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aat2803 data sheet six-channel white led backlight charge pump with flash 1 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 ge n e r a l d e scr ipt ion the aat2803 is a dual charge pump designed to support both white led backlight and flash applications for sys- tems operating with lithium-ion/polymer batteries. the backlight charge pump is capable of driving up to six leds at a total of 180ma. the current sinks may be operated in group or in parallel for driving higher current leds. to maximize power efficiency, the charge pump operates in 1x, 1.5x, or 2x mode, where the mode of operation is automatically selected by comparing the forward voltage of each led with the input voltage. skyworks' as 2 cwire? (advanced simple serial control?) serial digital input is used to enable, disable, and set current for each led with a 16-level logarithmic scale plus four low-current settings down to 50 a for optimized efficiency, with a low house- keeping current of only 50 a. the flash charge pump is a charge pump doubler with a regulated output voltage. it is designed to deliver 120ma of continuous current and up to 300ma of pulsed cur- rent. it has an independent enable pin for improved power savings. the aat2803 is equipped with built-in protection, short- circuit, and auto-disable for load short-circuit condition. built-in soft-start circuitry prevents excessive inrush cur- rent during start-up. a low-current shutdown feature disconnects the load from v in and reduces quiescent cur- rent to less than 1 a. the aat2803 is available in a pb-free, space-saving, thermally enhanced 24-pin 4x4mm qfn package and is rated over the -40c to +85c temperature range. fe a t u r e s v in range: 2.7v to 5.5v dual charge pump: ? flash: charge pump doubler ? backlight: tri-mode charge pump backlight charge pump: ? programmable current with single gpio ? 16 current steps ? 15/20/30ma max current ? four low current settings ? individual main/sub-group control ? low i q (50 a) for low-current mode ? drives six channels of leds flash charge pump: ? regulated v out_fl 4.5/5.0 volts ? up to 300ma of current for flash 1mhz constant switching frequency independent backlight/flash control built-in thermal protection built-in auto-disable for open circuit automatic soft start i q <1 a in shutdown available in qfn44-24 package applica t ion s color (rgb) lighting programmable current sink white led backlighting white photo flash for digital still cameras typica l applica t ion aat2803 c in 1 f v in c11 f d2 gnd backlight c21 f c31 f c2 + c out 1 f enfl en/set vin en_fl flash en/set c2 - c1 + c1 - c3 + c3 - vout d3 d2 d1 d4 d5 d6 d1 d3 d4 d5 d6 c ou t 1 f downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 2 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 pin d e scr ipt ion s pin # sym bol fu n ct ion 1 c1- flying capacitor 1 negative terminal. 2 c1+ flying capacitor 1 positive terminal. connect a 1 f capacitor between c1+ and c1-. 3 vout_fl flash output voltage. requires 1 f capacitor connected between this pin and ground. 4, 14 vin input power supply. requires 1 f capacitor connected between this pin and ground. 5 en_fl enable pin for ? ash charge pump. for normal operation, connect to v in . when connected low, the ? ash charge pump shuts down and consumes less than 1 a of current. 6, 7, 23 n/c no connect. 8 vout_bl backlight output voltage charge pump. requires 1 f capacitor connected between this pin and ground. 9 c2+ flying capacitor 2 positive terminal. connect a 1 f capacitor between c2+ and c2-. 10 c3+ flying capacitor 3 positive terminal. connect a 1 f capacitor between c3+ and c3-. 11 c3- flying capacitor 3 negative terminal. 12 c2- flying capacitor 2 negative terminal. 13, 15, 24 gnd ground. 16 d1 current sink input #1. 17 d2 current sink input #2. 18 d3 current sink input #3. 19 d5 current sink input #5. 20 d4 current sink input #4. 21 d6 current sink input #6. 22 en/set as 2 cwire serial interface control pin for backlight charge pump. it controls the current settings for all six channels. this pin should not be left ? oating. ep exposed paddle (bottom); connect to gnd directly beneath package. pin con figu r a t ion qfn 4 4 - 2 4 ( top vie w ) 1 3 2 5 4 6 18 16 17 14 15 13 10 11 12 8 9 7 19 21 20 23 22 24 c1- c1+ vout_fl vin en_fl n/c n/c vout_b l c2+ c3+ c3- c2- gnd d1vin gnd d2 d3 aat2803 d5 d4 d6 en/set n/c gnd downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 3 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 1. stresses above those listed in absolute maximum ratings may cause permanent damage to the device. functional operation at conditions other than the operating conditions specified is not implied. only one absolute maximum rating should be applied at any one time. 2. mounted on an fr4 board. 3. derate 6.25mw/c above 25c. absolu t e m a x im u m ra t in gs 1 sym bol d e scr ipt ion va lu e un it s v in input voltage -0.3 to 6 v v en/set en/set to gnd voltage -0.3 to v in + 0.3 v t j operating junction temperature range -40 to 150 c t lead maximum soldering temperature (at leads, 10 sec) 300 c th e r m a l i n for m a t ion 2 sym bol d e scr ipt ion va lu e un it s p d maximum power dissipation 3 2.0 w ? ja maximum thermal resistance 50 c/w downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 4 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 1. the aat2803 is guaranteed to meet performance specifications over the -40c to +85c operating temperature range and is assu red by design, characterization, and correla- tion with statistical process controls. 2. determined by the average of all active channels. 3. current matching is defined as the deviation of any sink current from the average of all active channels. 4. specification applies only to the tri-mode charge pump. 5. specification applies only to the charge pump doubler. ele ct r ica l ch a r a ct e r ist ics 1 v in = 3.6v, c in = c out = c 1 = c 2 = c 3 = 1.0 f; t a = -40c to +85c, unless otherwise noted. typical values are t a = 25c. sym bol d e scr ipt ion con dit ion s m in typ m a x un it s v in operation range 2.7 5.5 v i cc operating current 1x mode, 3.0 v in 5.5, active, no load current; en/set = v in ; en_fl= gnd 0.3 1 ma 1.5x mode, 3.0 v in 5.5, active, no load current; en/set = v in ; en_fl= gnd 1.0 3.0 2x mode, 3.0 v in 5.5, active, no load current; en/set = v in ; en_fl = gnd 2.0 3.7 v out_flash = 5v; en/set = gnd; en_fl = v in 2.0 4.5 50 a setting, 1x mode; en/set = v in ; en_fl = gnd 50 a i shdn shutdown current en/set = 0 1.0 a i dx i sink average current accuracy 2 i set = 30ma, t a = 25c 27 30 33 ma i set = 4.1ma, t a = 25c 3.69 4.1 4.51 i (d-match) current matching between any two current sink inputs 3, 4 v f :d1:d4 = 3.6v 0.5 % v th 1x to 1.5x or 1.5x to 2x transi- tion threshold at any d x pin 150 mv v out output voltage (flash charge pump) 5 3.0< v in < 5v, i out = 120ma; en_fl = v in 4.3 4.5 4.7 v i out max continuous output current(flash charge pump) 5 v in = 3.3v; v out = 4.5v; en_fl = v in 120 ma max pulsed output current 5 v in = 3.6v; v out = 4.5v; i pulsed = 250ms 300 t ss soft-start time backlight charge pump 100 s flash charge pump 200 f clk clock frequency 1.0 mhz v en(l) enable threshold low v in = 2.7v 0.4 v v en(h) enable threshold high v in = 5.5v 1.4 v t en/set lo en/set low time 0.3 75 s t en/set_hi_min minimum en/set high time 50 ns t en/set_hi_max maximum en/set high time 75 s t off en/set off timeout 500 s t lat en/set latch timeout 500 s i en/set;en_fl input leakage v en/set;en_fl = 5v; v in = 5v -1.0 1.0 a downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 5 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 typica l ch a r a ct e r ist ics? fla sh d r ive r ch a r ge pu m p se ct ion output voltage vs. output current (v out_fl = 4.5v; en_fl = v in ; en/set = gnd) output current (ma) output voltage (v) 4.40 4.44 4.48 4.52 4.56 4.60 0.1 1.0 10.0 100.0 100 0 3.6v 3.0v 3.3v 2.7v maximum current pulse vs. supply voltag e (v out_fl = 4.5v; en_fl = v in ; en/set = gnd) supply voltage (v) maximum current pulse (ma) 0 50 100 150 200 250 300 350 400 450 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4. 2 one-shot pulse duration = 250msv out > 4.0v start-up time (50ma load) 100 s/div en_flsh (1v/div) v out_fl (1v/div) start-up time (100ma load) 100 s/div en_flsh (1v/div) v out_fl (1v/div) load response vs. time (50ma load) 5ms/div v out_fl (10mv/div) i out (20ma/div) v in = 3.5v load response vs. time (100ma load) 5ms/div v out_fl (10mv/div) i out (50ma/div) v in = 3.5v downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 6 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 typica l ch a r a ct e r ist ics? fla sh d r ive r ch a r ge pu m p se ct ion output ripple voltage vs. time (i out = 50ma @ v in = 3.5v) 500ns/div i in (10ma/div) v out (10mv/div) v in (10mv/div) output ripple voltage vs. time (i out = 100ma @ v in = 3.5v) 500ns/div i in (10ma/div) v out (20mv/div) v in (10mv/div) supply current vs. supply voltage supply voltage (v) supply current (ma) 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 2.5 3.0 3.5 4.0 4.5 5. 0 i out = 0 a c 3 = 1 f v en_fl = v in oscillator frequency vs. supply voltage supply voltage (v) oscillator frequency (mhz) 1.10 1.15 1.20 1.25 1.30 2.7 3.2 3.7 4.2 4.7 -40 c +85 c +25 c downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 7 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 typica l ch a r a ct e r ist ics? w h it e led ba ck ligh t d r ive r se ct ion unless otherwise noted, v in = 3.6v, c in = c out = c 1 = c 2 = c 3 = 1.0 f; t a = 25c. efficiency vs. supply voltage supply voltage (v) efficiency (%) 50 60 70 80 90 100 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4. 2 4.1ma v f = 2.9v 20ma v f = 3.4v 10.2ma v f = 3.1v turn-on to 1x mode (v in = 4.2v; 20ma load) 100 s/div en (2v/div) cp (2v/div) i in (200ma/div) v sink (500mv/div) turn-on to 1.5x mode (v in = 3.8v; 20ma load) 100 s/div en (2v/div) cp (2v/div) i in (200ma/div) v sink (500mv/div) turn-on to 2x mode (v in = 2.8v; 20ma load) 100 s/div en (2v/div) cp (2v/div) i in (200ma/div) v sink (500mv/div) turn-off from 1.5x mode (v in = 3.5v; 20ma load) 100 s/div en (2v/div) i in (100ma/div) v f (1v/div) current matching vs. temperature temperature ( c) current (ma) 19.2 19.4 19.6 19.8 20.0 20.2 -40 -20 0 20 40 60 80 channel 2 channel 1 channel 5 channel 3 channel 4 channel 6 downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 8 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 typica l ch a r a ct e r ist ics? w h it e led ba ck ligh t d r ive r se ct ion unless otherwise noted, v in = 3.6v, c in = c out = c 1 = c 2 = c 3 = 1.0 f; t a = 25c. load characteristics (v in = 3.8v; 1.5x mode; 15ma load) 500ns/div v in (40mv/div) v sink (40mv/div) cp (40mv/div) load characteristics (v in = 2.9v; 2x mode; 15ma load) 500ns/div v in (40mv/div) v sink (40mv/div) cp (40mv/div) load characteristics (v in = 4.0v; 1.5x mode; 20ma load) 500ns/div v in (40mv/div) v sink (40mv/div) cp (40mv/div) load characteristics (v in = 3.1v; 2x mode; 20ma load) 500ns/div v in (40mv/div) v sink (40mv/div) cp (40mv/div) load characteristics (v in = 4.3v; 1.5x mode; 30ma load) 500ns/div v in (40mv/div) v sink (40mv/div) cp (40mv/div) load characteristics (v in = 3.6v; 2x mode; 30ma load) 500ns/div v in (40mv/div) v sink (40mv/div) cp (40mv/div) downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 9 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 typica l ch a r a ct e r ist ics? w h it e led ba ck ligh t d r ive r se ct ion unless otherwise noted, v in = 3.6v, c in = c out = c 1 = c 2 = c 3 = 1.0 f; t a = 25c. t lat vs. v in v in (v) t lat ( s) 0 50 100 150 200 250 300 350 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5. 5 -40 c 25 c 85 c t off vs. v in v in (v) t off ( s) 0 50 100 150 200 250 300 350 400 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5. 5 -40 c 25 c 85 c input ripple vs. v in v in (v) amplitude (mv) 0 5 10 15 20 25 2.50 2.67 2.84 3.01 3.18 3.35 3.52 3.69 3.86 4.03 4.2 10.2ma 20ma 30ma v ih vs. v in v in (v) v ih (v) 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5. 5 -40 c 25 c 85 c v il vs. v in v in (v) v il (v) 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5. 5 -40 c 25 c 85 c downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 10 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 fu n ct ion a l d e scr ipt ion the aat2803 is a dual charge pump targeted for back- light and flash applications. the charge pump for white led applications is a tri-mode load switch (1x) and high efficiency (1.5x or 2x) charge pump device. to maximize power conversion efficiency, an internal sensing circuit monitors the voltage required on each constant current sink input and sets the load switch and charge pump modes based on the input battery voltage and the cur- rent sink input voltage. as the battery discharges over time, the backlight charge pump is enabled when any of the six current sink inputs near dropout. the charge pump initially starts in 1.5x mode. if the charge pump output drops enough for any current source output to become close to dropout, the charge pump will auto- matically transition to 2x mode. for flash applications, charge pump doubler architecture is used to support the high current demand required by the application. charge pump regulation is achieved by sensing the output voltage 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 120ma of continuous current and 300ma of pulsed current. the aat2803 requires only six external components: three 1 f ceramic capacitors for the charge pump flying capacitors (c 1 , c 2 , and c 3 ), one 1 f ceramic input capac- itor (c in ), one 0.33 f to 1 f ceramic capacitor for the backlight charge pump output, and one 1 f for the flash charge pump output. the six constant current sink inputs (d1 to d6) can drive six individual leds with a maximum current of 30ma each. the unused sink inputs must be connected to v out_bl , otherwise the part will operate only in 2x charge pump mode. the as 2 cwire serial interface enables the backlight charge pump and sets the current sink magnitudes. as 2 cwire addressing allows independent control of two groups of current sink input: d1 to d4 and d5 to d6. fu n ct ion a l block d ia gr a m 1x 1.5x 2x charge pump soft-start control 1mhz oscillator voltage reference c2 + c2 - c3 + c3 - v out_b l en/set v in v out_fl v ref soft-start 1mhz oscillator 2x charge pump c1 + c1 - en_fl d/a d/a d/a d/a d/a d/a 6 x 16 bit rom 6 x 16 bit rom as 2 cwire interface d6 gnd d5 d4 d3 d2 d1 downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 11 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 con st a n t cu r r e n t ou t pu t le ve l se t t in gs the constant current sink levels for the white led back- light (d1 to d6) are set via the serial interface according to a logarithmic scale where each code is 1db lower than the previous code. in this manner, led brightness appears linear with each increasing code count. because the inputs d1 to d6 are true independent constant cur- rent sinks, the voltage observed on any single given input will be determined by the actual forward voltage (v f ) for the led being driven. since the input current sinks are programmable, no pwm (pulse width modulation) or additional control circuitry is needed to control led brightness. this feature greatly reduces the burden on a microcontroller or system ic to manage led or display brightness, allowing the user to set it and forget it. with its high-speed serial interface (1mhz data rate), the input sink current can be changed successively to brighten or dim leds in smooth transi- tions (e.g., to fade-out) or in abrupt steps, giving the user complete programmability and real-time control of led brightness. d a t a 3 0 m a m a x i out ( m a) 2 0 m a m a x i out ( m a) 1 5 m a m a x i out ( m a) 1 30.0 20.0 15.0 2 26.7 17.8 13.3 3 23.8 15.9 11.9 4 21.4 14.3 10.7 5 19.0 12.7 9.5 6 16.7 11.1 8.3 7 15.2 10.2 7.6 8 13.3 8.9 6.7 9 11.9 7.9 6.0 10 10.5 7.0 5.2 11 9.5 6.3 4.8 12 8.6 5.7 4.3 13 7.6 5.1 3.8 14 6.7 4.4 3.3 15 6.2 4.1 3.1 16 0.0 0.0 0.0 ta ble 1 : cu r r e n t le ve l se t t in gs. the 16 individual current level settings are each approxi- mately 1db apart (see current level settings table). code 1 is full scale, code 15 is full scale attenuated by 14db, and code 16 is reserved as a no current setting. as 2 cw ir e se r ia l i n t e r fa ce the advanced simple serial control (as 2 cwire) single wire interface is used to set the possible combinations of current levels and led channel states. as 2 cwire has addressing capability for multiple data registers. with multiple data registers, the backlight charge pump main and sub-channels can be programmed together or inde- pendently from one another. as 2 cwire relies on the number of rising edges of the en/ set pin to address and load the registers. as 2 cwire latches data or address after the en/set pin has been held high for time t lat . address or data is differentiated by the number of en/set rising edges. since the data registers are 4 bits each, the differentiating number of pulses is 24 or 16, so that address 1 is signified by 17 rising edges, address 2 by 18 rising edges, and so forth. data is set to any number of rising edges between 1 and including 16. a typical write protocol is a burst of en/set rising edges, signifying a particular address, followed by a pause with en/set held high for the t lat timeout peri- od, a burst of rising edges signifying data, and a t lat timeout for the data registers. once an address is set, then multiple writes to the corresponding data register are allowed. when en/set is held low for an amount of time greater than t off , the backlight charge pump enters into shutdown mode and draws less than 1 a from the supply. address 1 is the default address on the first rising edge after the backlight charge pump has been disabled. whenever shutdown mode is entered, all registers are reset to 1. downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 12 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 as 2 cw ir e se r ia l i n t e r fa ce tim in g address data 1 en/set 2 17 18 address data reg 1 data reg 2 1 2 . . . n <= 16 12 11 n t hi t lo t lat t lat as 2 cw ir e addr e ssin g five addresses are available to enable all of the parts functionality. two 4-bit registers control the main and sub-channels, giving 16 settings for each. the main and sub-channels are programmed to the same constant cur- rent level by using address 1. use addresses 2 and 3 to program the main and sub-channels independently. use address 4 to program the max current register, which sets the max current scale. lastly, address 5 programs the low current register. the low current register con- trols the efficient low current mode. when the max current register is programmed to 1, 2, or 3, changing the data for addresses 1-3 will result in the correspond- ing values found in the constant current programming levels table. when the max current register is programmed to 4, the part is programmed to operate in low current mode and the data for addresses 1-3 is irrelevant. in low current mode, the low current register takes precedence. see the low current register settings table below for the current level settings and main/sub-configurations that result. addr e ss en / set edge s addr e sse d re gist e r 1 17 1&2: d1-d6 current 2 18 1: d1-d4 current 3 19 2: d5-d6 current 4 20 3: max current 5 21 4: low current ta ble 2 : low cu r r e n t re gist e r se t t in gs. m a x cu r r e n t a n d low cu r r e n t re gist e r s use the max current and low current registers to pro- gram constant current settings outside of the 20ma max scale. by default (without changing the max current reg- ister), the backlight charge pump operates in the 20ma max scale (see constant current program ming levels). for example, to change to the 30ma max scale, address the max current register with 20 rising edges and pause for t lat . program the max current register with 2 rising edges and pause for t lat . the part will next operate in the same data row, but for the setting found in the 30ma max column. next, to change to a different setting on the 30ma max scale, address the d1-d6 register with 17 rising edges. program the new constant current level with 1-16 rising edges. the part will update to the new data setting according to the constant current programming levels table. the backlight charge pump has a distinct low current mode with ultra-low quiescent current. for drive currents of 2ma or less, the part operates with significantly reduced quiescent current. this is particularly useful for applications requiring an always on condition such as transmissive displays. as an example, to change to low current mode, address the max current register with 20 rising edges and pause for t lat . program the max current register with 4 rising edges and pause for t lat . address the low current register with 21 rising edges and pause for t lat . program the low current register with 1-16 ris- ing edges. the part will update to the new low current mode setting and operate with significantly reduced qui- escent current. downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 13 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 d a t a m a x cu r r e n t 1 20ma max scale 2 30ma max scale 3 15ma max scale 4 low current mode ta ble 3 : m a x cu r r e n t re gist e r se t t in gs?addr e ss 4 . d a t a d 1 - d 4 ( m a) d 5 - d 6 ( m a) 10 0 20 0 30 0 40 0 5 0 0.05 6 0 0.5 70 1 80 2 9 0.05 0 10 0.5 0 11 1 0 12 2 0 13 0.05 0.05 14 0.5 0.5 15 1 1 16 2 2 ta ble 4 : low cu r r e n t re gist e r se t t in gs?addr e ss 5 . d isa ble d cu r r e n t sin k s the backlight charge pump is equipped with an auto- disable feature to protect against an led failure condi- tion. current sink inputs that are not used should be disabled. to disable and properly terminate unused cur- rent sink inputs, they must be tied to v out . if left uncon- nected or terminated to ground, the part will be forced to operate in 2x charge pump mode. properly terminating unused current sink inputs is important to prevent the charge pump modes from acti- vating prematurely. when properly terminated, only a small sense current flows for each disabled channel. the sense current for each disabled channel is less than 120 a. applica t ion s i n for m a t ion led se le ct ion although the aat2803 is specifically intended for driving white leds, the device can also be used to drive most types of leds with forward voltage specifications ranging from 2.0v to 4.7v. led applications may include main and sub-lcd display backlighting, camera photo-flash applications, color (rgb) leds, infrared (ir) diodes for remotes, and other loads benefiting from a controlled output current generated from a varying input voltage. in some instances (e.g., in high-luminous-output appli- cations such as photo flash), it may be necessary to drive high-v f type leds. the low-dropout current sinks in the aat2803 make it capable of driving leds with forward voltages as high as 4.7v at full current from an input supply as low as 3.0v. outputs can be paralleled to drive high-current leds without complication. d e vice sw it ch in g n oise pe r for m a n ce the aat2803 operates at a fixed frequency of approxi- mately 1mhz to control noise and limit harmonics that can interfere with the rf operation of cellular telephone handsets or other communication devices. back-injected noise appearing on the input pin of the charge pump is 20mv peak-to-peak, typically ten times less than induc- tor-based dc/dc boost converter white led backlight solutions. the aat2803 soft-start feature prevents noise transient effects associated with inrush currents during start-up of the charge pump circuit. ca pa cit or se le ct ion careful selection of the six external capacitors c in , c 1 , c 2 , c 3 , and c out (for backlight and flash) is important because they will affect turn-on time, output ripple, and transient performance. 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 1 f for all four capacitors is a good starting point when choosing capac- itors. if the led current sources are only programmed for light current levels, then the capacitor size may be decreased. downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 14 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 ca pa cit or ch a r a ct e r ist ics ceramic composition capacitors are highly recommended over all other types of capacitors for use with the aat2803. ceramic capacitors offer many advantages over their tantalum and aluminum electrolytic counter- parts. a ceramic capacitor typically has very low esr, is lowest cost, has a smaller pcb footprint, and is non- polarized. low esr ceramic capacitors help maximize charge pump transient response. since ceramic capaci- tors are non-polarized, they are not prone to incorrect connection damage. equ iva le n t se r ie s re sist a n ce esr is an important characteristic to consider when selecting a capacitor. esr is a resistance internal to a capacitor that is caused by the leads, internal connec- tions, size or area, material composition, and ambient temperature. capacitor esr is typically measured in mil- liohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors. ce r a m ic ca pa cit or m a t e r ia ls ceramic capacitors less than 0.1 f are typically made from npo or c0g materials. npo and c0g materials typically have tight tolerance and are stable over tem- perature. larger capacitor values are typically composed of x7r, x5r, z5u, or y5v dielectric materials. large ceramic capacitors, typically greater than 2.2 f, are often available in low-cost y5v and z5u dielectrics, but capacitors greater than 1 f are not typically required. capacitor area is another contributor to esr. capacitors that are physically large will have a lower esr when compared to an equivalent material smaller capacitor. these larger devices can improve circuit transient response when compared to an equal value capacitor in a smaller package size. downloaded from: http:///
aat2803 data sheet six-channel white led backlight charge pump with flash 15 skyworks solutions, inc. phone [781] 376-3000 fax [781] 376-3100 sales@skyworksinc.com www.skyworksinc.com 202064a skyworks proprietary information products and product information are subject to change without notice. june 14, 2012 copyright ? 2012 skyworks solutions, inc. all rights reserved. information in this document is provided in connection with skyworks solutions, inc. (skyworks) products or services. these materials, including the information contained herein, are provided by sky works as a service to its customers and may be used for informational purposes only by the customer. skyworks assumes no responsibility fo r errors or omissions in these materials or the information contained herein. sky- works may change its documentation, products, services, speci ? cations or product descriptions at any time, without notice. skyworks makes no commitment to update the materials or information and shall have no responsibility whatsoever for con ? icts, incompatibilities, or other dif ? culties arising from any future changes. no license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. skyworks assumes no liability for any materials, products or informatio n provided here- under, including the sale, distribution, reproduction or use of skyworks products, information or materials, except as may be provided in skyworks terms and conditions of sale. the materials, products and information are provided as is without warranty of any kind, whether express, implied, statutory, or otherwise, including fitness for a particular purpose or use, merchantability, performance, quality or non-infringement of any intellectual property right; all such warranti es are hereby expressly disclaimed. skyworks does not warrant the accuracy or completeness of the information, text, graphics or other items contained within these materials. skyworks shall not be liable for any damages, in- cluding but not limited to any special, indirect, incidental, statutory, or consequential damages, including without limitation, lost revenues or lost profits that may result from the use of the materials or information, whether or not the recipient of materials has been advised of the possibility of such damage. skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the skyworks products could lead to personal injury, death, physical or en- vironmental damage. skyworks customers using or selling skyworks products for use in such applications do so at their own risk and agree to fully indemnify skyworks for any damages resulting from such improper use or sale. customers are responsible for their products and applications using skyworks products, which may deviate from published speci ? cations as a result of design defects, errors, or operation of products outside of pub- lished parameters or design speci ? cations. customers should include design and operating safeguards to minimize these and other risks. skyworks assumes no liabi lity for applications assistance, customer product design, or damage to any equipment resulting from the use of skyworks products outside of stated published speci ? cations or parameters. skyworks, the skyworks symbol, and breakthrough simplicity are trademarks or registered trademarks of skyworks solutions, inc., in the united states and other countries. third-party brands and names are for identi ? cation purposes only, and are the property of their respective owners. additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference. 1. xyy = assembly and date code. 2. sample stock is generally held on part numbers listed in bold . 3. the leadless package family, which includes qfn, tqfn, dfn, tdfn and stdfn, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing process. a solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder c onnection. or de r in g i n for m a t ion pa ck a ge m a r k in g 1 pa r t n u m be r ( ta pe a n d re e l) 2 qfn44-24 ofxyy aat2 8 0 3 i sk- 4 .5 - t1 skyworks green? products are compliant with all applicable legislation and are halogen-free. for additional information, refer to skyworks de?ition of green , document number sq04-0074. pa ck a ge i n for m a t ion 3 qfn 4 4 - 2 4 4.000 0.050 2.7 0.05 0.300 45 pin 1 dot by marking 4.000 0.050 2.7 0.05 0.5 bsc 0.4 0.05 0.305 0.075 0.900 0.050 0.025 0.025 0.214 0.036 pin 1 identification r0.030max 16 7 12 13 18 19 24 top view bottom view side view all dimensions in millimeters. downloaded from: http:///

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