tc1221/1222-2 5/4/00 tc1221 tc1222 ?2001 microchip technology inc. ds21367a high frequency switched capacitor voltage converters with shutdown in sot packages features charge pumps in 6-pin sot-23a package 96% voltage conversion efficiency voltage inversion and/or doubling operates from +1.8v to +5.5v up to 25 ma output current only two external capacitors required power-saving shutdown mode fully compatible with 1.8v logic systems applications lcd panel bias cellular phones pagers pdas, portable dataloggers battery-powered devices general description the tc1221/1222 are cmos ?harge-pump?voltage converters in ultra-small 6-pin sot-23a packages. they invert and/or double an input voltage which can range from +1.8v to +5.5v. conversion efficiency is typically 96%. switching frequency is 125 khz for the tc1221, 750khz for the tc1222. when the shutdown pin is held at a logic low, the device goes into a very low power mode of operation, consuming less than 1 a of supply current. for standard voltage inverter applications, the device requires only two external capacitors. with a few additional components a positive doubler can also be built. all other circuitry, including control, oscillator, power mosfets are integrated on-chip. typical supply currents are 290 a (tc1221) and 1800 a (tc1222). all devices are available in 6-pin sot-23a surface mount packages. typical operating circuit ordering information osc. freq. temperature part no. package (khz) range tc1221ech 6-pin sot-23a 125 40 c to +85 c tc1222ech 6-pin sot-23a 750 40 c to +85 c pin configuration 6-pin sot-23a* note: * 6-pin sot-23a is equivalent to eiaj sc-74 negative voltage inverter tc1221 tc1222 v in v ? output c + c c 1 c 2 input gnd out shdn on off c + c out tc1221ect tc1222ect 1 2 3 6 gnd v in 4 5 shdn
2 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a absolute maximum ratings* input voltage (v in to gnd) ......................... +6.0v, ?0.3v output voltage (out to gnd) .................... ?.0v, + 0.3v current at out pin .................................................50 ma short-circuit duration ?out to gnd ................ indefinite operating temperature range ............... ?40 c to +85 c power dissipation (t a 70 c) 6-pin sot-23a .............................................. 240 mw storage temperature (unbiased) ......... ?65 c to +150 c lead temperature (soldering, 10 sec) ................. +260 c *this is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. electrical characteristics: t a = ?0 c to +85 c, v in = +5v, c1 = c2 = 1 f (tc1221), c1 = c2 = 0.22 f (tc1222), unless otherwise noted. typical values are at t a = +25 c. symbol parameter device test conditions min typ max unit i dd supply current tc1221 290 600 a tc1222 1800 2800 i shdn shutdown supply current shdn = gnd, 0.01 1.0 a v in = 5v (note 2) v min minimum supply voltage r load = 1 k ? : 1.8 v v max maximum supply voltage r load = 1 k ? 5.5 v f osc oscillator frequency tc1221 81 125 169 khz tc1222 550 750 950 v ih shutdown input v in = v min to v max 1.4 v logic high v il shutdown input logic low v in = v min to v max 0.4 v p eff power efficiency tc1221 r load = 1 k ? ?0 % tc1222 70 v eff voltage conversion r load = 94 96 % efficiency r out output resistance tc1221 i load = 0.5ma to 25ma 25 65 ? (note 1) tc1222 t wk wake-up time from tc1221 r load = 1k ? ?0 sec shutdown mode tc1222 25 notes: 1. capacitor contribution is approximately 20% of the output impedance [esr = 1 / pump frequency x capacitance)]. 2. v in is guaranteed to be disconnected from out when the converter is in shutdown. pin description pin no. (6-pin sot-23a) symbol description 1 out inverting charge pump output. 2v in positive power supply input. 3c commutation capacitor negative terminal. 4 gnd ground. 5 shdn shutdown input (active low). 6c + commutation capacitor positive terminal.
3 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a detailed description the tc1221/1222 charge pump converters invert the voltage applied to the v in pin. conversion consists of a two- phase operation (figure 1). during the first phase, switches s2 and s4 are opened and s1 and s3 are closed. during this time, c1 charges to the voltage on v in and load current is supplied from c2. during the second phase, s2 and s4 are closed, and s1 and s3 are opened. this action connects c1 across c2, restoring charge to c2. applications information output voltage considerations the tc1221/1222 perform voltage conversion but do not provide regulation . the output voltage will droop in a linear manner with respect to load current. the value of this equivalent output resistance is approximately 25 ? nominal at +25 c and v in = +5v. v out is approximately ?5v at light loads, and droops according to the equation below: v drop = i out x r out v out = ?(v in ?v drop ) charge pump efficiency the overall power efficiency of the charge pump is affected by four factors: (1) losses from power consumed by the internal oscil- lator, switch drive, etc. (which vary with input volt- age, temperature and oscillator frequency). (2) i 2 r losses due to the on-resistance of the mosfet switches on-board the charge pump. (3) charge pump capacitor losses due to effective series resistance (esr). figure 1. ideal switched capacitor charge pump (4) losses that occur during charge transfer (from the commutation capacitor to the output capacitor) when a voltage difference between the two capaci- tors exists. most of the conversion losses are due to factors (2) and ( 3) above. these losses are given by equation 1(b). (a) p loss (2, 3) = i out 2 x r out (b) where r out = [ 1 +8r switch + 4esr c1 + esr c2 ] f osc (c1) the 1/(f osc )(c1) term in equation 1(b) is the effective output resistance of an ideal switched capacitor circuit (figures 2a, 2b). the value of r switch can be approximated at 0.5 ? for the tc1221/1222. the remaining losses in the circuit are due to factor (4) above, and are shown in equation 2. the output voltage ripple is given by equation 3. p loss (4) = [ (0.5)(c1)(v in 2 ?v out 2 ) + (0.5)(c2)(v ripple 2 ?2v out v ripple ) ] x f osc v ripple = i out +2(i out )(esr c2 ) (f osc )(c2) equation 2. equation 1. equation 3. figure 2a. ideal switched capacitor model figure 2b. equivalent output resistance v out = (v in ) c1 c2 tc1221/1222 v in s1 s3 s4 s2 osc v + v out r l c1 c2 f v + v out r equiv r equiv = r l c2 f x c1 1
4 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a cascading devices two or more tc1221/1222 can be cascaded to in- crease output voltage (figure 4). if the output is lightly loaded, it will be close to (?2 x v in ) but will droop at least by r out of the first device multiplied by the i q of the second. it can be seen that the output resistance rises rapidly for multiple cascaded devices. paralleling devices to reduce the value of r out , multiple tc1221/1222's can be connected in parallel (figure 5). the output resis- tance will be reduced by a factor of n where n is the number of tc1221/1222. each device will require its own pump capacitor (c1), but all devices may share one reservoir capacitor (c2). however, to preserve ripple performance the value of c2 should be scaled according to the number of paralleled tc1221/1222. figure 4. cascading multiple devices to increase output voltage capacitor selection in order to maintain the lowest output resistance and output voltage ripple, it is recommended that low esr capacitors be used. additionally, larger values of c1 will lower the output resistance and larger values of c2 will reduce output ripple. (see equation 1(b) and equation 3). table 1 shows various values of c1 and the correspond- ing output resistance values @ +25 c. it assumes a 0.1 ? esr c1 and 2 ? r sw . table 2 shows the output voltage ripple for various values of c2. the v ripple values assume 10ma output load current and 0.1 ? esr c2 . table 1. output resistance vs. c1 (esr = 0.1 ? ) c1( f) tc1221 tc1222 r out ( ? ) r out ( ? ) 0.22 52.9 22.6 0.33 40.8 20.5 0.47 33.5 19.4 1.0 25 17.8 table 2. output voltage ripple vs. c2 (esr = 0.1 ? ) i out 10ma c2 tc1221 tc1222 ( f) v ripple (mv) v ripple (mv) 0.22 366 63 0.33 244 42 0.47 172 30 1.0 82 15 input supply bypassing the v in input should be capacitively bypassed to reduce ac impedance and minimize noise effects due to the internal switching of the device. the recommended capacitor de- pends on the configuration of the tc1221/1222. shutdown input the tc1221/1222 is enabled when shdn is high, and disabled when shdn is low. this input cannot be allowed to float. the shdn input should be limited to 0.5v above vin to avoid significant current flows. voltage inverter the most common application for charge pump devices is the inverter (figure 3). this application uses two exter- rnal capacitors: c1 and c2 (plus a power supply bypass capacitor, if necessary). the output is equal to ? in plus any voltage drops due to loading. refer to table 1 and table 2 for capacitor selection. figure 3. test circuit 3 2 4 5 1 c3 c1 c2 v in v out r l tc1221 tc1222 c1 in out c1 + gnd voltage inverter device c1 c2 c3 tc1221 tc1222 shdn 6 1f 1f 1f 0.22 f 0.22 f 0.22 f c1 c1 c2 6 6 4 3 4 1 2 2 1 3 c2 v in v out v out = n v in tc1221 tc1222 "1" tc1221 tc1222 "n" . . . . . . shdn shdn v in 5 5
5 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a voltage doubler/inverter another common application of the tc1221/1222 is shown in figure 6. this circuit performs two functions in combination. c1 and c2 form the standard inverter circuit described above. c3 and c4 plus the two diodes form the voltage doubler circuit. c1 and c3 are the pump capacitors and c2 and c4 are the reservoir capacitors. because both sub-circuits rely on the same switches if either output is loaded, both will droop toward gnd. make sure that the total current drawn from both the outputs does not total more than 40 ma. diode protection for heavy loads when heavy loads require the out pin to sink large currents being delivered by a positive source, diode protec- tion may be needed. the out pin should not be allowed to be pulled above ground. this is accomplished by connect- ing a schottky diode (1n5817) as shown in figure 7. figure 5. paralleling multiple devices to reduce output resistance figure 6. combined doubler and inverter figure 7. high v load current layout considerations as with any switching power supply circuit, good layout practice is recommended. mount components as close together as possible to minimize stray inductance and capacitance. noise leakage into other circuitry can be minimized with the use of a large ground plane. c1 c1 6 5 4 3 4 1 2 2 1 3 c2 v out v out = v in r out = r out of single device v in number of devices tc1221 tc1222 "1" tc1221 tc1222 "n" . . . . . . shdn shdn shutdown control 5 6 v in tc1221 tc1222 gnd out 4 1 c1 d1 d2 d1, d2 = 1n4148 6 4 1 2 3 c2 c4 c3 v in v out = v in v out = ( 2v in ) (v fd1 ) (v fd2 ) tc1221 tc1222 shutdown control 5
6 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a typical characteristics tc1221 output resistance vs.supply voltage 35 40 45 50 55 60 65 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 supply voltage (v) output resistance (ohms) circuit of figure 3, c1= c2= c3 = 1f, +25c tc1221 oscillator frequency vs. supply voltage 90 100 110 120 130 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 supply voltage (v) oscillator frequency (khz) circuit of figure 3, c1 = c2 = c3 = 1f, rl = infinity, +25c tc1221 output voltage droop vs. capacitance 0 100 200 300 400 500 600 0 5 10 15 capacitance (f) output voltage droop (mv) circuit of figure 3, vin = 3.3v, rl = 1k, +25c circuit of figure 3, vin = 5.0v, rl = 1k, +25c tc1221 output voltage ripple vs. capacitance 0 50 100 150 200 250 300 0 5 10 15 capacitance (f) circuit of figure 3, vin = 3.3v, rl = 1k, +25c circuit of figure 3, vin = 5.0v, rl = 1k, +25c tc1221 supply current vs. supply voltage 50 100 150 200 250 300 350 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 supply voltage (v) supply current (ua) circuit of figure 3, c1 = c2 = c3 = 1f, rl = infinity, +25c supply current ( a) output voltage droop (mv) output resistance (ohms) oscillator frequency (khz) output voltage ripple (mvp-p) c 2 , , c 2 c 1 , c 2 , , c 1 = c 2
7 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a typical characteristics tc1222 output resistance vs. supply voltage 35 40 45 50 55 60 65 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 supply voltage (v) output resistance (ohms) circuit of figure 3, c1 = c2 = c3 = 0.22f, +25c tc1222 output voltage droop vs. capacitance) 100 150 200 250 300 350 400 450 500 012345 capacitance (f) output voltage droop (mv) circuit of figure 3, vin = 3.3v, rl = 1k, +25c circuit of figure 3, vin = 5.0v, rl = 1k, +25c tc1222 supply current vs. supply voltage 250 500 750 1000 1250 1500 1750 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 supply voltage (v) supply current (ua) circuit of figure 3, c1 = c2 = c3 = 0.22f, rl = infinity, +25c tc1222 oscillator frequency vs. supply voltage 500 550 600 650 700 750 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 supply voltage (v) oscillator frequency (khz) circuit of figure 3, c1 = c2 = c3 = 0.22f, rl = infinity, +25c tc1222 output voltage ripple vs. capacitance 0 40 80 120 160 012345 capacitance (f) output voltage ripple (mvp-p) circuit of figure 3, vin = 3.3v, rl = 1k, +25c circuit of figure 3, vin = 5.0v, rl = 1k, +25c output resistnance (ohms) output voltage droop (mv) supply current ( a) output voltage ripple (mvp-p) oscillator frequency (khz) c 1 , c 2 , , c 1 = c 2 c 2 , , c 2
8 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a taping form 6-pin sot-23a marking part numbers and part marking & = part number code + temperature range (two-digit code). tc1221/1222 code tc1221ech ga tc1222ech gb ex: 1221ech = 1222ech = represents year and 2-month code represents lot id number g a g b user direction of feed user direction of feed device marking component taping orientation for 6-pin sot-23a (eiaj sc-74) devices device marking pin 1 pin 1 standard reel component orientation for tr suffix device (mark right side up) reverse reel component orientation for rt suffix device (mark upside down) w p package carrier width (w) pitch (p) part per full reel reel size 6-pin sot-23a 8 mm 4 mm 3000 7 in carrier tape, number of components per reel and reel size
9 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a taping form dimensions: inches (mm) 6-pin sot-23a (eiaj sc-74) .069 (1.75) .059 (1.50) .122 (3.10) .098 (2.50) .075 (1.90) ref. .020 (0.50) .014 (0.35) .037 (0.95) ref. .118 (3.00) .110 (2.80) .057 (1.45) .035 (0.90) .006 (0.15) .000 (0.00) .024 (0.60) .004 (0.10) 10 max. .008 (0.20) .004 (0.09)
10 tc1221/1222-2 5/4/00 tc1221 tc1222 high frequency switched capacitor voltage converters with shutdown in sot packages ?2001 microchip technology inc. ds21367a information contained in this publication regarding device applications and the like is intended through suggestion only and ma y be superseded by updates. it is your responsibility to ensure that your application meets with your specifications. no representation or warrant y is given and no liability is assumed by microchip technology incorporated with respect to the accuracy or use of such information, or infringement of patent s or other intellectual property rights arising from such use or otherwise. use of microchip?s products as critical components in life support systems is not authori zed except with express written approval by microchip. no licenses are conveyed, implicitly or otherwise, except as maybe explicitly expressed herein, under any intellec- tual property rights. the microchip logo and name are registered trademarks of microchip technology inc. in the u.s.a. and othe r countries. all rights reserved. all other trademarks mentioned herein are the property of their respective companies. all rights reserved. ? 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