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AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 1 www.analogictech.com general description the AAT2862 is a highly integrated charge pump-based lighting management unit with four linear regulators optimized for single-cell lithium-ion/polymer systems. the charge pump provides power for all led outputs and multiple led configurations are available. the led out- puts can be programmed up to 30ma each and two led outputs can be programmed up to 60ma each. an i 2 c serial digital interface is used to enable, disable, and set the current to one of 32 levels. current matching is bet- ter than 3% for uniform display brightness, and high current matching is better than 5% for uniform power dissipation. the AAT2862 also offers four high-performance low- noise micropower? low dropout (ldo) linear regulators. the regulators are enabled and their output voltages are set through the i 2 c serial interface. each ldo can supply up to 200ma load current and ground-pin current is only 80 a making the AAT2862 ideal for battery-operated applications. the AAT2862 is available in a pb-free, space saving tqfn34-24 package and operates over the -40c to +85c ambient temperature range. features ? input voltage range: 2.7v to 5.5v ? tri-mode charge pump ? drives up to eight leds ? 32 programmable backlight current with auto-fade ? settings ranging from 500 a to 30ma ? drives up to two auxiliary leds ? 1mhz switching frequency ? automatic soft start ? i 2 c selectable drivers ? four linear regulators ? 200ma output current ? 200mv dropout ? i 2 c programmable output voltage from 1.2v to 3.3v ? output auto-discharge for fast shutdown ? built-in thermal protection ? automatic soft start ? -40c to +85c temperature range ? tqfn34-24 package applications ? camera enabled mobile devices ? digital still cameras ? multimedia mobile phones
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2 2862.2009.03.1.2 www.analogictech.com typical application cf1 1f cf2 1f c1+ c1- c2+ c2- in v out out bl1 bl2 bl3 bl4 bl5 bl6 bl7/aux1 ldoa v bat 3.6v c in 2.2f c ldoa 2.2f v ldoa at 200ma v ldob at 200ma v ldoc at 200ma v ldod at 200ma c ldob 2.2f c ldoc 2.2f c ldod 2.2f c out 2.2f AAT2862 en enable ldob ldoc pgnd sda sda scl scl i 2 c serial interface wleds in ldod bl8/aux2 agnd
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 3 www.analogictech.com pin descriptions pin # symbol function description 1 out o charge pump output. out is the output of the charge pump and supplies current to the backlight and ash leds. connect the backlight and ash led anodes to out. bypass out to pgnd with a 2.2 f or larger ceramic capacitor as close to the AAT2862 as possible. 2 c2+ i positive terminal of charge pump capacitor 2. connect the 1 f charge pump capacitor 2 from c2+ to c2-. 3 sda i i 2 c serial data input. sda is the data input of the i 2 c serial interface. drive sda with the i 2 c data. 4 scl i i 2 c serial clock input. scl is the clock input of the i 2 c serial interface. drive scl with the i 2 c clock. 5en i programming enable input. when en is strobed high, the backlight and ldo registers can be pro- grammed via the i 2 c serial interface. when en is strobed low, all backlight and ldo outputs are turned off and the backlight and ldo registers are reset to their default (por) values and forces all ldo outputs to 0 (zero) volts. 6 agnd g analog ground. connect to pgnd as close to the AAT2862 as possible. 7 in pi input power pin for all four ldos. connect pin 7 to pin 23 with as short a pcb trace as practical. 8 ldoc o ldo c regulated voltage output. bypass ldoc to agnd with a 2.2 f or larger ceramic capacitor as close to the AAT2862 as possible. 9 ldob o ldo b regulated voltage output. bypass ldob to agnd with a 2.2 f or larger capacitor as close to the AAT2862 as possible. 10 ldoa o ldo a regulated voltage output. bypass ldoa to agnd with a 2.2 f or larger capacitor as close to the AAT2862 as possible. 11 ldod o ldo d regulated voltage output. bypass ldod to agnd with a 2.2 f or larger ceramic capacitor as close to the AAT2862 as possible. 12 bl1 o backlight led 1 current sink. bl1 controls the current through backlight led 1. connect the cathode of backlight led 1 to bl1. if not used, connect bl1 to out. 13 bl2 o backlight led 2 current sink. bl2 controls the current through backlight led 2. connect the cathode of backlight led 2 to bl2. if not used, connect bl2 to out. 14 bl3 o backlight led 3 current sink. bl3 controls the current through backlight led 3. connect the cathode of backlight led 3 to bl3. if not used, connect bl3 to out. 15 bl4 o backlight led 4 current sink. bl4 controls the current through backlight led 4. connect the cathode of backlight led 4 to bl4. if not used, connect bl4 to out. 16 bl8/ aux2 o backlight or auxiliary led 8 current sink. bl8 controls the current through backlight led 8. connect the cathode of backlight led 8 to bl8. if not used, connect bl8 to out. 17 bl7/ aux1 o backlight or auxiliary led 7 current sink. bl7 controls the current through backlight led 7. connect the cathode of backlight led 7 to bl7. if not used, connect bl7 to out. 18 bl6 o backlight led 6 current sink. bl6 controls the current through backlight led 6. connect the cathode of backlight led 6 to bl6. if not used, connect bl6 to out. 19 bl5 o backlight led 5 current sink. bl5 controls the current through backlight led 5. connect the cathode of backlight led 5 to bl5. if not used, connect bl5 to out. 20 pgnd g power ground. connect to agnd as close to the AAT2862 as possible. 21 c2- i negative terminal of charge pump capacitor 2. 22 c1- i negative terminal of charge pump capacitor 1. 23 in pi power input. connect in to the input source voltage. bypass in to pgnd with a 2.2 f or larger ceramic capacitor as close to the AAT2862 as possible. 24 c1+ i positive terminal of charge pump capacitor 1. connect the 1 f charge pump capacitor 1 from c1+ to c1-. ep exposed paddle (bottom) connect to pgnd/agnd as close to the AAT2862 as possible.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 4 2862.2009.03.1.2 www.analogictech.com pin configuration tqfn34-24 (top view) 1 2 3 4 5 6 7 8 9 24 23 22 21 20 10 11 12 19 18 17 16 15 14 13 out c2+ sda scl en a gnd in ldoc ldob ldoa ldod bl1 bl8/aux2 bl7/aux1 bl4 bl3 bl2 bl6 bl5 pgnd c2- c1- in c1+ programmable options 1 main channels sub channels aux channels aux channels with 2x i out 8* 0* 0* 0* 620 0 530 0 521 0 440 0 431 0 422 0 520 1 420 2 1. "*" denotes default values.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 5 www.analogictech.com absolute maximum ratings 1 t a = 25 o c unless otherwise noted. symbol description value units in, out, bl1, bl2, bl3, bl4, bl5, bl6, bl7/aux1, bl8/aux2 voltage to pgnd and agnd -0.3 to 6.0 v c1+, c2+ voltage to pgnd and agnd -0.3 to v out + 0.3 v c1-, c2-, ldoa, ldob, ldoc, ldod, en, sda, scl voltage to pgnd and agnd -0.3 to v in + 0.3 v pgnd to agnd -0.3 to + 0.3 v thermal information 2, 3 symbol description value units ja thermal resistance 50 o c/w p d maximum power dissipation 2w t j operating junction temperature range -40 to 150 c t lead maximum soldering temperature (at leads) 300 1. stresses above those listed in absolute maximum ratings may cause permanent damage to the device. functional operation at co nditions other than the operating conditions specified is not implied. only one absolute maximum rating should be applied at any one time. 2. derate 20mw/c above 25c ambient temperature. 3. mounted on a fr4 circuit board.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 6 2862.2009.03.1.2 www.analogictech.com electrical characteristics 1 v in = 3.6v; c in = c out = 2.2 f; c 1 = c 2 = 1 f; t a = -40c to +85c, unless otherwise noted. typical values are t a = 25 c. symbol description conditions min typ max units v in in operating voltage range 2.7 5.5 v i in in operating current 1x mode; 3.0 v in 5.5; ldos off; no load 0.15 0.20 ma 1.5x mode; 3.0 v in 5.5; ldos off; charge pump on; no load 3.0 ma 2x mode; 3.0 v in 5.5; ldos off; charge pump on; no load 5.0 ma 2.7 v in 5.5; all ldos on; charge pump off; no load 225 a 2.7 v in 5.5; any one ldo on; charge pump off; no load 80 a i in(shdn) in shutdown current en = gnd 1.0 a t sd over-temperature shutdown threshold 140 c t sd(hys) over-temperature shutdown hysteresis 15 c charge pump section v out out output voltage 5.2 v i out(max) out maximum output current v in = 3.0v, v out = 4.0v 800 ma v in(th_h, bl) bl1-bl8 charge pump mode transition hysteresis en/set = in; v in ? v f = 1v 300 mv f osc charge pump oscillator frequency address 07h data=20 (0010 0000); t a = 25c 1.2 mhz t cp(ss) charge pump soft-start time t a = 25c 100 s bl1-bl6, bl7/aux1, bl8/aux2 led drivers t led(su) led output current startup time out: 0v to in 20 us i bl_(max) bl1-bl8 maximum current address 03h data=e0 (1110 0000) 27 30 33 ma i bl_(data29) bl1-bl8 current address 03h data=fd (1111 1101) 1.75 1.94 2.13 ma v bl_(th) bl1-bl8 charge pump transition threshold address 03h data=e0 (1110 0000) 180 mv i aux[1/2](max) aux maximum current address 05h data=e0 (1110 0000) address 06h data=e0 (1110 0000) 54 60 66 ma i aux[1/2](data13) aux current address 05h data=ac (1010 1100) address 06h data=ac (1010 1100) 18.4 ma i (aux[1/2]) / i aux(avg) aux1 aux2 current matching 2 address 05h data=e0 (1110 0000) address 06h data=e0 (1110 0000) 5% 1. the AAT2862 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. current matching is defined as the deviation of any sink current from the average of all active channels.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 7 www.analogictech.com electrical characteristics 1 v in = 3.6v; c in = c out = 2.2 f; c 1 = c 2 = 1 f; t a = -40 c to +85 c, unless otherwise noted. typical values are t a = 25 c. symbol description conditions min typ max units linear regulators v ldo[a/b/c,d] /v ldo[a/b/c,d] ldoa, ldob, ldoc, ldod output voltage tolerance i out = 1ma to 200ma; t a = 25c -1.5 1.5 % i out = 1ma to 200ma; t a = -40c to +85c -3.0 3.0 % i ldo[a/b/c,d](max) ldoa, ldob, ldoc, ldod maximum load current 200 ma v ldo[a/b/c,d](do) ldoa, ldob, ldoc, ldod dropout voltage 2 v ldo[a/b/c/d] 3.0v; i out = 150ma 75 200 mv v ldo / v ldo * v in ldoa, ldob, ldoc, ldod line regulation v ldo = (v out[a/b/c/d] + 1v) to 5v 0.09 %/v psrr [a/b/c,d] ldoa, ldob, ldoc, ldod power supply rejection ratio i ldo[a/b/c/d] =10ma, 1khz 50 db r out_(dchg) ldoa, ldob, ldoc, ldod auto- discharge resistance 20 i 2 c logic and control interface v il sda, scl, en input low threshold 2.7v v in 5.5v 0.4 v v ih sda, scl, en input high threshold 2.7v v in 5.5v 1.4 v v ol sda output low voltage i pullup = 3ma 0.4 v i in sda, scl, en input leakage current v sda = v scl = v led_sel = v ldo_sel = in = 5v -1 1 a f scl scl clock frequency 0 400 khz t low scl clock low period 1.3 s t high scl clock high period 0.6 s t hd_sta hold time start condition 0.6 s t su_sta setup time for repeat start 0.6 s t su_dat sda data setup time 100 ns t hd_dat sda data hold time 0 0.9 s t su_sto setup time for stop condition 0.6 s t buf bus free time between stop and start conditions 1.3 s 1. the AAT2862 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. v do[a/b/c/d] is defined as v in ? ldo[a/b/c/d] when ldo[a/b/c/d] is 98% of nominal.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 8 2862.2009.03.1.2 www.analogictech.com i 2 c interface timing details t t t t t t t t t
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 9 www.analogictech.com typical characteristics backlight efficiency vs. input voltage input voltage (v) efficiency (%) 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 30 40 50 60 70 80 90 100 30ma/ch, v f = 3.85v 20.32ma/ch, v f = 3.55v 4.84ma/ch, v f = 3.0v backlight current matching vs. temperature (v in = 3.6v; 30ma/ch) temperature (c) backlight output current (ma) -40 -15 10 35 60 85 25 26 27 28 29 30 31 32 33 channel 1 - channel 8 charge pump output turn on characteristic (v in = 3.6v; i led = 0ma; c out = 2.2f) time (50s/div) v en (top) (v) charge pump output (bottom) (v) 0.0 2.0 4.0 0.0 1.0 2.0 3.0 4.0 turn on to 1x mode backlight (v in = 4.5v; 30ma/ch) time (200s/div) sda (2v/div) v out (2v/div) i in (100ma/div) v sink (2v/div) 0v 0v 0a turn on to 1.5x mode backlight (v in = 3.5v; 30ma/ch) time (200s/div) sda (2v/div) v out (2v/div) i in (100ma/div) v sink (2v/div) 0v 0v 0a turn on to 2x mode backlight (v in = 3.2v; 30ma/ch) time (200s/div) sda (2v/div) v out (2v/div) i in (200ma/div) v sink (2v/div) 0v 0v 0a
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 10 2862.2009.03.1.2 www.analogictech.com typical characteristics turn off from 1.5x mode backlight (v in = 3.5v; 30ma/ch) time (200s/div) v en (2v/div) v diode (2v/div) i in (200ma/div) 0v 0v 0a operating characteristic ( v in = 3.3v; 30ma/ch backlight; 1.5x mode; c out = 2.2f; f osc = 1.2mhz) time (500ns/div) input voltage (ac coupled) (top) (mv) charge pump out put voltage (ac coupled) (bottom) (mv) 0 10 20 -50 0 50 operating characteristic ( v in = 3.0v; 30ma/ch backlight; 2x mode; c out = 2.2f; f osc = 1.2mhz) time (500ns/div) input voltage (ac coupled) (top) (mv) charge pump out put voltage (ac coupled) (bottom) (mv) 0 10 20 -20 -10 0 10 20 ldoa/b/c/d output voltage vs. temperature (v in = 3.6v; i ldo = 0ma) temperature (c) ldo output voltage deviatoin (%) -40 -15 10 35 60 85 -1.5 -1 -0.5 0 0.5 1 1.5 v out = 1.8v v out = 3.3v ldo a/b/c/d load regulation (v in = 3.6v) load current (ma) ldo output voltage deviation (%) 0.1 1 10 100 1000 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 v out = 1.2v v out = 3.3v ldo a/b/c/d line regulation (i ldo = 10ma) input voltage (v) ldo output voltage deviation (%) 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 v out = 1.8v v out = 3.3v
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 11 www.analogictech.com typical characteristics ldo a/b/c/d load transient response ( i ldo = 10ma to 200ma; v in = 3.6v; v out = 1.8v; c ldo = 2.2f) time (20s/div) ldo output current (top) (ma) ldo output voltage (bottom) (v) 0 100 200 1.60 1.70 1.80 1.90 2.00 ldo a/b/c/d line transient response ( v in = 3.6v to 4.2v; i ldo = 10ma; v out = 1.8v; c ldo = 2.2f) time (1ms/div) input voltage (top) (v) ldo output voltage (bottom) (v) 3.6 4.0 4.4 1.78 1.79 1.80 1.81 1.82 ldo a/b/c/d turn on characteristic ( v in = 3.6v; v out = 1.8v; c ldo = 2.2f) time (20s/div) v sda (top) (v) ldo output (bottom) (v) 0.0 2.0 4.0 0.0 0.5 1.0 1.5 2.0 ldo a/b/c/d turn on characteristic ( v in = 3.6v; v out = 3.3v; c ldo = 2.2f) time (20s/div) v sda (top) (v) ldo output (bottom) (v) 0.0 2.0 4.0 0.0 1.0 2.0 3.0 4.0 en, sda, scl input high threshold voltage vs. input voltage input voltage (v) v en(h) , v sda(h) , v scl(h) (v) 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 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 -40c 25c 85c en, sda, scl input low threshold voltage vs. input voltage input voltage (v) v en(l) , v sda(l) , v scl(l) (v) 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 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 -40c 25c 85c
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 12 2862.2009.03.1.2 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 12 2862.2009.03.1.2 www.analogictech.com functional block diagram bl 5 1x/1.5x/2x tri-mode charge pump c1- c1+ c2- c2+ in ldoa out bl 1 bl 2 bl 3 bl 4 bl 6 control logic bl7/aux1 en ldob ldoc in sda scl pgnd 8 ldod ref bl8/aux2 agnd
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 13 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 13 www.analogictech.com functional description the AAT2862 is a highly integrated backlight driver with four ldo regulators. the charge pump led driver powers the backlight leds from the 2.7v to 5.5v input voltage. the ldo regulators get their power from the same input and produce regulated output voltage between 1.2v and 3.3v. control of the leds and the ldo output voltage is through an i 2 c serial interface for easy programming. led drivers the AAT2862 drives up to eight backlight leds up to 30ma each. the leds are driven from a charge pump to insure that constant current is maintained over the entire battery voltage range. the charge pump auto- matically switches from 1x, to 1.5x, to 2x modes and back to maintain the led current while minimizing power loss for high efficiency. the charge pump operates at the high 1mhz switching frequency allowing the use of small 1 f ceramic capacitors. depending on the battery voltage and led forward volt- age, the charge pump drives the leds directly from the input voltage (1x or bypass mode) or steps up the input voltage by a factor of 1.5 (1.5x mode) or 2 (2x mode). the charge pump requires only two tiny 2.2 f ceramic capacitors, making a more compact solution than an inductor-based step-up converter solution. each indi- vidual led is driven by a current sink to gnd, allowing individual current control with high accuracy over a wide range of input voltages and led forward voltages while maintaining high efficiency. the charge pump is controlled by the voltage across the led current sinks. when any one of the active backlight current sink voltages drops below 180mv, the charge pump goes to the next higher mode (from 1x to 1.5x or from 1.5x to 2x mode) to maintain sufficient led voltage for constant led current. the AAT2862 continuously monitors the led forward voltages and uses the input voltage to determine when to reduce the charge pump mode for better efficiency. there is also a 300mv mode- transition hysteresis that prevents the charge pump from oscillating between modes. led current control the eight backlight led channels are programmed through the i 2 c serial interface and can be set between 0.5 and 30ma in ~1ma steps. the currents match to within typically 3%. there are fade-in and fade-out timers that can be programmed through the interface as well. see the ?i 2 c serial interface? section for more informa- tion on setting the led currents. ldo regulators the AAT2862 includes four low dropout (ldo) linear regulators. these regulators are powered from the bat- tery and produce a fixed output voltage set through the i 2 c serial interface. the output voltages can be pro- grammed to one of 16 output voltages between 1.2v and 3.3v. the ldos can also be turned on/off through the i 2 c serial interface. the ldo regulators require only a small 2.2 f ceramic output capacitor for stability. if improved load transient response is required, larger-valued capacitors can be used without stability degradation. i 2 c serial interface the AAT2862 uses an i 2 c serial interface to set the led currents, the ldo's output voltages, and to turn on/off all ldos, as well as other housekeeping functions. the i 2 c interface takes input from a master device while the AAT2862 acts as a target to the master. the i 2 c protocol uses two open-drain inputs; sda (seri- al data line) and scl (serial clock line). both inputs require an external pull up resistor, typically to the input voltage. the i 2 c protocol is bidirectional and allows tar- get devices and masters to both read and write to the bus. the AAT2862 only supports the write protocol; therefore, the read/write bit must always be set to ?0?. the timing diagram in figure 1 shows the typical trans- mission protocol.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 14 2862.2009.03.1.2 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 14 2862.2009.03.1.2 www.analogictech.com AAT2862 device address = 60 h wack addr = 00h ack data = 06 h ack stop start sda scl start msb chip address lsb wack msb register add lsb ack msb data lsb ack stop figure 1: typical i 2 c timing diagram. i 2 c serial interface protocol the i 2 c serial interface protocol is shown in figure 1. devices on the bus can be either master or target devic- es. both master and target devices can both send and receive data over the bus, with the difference being that the master device controls all communication on the bus. the AAT2862 acts as a target device on the bus and is only capable of receiving data and does not transmit data over the bus. the i 2 c communications begin with the master making a start condition. next, the master transmits the 7-bit device address and a read/write bit. each target device on the bus has a unique address. the AAT2862 device address is 60h. if the address transmitted by the master matches the device address, the target device transmits an acknowledge (ack) signal to indicate that it is ready to receive data. since the AAT2862 only reads from the master, the read/write bit must be set to ?0?. next, the master transmits the 8-bit register address, and the tar- get device transmits an ack to indicate that it received the register address. next, the master transmits the 8-bit data word, and again the target device transmits an ack indicating that it received the data. this process continues until the master is finished writing to the tar- get device, at which time the master generates a stop condition. start and stop conditions start and stop conditions are always generated by the master. prior to initiating a start, both the sda and scl pin are inactive and are pulled high through external pull- up resistors. as shown in figure 1, a start condition is when the master pulls the sda line low and, after the start condition hold time (t ht_sta ), the master strobes the scl line low. a start condition acts as a signal to devic- es on the bus that the device producing the start condi- tion is active and will be communicating on the bus. a stop condition, as shown in figure 1, is when scl changes from low to high followed after the stop condi- tion setup time (t su_sto ), by an sda low-to-high transi- tion. the master does not issue an ack and releases scl and sda. transferring data addresses and data are sent with the most significant bit first transmitted and the least significant bit transmitted last. after each address or data transmission, the target device transmits an ack signal to indicate that it has received the transmission. the ack signal is generated by the target after the master releases the sda data line by driving sda low.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 15 www.analogictech.com sda scl sd a scl start stop figure 2: i 2 c stop and start conditions; start: a high ?1? to low ?0? transition on the sda line while scl is high ?1? stop: a low ?0? to high ?1? transition on the sda line while scl is high ?1?. scl 1 2 3 4 567 8 9 sdaa6a5a4a3a2a1a0r/wack device address lsb msb figure 3: i 2 c address bit map; 7-bit slave address (a6-a0), 1-bit read/write (r/w), 1-bit acknowledge (ack). scl 1 2 3 4 567 8 9 sdad7d6d5d4d3d2d1 d0ack register address / data lsb msb figure 4: i 2 c register address and data bit map; 8-bit data (d7-d0), 1-bit acknowledge (ack).
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 16 2862.2009.03.1.2 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 16 2862.2009.03.1.2 www.analogictech.com register functional description data bit7 data bit6 data bit5 data bit4 data bit3 data bit2 data bit1 data bit0 number hex address reg0 00h ldo a & b output voltage control ldoa[3] ldoa[2] ldoa[1] ldoa[0] ldob[3] ldob[2] ldob[1] ldob[0] reg1 01h ldo c & d output voltage control ldoc[3] ldoc[2] ldoc[1] ldoc[0] ldod[3] ldod[2] ldod[1] ldod[0] reg2 02h ldo en control x x x x enldo_d enldo_c enldo_b enldo_a reg3 03h backlight current control main meqs disable fade_main main_on blm[4] blm[3] blm[2] blm[1] blm[0] reg4 04h backlight current control sub x disable fade_sub sub_on bls[4] bls[3] bls[2] bls[1] bls[0] reg5 05h backlight current control aux1 aux1[1] aux1[0] aux1_on bla1[4] bla1[3] bla1[2] bla1[1] bla1[0] reg6 06h backlight current control aux2 aux2[2] aux2[0] aux2_on bla2[4] bla2[3] bla2[2] bla2[1] bla2[0] reg7 07h backlight fade control x x fade_time[1] fade_time[0] fade_main fade_sub floor[1] floor[0] table 1: AAT2862 configuration/control register allocation (?x? = ?reserved?). applications information i 2 c serial programmed registers the AAT2862 i 2 c programmable registers are listed in table 1. there are eight registers, five for the backlight led control, and three to control the four ldos. all backlight channels can be easily configured in many different ways through the i 2 c interface. the default assignment for the drivers is four backlight for main, two backlight for sub, and two extra that can be applied to main, sub, or auxiliary. all eight backlight channels can be driven to the same current level by writting the meqs = 1 bit in reg3. the main and sub backlights can be programmed independently to one of 32 levels described in table 2. backlight control registers the AAT2862 has five backlight registers: ? reg3 (i 2 c address 03h) controls main backlight. ? reg4 (i 2 c address 04h) controls sub backlight. ? reg5 (i 2 c address 05h) controls auxiliary aux1 backlight. ? reg6 (i 2 c address 06h) controls auxiliary aux2 backlight. ? reg7 (i 2 c address 07h) controls backlight fade-in and fade-out function.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 17 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 17 www.analogictech.com table 3 describes the floor current per channel for the fade-in and fade-out functions. in fade-out sequence floor will be the final current that will continue to be present until the main, sub or aux1,2 channels are dis- abled by writing main_on = 0 to reg3, sub_on = 0 to reg4, a1_on = 0 to reg5, and/or a2_on = 0 to reg6. in fade-in sequence floor is the direct current all chan- nels will be turned on by writing main_on = 1 to reg3, sub_on = 1 to reg4, a1_on = 1 to reg5, and/or a2_ on = 1 to reg6. fade-out can be initiated only after the fade in sequence has been programmed first by writing fade_main = 1 and/or fade_sub = 1 as is shown in table 4. data bit4 data bit3 data bit2 data bit1 data bit0 led current (ma) blm[4] blm[3] blm[2] blm[1] blm[0] reg3 bls[4] bls[3] bls[2] bls[1] bls[0] reg4 bla1[4] bla1[3] bla1[2] bla1[1] bla1[0] reg5 bla2[4] bla2[3] bla2[2] bla2[1] bla2[0] reg6 0 0000 30* 0 0 0 0 1 29.03 0 0 0 1 0 28.06 0 0 0 1 1 27.10 0 0 1 0 0 26.13 0 0 1 0 1 25.16 0 0 1 1 0 24.19 0 0 1 1 1 23.23 0 1 0 0 0 22.26 0 1 0 0 1 21.29 0 1 0 1 0 20.32 0 1 0 1 1 19.35 0 1 1 0 0 18.38 0 1 1 0 1 17.42 0 1 1 1 0 16.45 0 1 1 1 1 15.48 1 0 0 0 0 14.52 1 0 0 0 1 13.55 1 0 0 1 0 12.58 1 0 0 1 1 11.61 1 0 1 0 0 10.65 1 0 1 0 1 9.68 1 0 1 1 0 8.71 1 0 1 1 1 7.74 1 1 0 0 0 6.77 1 1 0 0 1 5.81 1 1 0 1 0 4.84 1 1 0 1 1 3.87 1 1100 2.9 1 1 1 0 1 1.94 1 1 1 1 0 0.97 1 1 1 1 1 0.48 table 2: main/sub/aux backlight led current - blm/bls/bla1,2[4:0]. *denotes default (power-on-reset) value.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 18 2862.2009.03.1.2 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 18 2862.2009.03.1.2 www.analogictech.com data bit1 data bit0 fade in and out current level (ma) floor[1] floor[0] reg7 0* 0* 0.48* 0 1 0.97 1 0 1.94 1 1 2.90 table 3: main/sub led current fade in and out level control. data bit3 data bit2 fade in and out control reg7 fade_main fade_sub main sub 0* 0* fade out* fade out* 0 1 fade out fade in 1 0 fade in fade out 1 1 fade in fade in table 4: main/sub led current fade in and out control. data bit5 of reg3, reg4, reg5 and reg6 controls the turn on and off of the main, sub, aux1 and aux2 chan- nels according to table 5. both aux1 and aux2 channels are considered part of the sub backlight channels unless explicitly turned on as part of the main backlight or inde- pendently. data bit5 backlight channel on/off main_on reg3 sub_on reg4 aux1_on reg5 aux2_on reg6 0* off* 1on table 5: main/sub/aux1/aux2 led current on/off control. data bit6 of reg3 and reg4 enables the fade in and out control of the main and sub channels. fade function is enabled by default and can be explicitly disabled by writ- ing disable fade_main = 1 and/or disable fade_sub = 1 as shown in table 6. data bit6 backlight channel fade in and out enable/disable disable fade_main reg3 disable fade_sub reg4 0* enable* 1 disable table 6: main/sub current fade on/off control. data bit7=1 of reg3 programs all sub channels as main backlight as described in table 7. if the main fade-in or fade-out function is enabled; all eight main and sub channels will be faded-in or out simultaneously. data bit7 main equal sub (meqs) meqs reg3 0* false* 1 true table 7: main/sub current fade on/off control. data bit4 and data bit5 of reg7 control the duration of the fade-in/out function. the default timing is 850ms with options for 650ms and 425ms according to table 8. the charge pump oscillator frequency is related to the fade-in/out timing as follows: for the 850ms fade-in/out timer, typical f osc = 600khz for the 650ms fade-in/out timer, typical f osc = 800khz for the 425ms fade-in/out timer, typical f osc = 1.2mhz respectively. data bit5 data bit4 fade in and out timing (ms) fade_time[1] fade_time[0] 0* 0* 850* 0 1 650 1 0 425 1 1 850 table 8: main/sub led current fade in and out timing *denotes default (power-on-reset) value.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 19 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 19 www.analogictech.com main/sub backlight 30ma/ch main/sub backlight 2.90ma/ch main/sub backlight off reg3 address 03h, data 20(0010 0000): enable fade function reg7 address 07h, data 03(0000 0011): fade-out is programmed to 2.90ma/ch reg3 address 03h data 00(0000 0000 ) main and sub fade out only max. 30ma /ch to 2.90ma/ch i2c sequence: AAT2862 chip address 60h reg3 address 03h, data c0(0100 0000): disable fade function reg7 address 07h, data 0c(0000 1100): fade-in is programmed reg3 address 03h, data 60(0110 0000): main/sub is turned on with 30ma/ch reg3 address 03h, data 20(0010 0000): enable fade function reg3 address 03h, data 60(0110 0000): main/sub is turned on with 30ma/ch reg7 address 07h, data 08(0000 1000): fade-in is programmed reg3 address 03h, data c0(0100 0000): disable fade function reg7 address 07h, data 0c(0000 1100): fade-in is programmed reg3 address 03h, data 60(0110 0000): main/sub is turned on with 30ma/ch figure 5: example of AAT2862 fade out programming. examples of fade-out programming main only (sub is off): address 03h, data 40: disable fade address 07h, data 08: fade-in is programmed address 03h, data 6f: turn on directly to 15.48ma/ch address 03h, data 20: re-enable fade address 07h, data 00: fade-out to 0.48ma/ch sub only (main is off): address 04h, data 40: disable fade address 07h, data 04: fade-in is programmed address 04h, data 6f: turn on directly to 15.48ma/ch address 04h, data 2f: enable fade address 07h, data 02: fade-out to 1.94ma/ch main and sub (as shown in figure 5): address 03h, data c0: disable fade address 07h, data 0c: fade-in is programmed address 03h, data 60: turn on directly to 30ma/ch address 03h, data 20: enable fade address 07h, data 03: fade-out to 2.90ma/ch examples of fade-in/out programming main only (sub is off): address 03h, data 20: main backlight is turned on with 0.48ma/ch address 07h, data 08: fade-in to 30ma/ch address 07h, data 03: fade-out to 2.90ma/ch sub only (main is off): address 07h, data 02: fade-in is programmed to 1.94ma/ch address 04h, data 2e: sub backlight is turned on with 1.94ma/ch address 07h, data 04: fade-in to 16.45ma/ch address 07h, data 02: fade-out to 1.94ma/ch main and sub (as shown in figure 6): address 07h, data 01: fade-in is programmed to 0.97ma/ch address 03h, data aa: main and sub backlight is turned on with 0.97ma/ch address 07h, data 0c: fade-in to 20.32ma/ch address 07h, data 01: fade-out to 0.97ma/ch
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 20 2862.2009.03.1.2 www.analogictech.com main/sub backlight 20.32ma/ch main/sub backlight 0.97ma/ch main/sub backlight off reg7 address 07h, data 01(0000 0001): fade-out is programmed to 0.97ma/ch reg3 address 03h data 80(1000 0000) i2c sequence: AAT2862 chip address 60h reg7 address 07h, data 01(0000 0001): fade-in is programmed as 0.97ma/ch reg3 address 03h, data aa(1010 1010): main/sub backlight is turned on with 0.97ma/ch reg7 address 07h, data 0c(0000 1100): fade-in programmed to 20.32ma/ch reg7 address 07h, data 0c(0000 1100): fade-in is programmed as 20.32ma/ch main and sub fade in/out max. 20.32ma/ch to 0.97ma/ch reg7 address 07h, data 01(0000 0001): fade-in is programmed as 0.97ma/ch reg3 address 03h, data aa(1010 1010): main/sub backlight is turned on with 0.97ma/ch reg7 address 07h, data 0c(0000 1100): fade-in is programmed to 20.32ma/ch figure 6: example of AAT2862 fade in/out programming. ldo control registers the four ldo regulators have three dedicated control registers: ? reg0 (i 2 c address 00h) and reg1 (i 2 c address 01h) set the output voltages of ldoa/b/c/d to one of 16 pre-set values according to table 9 and table 10. ? reg2 (i 2 c address 02h) controls turning on/off of ldoa/b/c/d regulators according to table 11.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 21 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 21 www.analogictech.com data bit7 data bit6 data bit5 data bit4 ldo v ldo[a/c] (v) ldoa[3] ldoa[2] ldoa[1] ldoa[0] reg0 ldoc[3] ldoc[2] ldoc[1] ldoc[0] reg1 0* 0* 0* 0* 1.2* 0 0 0 1 1.3 0 0 1 0 1.5 0 0 1 1 1.6 0 1 0 0 1.8 0 1 0 1 2.0 0 1 1 0 2.2 0 1 1 1 2.5 1 0 0 0 2.6 1 0 0 1 2.7 1 0 1 0 2.8 1 0 1 1 2.9 1 1 0 0 3.0 1 1 0 1 3.1 1 1 1 0 3.2 1 1 1 1 3.3 table 9: ldoa/ldoc output voltage control data. data bit3 data bit2 data bit1 data bit0 ldo v ldo[b/d] (v) ldob[3] ldob[2] ldob[1] ldob[0] reg0 ldod[3] ldod[2] ldod[1] ldod[0] reg1 0* 0* 0* 0* 1.2* 0 0 0 1 1.3 0 0 1 0 1.5 0 0 1 1 1.6 0 1 0 0 1.8 0 1 0 1 2.0 0 1 1 0 2.2 0 1 1 1 2.5 1 0 0 0 2.6 1 0 0 1 2.7 1 0 1 0 2.8 1 0 1 1 2.9 1 1 0 0 3.0 1 1 0 1 3.1 1 1 1 0 3.2 1 1 1 1 3.3 table 10: ldob/ldod output voltage control data. *denotes default (power-on-reset) value. data bit3 data bit2 data bit1 data bit0 ldod output ldoc output ldob output ldoa output enldo_d enldo_c enldo_b enldo_a 0* 0* 0* 0* off* off* off* off* 0 0 0 1 off off off on 0 0 1 0 off off on off 0 0 1 1 off off on on 0 1 0 0 off on off off 0 1 0 1 off on off on 0 1 1 0 off on on off 0 1 1 1 off on on on 1 0 0 0 on off off off 1 0 0 1 on off off on 1 0 1 0 on off on off 1 0 1 1 on off on on 1 1 0 0 on on off off 1 1 0 1 on on off on 1 1 1 0 on on on off 1 1 1 1 on on on on table 11: ldoa/ldob/ldoc/ldod on/off control data.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 22 2862.2009.03.1.2 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 22 2862.2009.03.1.2 www.analogictech.com auxillary backlight selection each of the auxiliary drivers (aux1, aux2) can also be programmed to one of the 32 levels described in table 2. the auxiliary drivers can be driven independently, or combined with the main or sub by changing data bit6 and data bit7 in reg5 (i 2 c address 05h) and reg6 (i 2 c address 06h) according to table 12. the auxiliary drivers can also be set to operate at twice their programmed current if aux1[1] = 1 and aux1[0] = 1 in reg5 and aux2[1] = 1 and aux2[0] = 1 in reg6. data bit7 data bit6 auxillary channel assignment aux1[1] aux1[0] reg5 aux2[1] aux2[0] reg6 0* 0* i aux1 = sub* i aux2 = sub* 01 i aux1 = main i aux2 = main 10 i aux1 = aux1 i aux2 = aux2 11 i aux1 = 2?aux1 i aux2 = 2?aux2 table 12: auxiliary channel assignment. led selection the AAT2862 is specifically intended for driving white leds. however, the device design will allow the AAT2862 to drive most types of leds with forward voltage specifi- cations ranging from 2.0v to 4.7v. led applications may include mixed arrangements for display backlighting, color (rgb) leds, infrared (ir) diodes and any other load needing a constant current source generated from a vary- ing input voltage. since the d1 to d8 constant current sinks are matched with negligible voltage dependence, the constant current channels will be matched regardless of the specific led forward voltage (v f ) levels. the low-dropout current sinks in the AAT2862 maximize performance and make it capable of driving leds with high forward voltages. multiple channels can be com- bined to obtain a higher led drive current without com- plication. device switching noise performance the AAT2862 operates at three fixed frequencies, typi- cally 600khz, 800khz, and 1.2mhz, in order to help 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 inductor-based dc/dc boost converter white led backlight solutions. the AAT2862 soft-start feature prevents noise transient effects associated with in-rush currents during the start up of the charge pump circuit. power efficiency and device evaluation charge-pump efficiency discussion in the following sec- tions accounts only for the efficiency of the charge pump section itself. due to the unique circuit architecture and design of the AAT2862, it is very difficult to measure efficiency in terms of a percent value comparing input power over output power. since the AAT2862 outputs are pure constant current sinks and typically drive individual loads, it is difficult to measure the output voltage for a given output (bl1 to bl8) to derive an overall output power measurement. for any given application, white led forward voltage levels can differ, yet the output drive current will be maintained as a constant. this makes quantifying output power a difficult task when taken in the context of comparing to other white led driver circuit topologies. a better way to quantify total device efficiency is to observe the total input power to the device for a given led current drive level. the best white led driver for a given application should be based on trade-offs of size, external component count, reliability, operating range and total energy usage... not just ?% efficiency?. *denotes default (power-on-reset) value.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 23 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 23 www.analogictech.com the AAT2862 efficiency may be quantified under very specific conditions and is dependent upon the input volt- age versus the output voltage seen across the loads applied to outputs d1 through d8 for a given constant current setting. depending on the combination of v in and voltages sensed at the current sinks, the device will operate in load switch mode. when any one of the volt- ages sensed at the current sinks nears dropout the device will operate in 1.5x or 2x charge pump mode. each of these modes will yield different efficiency values. refer to the following two sections for explanations of each operational mode. 1x mode efficiency the AAT2862 1x mode is operational at all times and functions alone to enhance device power conversion effi- ciency when v in is greater then the voltage across the load. when in 1x mode, the voltage conversion efficiency is defined as output power divided by input power: = p ou t p in the expression to define the ideal efficiency ( ) can be rewritten as: = p out = v out i out = v out p in v in i out v in -or- (%) = 100 v out v in ?? ?? 1.5x/2x charge pump mode efficiency the AAT2862 contains a fractional charge pump which will boost the input supply voltage in the event where v in is less then the voltage required to supply the output. the efficiency ( ) can be simply defined as a linear volt- age regulator with an effective output voltage that is equal to one and a half or two times the input voltage. efficiency ( ) for an ideal 1.5x charge pump can typi- cally be expressed as the output power divided by the input power. = p ou t p in in addition, with an ideal 1.5x charge pump, the output current may be expressed as 2/3 of the input current. the expression to define the ideal efficiency ( ) can be rewritten as: = p out = v out i out = v out p in v in 1.5i out 1.5v in (%) = 100 v out 1.5v in ?? ?? for a charge pump with an output of 5v and a nominal input of 3.5v, the theoretical efficiency is 95%. due to internal switching losses and ic quiescent current con- sumption, the actual efficiency can be measured at 93%. these figures are in close agreement for output load conditions from 1ma to 100ma. efficiency will decrease substantially as load current drops below 1ma or when level of v in approaches v out . the same calculations apply for 2x mode where the output current then becomes 1/2 of the input current. capacitor selection careful selection of the four external capacitors c in , c 1 , c 2 , and c out is important because they will affect turn on time, output ripple and transient performance. optimum performance will be obtained when low esr (<100m ) ceramic capacitors are used. in general, low esr may be defined as less than 100m . a capacitor value of 1 f for all four capacitors is a good starting point when choosing capacitors. if the constant current sinks are only pro- grammed for light current levels, then the capacitor size may be decreased. capacitor characteristics ceramic composition capacitors are highly recommended over all other types of capacitors for use with the AAT2862. 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.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 24 2862.2009.03.1.2 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 24 2862.2009.03.1.2 www.analogictech.com manufacturer part number value voltage temp. co. case avx 0603zd105k 1 f10 x5r 0603 0603zd225k 2.2 f10 tdk c1608x5r1e105k 1 f25 x5r 0603 c1608x5r1c225k 2.2 f16 c1608x5r1a475k 4.7 f10 murata grm188r61c105k 1 f16 x5r 0603 grm188r61a225k 2.2 f10 taiyo yuden lmk107bj475ka 4.7 f 10 x5r 0603 table 13: surface mount capacitors. equivalent series resistance (esr) esr is an important characteristic to consider when selecting a capacitor. esr is a resistance internal to a capacitor, which 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. ceramic capacitor materials ceramic capacitors less than 0.1 f are typically made from npo or cog materials. npo and cog 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 capac- itors greater than 1 f are typically not required for AAT2862 applications. 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. evaluation board user interface the user interface for the AAT2862 evaluation board is provided by three buttons and three connection termi- nals. the board is operated by supplying external power and pressing individual buttons or button combinations. table 14 indicates the function of each button or button combination. to power-on the evaluation board, connect a power sup- ply or battery to the dc- and dc+ terminals. close the board?s supply connection by positioning the j1 jumper to the on position. a red led indicates that power is applied. the evaluation board is made flexible so that the user can disconnect the data, clock and enable lines from the microcontroller and apply external signal sources by removing the jumpers from j2, j3 and/or j4. external enable signal must be applied to the on pin of j4 termi- nal. external i 2 c clock scl can be applied to j2 pin and data sda to j3 pin. when applying external enable signals, consideration must be given to the voltage levels. the externally applied voltages should not exceed the supply voltage that is applied to the in pins of the device (dc+). the ldo loads can be connected directly to the evalua- tion board. for adequate performance, be sure to con- nect the load between ldoa/ldob/ldoc/ldod and dc- as opposed to some other gnd in the system.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 25 www.analogictech.com AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 25 www.analogictech.com button(s) pushed description sw1 (ldos) [push/release once] all ldos will be turned on with default output voltage 1.2v. every push release will increment output voltage according to datasheet table. sw2 (main backlight) [push/release once] turning on the main and sub backlight leds with default current 30ma per channel. every push release will decrement the current according to datasheet table. sw3 (sub backlight) [push/release once] turning on only the sub backlight leds with default current 30ma. every push release will decrement the current according to datasheet table. sw1 + sw2 [push/release once] turning on the fade-out sequence of the backlight leds with default current 30ma down to 0.5ma per channel. sw1 + sw3 [push/release once] turning on the fade-in sequence of the backlight leds with default current 0.5ma up to 30ma per channel. sw1 + sw2 + sw3 [push/release once] reset all registers to default. table 14: AAT2862 evaluation board user interface functionality. d1 d2 d3 d4 d7 vout d8 vout ldoc ldoa dc+ 1 23 j1 100f (optional) lab supply bypass c11 100f c5 4.7f c4 4.7f c3 2.2f c8 2.2f c7 2.2f c6 2.2f c9 2.2f c1 1.0f c2 1.0f vin ldod d6 d5 scl en sda ldob 10 11 12 bl2 bl3 bl4 bl6 bl7/aux1 bl8/aux2 bl5 13 14 15 16 17 18 19 pgnd 20 c2 - 21 c1 - 22 in 23 c1+ 24 c2+ 2 sda 3 scl 4 en 5 agnd 6 in 7 ldoc ldob ldoa ldod bl1 8 9 out 1 AAT2862 u1 figure 7: AAT2862 evaluation board schematic.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 26 2862.2009.03.1.2 www.analogictech.com vdd 1 gp5 2 gp4 3 gp3 vss gp0 gp1 gp2 4 5 6 7 8 pic12f675 u2 c10 1f r7 330 r6 100k r4 10k r5 10k red led9 sw1 sw2 sw3 1k r1 vin scl vin 1k r2 1k r3 dc- en j4 en sda vin vin scl j2 sda j3 figure 8: AAT2862 evaluation board microcontroller schematic. figure 9: AAT2862 evaluation board figure 10: AAT2862 evaluation board top side layout. bottom side layout.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 2862.2009.03.1.2 27 www.analogictech.com component part number description manufacturer u1 AAT2862imk backlight led driver with 4 ldos analogictech u2 pic12f675 8-bit cmos, flash-based c; 8-pin pdip package microchip sw1 ? sw3 pts645tl50 switch tact, spst, 5mm itt industries r1, r2, r3 chip resistor 1k , 5%, 1/4w; 0603 vishay r4, r5 chip resistor 10k , 5%, 1/4w; 0603 vishay r6 chip resistor 100k , 5%, 1/4w; 0603 vishay r7 chip resistor 300 , 5%, 1/4w; 0603 vishay c3, c6, c7, c8, c9 grm188r71a225ke15 2.2 f, 10v, x7r, 0603 murata c1, c2 grm216r61a105ka01 1 f, 10v, x5r, 0603 murata c4, c5 grm18x 4.7 f, 10v,x5r, 0603 murata d1-d8 lw m673 mini topled white led; smt osram led9 cmd15-21src/tr8 red led; 1206 chicago miniature lamp j1, j2, j3, j4 prpn401paen conn. header, 2mm zip sullins electronics table 15: AAT2862 evaluation board component listing.
AAT2862 backlight led driver and multiple ldo lighting management unit chargepump tm product datasheet 28 2862.2009.03.1.2 www.analogictech.com advanced analogic technologies, inc. 3230 scott boulevard, santa clara, ca 95054 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 speci cations or to discontinue any product or service without notice. except as provided in analogictech?s terms and conditions of sale, analogictech assumes no liability whatsoever, and analogictech disclaims any express or implied warranty re lating to the sale and/or use of analogictech products including liability or warranties relating to tness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right . in order to minimize risks associated with the customer?s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. testing and other quality control techniques are utilized to the extent analogictech deems necessary to support this warranty. speci c testing of all parameters of each device is not necessarily performed. analogictech and the analogictech logo are trademarks of advanced analogic technologies incorporated. all other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. 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 th e 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. ordering information package part marking 1 part number (tape and reel) 2 tqfn34-24 6rxyy AAT2862imk-t1 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/about/quality.aspx. package information tqfn34-24 3 3.000 0.050 4.000 0.050 top view bottom view side view detail ?a? 1.700 0.050 detail ?a? r(5x) index area 0.210 0.040 2.700 0.050 0 + 0.10 - 0.00 0.750 0.050 0.203 ref 0.400 bsc 0.400 0.050 all dimensions in millimeters.

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