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general description the MAX16803 current regulator operates from a 6.5v to 40v input-voltage range and delivers up to a total of 350ma to one or more strings of high-brightness leds (hb leds). the output current of the MAX16803 is adjusted by using an external current-sense resistor in series with the leds. a dimming input allows wide- range ?ulsed?pwm operation. wave-shaping circuitry reduces emi. the differential current-sense input increases noise immunity. the MAX16803 is well suited for applications requiring high-voltage input and is able to withstand automotive load-dump events up to 40v. an on-board pass element minimizes external compo- nents while providing ?.5% output-current accuracy. additional features include a 5v regulated output and short-circuit and thermal protection. the MAX16803 is available in a thermally enhanced, 5mm x 5mm, 16-pin tqfn package and is specified over the automotive -40? to +125? temperature range. applications automotive interior: map, courtesy, and cluster lighting automotive exterior: rear combination lights (rcls) emergency vehicle warning lights navigation and marine indicators general lighting signage, gasoline canopies, beacons features ? +6.5v to +40v operating range ? adjustable led current (35ma to 350ma) ? ?.5% led current accuracy ? high-voltage dim pin for dimming interface ? integrated pass element with low-dropout voltage (0.5v typ) ? +5v regulated output with 4ma source capability ? parallel operation for led current > 350ma ? differential led current sense ? low shutdown supply current (12 a typ) ? low 204mv current-sense reference reduces power losses ? wave-shaped edges reduce radiated emi during pwm dimming ? thermal shutdown ? output short-circuit protection ? available in small, thermally enhanced, 5mm x 5mm, 16-pin tqfn package ? -40? to +125? operating temperature range MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator ________________________________________________________________ maxim integrated products 1 15 16 + 14 13 6 5 7 in n.c. 8 out v5 cs+ gnd 12 n.c. 4 12 11 9 en out n.c. n.c. n.c. n.c. MAX16803 in cs- 3 10 dim tqfn top view pin configuration ordering information MAX16803 in out v5 leds r sense 0.1 f +6.5v to +40v +5v reg cs+ 0.1 f cs- dim pwm dimming gnd en simplified diagram 19-0532; rev 1; 4/09 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. +denotes a lead(pb)-free/rohs-compliant package. * ep = exposed pad. /v denotes an automotive qualified part. part temp range pin-package MAX16803ate+ -40? to +125? 16 tqfn-ep* MAX16803ate/v+ -40? to +125? 16 tqfn-ep* evaluation kit available
MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = v en = +12v, c v5 = 0.1? to gnd, i v5 = 0, v cs- = 0v, v dim = +4v, connect r sense = 0.58 ? between cs+ and cs- (note 1). t j = -40? to +125?, unless otherwise noted. typical values are at t a = +25?.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. in, out, dim, and en to gnd ...............................-0.3v to +45v cs+, cs-, v5 to gnd ...............................................-0.3v to +6v out short circuited to gnd duration (at v in = +16v) ........................................................60 minutes maximum current into any pin (except in and out).........?0ma continuous power dissipation (t a = +70?) 16-pin tqfn (derate 33.3mw/ c above +70 c) ......2666.7mw operating junction temperature range ...........-40? to +125? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? parameter symbol conditions min typ max units supply voltage range v in (note 2) 6.5 40.0 v ground current i g i load = 350ma 1.4 3 ma shutdown supply current i shdn v en 0.6v 12 40 ? guaranteed output current i out r sense = 0.55 ? 350 ma output current accuracy 35ma < i out < 350ma ?.5 % i out = 350ma (current pulsed), 12v < v in < 40v 0.5 1.2 dropout voltage (note 3) ? vdo i out = 350ma (current pulsed), 6.5v < v in < 12v 0.5 1.5 v current rising, dim rising to 4v 17 output current slew rate current falling, dim falling to 0.6v 17 ma/? short-circuit current v out = 0v, v in = 12v 400 600 800 ma logic input en input current i en 100 na en input voltage high v ih 2.8 v en input voltage low v il 0.6 v turn?n time t on en rising edge to 90% of out 80 ? current sense (note 4) regulated r sense voltage v rsns v sense = v cs+ - v cs- 196 203 210 mv cs- voltage range -0.3 +4.1 v input current (cs+) v cs+ = 220mv +14 ? input current (cs-) v cs+ = 220mv -84 ? dim input current 1a dim input voltage high v ih 4v dim input voltage low v il 0.6 v turn-on time t on after dim rising to 4v (note 5) 52 ? turn-off time t off after dim falling to 0.6v (note 5) 38 ?
MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator _______________________________________________________________________________________ 3 note 1: all devices 100% production tested at t a = +25?. limits over the operating temperature range are guaranteed by design. note 2: resistors were added from out to cs+ to aid with the power dissipation during testing. note 3: dropout is measured as follows: connect r o = 27 ? from out to cs+. connect r sense = 0.58 ? from cs+ to cs-. set v in = +12v (record v out as v out1 ). reduce v in until v out = 0.97 x v out1 (record as v in2 and v out2 ). ? v do = v in2 - v out2 . note 4: i v5 = 0ma. note 5: t on time includes the delay and the rise time needed for i out to reach 90% of its final value. t off time is the time needed for i out to drop below 10%. see the typical operating characteristics . t on and t off are tested with 13 ? from out to cst. note 6: current regulation varies with v5 load (see the typical operating characteristics ). note 7: thermal shutdown does not function if the output of the 5v reference is shorted to ground. electrical characteristics (continued) (v in = v en = +12v, c v5 = 0.1? to gnd, i v5 = 0, v cs- = 0v, v dim = +4v, connect r sense = 0.58 ? between cs+ and cs- (note 1). t j = -40? to +125?, unless otherwise noted. typical values are at t a = +25?.) (note 1) parameter symbol conditions min typ max units thermal overload thermal-shutdown temperature +155 ? thermal-shutdown hysteresis 23 ? +5v regulator output voltage regulation v5 (note 6) 5.0 5.27 5.5 v v5 short-circuit current v5 = 0v (note 7) 16 ma typical operating characteristics (v in = v en = +12v, t a = +25?, unless otherwise noted.) output current vs. temperature MAX16803 toc01 temperature ( c) output current (ma) 110 95 65 80 -10 5 20 35 50 -25 50 100 150 200 250 300 350 400 450 0 -40 125 i load = 350ma i load = 35ma i load = 200ma i load = 100ma (v cs+ - v cs- ) vs. output current MAX16803 toc02 output current (ma) (v cs+ - v cs- ) (v) 320 290 230 260 80 110 140 170 200 50 0.201 0.202 0.203 0.204 0.205 0.206 0.207 0.208 0.209 0.210 0.200 20 350 v in = 12v output current vs. input voltage MAX16803 toc03 input voltage (v) output current (ma) 35 30 5 10 15 20 25 50 100 150 200 250 300 350 400 0 040
MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator 4 _______________________________________________________________________________________ typical operating characteristics (continued) (v in = v en = +12v, t a = +25?, unless otherwise noted.) dropout voltage vs. temperature MAX16803 toc04 temperature ( c) dropout voltage (v) 110 95 65 80 -10 5 20 35 50 -25 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 -40 125 i load = 350ma shutdown current vs. temperature MAX16803 toc05 temperature ( c) shutdown current ( a) 110 95 80 65 50 35 20 5 -10 -25 5 10 15 20 25 30 35 0 -40 125 v in = 40v v in = 20v v in = 12v v in = 6.5v +5v regulator output vs. temperature MAX16803 toc06 temperature ( c) 5v regulator output (v) 110 95 80 65 50 35 20 5 -10 -25 5.1 5.2 5.3 5.4 5.5 5.0 -40 125 i load = 1ma no load i load = 5ma (v cs+ - v cs- ) vs. i v5 MAX16803 toc07 i v5 (ma) (v cs+ - v cs- ) (v) 7 6 4 5 2 3 1 0.199 0.200 0.201 0.202 0.203 0.204 0.205 0.206 0.207 0.208 0.209 0.210 0.198 08 i load = 410ma +5v regulator output vs. v in MAX16803 toc08 v in (v) 5v regulator output (v) 35 30 25 20 15 10 5.15 5.20 5.25 5.30 5.10 540 load = 1ma no load load = 5ma 200hz dimmed operation MAX16803 toc09 20 s/div v dim 2v/div i load 200ma/div 0a i load = 350ma v in = v en = 12v dim pulsed at 200hz (1% duty cycle) 0v 200hz dimmed operation (expanded) MAX16803 toc10 20 s/div v dim 2v/div i load 200ma/div 0a i load = 350ma v in = v en = 12v dim pulsed at 200hz (50% duty cycle) 0v 200hz dimmed operation (expanded) MAX16803 toc11 20 s/div v dim 2v/div i load 200ma/div 0a i load = 350ma v in = v en = 12v dim pulsed at 200hz (50% duty cycle) 0v
MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator _______________________________________________________________________________________ 5 i dim vs. v dim MAX16803 toc13 v dim (v) i dim ( a) 14 12 10 8 6 4 2 50 100 150 200 250 300 0 016 v snse vs. v cs- MAX16803 toc12 v cs- (v) v snse (mv) 4.5 4.0 3.5 3.0 2.5 201 202 203 204 205 200 2.0 5.0 v in = 12v i load = 350ma typical operating characteristics (continued) (v in = v en = +12v, t a = +25?, unless otherwise noted.) pin description pin name function 1, 16 out current-regulated output. connect pin 1 to pin 16. 2, 3 in positive input supply. bypass in with a 0.1? (min) capacitor to gnd. connect pin 2 to pin 3. 4?, 14 n.c. not internally connected 9 cs+ positive input of the internal differential amplifier. connect the current-sense resistor between cs+ and cs- to program the output current level. 10 cs- negative input of the internal differential amplifier. connect the current-sense resistor between cs- and cs+ to program the output current level. 11 v5 +5v regulated output. connect a 0.1? capacitor from v5 to gnd. 12 gnd ground 13 dim pulsed dimming input. drive dim low to disable the output. drive dim high to enable the output. must not be left unconnected. 15 en enable input. drive en high to enable the output. ?p exposed pad. connect to the ground plane for effective power dissipation. do not use as the only ground connection.
MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator 6 _______________________________________________________________________________________ functional diagram MAX16803 enable en reference generator regulator in v5 differential sense amplifier thermal shutdown dim i_ reg in out cs+ cs- detailed description the MAX16803 is a high-current regulator capable of providing up to a total of 350ma of current to one or more strings of hb leds. a wide operating input volt- age range of +6.5v to +40v makes the MAX16803 ideal for automotive applications. a +5v regulated out- put provides up to 4ma of current to power external cir- cuitry. in addition, the MAX16803 features thermal and output short-circuit protection. the wide operating volt- age range helps protect the MAX16803 against large transients such as those found in load-dump situations up to 40v. the MAX16803 uses a feedback loop to control the out- put current. the differential voltage across the sense resistor is compared to a fixed reference voltage, and the error is amplified to serve as the drive to the internal power series pass device (see the functional diagram ). the regulation point is factory-set at (v cs+ - v cs- ) = 203mv ?.5%. the regulated current is user defined by the value of r sense . the MAX16803 is a current controller internally opti- mized for driving the impedance range expected from one or more hb leds. +5v regulator the MAX16803 includes a fixed +5v output regulator that delivers up to 4ma of load current throughout the +6.5v to +40v input voltage range. connect a 0.1? compensation capacitor from v5 to ground. shorting v5 to ground disables the thermal shutdown. when en is low, v5 is off. v5 stays on during pwm dimming. thermal protection the MAX16803 enters a thermal-shutdown mode in the event of overheating. this typically occurs in overload or output short-circuit conditions. if the junction tempera- ture exceeds t j = +155? (typ), the internal thermal-pro- tection circuitry turns off the series pass device. the MAX16803 recovers from thermal-shutdown mode once the junction temperature drops by 23? (typ). the part therefore protects itself by thermally cycling in the event of a short-circuit or overload condition. applications information programming the led current the MAX16803 uses a sense resistor across cs+ and cs- to set the led current. the differential sense ampli- fier connected across r sense provides ground-loop immunity and low-frequency noise rejection. the led current is given by i led = v sense / r sense
MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator _______________________________________________________________________________________ 7 input-voltage considerations for proper operation, the minimum input voltage must always be: v in(min) v rsense(max) + v ft(max) + ? v do(max) where v ft(max) is the total forward voltage of all series connected leds. the minimum operating voltage of the device is +6.5v. the device operates below +6.5v; how- ever, output current may not meet the full regulation specification (see the typical operating characteristics ). low-frequency pwm dimming at the output the MAX16803 provides pulsed or chopped current dimming input (dim). the other method is to connect dim to v5 and en to in and pulse en. both methods generate a regulated-amplitude pwm current (variable duty cycle) that can provide control over the led brightness (see figures 1 and 2). paralleling multiple MAX16803s to drive one high-power led for applications that require more than 350ma of led current, two or more MAX16803s can be paralleled (see figure 3). v cs - should not exceed 4.1v. 3 4 2 1 10 9 11 12 56 in 8 16 15 13 in c1 v in n.c. gnd v5 cs- c2 d1 r sense cs+ MAX16803 7 n.c. n.c. n.c. n.c. out en dim n.c. 14 out v dim i led figure 1. dimming with en connected to v in at a constant voltage and dim pulsed 3 4 2 1 10 9 11 12 56 in 8 16 15 13 in c1 v in n.c. gnd v5 cs- c2 d1 r sense cs+ MAX16803 7 n.c. n.c. n.c. n.c. out en dim n.c. 14 out i led figure 2. dimming with dim connected to v5, en connected to v in MAX16803 in out v5 v5 c1 cs+ c2 r1 cs- gnd en dim v5 leds MAX16803 in out v5 v5 c3 cs+ c4 r2 cs- gnd en dim figure 3. paralleling MAX16803s
MAX16803 two brightness levels for tail/stop lights figure 4 shows pwm dimming operation for the MAX16803 with an icm7555 timer. the icm7555 pro- vides adjustable duty cycle using two external resistors and a capacitor. in tail operation, the output of the icm7555 feeds into dim and lights up the leds. the led? brightness depends on the duty cycle of the icm7555. when v stop is present, dim is pulled up to v stop . the pwm dimming operation is disabled and the leds light up to full brightness. see the icm7555 data sheet for formulas to calculate the dimming fre- quency and the duty cycle. led current thermal foldback with a minimum number of external components, the MAX16803 provides led current thermal foldback using a negative temperature coefficient (ntc) thermis- tor. figure 5 shows a thermistor connected to v5 and the cs+ of the MAX16803. as the temperature increas- es, the voltage drop across r2 increases causing the led current to decrease. i led = [v sense - [r2 / (r2 + rt)] x v5] / r1 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator 8 _______________________________________________________________________________________ in en dim cs- cs+ out gnd gnd out trg dis in r2 icm7555 c1 d2 tail stop v5 r sense th MAX16803 c2 +5v reg d1 d4 d3 r1 leds r3 c3 figure 4. pwm dimming operation with icm7555 timer in en dim cs- cs+ out gnd r1 leds c1 v in v5 r2 rt pwm dimming MAX16803 c2 figure 5. led current thermal foldback with an ntc thermistor
other applications the application circuit in figure 6 implements a two- level brightness current for tail/stop lights. in tail operation, q1 is off and the r1 sets the output current. in stop operation, q1 turns on and the output current is set by a parallel combination of r1 and r2. figure 7 shows an application circuit with the MAX16803 using a single bjt to provide high output current. for proper operation: v in(min) > v cesat(max) + v ft(max) + v rsense where v cesat(max) is the maximum saturation voltage of the external bjt. MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator _______________________________________________________________________________________ 9 in en v5 dim cs- cs+ out gnd r2 c1 tail stop v5 r1 MAX16803 c2 leds q1 figure 6. two brightness level with current level switch for tail/stop lights in en dim cs- cs+ out gnd r sense leds q1 c1 v in v5 pwm dimming MAX16803 c2 figure 7. increased led current (amper range) with a single bjt
MAX16803 multichannel hb led driver figure 8 shows an array of MAX16803s with independent dim control. the max5094c, a current-mode pwm con- troller, provides the input power to each led driver pre- regulated voltage to multiple MAX16803 drivers. high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator 10 ______________________________________________________________________________________ chip information process: bicmos 3 4 2 1 10 9 11 12 56 in 8 16 15 13 in c1 v in n.c. gnd v5 cs- c2 d1 r sense cs+ MAX16803 7 n.c. n.c. n.c. n.c. out en dim n.c. 14 out v dim typical operating circuit ref c3 r3 c6 r4 c4 l1 comp fb cs gnd v cc v in c t /r t ct out max5094c MAX16803 u2 c ref c2 d1 c comp r comp in en dim r2 cs- cs+ out gnd v5 r5 c7 leds q1 c10 MAX16803 u4 in en dim cs- cs+ out gnd v5 r7 c11 leds c8 MAX16803 u3 in en dim cs- cs+ out gnd v5 r6 c9 leds figure 8. multichannel hb led driver for lcd backlight package information for the latest package outline information and land patterns, go to www.maxim-ic.com/packages . package type package code document no. 16 tqfn-ep t1655-3 21-0140
MAX16803 high-voltage, 350ma, high-brightness led driver with pwm dimming and 5v regulator heaney maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 11 2009 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 0 5/06 initial release 1 4/09 updated ordering information table and added package information table. 1, 10

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