general description the MAX16800 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. the output current of the MAX16800 is adjusted by using an external current-sense resistor in series with the leds. an enable input allows wide-range ?ulsed dimming. wave-shaping circuitry reduces emi. the dif- ferential current-sense input increases noise immunity. the MAX16800 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 ele- ment minimizes external components while providing ?.5% output current accuracy. additional features include a 5v regulated output and short-circuit and thermal protection. the MAX16800 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: tail lights and chmsl warning lights for emergency vehicles navigation and marine indicators general illumination signage, gasoline canopies, beacons features ? +6.5v to +40v operating range ? adjustable level (35ma to 350ma) ? 3.5% output current accuracy ? integrated pass element with low-dropout voltage (0.5v typ) ? output short-circuit protection ? +5v regulated output with 4ma source capability ? thermal shutdown ? differential led current sense ? high-voltage enable pin for dimming interface ? low shutdown supply current (12a typ) ? low 204mv current-sense reference reduces power losses ? wave-shaped soft edges reduce radiated emi during pwm dimming ? available in small, thermally enhanced, 5mm x 5mm, 16-pin tqfn package ? -40c to +125c operating temperature range MAX16800 high-voltage, 350ma, adjustable linear high-brightness led (hb led) driver ________________________________________________________________ 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. MAX16800 in cs- 3 10 n.c. tqfn top view pin configuration ordering information MAX16800 in out v5 leds r sense 0.1 f +6.5v to +40v +5v reg cs+ 0.1 f cs- en pwm dimming gnd simplified diagram 19-3803; 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 paddle. /v denotes an automotive qualified part. part temp range pin-package MAX16800ate+ -40c to +125c 16 tqfn-ep* MAX16800ate/v+ -40c to +125c 16 tqfn-ep*
MAX16800 high-voltage, 350ma, adjustable linear high-brightness led (hb led) driver 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = +12v, en = v in , c v5 = 0.1? to gnd, i v5 = 0, cs- = gnd, connect r sense = 0.58 between cs+ and cs-. connect out to cs+ (note 1). t j = -40? to +125?, unless otherwise noted. typical values are at t a = +25?.) (note 2) 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, and en to gnd........................................-0.3v to +45v cs+, v5 to gnd .......................................................-0.3v to +6v cs- to gnd............................................................-0.3v to +0.3v out short circuited to gnd duration (at v in = +16v) ........................................................60 minutes maximum current into any pin (except v in and out) .......?0ma continuous power dissipation (t a = +70?) 16-pin tqfn 5mm x 5mm (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 1) 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 a guaranteed output current i out r sense = 0.55 350 ma output current accuracy 35ma < i out < 350ma 3.5 % i out = 350ma (current pulsed), 12v < v in < 40v 0.5 1.2 v dropout voltage (note 3) vdo i out = 350ma (current pulsed), 6.5v < v in < 40v 0.5 1.5 v current rising 5.4 output current slew rate current falling 90 ma/s 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 turnCon time t on en rising edge to 90% of out 135 350 s current sense (note 4) regulated r sense voltage v rsns v sense = v cs+ - v cs- 197 204 211 mv input current (cs+) v cs+ = 220mv -14 a input current (cs-) v cs+ = 220mv +84 a
MAX16800 high-voltage, 350ma, adjustable linear high-brightness led (hb led) driver _______________________________________________________________________________________ 3 note 1: resistors were added from out to cs+ to aid with the power dissipation during testing. note 2: all devices 100% production tested at t a = +25?. limits over the operating temperature range are guaranteed by design. 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: current regulation varies with v5 load (see the typical operating characteristics ). note 6: thermal shutdown does not function if the output of the 5v reference is shorted to ground. electrical characteristics (continued) (v in = +12v, en = v in , c v5 = 0.1? to gnd, i v5 = 0, cs- = gnd, connect r sense = 0.58 between cs+ and cs-. connect out to cs+ (note 1). t j = -40? to +125?, unless otherwise noted. typical values are at t a = +25?.) (note 2) parameter symbol conditions min typ max units thermal overload thermal-shutdown temperature +155 c thermal-shutdown hysteresis 23 c +5v regulator output voltage regulation v5 5.0 5.27 5.5 v output voltage change v5 0 < i load < 4ma (note 5) 15 60 v5 short-circuit current v5 = 0v (note 6) 30 ma typical operating characteristics (v in = v en = +12v, t a = +25?, unless otherwise noted.) output current vs. temperature MAX16800 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 MAX16800 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 MAX16800 toc03 input voltage (v) output current (ma) 35 30 5 10 15 20 25 50 100 150 200 250 300 350 400 0 040
MAX16800 high-voltage, 350ma, adjustable linear high-brightness led (hb led) driver 4 _______________________________________________________________________________________ typical operating characteristics (continued) (v in = v en = +12v, t a = +25?, unless otherwise noted.) dropout voltage vs. temperature MAX16800 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 MAX16800 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 MAX16800 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 MAX16800 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 MAX16800 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 MAX16800 toc09 1ms/div v in 5v/div 0v i load 200ma/div i load = 350ma, v in = v en , v in pulsed at 200hz (50% duty cycle) 200hz dimmed operation expanded MAX16800 toc10 20 s/div v in 5v/div 0v 0 i load 100ma/div i load = 350ma, v in = v en , v in pulsed at 200hz (50% duty cycle) 200hz dimmed operation expanded MAX16800 toc11 4 s/div v in 5v/div 0v 0 i led 100ma/div i load = 350ma, v in = v en , v in pulsed at 200hz (50% duty cycle) 200hz dimmed operation MAX16800 toc12 1ms/div en 10v/div 0v 0 i led 100ma/div i load = 350ma, v in = 12v, en pulsed at 200hz (50% duty cycle)
MAX16800 high-voltage, 350ma, adjustable linear high-brightness led (hb led) driver _______________________________________________________________________________________ 5 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?, 13, 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 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. functional diagram MAX16800 enable en reference generator regulator in v5 differential sense amplifier thermal shutdown i_ req in out cs+ cs- detailed description the MAX16800 is a high-current regulator capable of providing up to a total of 350ma of current to one or more strings of high-brightness leds. a wide operating input voltage range of +6.5v to +40v makes the MAX16800 ideal for automotive applications. a +5v regulated output provides up to 4ma of current to power external circuitry. in addition, the MAX16800 fea- tures thermal and output short-circuit protection. the wide operating voltage range helps protect the MAX16800 against large transients such as those found in load-dump situations up to 40v. the MAX16800 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
MAX16800 high-voltage, 350ma, adjustable linear high-brightness led (hb led) driver 6 _______________________________________________________________________________________ power series pass device (see the functional diagram ). the regulation point is factory set at (v cs+ - v cs- ) = 204mv ?.5%. the regulated current is user defined by the value of r sense . the MAX16800 is a current controller internally opti- mized for driving the impedance range expected from one or more hb leds. +5v regulator the MAX16800 includes a fixed +5v output regulator that delivers up to 4ma of load current for low-power applications throughout the +6.5v to +40v input volt- age range. connect a 0.1? compensation capacitor from v5 to ground. shorting v5 to ground disables the thermal shutdown. thermal protection the MAX16800 enters a thermal-shutdown mode in the event of overheating. this typically occurs in overload or output short-circuit conditions. when the junction tem- perature exceeds t j = +155? (typ), the internal ther- mal-protection circuitry turns off the series pass device. the MAX16800 recovers from thermal-shutdown mode once the junction temperature drops by 23? (typ). the part will therefore protect itself by thermally cycling in the event of a short-circuit or overload condition. applications information programming the led current the MAX16800 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 the equation below: i led = v sense / r sense input voltage considerations for proper operation, the minimum input voltage must always be +1.2v (+1.5v for v in <+12v) higher than the worst-case sum of all the forward drops of all series- connected leds to the output of the MAX16800. the minimum operating voltage of the device is +6.5v. the device will operate below +6.5v; however, output cur- rent may not meet the full regulation specification (see the typical operating characteristics ). low-frequency pwm at the output the MAX16800 provides pulsed or chopped current dimming. generally, high-brightness leds are binned to match at their full-rated current; however, leds from the same bin exhibit poor matching at currents other than full-rated current. to achieve uniformity, hb led manufacturers recommend pwm pulsing of the led current at their full-rated value. there are two methods for producing a pwm output. one method is by pulsing the enable input (en) while having a constant voltage at in. the other method is to connect en to in and pulse both en and in. both methods generate a regu- lated-amplitude pwm current (variable duty cycle) that can provide control over the led brightness (see figures 1 and 2). 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+ MAX16800 7 n.c. n.c. n.c. n.c. out en n.c. n.c. 14 out v en i led figure 1. pulse application with v in at a constant voltage 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+ MAX16800 7 n.c. n.c. n.c. n.c. out en n.c. n.c. 14 out i led figure 2. pulse application with en connected to v in
MAX16800 high-voltage, 350ma, adjustable linear high-brightness led (hb led) driver _______________________________________________________________________________________ 7 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+ MAX16800 7 n.c. n.c. n.c. n.c. out en n.c. n.c. 14 out typical operating circuit 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
MAX16800 high-voltage, 350ma, adjustable linear high-brightness led (hb led) driver 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. 8 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2009 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 0 8/05 initial release 1 4/09 updated data sheet with automotive part. 1, 8
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