2) increasing the output capacitance reduces the output ripple voltage. decreasing its esr reduces both output resistance and ripple. smaller capacitance values can be used with light loads. use the following equation to calculate the peak-to-peak ripple: v ripple = i out / (f osc x c2) + 2 x i out x esr c2 input bypass capacitor bypass the incoming supply to reduce its ac imped- ance and the impact of the max1682/max1683? switching noise. when loaded, the circuit draws a con- tinuous current of 2 x i out . a 0.1? bypass capacitor is sufficient. p / c1 4v v / c2 2v v v x f conversion loss 1 2in 2 out 2 1 2 out ripple 2 ripple osc =? ? ? ? ? ? ? + ? ? ? ? ? ? ? ? ? ? ? ? ? ? switched-capacitor voltage doublers 6 _______________________________________________________________________________________ table 1. recommended capacitor manufacturers table 2. suggested capacitor values for low output resistance table 3. suggested capacitor values for minimum size manufacturer avx production method series tps phone fax 803-946-0690 803-448-2170 matsuo 267 714-969-2491 714-960-6492 surface-mount tantalum sprague 593d, 595d 603-224-1961 603-224-1430 avx x7r 803-946-0590 803-626-3123 surface-mount ceramic matsuo x7r 714-969-2491 714-960-6492 part frequency (khz) max1682 12 max1683 35 capacitor value (f) 10 3.3 typical r out ( ) 20 20 part frequency (khz) capacitor value (f) max1682 12 3.3 1 typical r out ( ) 35 35 max1683 35
cascading devices devices can be cascaded to produce an even larger voltage (figure 3). the unloaded output voltage is nom- inally (n + 1) x v in , where n is the number of voltage doublers used. this voltage is reduced by the output resistance of the first device multiplied by the quiescent current of the second. the output resistance increases when devices are cascaded. using a two-stage dou- bler as an example, output resistance can be approxi- mated as r out = 2 x r out1 + r out2 , where r out1 is the output resistance of the first stage and r out2 is the output resistance of the second stage. a typical value for a two-stage voltage doubler is 60 (with c1 at 10? for max1682 and 3.3? for max1683). for n stages with the same c1 value, r out = (2 n - 1) x r out1 . paralleling devices paralleling multiple max1682 or max1683s reduces the output resistance. each device requires its own pump capacitor (c1), but the reservoir capacitor (c2) serves all devices (figure 4). increase c2? value by a factor of n, where n is the number of parallel devices. figure 4 shows the equation for calculating output resistance. layout and grounding good layout is important, primarily for good noise per- formance. to ensure good layout, mount all compo- nents as close together as possible, keep traces short to minimize parasitic inductance and capacitance, and use a ground plane. max1682/max1683 switched-capacitor voltage doublers _______________________________________________________________________________________ 7 max1682 max1683 c1 c2 c2 c1+ in out gnd c1- max1682 max1683 c1 c1+ input supply voltage output voltage in out gnd c1- figure 3. cascading devices max1682 max1683 r out = r out of single device number of devices c2 c1+ in out gnd c1- max1682 max1683 c1 c1 c1+ input supply voltage output voltage in out gnd c1- figure 4. paralleling devices
max1682/max1683 switched-capacitor voltage doublers 8 _______________________________________________________________________________________ sot-23 5l .eps package information for the latest package outline information and land patterns, go to www.maxim-ic.com/packages . note that a ?? ?? or ??in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to th e package regardless of rohs status. package type package code outline no. land pattern no. 5 sot23 u5+2 21-0057 90-0174
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. 9 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2010 maxim integrated products maxim is a registered trademark of maxim integrated products. switched-capacitor voltage doublers revision history revision number revision date description pages changed 3 11/10 added lead-free parts 1
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