four - string , white led driver for lcd backlight applications preliminary technical data add5211 rev. pra document feedback information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. specifications subject to change without notice. no license is granted by implication or otherwise under any patent or patent rights o f analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062 - 9106, u.s.a. tel: 781.329.4700 ? 2013 analog devices, inc. all rights reserved. technical support www.analog.com features white led driver based on an inductive boost controller wide i nput voltage range: 4.5 v to 40 v adaptive output voltage to minimize power dissipation a djustable operating frequency : 2 00 khz to 1 .2 mhz programmable uvlo programmable soft start tim e for boost converter programmable external mosfet switching rising/falling time drives up to 4 led current sinks with internal mosfets brightness control with pwm input a djustable led current : 40 ma up to 200 ma headroom control to maximize efficiency le d dimming frequency : u p to 25 khz 1000:1 pwm dimming at 300 hz open drain fault indicator led open and led short fault protection thermal shutdown undervoltage lockout 24- lead, 4 mm 4 mm lfcsp applications lcd monitor and tv led backlights industrial li ghting general description the add5211 is a 4 channel , white led driver for backlight a pplications based on high efficiency, current mode, step - up converter tech nology. the b oost controller drives an external mosfet switch for step - up regulation from an input voltage of 4.5 v to 40 v and a pin adjustable operating frequency between 2 00 khz and 1 .2 mhz. a n a djustable uvlo function is implemented to redu ce input current during power - off. the add5211 contains four regulated current sinks for uniform brightness intensity. each current sinks can be drive n from 40 ma up to 200 ma and the led driving current is pin adjustable by an external resistor. the add5211 with an input pwm interface drives up to four parallel strings of multiple series connected leds with 1.5 % current matching between strings . additional features i nclude f ault indicator output led short protection, le d open protection, boost output short protection , overvoltage protection, cycle - by - cycle current limit, and thermal shutdown for both the ic and led array . the programmable soft start is implemented to reduce inrush current during startup. typical applic ation 10555-001 vin uvlo gate_p gate_n + off on en iset lsd vdd fault pwm vdr lgnd ovp fb4 fb3 fb2 fb1 pgnd ramp cs freq comp agnd ss add5211 vin figure 1.
add5211 preliminary technical data rev. pra | page 2 of 6 detailed functional block dia gram add5211 10555-002 comp vin en uvlo vdd pwm freq agnd fault ovp vdr ss gate_p cs lgnd lsd pgnd gate_n ramp ovp fb_ref boost control fb_min error amp pwm comp gm osc ramp soft start current sense r s q r vdr switch driver dcomp dref + + start-up ovp ref ovp scp fault detector thermal shutdown por open string detector short string detector unused string detector ovp por 10 linear regulator bandgap reference voltage reference por uvlo detector device enable control logic start-up boost control dimming control dimming control boost scp ref thermal shutdown boost short 500k? vdd current source fb1 fb2 fb3 fb4 500k? agnd agnd string voltage detector fb_min current source1 current source2 ref current source3 iset figure 2.
preliminary technical data add5211 rev. pra | page 3 of 6 a bsolute m aximum r atings t a = 25c, unless otherwise noted. table 1 . parameter rating vin , uvlo ?0.3 v to + 45 v fb1, fb2, fb3, fb4 ?0.3 v to + 55 v en ?0.3 v to + 2 0 v pwm , fault ?0.3 v to + 10 v vdr, gate _n , gate _p ?0.3 v to + 7 v vdd, lsd , ovp, cs, ramp, ss ?0.3 v to +3. 7 v freq, iset, comp ?0.3 v to +3. 5 v agnd, pgnd, lgnd ?0.3 v to + 0.3 v maximum junction t emperature (t j max) 150 c operating temperature range (t a ) ? 25 c to +85 c storage temperature range (t s ) ?6 5 c to +150 c reflow peak temperature (20 sec to 40 sec) 260 c stresses above those listed under absolute maximum ratings may cause permanent dam age to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for e xtended periods may affect device reliability. thermal resistance ja is specified for the worst - case conditions, that is, a device soldered in a circuit board for surface - mount packages. table 2 . thermal resistance package type ja jc unit 24- lead lfcsp 40.5 3.8 c/w esd caution
add5211 preliminary technical data rev. pra | page 4 of 6 pin configuration and fu nction descriptions 10555-003 2 1 3 4 5 6 18 17 16 15 14 13 f au l t pwm en vin uvlo vdr fb1 fb2 lgnd fb3 fb4 ov p 8 9 10 1 1 7 com p freq iset vdd 12 lsd ss 20 19 21 ram p pgnd cs 22 ga te_n 23 ga te_ p 24 agnd add52 1 1 t o p view notes 1. connect the exposed p addle t o ground. figure 3 . pin configuration table 3 . pin function descriptions pin no. mnemonic description 1 vdr switching mosfet g ate d river s upply p in. bypass vdr to a gnd with a 1 f bypass capacitor . 2 uvlo input u ndervoltage l ockout. set the start - up and shutdown input voltage level by connecting this pin to the input voltage through a voltage divide resistor. 3 vin supply i nput pin. bypass vin to a gnd with a 1 f bypass capa citor. 4 en shutdown control pin for pwm input operation mode. 5 pwm pwm s ignal i nput . 6 fau lt open d rain f ault o utput . 7 ss soft s tart p in . 8 comp compensation for the boost converter. two capacitors and a resistor are connected in series between g round and this pin for stable operation. 9 freq frequency select. a resistor from this pin to pin no. mnemonic description ground sets the boost switching frequency from 20 0 khz to 1 .2 mhz. 10 iset full - scale led current set. a resistor from this pin to ground sets the led current u p to 200 ma . 11 vdd internal linear regulator output. this regulator provides power to the add5211 . bypass vdd to a gnd with a 1 f bypass capacitor. 12 lsd led s hort v oltage l evel s etting p in . to disable led short protection, connect this pin to vdd . 13 fb1 regulated current sink. connect the bottom cathode of the led string to this pin. if u nused , connect fb1 to l gnd. 1 4 fb2 regulated current sink. connect the bottom cathode of the led string to this pin. if u nused , connect fb2 to l gnd. 1 5 lgnd led c urrent s ink g round . 1 6 fb3 regulated current sink. connect the bottom cathode of the led string to this pin. if u nused , connect fb3 to l gnd. 1 7 fb4 regulated current sink. connect the bottom cathode of the le d string to this pin. if u nused , connect fb4 to l gnd. 1 8 ovp overvoltage p rotection. the boost converter output is connected to this pi n with voltage divide resistors . 1 9 pgnd power g round . 20 ramp ramp c ompensation p in . 21 cs current s ense i nput . allo ws the current sensing to control the boost and to limit the switching current . 22 gate _n switching mosfet g ate l ow d riving p in . 23 gate _p switching mosfet g ate h igh d riving p in . 2 4 agnd analog g round . ep exposed paddle. connect the exposed paddle to ground.
preliminary technical data add5211 rev. pra | page 5 of 6 typical application s circuits r freq 47k? r c 68? c c 2.2f c c2 open c ss 30nf 10555-022 vin uvlo gate_p gate_n + r uvlo1 100k r uvlo2 7.5k c in2 0.1f c in 20f c out 10f l1 33h r on 20 r ramp 6.8k r cs 0.1 r ovp1 560k r ovp2 16k d1 s310 mosfet1 fdd86012lz c bypass2 1f off on en iset lsd vdd fault pwm vdr lgnd ovp fb4 fb3 fb2 fb1 pgnd ramp cs vcc_receiver r pull_up 10k r lsd1 24k r lsd2 4.7k r set 15k freq comp agnd ss 18v ~ 36v c bypass1 1f 22 leds/ch, 100ma/ch add5211 figure 4. typical four - string application circuit r freq 47k? r c 68? c c 2.2f c c2 open c ss 30nf add5211 10555-023 vin uvlo gate_p gate_n + r uvlo1 100k r uvlo2 7.5k c in2 0.1f c in 20f c out 10f l1 33h r on 20 r ramp 6.8k r cs 0.1 r ovp1 560k r ovp2 16k d1 s310 mosfet1 fdd86012lz c bypass2 1f off on en iset lsd vdd fault pwm vdr lgnd ovp fb4 fb3 fb2 fb1 pgnd ramp cs vcc_receiver r pull_up 10k r lsd1 24k r lsd2 4.7k r set 15k freq comp agnd ss 18v ~ 36v c bypass1 1f 22 leds/ch, 100ma/ch figure 5. typical two - string application circuit
add5211 preliminary technical data rev. pra | page 6 of 6 outline dimensions 0.50 bsc 0.50 0.40 0.30 0.30 0.25 0.18 compliant t o jedec standards mo-220-wggd. 112108-a b o t t o m v i e w t o p v i e w e x p o s e d p a d p i n 1 i n d i c a t o r 4.10 4.00 sq 3.90 sea ting plane 0.80 0.75 0.70 0.05 max 0.02 nom 0.20 ref 0.25 min coplanarity 0.08 pin 1 indica t or 1 2 4 7 1 2 1 3 1 8 1 9 6 2.65 2.50 sq 2.45 for proper connection of the exposed pad, refer to the pin configuration and function descriptions section of this data sheet. figure 6. 24 - lead lead frame chip scale package [lfcsp_w q ] 4 mm 4 mm body, very very thin quad (cp - 24 - 7) dimensions shown in millimeters ordering guide model 1 temperature range package description package option add5211 a cpz -r 7 ? 25 c to +85 c 24- lead lfcsp_wq , 7 t ape and reel cp -24-7 add5211 a cpz -rl ? 25 c to +85 c 24- lead lfcsp_wq , 13 tape and reel cp -24-7 1 z = rohs compliant part. ? 2013 analog devices, inc. all rights reserved. trademarks and registered trademarks are the property of t heir respective owners. d10555 - 0- 2/13(pra)
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