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AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 1 chargepump ? general description the AAT2820 is a member of analogictech's total power management ic? (tpmic?) product fam- ily. it is a triple output charge pump targeted for active matrix thin-film transistor (tft), liquid crys- tal displays (lcds), and ccd camera bias for sys- tems operating with lithium-ion/polymer batteries. the device generates three regulated output volt- ages for turn-on gate drive bias (v pos ), turn-off gate voltage bias (v neg ), and logic voltage. the v pos and v neg output voltages are independ- ently regulated. both outputs use external diode and capacitor multiplier stages (as many stages as required) to regulate output voltages up to +25v and -25v. an additional regulated output voltage is provided for biasing the display module. built-in soft-start circuitry prevents excessive inrush current during start-up. a high switching frequency enables the use of very small external capacitors. a low shutdown feature disconnects the load from v in and reduces quiescent current to less than 0.1a. the AAT2820 is available in a pb-free tdfn44-16 package and is specified over the -40c to +85c operating temperature range. features ? v in range: 2.7v to 5.5v ? 5v regulated output voltage ? two adjustable regulated output voltages: v pos and v neg ? positive charge pump up to +25v ? negative charge pump down to -25v ? optional power-up sequence with AAT2820-1 ? internal power mosfets ? <1a of shutdown current ? internally controlled soft start ? fast transient response ? ultra-thin solution (no inductors) ? 16-pin tdfn44 package ? temperature range: -40c to +85c applications ? ccd cameras ? hand-held instruments ? passive-matrix displays ? personal digital assistants (pdas) ? tft active-matrix lcds typical application v pos c in v in c fly in c+ c- drvp fbp gnd fbn ref drvn c out AAT2820 v neg v out out en en/pn enable (positive and negative output) enable
pin description pin configuration tdfn44-16 (top view) pin # symbol function 1 dvrp positive charge pump driver output. output high level is v supp and low level is pgnd. 2 drvn negative charge pump driver output. output high level is v supn and low level is pgnd. 3, 4, 8, 9, 12 gnd ground connection. 5 out regulated 5v output. requires a 4.7f bypass capacitor to ground. 6 in input power supply. a 1a capacitor should be connected between this pin and ground. 7 en enable input control pin. when low, the device is powered down and consumes less than 0.1a. this pin should not be left floating. 10 c- flying capacitor negative terminal. 11 c+ flying capacitor positive terminal. connect a 1f capacitor between c+ and c-. 13 fbp positive charge pump feedback input. regulates to 1.2v nominal. connect feedback resistive divider to analog ground (gnd). 14 en/pn enable input. when en/pn is pulled low, v pos and v neg are turned off. 15 ref internal reference bypass terminal. connect a 0.1f capacitor from this terminal to ana- log ground (gnd). external load capability to 50ua. ref is disabled in shutdown. 16 fbn negative charge pump regulator feedback input. regulates to 0v nominal. connect feed- back resistive divider to the reference (ref). ep exposed paddle (bottom); connect to gnd directly beneath package. AAT2820 triple-output charge pump regulator 2 2820.2006.04.1.4 gnd gnd out drvp drvn 3 in en gnd en/pn fbp gnd fbn ref c+ c- gnd 4 5 1 2 6 7 8 14 13 12 16 15 11 10 9
absolute maximum ratings 1 thermal information 2 symbol description value units ja maximum thermal resistance 50 c/w p d power dissipation 3 2.0 w symbol description value units v in input voltage -0.3 to 6.0 v v out charge pump output -0.3 to 6.0 v v en en or en/pn to gnd -0.3 to 6.0 v v n_ch drvn to gnd -0.3v to (v in + 0.3v) v v p_ch drvp to gnd -0.3v to (v in + 0.3v) v other inputs ref, fbn, fbp to gnd -0.3v to (v in + 0.3v) v i max continuous current into drvn, drvp, out 200 ma all other pins 10 t lead maximum soldering temperature (at leads, 10 sec) 300 c AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 3 1. stresses above those listed in absolute maximum ratings may cause permanent damage to the device. functional operation at co ndi- tions other than the operating conditions specified is not implied. only one absolute maximum rating should be applied at any o ne time. 2. mounted on an fr4 board. 3. derate 6.25mw/c above 25c.
electrical characteristics 1 v in = 3.3v; c in = c out = c fly = 1.0f, t a = 0c to +85c, unless otherwise noted. typical values are t a = 25c. symbol description conditions min typ max units v in input supply range 2.7 5.5 v uvlo input under-voltage lockout v in rising 1.8 threshold v in falling 1.6 v v fbp = 1.5v, v fbn = -0.2v, no load on i cc operating current drvn and drvp; en = en/pn = v in 5.0 ma i sd shutdown supply current v en = v en/pn = 0v 0.1 1.0 a t ss soft-start time 200 s f osc operating frequency 1.0 mhz negative low-power charge pump v fbn fbn regulation voltage -100 0 +100 mv i fbn fbn input bias current v fbn = -50mv -100 +100 na i neg maximum negative output current 2 3.3 v in 5.5; no load at v pos and v out 25 ma r ds_nch drvn nch on-resistance 1.5 5.0 r ds_pch min drvn pch on-resistance v fbn = 100mv, v in = 4v 1.0 5.0 max drvn pch on-resistance v fbn = -100mv, v in = 4v 20 k positive low-power charge pump v fbp fbp regulation voltage 1.15 1.2 1.25 v i fbp fbp input bias current v fbp = 1.5v -60 +100 na i pos maximum positive output current 2 3.3 v in 5.5; no load at v neg and v out 25 ma r ds_pch drvp pch on-resistance 1.0 5.0 r ds_nch min drvp nch on-resistance v fbp = 1.15v, v in = 4v 3 15 max drvp nch on-resistance v fbp = 1.25v, v in = 4v 20 k reference reference voltage -2.0a < i ref < 50a 1.18 1.2 1.22 v ref reference under-voltage lockout v ref rising 0.8 v threshold v en(l) en and en/pn threshold low 0.5 v v en(h) en and en/pn threshold high 1.5 v i i enable input current -1.0 1.0 a t sd over-temperature shutdown 140 c threshold t hys over-temperature shutdown 15 c hysteresis regulated 5v charge pump v out output voltage tolerance 2.7v < v in < 5v, i out = 50ma 4.0 % output voltage 3.0v < v in < 5v, i out = 100ma 4.8 5.0 5.2 v i out maximum output current 2 3.3 v in 5.5; no load at v pos and v neg 150 ma AAT2820 triple-output charge pump regulator 4 2820.2006.04.1.4 1. the AAT2820 is guaranteed to meet performance specifications from 0c to 70c. specification over the -40c to +85c operati ng temperature range is assured by design, characterization, and correlation with statistical process controls. 2. loads greater than those listed in maximum output load conditions may cause permanent damage to the device.
typical characteristics v in = 3.3v, v out = 5v, v pos = 12.5v, v neg = -7.8v, c in = c fly = 1f, c out = 4.7f; t a = 25c, unless otherwise noted. AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 5 operating current vs. temperature temperature ( c) operating current (ma) -40 -20 0 20 40 60 80 100 4.9 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 switching frequency vs. temperature temperature ( c) switching frequency (khz) 840 850 860 870 880 890 900 910 920 930 -40 -20 0 20 40 60 80 100 5v output efficiency vs. output current (v out = 5v; v pos = 12.5v @ 10ma; v neg = -7.8v @ 5ma) output current (ma) efficiency (%) 0 10 20 30 40 50 60 70 0 20 40 60 80 100 120 140 160 v in = 2.7v v in = 3.3v v in = 4.2v 5v output voltage vs. temperature (no-load at v pos and v neg ) temperature ( c) 5v output voltage (v) 4.90 4.92 4.94 4.96 4.98 5.00 5.02 -40 -20 0 20 40 60 80 100 v in = 2.7v v in = 3.3v v in = 4.2v 5v output efficiency vs. output current (no-load at v pos and v neg ) output current (ma) efficiency (%) 0 10 20 30 40 50 60 70 80 90 100 0.1 1.0 10 100 100 0 v in = 4.2v v in = 3.3v v in = 2.7v v in = 3.0v 5v output vs. output current output current (ma) output voltage (v) 4.2 4.4 4.6 4.8 5.0 5.2 0 50 100 150 200 250 300 v in = 2.7v v in = 4.2v v in = 3.3v v in = 3.0v
typical characteristics v in = 3.3v, v out = 5v, v pos = 12.5v, v neg = -7.8v, c in = c fly = 1f, c out = 4.7f; t a = 25c, unless otherwise noted. AAT2820 triple-output charge pump regulator 6 2820.2006.04.1.4 negative charge pump output vs. output current (no load at v pos and v out ) output current (ma) output voltage (v) -7.1 -7.4 -7.3 -7.4 -7.5 -7.6 0 5 10 15 20 25 30 v in = 2.7v v in = 3.3v v in = 4.2v negative charge pump output voltage vs. temperature (no load at v pos and v out ) temperature ( c) negative output voltage (v) -8.15 -8.10 -8.05 -8.00 -7.95 -7.90 -7.85 -7.80 -7.75 -7.70 -7.65 -40 -20 0 20 40 60 80 100 v neg = -7.8v i neg = 15ma i neg = 5ma positive charge pump efficiency vs. output current (no load at v neg and v out ) output current (ma) efficiency (%) 20 30 40 50 60 70 80 0 5 10 15 20 25 30 v in = 2.7v v in = 3.0v v in = 4.2v v in = 3.3v positive charge pump output voltage vs. output current (no load at v neg and v out ) output current (ma) positive output voltage (v) 12 12.1 12.2 12.3 12.4 12.5 0 5 10 15 20 25 30 v in = 4.2v v in = 3.3v v in = 2.7v positive charge pump output voltage vs. temperature (no load at v neg and v out ) temperature ( c) positive output voltage (v) 12.30 12.35 12.40 12.45 12.50 12.55 12.60 12.65 12.70 -40 -20 0 20 40 60 80 10 0 v pos = 12.5v i pos = 5ma i pos = 15ma reference voltage vs. temperature temperature ( c) reference voltage (v) 1.17 1.18 1.19 1.20 1.21 1.22 -40 -20 0 20 40 60 80 10 0
typical characteristics v in = 3.3v, v out = 5v, v pos = 12.5v, v neg = -7.8v, c in = c fly = 1f, c out = 4.7f; t a = 25c, unless otherwise noted. AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 7 load transient response (10ma - 100ma; v in = 3.3v) output voltage (50mv/div) (top) output current (50ma/div) (bottom) time (50 s/div) 4.85 4.90 4.95 5.00 5.05 -0.05 0.00 0.05 0.10 0.15 100ma 10ma r out = 500 to 55 negative charge pump efficiency vs. output current (no load at v pos and v out ) output current (ma) efficiency (%) 20 25 30 35 40 45 50 55 60 65 70 0 5 10 15 20 25 30 v in = 2.7v v in = 4.2v v in = 3.3v v in = 3.0v AAT2820-1 power-up sequence (v in = 4.2v) time (250 s/div) enable (2v/div) v out (5v/div) v neg (10v/div) v pos (10v/div) 5v 4v 0v -10 v 0v 0v 10v 0v AAT2820 power-up sequence time (250 s/div) enable (2v/div) v out (5v/div) v neg (10v/div) v pos (10v/div) 5v 4v 0v -10 v 0v 0v 10v 0v 5v output startup time with 100ma load time (100 s/div) enable (1v/div) v out (1v/div) +5v 3v 0v 0v output ripple waveform (v out = 5v @ 100ma; v pos = 12.5v @ 10ma; v neg = -7.8v @ 10ma) time (250ns/div) v neg (10mv/div) v out (20mv/div) v pos (10mv/div)
typical characteristics v in = 3.3v, v out = 5v, v pos = 12.5v, v neg = -7.8v, c in = c fly = 1f, c out = 4.7f; t a = 25c, unless otherwise noted. AAT2820 triple-output charge pump regulator 8 2820.2006.04.1.4 8 2820.2006.04.1.4 maximum line load (negative charge pump) i neg (ma) v neg (v) -27 -24 -21 -18 -15 -12 -9 -6 -3 0 5 10 15 20 25 30 2 stages 4 stages 5 stages 6 stages 3 stages maximum line load (positive charge pump) i pos (ma) v pos (v) 6 9 12 15 18 21 24 27 0 5 10 15 20 25 30 2 stages 3 stages 4 stages 5 stages 6 stages
AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 9 functional block diagram functional description 5v regulated output the main power supply is a charge pump doubler architecture used to support the high-current demand required by the application. charge pump regulation is achieved by sensing the output volt- age through an internal resistor divider network. a switch doubling circuit is enabled when the divided output drops below a preset trip point controlled by an internal comparator. the free-running charge pump switching frequency is approximately 1mhz. the charge pump is designed to deliver 150ma of continuous current (loads greater than the maxi- mum load condition may cause permanent dam- age to the device). dual charge pump regulators the dual charge pump provides low-power regu- lated output voltages from two individual charge pumps. using a single stage, the first charge pump inverts the supply voltage (v in ) and provides a reg- ulated negative output voltage. the second charge pump doubles v in and provides a regulated posi- tive output voltage. these outputs use external schottky diodes and capacitor multiplier stages (as many as required) to regulate up to 25v. a con- stant switching frequency of 1mhz minimizes the output ripple and capacitor size. negative charge pump regulator during the first half-cycle, the p-channel mosfet turns on and the flying capacitor c11 charges to v in minus a diode drop (figure 1). during the sec- ond half-cycle, the p-channel mosfet turns off and the n-channel mosfet turns on, level shifting c11. this connects c11 in parallel with the output reservoir capacitor c23. if the voltage across c23 minus a diode drop is less than the voltage across c11, current flows from c11 to c23 until the diode turns off. soft start 2x charge pump charge pump v ref v ref 1mhz oscillator reference oscillator over- temperature protection control logic en in en/pn out dvrp dvrn fbp ref fbn gnd c+ c-
AAT2820 triple-output charge pump regulator 10 2820.2006.04.1.4 positive charge pump regulator during the first half-cycle, the n-channel mosfet turns on and charges the flying capacitor c12 (figure 2). during the second half-cycle, the n- channel mosfet turns off and the p-channel mosfet turns on, level shifting c12 the input volt- age. this connects c12 in parallel with the reser- voir capacitor c24. if the voltage across c24 plus a diode drop is less than the level shifted by the fly- ing capacitor (c12 + v in ), charge is transferred from c12 to c24 until the diode turns off. if the positive charge pump output is connected to ground, output may not recover until power is recy- cled. loads greater than the maximum load condi- tion may cause permanent damage to the device; please review the maximum line load curves and the electrical characteristics table. voltage reference the voltage reference is a simple band gap with an output voltage equal to v be + k*v t . the band gap reference amplifier has an additional compensation capacitor from the negative input to the output. this capacitor serves to slow down the circuit during startup and soft starts the voltage reference and the regulator output from overshoot. the reference cir- cuit amplifier also increases the overall psrr of the device. an 80k resistor serves to isolate and buffer the amplifier from a small internal filter capacitor and an optional large external filter capacitor. enable in the normal operating state, the AAT2820 typical- ly consumes 5ma of quiescent operating current. by pulling the enable pin (en) low, the AAT2820 disables all three outputs. once the device is shut down, the supply current drops to less than 1a to maximize battery life. the AAT2820 gives the application an option to independently turn on/off the positive and negative charge pump outputs. these two outputs can be disabled by pulling the en/pn pin low. the thresh- old levels lie between 0.5v and 1.5v. depending on the application, the supplies must be sequenced properly to avoid damage or latch-up. soft-start and start-up sequence the AAT2820 has an internal soft-start circuit to guarantee a smooth transition to 5v for the main out- put when the device is enabled (typical 200s). this device has two versions for the start-up sequence. the AAT2820 ramps up the positive charge pump after the negative charge pump is present; the AAT2820-1 ramps up the positive charge pump before the negative charge pump. over-temperature protection to protect the AAT2820, as well as the system appli- cation, this device has a thermal protection circuit that will shut down all the charge pumps if the die temperature rises above the preset internal thermal limit. this protects the device if the ambient temper- ature exceeds the operating limit for the device. figure 1: negative charge pump block diagram. figure 2: postive charge pump block diagram. r4 r3 v ref 1.2v fbp drvp v in gnd 1/2 a4 bat54sdw c12 c24 osc ctl in v op v op = 1 + v ref r4 r3 ?? ?? r1 r2 v ref fbn drvn gnd 1/2 a3 bat54sdw c11 c23 osc ctl in v on v on = -(r1/r2) x v ref c5 1.2v
AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 11 design procedure and component selection number of stages for dual charge pump regulators the number of stages required can be determined by: for the positive output, and for the negative output. where, v neg = negative output voltage v pos = positive output voltage v fwd = forward voltage drop of the schottky diode (0.31v, based on bat54sdw diode when i f = 4ma) after solving for the number of stages (n pos and n neg ), round up the solutions to the next highest integers for the number of stages required. tables 1 and 2 show the number of stages required for positive and negative charge pumps, respectively. table 1: number of stages required for positive charge pump. table 2: number of stages required for negative charge pump. v neg (v) # of stages (n) -7 2 -8 2 -9 3 -10 3 -11 3 -12 3 -13 3 -14 4 -15 4 -16 4 -17 4 -18 5 -19 5 -20 5 -21 5 -22 6 -23 6 -24 6 -25 6 v pos (v) # of stages (n) 71 81 91 10 2 11 2 12 2 13 2 14 3 15 3 16 3 17 3 18 3 19 4 20 4 21 4 22 4 23 5 24 5 25 5 n neg = v neg 2v fwd - 5 n pos = v pos - 5 5 - 2v fwd
AAT2820 triple-output charge pump regulator 12 2820.2006.04.1.4 v neg the negative output voltage is adjusted by a resis- tive divider from the output (v neg ) to the fbn and ref pin. the maximum reference voltage current is 50a; therefore, the minimum allowable value for r2 of figure 1 is 24k . it is best to select the small- est value possible for r2 as this will keep r1 to a minimum. this limits errors due to the fbn input bias current. the fbn input has a maximum input bias current of 100na. using the full 50a refer- ence current for programming v neg : will limit the error due to the input bias current at fbn to less than 0.2%. with r2 selected, r1 can be determined by: see the example in table 3. table 3: closest value for r1 if using 24.3k as r2. v pos the positive output voltage is set by way of a resis- tive divider from the output (v pos ) to the fbp and ground pin. limiting the size of r3 reduces the effect of the fbp bias current. for less than 0.1% error, limit r3 to less than 12k . once r3 has been determined, then solve for r4 (see example in table 4). v neg (v) r1, closest value (k ) -7 143 -8 162 -9 182 -10 205 -11 226 -12 243 -13 267 -14 287 -15 309 -16 324 -17 348 -18 360 -19 390 -20 412 -21 430 -22 453 -23 470 -24 487 -25 510 ?? ?? r4 = r3 -1 v pos v ref = = 0.1% i fbn i pgm 0.1 a 100 a i pgm = = = 100 a v ref r3 1.2v 12k r1 = v neg r2 -v ref = = 0.2% i fbn i pgm 0.1 a 50 a i pgm = = = 50 a v ref r2 1.2v 24k
AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 13 table 4: closest value for r4 if using 12.1k as r3. capacitor selection careful selection of the three external capacitors c in , c fly , and c out is important because they will affect turn-on time, output ripple, efficiency, and load transient response. optimum performance will be obtained when low equivalent series resistance (esr) ceramic capacitors are used. in general, low esr may be defined as less than 100m . a value of 1f for input and flying capacitors is a good starting point when designing with the AAT2820. this not only provides for a very small printed cir- cuit board area, but cost is further reduced by the minimized bill of materials. input capacitor a 1f multilayer ceramic chip capacitor is suggest- ed for the input. this capacitor should be connect- ed between the in pin and ground; 1f should be suitable for most applications. even though the AAT2820 switching ripple and noise are very low, back-injected line noise may be further reduced by increasing the value of c in . a low equivalent series inductance (esl) ceramic capacitor is ideal for this function. the size required will vary depending on the load, output voltage, and input voltage charac- teristics. other types of capacitors may be used for c in at the cost of compromised circuit performance. output capacitor the output capacitor (c out ) should be connected between the out pin and ground. switching noise and ripple seen on the charge pump output increases with load current. typically, the output capacitor should be 5 to 10 times greater than the flying capacitor. to minimize stray inductance, the capacitor should be placed as closely as possible to the ic. this keeps the high frequency content of the input current localized, minimizing radiated and conducted emi. a 1f ceramic capacitor is recommended for most applications for optimum transient response. however, if the application has a larger load from the main and multiplier stage charge pump outputs, a 4.7f ceramic capacitor is suggested to reduce the feedback injection noise from the multiplier stage and lower switching ripple. capacitor types other than ceramic capacitors can be used for c out . however, capacitors composed of non-ceramic material will typically have a greater value of esr, resulting in increased output switching ripple. charge pump capacitor (c fly ) due to the switching operation of the voltage dou- bling circuit topology, current flow through the flying capacitor is bi-directional. the flying capacitor selected must be a non-polarized type. a 1f low esr ceramic capacitor is ideal for most applications. capacitor characteristics ceramic composition capacitors are highly recom- mended over all other types of capacitors for use with the AAT2820. ceramic capacitors offer many advantages over their tantalum and aluminum elec- trolytic counterparts. a ceramic capacitor typically has very low esr, is lowest cost, has a smaller v pos (v) r4, closest value (k ) 7 59.0 8 69.8 9 78.7 10 88.7 11 100.0 12 110.0 13 120.0 14 130.0 15 140.0 16 150.0 17 160.0 18 169.0 19 180.0 20 191.0 21 200.0 22 210.0 23 220.0 24 232.0 25 240.0
AAT2820 triple-output charge pump regulator 14 2820.2006.04.1.4 pcb footprint, and is non-polarized. low esr ceramic capacitors help maximize charge pump transient response. since ceramic capacitors are non-polarized, they are not prone to incorrect con- nection damage. rectifier diodes for the rectifiers, use schottky diodes with a volt- age rating of 1.5x the input voltage. the maximum steady-state voltage seen by the rectifier diodes for both the positive and negative charge pumps (regardless of the number of stages) is: the bat54sdw quad schottky in an sot363 (2x2mm) package is a good choice for multiple- stage charge pump configuration (see evaluation board schematic in figure 3). figure 3: AAT2820 evaluation board schematic (shown with six stages). v reserve = v in - v f 1 5 1 2 a3 a1 a2 4 6 3 2 1 2 3 4 5 6 7 8 AAT2820 drvp drvn gnd gnd out in en gnd fbn ref en/pn fbp gnd c+ c- gnd 16 15 14 13 12 11 10 9 1 5 4 6 3 2 1 5 4 1 5 4 2 4 5 1 2 4 5 1 2 6 123 enable 123 enable/pn u1 3 3 6 3 6 3 6 2 j5 12 j4 12 12 j3 j2 bat54sdw bat54sdw bat54sdw a4 a6 a5 bat54sdw bat54sdw bat54sdw stage 2 stage 3 stage 4 stage 5 stage 6 stage 2 stage 3 stage 4 stage 5 stage 6 12 j1 12 j6 12 j7 12 12 j8 j9 12 j10 c18 1 f 0.1 f 1 f 4.7 f1 f c6 c4 c3 c1 0.1 f c7 0.1 f c8 1 f c2 0.1 f c9 0.1 f c10 0.1 f c11 0.1 f c17 0.1 f c16 0.1 f c15 0.1 f c14 c5 0.1 f 0.1 f c13 0.1 f c12 sn sp r4 r1 r2 24.3k r3 12.1k vout_5v vin c19 1 f c20 1 f c21 1 f c22 1 f c23 1 f c29 1 f c28 1 f c27 1 f c26 1 f c25 1 f c24 1 f vout_n gnd gnd vout_p gnd c1 taiyo yuden lmk212 bj105kd 1 f 10v x7r 0805 c2 taiyo yuden lmk107 bj105ka 1 f 10v x7r 0603 c3 taiyo yuden lmk212 bj475kd 4.7 f 10v x5r 0805 c5, c9-c14 taiyo yuden emk107 bj104ma 0.1 f 16v x7r 0603 c6-c8, c15-c17 taiyo yuden tmk107 bj104ka 0.1 f 25v x5r 0603 c20-c27 taiyo yuden emk212 bj105kg 1 f 16v x7r 0805 c18, c19, c28, c29 taiyo yuden tmk212 bj105kg 1 f 25v x5r 0805 [optional] c4 taiyo yuden lmk212 bj105kd 1 f 10v x7r 0805
AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 15 flying and output capacitor multiplier stages a 0.1f x7r or x5r ceramic capacitor is typically used. the voltage rating of the flying and reservoir output capacitors will vary with the number of charge pump stages. the reservoir output capaci- tor should be roughly 10x the flying capacitor. use larger capacitors for reduced output ripple. a 1f x7r or x5r type ceramic is typically used. positive charge pump capacitor voltage ratings the absolute steady-state maximum output voltage (neglecting the internal r ds(on) drop of the internal mosfets) for the nth stage is: where v fwd is the estimated forward drop of the schottky diode. this is also the voltage rating required for the nth bulk capacitor in the positive output charge pump. the voltage rating for the nth flying capacitor in the positive stage is: where v bulk(0) is the input voltage (see table 5). table 5: positive charge pump capacitor voltages (v fwd = 0.31v). negative charge pump capacitor voltage ratings the absolute steady-state maximum output voltage (neglecting the internal r ds(on) drop of the internal mosfets) for the nth stage is: this is also the voltage rating required for the nth bulk capacitor in the negative output charge pump. the voltage rating for the nth flying capacitor in the negative stage (see table 6) is: table 6: negative charge pump capacitor voltages (v fwd = 0.31v). pc board layout the input and reference capacitor should be placed as closely to the ic as possible. place the programming resistors (r1-r4) close to the ic, minimizing trace length to fbn and fbp. place the main charge pump flying capacitor close to the c+ and c- pins, with wide traces and no vias. place all multiplier stage (charge pump) circuitry to the ic as closely as possible using wide traces, and avoid using vias when possible. figures 4 and 5 show the recommended evaluation board layout with the tdfn44-16 package. # of stages (n) v bulk(n) v fly(n) 1 -4.4v 4.7v 2 -8.8v 9.1v 3 -13.2v 13.5v 4 -17.6v 17.9v 5 -22.0v 22.3v 6 -26.4v 26.7v # of stages (n) v bulk(n) v fly(n) 1 9.4v 4.7v 2 13.8v 9.1v 3 18.2v 13.5v 4 22.6v 17.9v 5 27.0v 22.3v 6 31.4v 26.7v v fly(n) = v fwd - v bulk(n) v bulk(n) = -n v in + 2 n v fwd v fly(n) = v bulk(n + 1) - v fwd v bulk(n) = (n + 1) v in - 2 n v fwd
AAT2820 triple-output charge pump regulator 16 2820.2006.04.1.4 figure 4: AAT2820 evaluation board figure 5: AAT2820 evaluation board top side layout. bottom side layout.
AAT2820 triple-output charge pump regulator 2820.2006.04.1.4 17 ordering information package information all dimensions in millimeters package power-up sequence marking 1 part number (tape and reel) 2 tdfn44-16 -, + ocxyy AAT2820ixn-5.0-t1 tdfn44-16 +, - odxyy AAT2820ixn-5.0-1-t1 1. xyy = assembly and date code. 2. sample stock is generally held on part numbers listed in bold . index area (d/2 x e/2) detail "a" detail "b" top view bottom view detail "a" side view option a: c0.30 (4x) max chamfered corner option b: r0.30 (4x) max round corner detail "b" 0.16 pin 1 indicator (optional) 0.1 ref 4.00 + 0.375 all analogictech products are offered in pb-free packaging. the term ?pb-free? means semiconductor products that are in compliance with current rohs standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. for more information, please visit our website at http://www.analogictech.com/pbfree.
AAT2820 triple-output charge pump regulator 18 2820.2006.04.1.4 advanced analogic technologies, inc. 830 e. arques avenue, sunnyvale, ca 94085 phone (408) 737-4600 fax (408) 737-4611 ? advanced analogic technologies, inc. analogictech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an analogictech pr oduct. no circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. analogictech reserves the right to make changes to their products or specifi cations or to discontinue any product or service without notice. customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information b eing relied on is current and complete. all products are sold sub- ject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. analogictech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with anal ogictech?s standard warranty. testing and other quality con- trol techniques are utilized to the extent analogictech deems necessary to support this warranty. specific testing of all param eters of each device is not necessarily performed. analogictech and the analogictech logo are trademarks of advanced analogic technologies incorporated. all other brand and produ ct names appearing in this document are regis- tered trademarks or trademarks of their respective holders.

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