View MAX16810ATU_8378920.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

general description the max16809/max16810 are integrated, high-efficien- cy white or rgb led drivers. they are designed for lcd backlighting and other led lighting applications with multiple strings of leds. the max16809/ max16810? current-mode pwm controller regulates the necessary voltage to the led array. depending on the input voltage and led voltage range, it can be used with boost or buck-boost (sepic) topologies. the max16809/max16810 led drivers include 16 open-drain, constant-current-sinking led driver outputs rated for 36v continuous operation. the led current- control circuitry achieves ?% current matching among strings and enables paralleling of outputs for led string currents higher than 55ma. the output-enable pin is used for simultaneous pwm dimming of all output chan- nels. dimming frequency range is 50hz to 30khz and dimming ratio is up to 5000:1. the constant-current out- puts are single resistor programmable and the led cur- rent can be adjusted up to 55ma per output channel. the max16809/max16810 operate either in stand-alone mode or with a microcontroller (?) using an industry- standard, 4-wire serial interface. the max16810 includes a watchdog and circuitry that automatically detects open-circuit leds. the max16809/max16810 include overtemperature pro- tection, operate over the full -40? to +125? temperature range, and are available in a 5mm x 7mm thermally enhanced, 38-pin tqfn exposed paddle package. features ? 16 constant-current output channels (up to 55ma each) ? ?% current matching among outputs ? paralleling channels allows higher current per led string ? outputs rated for 36v continuous voltage ? output-enable pin for pwm dimming (up to 30khz) ? one resistor sets led current for all channels ? wide dimming ratio up to 5000:1 ? low current-sense reference (300mv) for high efficiency ? 8v to 26.5v input voltage or higher with external biasing devices ? open led detection and watchdog timer (max16810) ? 4-wire serial interface to control individual output channels applications lcd white or rgb led backlighting: lcd tvs, desktop, and notebook panels automotive navigation, heads-up, and infotainment displays industrial and medical displays ambient, mood, and accent lighting max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller ________________________________________________________________ maxim integrated products 1 19-0656; rev 0; 10/06 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. pin configuration appears at end of data sheet. ordering information part temp range pin- package pkg code max16809 atu+ -40? to +125? 38 tqfn-ep** t3857-1 max16810 atu+* -40? to +125? 38 tqfn-ep** t3857-1 + denotes lead-free package. * future product?ontact factory for availability. ** ep = exposed paddle. out0 fb out1 out2 out3 out4 out5 out6 out7 set le din pgnd v cc v+ oe dout clk ref rtct c ref r set c in c byp r cs c c2 c c1 out cs agnd comp r c1 r2 r1 c out r t c t 3v to 5.5v v in v out q1 l leds stand-alone operation max16809 max16810 out8 out9 out10 out11 out12 out13 out14 out15 typical operating circuits typical operating circuits continued at end of data sheet.
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (pwm controller) (v cc = +15v, v+ = +3v to +5.5v referenced to pgnd, r t = 10k ? , c t = 3.3nf, ref = open, comp = open, c ref = 0.1?, v fb = 2v, cs = agnd, agnd = pgnd = 0v; all voltages are measured with respect to agnd, unless otherwise noted. t j = t a = -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. v cc to agnd..........................................................-0.3v to +30v current into v cc (v cc > 24v) .............................................30ma v+ to pgnd..............................................................-0.3v to +6v out to agnd.............................................-0.3v to (v cc + 0.3v) out current (10? duration) .................................................?a fb, comp, cs, rtct, ref to agnd.......................-0.3v to +6v comp sink current.............................................................10ma out0?ut15 to pgnd..........................................-0.3v to +40v din, clk, le, oe , set to pgnd..................-0.3v to (v+ + 0.3v) dout current...................................................................?0ma out0?ut15 sink current.................................................60ma total pgnd current (1s pulse time) .................................960ma continuous power dissipation (t a = +70?) 38-pin tqfn (derate 35.7mw/?* above +70?) ......2857mw operating temperature range .........................-40? to +125? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? * per jedec51 standard (multilayer board). parameter symbol conditions min typ max units reference output voltage v ref i ref = 1ma, t j = +25? 4.95 5 5.05 v line regulation ? v line 12v< v cc < 25v, i ref = 1ma 0.4 4 mv load regulation ? v load 1ma < i ref < 20ma 6 50 mv total output-voltage variation v reft (note 2) 4.875 5.125 v output noise voltage v noise 10hz < f < 10khz 50 ? output short-circuit current i short v ref = 0v 30 180 ma oscillator initial accuracy t j = +25? 51 54 57 khz voltage stability 12v < v cc < 25v 0.2 0.5 % temperature stability 1% rtct ramp peak-to-peak 1.7 v rtct ramp valley 1.1 v v rtct = 2v, t j = +25? 7.9 8.3 8.7 discharge current i dis v rtct = 2v, -40 o c t j +125? 7.5 8.3 9.0 ma frequency range f osc 20 1000 khz error amplifier fb input voltage v fb fb shorted to comp 2.45 2.5 2.55 v input bias current i b(fb) -0.01 -0.1 a open-loop gain a vol 2v v comp 4v 100 db unity-gain bandwidth f gbw 1 mhz power-supply rejection ratio psrr 12v v cc 25v 60 80 db comp sink current i sink v fb = 2.7v, v comp = 1.1v 2 6 ma comp source current i source v fb = 2.3v, v comp = 5v 0.5 1.2 1.8 ma comp output-voltage high v oh v fb = 2.3v, r comp = 15k ? to agnd 5 5.8 v comp output-voltage low v ol v fb = 2.7v, r comp = 15k ? to v ref 0.1 1.1 v
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller _______________________________________________________________________________________ 3 electrical characteristics (pwm controller) (continued) (v cc = +15v, v+ = +3v to +5.5v referenced to pgnd, r t = 10k ? , c t = 3.3nf, ref = open, comp = open, c ref = 0.1?, v fb = 2v, cs = agnd, agnd = pgnd = 0v; all voltages are measured with respect to agnd, unless otherwise noted. t j = t a = -40? to +125?, unless otherwise noted. typical values are at t a = +25?.) (note 1) parameter symbol conditions min typ max units current-sense amplifier current-sense gain a cs (notes 3, 4) 2.85 3 3.40 v/v maximum current-sense signal v cs_max (note 3) 0.275 0.300 0.325 v power-supply rejection ratio psrr 12v v cc 25v 70 db current-sense input bias current i cs v comp = 0v -1 -2.5 ? current sense to out delay t pwm 50mv overdrive 60 ns mosfet driver t j = -40? to +85? (note 2) 4.5 10 out low-side on-resistance v rds_onl i sink = 200ma t j = -40? to +125? 4.5 12 ? t j = -40? to +85? (note 2) 3.5 7.5 out high-side on-resistance v rds_onh i source = 100ma t j = -40? to +125? 3.5 10 ? source current (peak) i source c load = 10nf 2 a sink current (peak) i sink c load = 10nf 1 a rise time t r c load = 1nf 15 ns fall time t f c load = 1nf 22 ns undervoltage lockout/startup startup voltage threshold v cc_start 7.98 8.4 8.82 v minimum operating voltage after turn-on v cc_min 7.1 7.6 8.0 v undervoltage-lockout hysteresis uvlo hyst 0.8 v pulse-width modulation (pwm) maximum duty cycle d max 94.5 96 97.5 % minimum duty cycle d min 0% supply current startup supply current i start v cc = 7.5v 32 65 ? operating supply current i cc v fb = v cs = 0v 3 5 ma v cc zener voltage v z i cc = 25ma 24 26.5 v
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 4 _______________________________________________________________________________________ electrical characteristics (led driver) (v+ = +3v to +5.5v, agnd = pgnd = 0v; all voltages are measured with respect to pgnd, unless otherwise noted. t a = t j = -40? to +125?, unless otherwise noted. typical values are at t a = +25?.) (note 1) parameter symbol conditions min typ max units operating supply voltage v+ 3.0 5.5 v output voltage v out _ _ 36 v standby current (interface idle, all output ports high impedance) r set = 360 ? , din, le, clk = pgnd or v+, oe = v+, dout unconnected 3.6 4.5 ma standby current (interface active, all output ports high impedance) r set = 360 ? , f clk = 5mhz, oe = v+, din, le = pgnd or v+, dout unconnected 3.8 4.8 ma supply current (interface idle, all output ports active low) i+ r set = 360 ? , oe = pgnd, din, le = v+, dout unconnected 30 52.5 ma interface (din, clk, dout, le, oe ) input-voltage high (din, clk, le, oe ) v ih 0.7 x v+ v input-voltage low (din, clk, le, oe ) v il 0.3 x v+ v hysteresis voltage (din, clk, le, oe ) v hyst 0.8 v input leakage current (din, clk) i leak -1 +1 ? oe pullup current to v+ i oe v+ = 5.5v, oe = pgnd 0.25 1.5 25 ? le pulldown current to pgnd i le v+ = 5.5v, le = v+ 0.25 1.5 25 ? output-voltage high (dout) v oh i source = 4ma v+ - 0.5v v output-voltage low (dout) v ol i sink = 4ma 0.5 v 0? t a +125?, v out = 1v to 2.5v, r set = 360 ? 43.25 47.5 51.75 out_ _ output current i out_ _ t a = -40?, v out = 1v to 2.5v, r set = 360 ? 40 55 ma out_ _ leakage current oe = v+ 1 a out_ _ fault detection threshold (max16810) v outth v+ = 5.5v, oe = v+ 0.8 v watchdog timeout period (max16810) t wd v+ = 5.5v 0.1 1 2.5 s
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller _______________________________________________________________________________________ 5 5v timing characteristics (v+ = +4.5v to +5.5v, agnd = pgnd = 0v; all voltages are measured with respect to pgnd, unless otherwise noted. t a = t j = -40? to +125?, unless otherwise noted. typical values are at t a = +25?.) (notes 1, 5) parameter symbol condition min typ max units interface timing characteristics clk clock period t cp 40 ns clk pulse-width high t ch 19 ns clk pulse-width low t cl 19 ns din setup time t ds 4ns din hold time t dh 8ns dout propagation delay t do 10 50 ns dout rise time t dr c dout = 10pf, 20% to 80% 10 ns dout fall time t df c dout = 10pf, 80% to 20% 10 ns le pulse-width high t lw 20 ns le setup time t ls 15 ns le rising to out_ _ rising delay t lrr (note 6) 110 ns le rising to out_ _ falling delay t lrf (note 6) 340 ns clk rising to out_ _ rising delay t crr (note 6) 110 ns clk rising to out_ _ falling delay t crf (note 6) 340 ns oe rising to out_ _ rising delay t oe r (note 6) 110 ns oe falling to out_ _ falling delay t oe f (note 6) 340 ns out_ _ turn-on fall time t f 80% to 20% (note 6) 210 ns out_ _ turn-off rise time t r 20% to 80% (note 6) 130 ns
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 6 _______________________________________________________________________________________ 3.3v timing characteristics (v+ = +3v to < +4.5v, agnd = pgnd = 0v; all voltages are measured with respect to pgnd, unless otherwise noted. t a = t j = -40? to +125?, unless otherwise noted. typical values are at t a = +25?.) (notes 1, 5) parameters symbol conditions min typ max units interface timing characteristics clk clock period t cp 52 ns clk pulse-width high t ch 24 ns clk pulse-width low t cl 24 ns din setup time t ds 4ns din hold time t dh 8ns dout propagation delay t do 12 70 ns dout rise time t dr c dout = 10pf, 20% to 80% 12 ns dout fall time t df c dout = 10pf, 80% to 20% 12 ns le pulse-width high t lw 20 ns le setup time t ls 15 ns le rising to out_ _ rising delay t lrr (note 6) 140 ns le rising to out_ _ falling delay t lrf (note 6) 400 ns clk rising to out_ _ rising delay t crr (note 6) 140 ns clk rising to out_ _ falling delay t crf (note 6) 400 ns oe rising to out_ _ rising delay t oe r (note 6) 140 ns oe falling to out_ _ falling delay t oe f (note 6) 400 ns out_ _ turn-on fall time t f 80% to 20% (note 6) 275 ns out_ _ turn-off rise time t r 20% to 80% (note 6) 150 ns note 1: all devices are 100% production tested at t j = +25? and +125?. limits to -40? are guaranteed by design. note 2: guaranteed by design, not production tested. note 3: parameter is measured at trip point of latch with v fb = 0v. note 4: gain is defined as a = ? v comp / ? v cs , 0.05v v cs 0.25v. note 5: see figures 3 and 4. note 6: a 65 ? pullup resistor is connected from out_ _ to 5.5v. rising refers to v out_ _ when current through out_ _ is turned off and falling refers to v out_ _ when current through out_ _ is turned on.
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller _______________________________________________________________________________________ 7 bootstrap uvlo vs. temperature max16809 toc01 temperature ( c) v cc (v) 110 95 65 80 -10 5 20 35 50 -25 0 1 2 3 4 5 6 7 8 9 10 -40 125 v cc rising v cc falling hysteresis 25 27 39 31 29 33 35 37 41 -40 -10 5 20 -25 35 50 95 80 110 65 125 startup current vs. temperature max16809 toc02 temperature ( c ) i cc ( a) v cc = 7.5v 3.5 3.7 4.9 4.1 3.9 4.3 4.5 4.7 5.1 operating supply current vs. temperature after startup (f osc = f sw = 300khz) max16809 toc03 i cc (ma) -40 -10 5 20 -25 35 50 95 80 110 65 125 temperature ( c ) c t = 560pf 4.90 4.94 4.92 5.00 4.98 4.96 5.02 5.04 5.06 5.08 reference voltage vs. temperature max16809 toc04 v ref (v) -40 -10 5 20 -25 35 50 95 80 110 65 125 temperature ( c) i ref = 1ma i ref = 20ma 4.65 4.75 4.70 4.85 4.80 5.00 4.95 4.90 5.05 020 10 30 40 50 60 70 reference voltage vs. reference load current max16809 toc05 i ref (ma) v ref (v) 4.980 4.984 4.982 4.988 4.986 4.992 4.990 4.994 4.998 4.996 5.000 10 14 16 12 18 20 22 24 26 reference voltage vs. supply voltage max16809 toc06 v cc (v) v ref (v) i ref = 1ma 450 470 460 500 490 480 510 520 540 530 550 -40 -10 5 -25 203550658095110125 oscillator frequency (f osc ) vs. temperature max16809 toc07 temperature ( c) oscillator frequency (khz) r t = 3.65k ? c t = 560pf 7.88 7.90 8.02 7.94 7.92 7.96 7.98 8.00 8.04 -40 -10 5 20 -25 35 50 95 80 110 65 125 oscillator r t /c t discharge current vs. temperature max16809 toc08 temperature ( c) r t /c t discharge current (ma) v rt/ct = 2v typical operating characteristics (v cc = +15v, v+ = 3v to 5.5v, r t = 10k ? , c t = 3.3nf, v ref = comp = open, c ref = 0.1?, v fb = 2v, cs = agnd = pgnd = 0v. typical values are at t a = +25?, unless otherwise noted.)
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 8 _______________________________________________________________________________________ 0.20 0.24 0.22 0.30 0.28 0.26 0.32 0.34 0.38 0.36 0.40 current-sense trip threshold vs. temperature max16809 toc09 cs threshold (v) -40 -10 5 20 -25 35 50 95 80 110 65 125 temperature ( c) timing resistance vs. oscillator frequency max16809 toc10 frequency (hz) r t (k ? ) 1m 100k 1 10 100 1000 0.1 10k 10m c t = 1nf c t = 560pf c t = 220pf c t = 100pf c t = 10nf c t = 4.7nf c t = 3.3nf c t = 2.2nf out impedance vs. temperature (r ds_on pmos driver) max16809 toc11 temperature ( c) r ds_on ( ? ) 110 95 65 80 -10 5 20 35 50 -25 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 2.0 -40 125 i source = 100ma 0 2 1 5 4 3 6 7 9 8 10 out impedance vs. temperature (r ds_on nmos driver) max16809 toc12 r ds_on ( ? ) -40 -10 5 20 -25 35 50 95 80 110 65 125 temperature ( c) i sink = 200ma 0 20 10 50 40 30 60 70 90 80 100 propagation delay from current-limit comparator to out vs. temperature max16809 toc13 propagation delay (ns) -40 -10 5 20 -25 35 50 95 80 110 65 125 temperature ( c) error-amplifier open-loop gain and phase vs. frequency max16809 toc14 frequency (hz) gain (db) 1m 100k 1k 10k 10 100 1 0 20 40 60 80 100 120 140 -20 0.01 100m 10m -165 -140 -115 -90 -65 -40 -15 10 -190 phase gain phase (degrees) 1.5 1.6 2.2 1.8 1.7 1.9 2.0 2.1 2.3 -40 -10 5 20 -25 35 50 95 80 110 65 125 comp voltage level to turn off device vs. temperature max16809 toc15 temperature ( c) v comp (v) v cc = 15v 2.0 3.0 2.5 4.0 3.5 5.0 4.5 5.5 6.5 6.0 7.0 20 220 320 420 120 520 620 720 920 820 1020 supply current vs. oscillator frequency max16809 toc16 frequency (khz) i cc (ma) t a = +125 c c t = 100pf t a = -40 c supply current vs. supply voltage (interface idle, all outputs off, r set = 720 ? ) max16809 toc17 supply voltage (v) supply current (ma) 5.0 4.5 4.0 3.5 1.85 1.90 1.95 2.00 1.80 3.0 5.5 t a = +125 c t a = +85 c t a = -40 c t a = +25 c typical operating characteristics (continued) (v cc = +15v, v+ = 3v to 5.5v, r t = 10k ? , c t = 3.3nf, v ref = comp = open, c ref = 0.1?, v fb = 2v, cs = agnd = pgnd = 0v. typical values are at t a = +25?, unless otherwise noted.)
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller _______________________________________________________________________________________ 9 supply current vs. supply voltage (interface idle, all outputs off, r set = 360 ? ) max16809 toc18 supply voltage (v) supply current (ma) 5.0 4.5 4.0 3.5 3.55 3.60 3.65 3.70 3.50 3.0 5.5 t a = +125 c t a = +85 c t a =-40 c t a = +25 c supply current vs. supply voltage (interface idle, all outputs on, r set = 720 ? ) max16809 toc19 supply voltage (v) supply current (ma) 5.0 4.5 4.0 3.5 20 25 30 35 40 45 t a = +125 c t a = +85 c t a = -40 c t a = +25 c 15 3.0 5.5 supply current vs. supply voltage (interface idle, all outputs on, r set = 360 ? ) max16809 toc20 supply voltage (v) supply current (ma) 5.0 4.5 4.0 3.5 20 25 30 35 40 t a = +125 c 45 15 3.0 5.5 t a = +85 c t a = -40 c t a = +25 c out_ _ current vs. out_ _ voltage (r set = 720 ? , v+ = 3.3v) max16809 toc21 out_ _ voltage (v) out_ _ current (ma) 2.5 2.0 1.5 1.0 0.5 5 10 15 20 25 30 t a = -40 c t a = +25 c t a = +85 c t a = +125 c 0 03.0 out_ _ current vs. out_ _ voltage (r set = 360 ? , v+ = 3.3v) max16809 toc22 out_ _ voltage (v) out_ _ current (ma) 2.5 2.0 1.5 1.0 0.5 10 20 30 40 50 60 t a = -40 c t a = +25 c t a = +85 c t a = +125 c 0 0 3.0 out_ _ current vs. out_ _ voltage (r set = 720 ? , v+ = 5.0v) max16809 toc23 out_ _ voltage (v) out_ _ current (ma) 2.5 2.0 1.5 1.0 0.5 5 10 15 20 25 30 t a = -40 c t a = +25 c t a = +85 c t a = +125 c 0 0 3.0 _______________________________________________________________________________________ 9 typical operating characteristics (continued) (v cc = +15v, v+ = 3v to 5.5v, r t = 10k ? , c t = 3.3nf, v ref = comp = open, c ref = 0.1?, v fb = 2v, cs = agnd = pgnd = 0v. typical values are at t a = +25?, unless otherwise noted.)
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 10 ______________________________________________________________________________________ typical operating characteristics (continued) (v cc = +15v, v+ = 3v to 5.5v, r t = 10k ? , c t = 3.3nf, v ref = comp = open, c ref = 0.1?, v fb = 2v, cs = agnd = pgnd = 0v. typical values are at t a = +25?, unless otherwise noted.) out_ _ current vs. v+ (r set = 360 ? , v out = 2v) max16809 toc26 supply voltage (v) out_ _ current (ma) 5.0 4.5 4.0 3.5 47 48 49 t a = -40 c t a = +25 c t a = +85 c t a = +125 c 46 3.0 5.5 out_ _ current vs. set resistance (v+ = 5.0v) max16809 toc27 set resistance (k ? ) out_ _ current (ma) 4 3 2 1 10 20 30 40 50 0 05 out_ _ current vs. out_ _ voltage (r set = 360 ? v+ = 5.0v) max16809 toc24 out_ _ voltage (v) out_ _ current (ma) 2.5 2.0 1.5 1.0 0.5 10 20 30 40 50 60 t a = -40 c t a = +25 c t a = +85 c t a = +125 c 0 0 3.0 out_ _ current vs. v+ (r set = 720 ? , v out = 2v) max16809 toc25 supply voltage (v) out_ _ current (ma) 5.0 4.5 4.0 3.5 23.5 24.0 24.5 25.0 t a = +125 c t a = +85 c t a = +25 c t a = -40 c 23.0 3.0 5.5
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller ______________________________________________________________________________________ 11 detailed description the max16809/max16810 led drivers include an internal switch-mode controller that can be used as boost or buck-boost (sepic) converters to generate the voltage necessary to drive the multiple strings of leds. these devices incorporate an integrated low-side dri- ver, a programmable oscillator (20khz to 1mhz), an error amplifier, a low-voltage (300mv) current sense for higher efficiency, and a 5v reference to power up external circuitry (see figures 1a, 1b, and 1c). the max16809/max16810 led drivers include a 4-wire serial interface and a current-mode pwm controller to generate the necessary voltage for driving 16 open- drain, constant-current-sinking output ports. the drivers use current-sensing feedback circuitry (not simple cur- rent mirrors) to ensure very small current variations over the full allowed range of output voltage (see the typical operating characteristics ). the 4-wire serial interface comprises a 16-bit shift register and a 16-bit transpar- ent latch. the shift register is written through a clock input, clk, and a data input, din, and the data propa- gates to a data output, dout. the data output allows multiple drivers to be cascaded and operated together. the contents of the 16-bit shift register are loaded into the transparent latch through a latch-enable input, le. the latch is transparent to the shift register outputs when high and latches the current state on the falling edge of le. each driver output is an open-drain, con- stant-current sink that should be connected to the pin description pin name function 1, 31, 32, 36, 38 n.c. no connection. not internally connected. leave unconnected. 2 fb error-amplifier inverting input 3 comp error-amplifier output 4?1 out8?ut15 led driver outputs. out8?ut15 are open-drain, constant-current-sinking outputs rated for 36v. 12 oe active-low, output enable input. drive oe low to pgnd to enable the out0?ut15. drive oe high to disable out0?ut15. 13 dout serial-data output. data is clocked out of the 16-bit internal shift register to dout on clk? rising edge. 14 set led current setting. connect r set from set to pgnd to set the led current. 15 v+ led driver positive supply voltage. bypass v+ to pgnd with a 0.1? ceramic capacitor. 16, 17 pgnd power ground 18 din serial-data input. data is loaded into the internal 16-bit shift register on clk? rising edge. 19 clk serial-clock input 20 le latch-enable input. data is loaded transparently from the internal shift register(s) to the output latch(es) while le is high. data is latched into the output latch(es) on le? falling edge, and retained while le is low. 21?8 out0?ut7 led driver outputs. out0?ut7 are open-drain, constant-current-sinking outputs rated for 36v. 29 rtct pwm controller timing resistor/capacitor connection. a resistor r t from rtct to ref and a capacitor c t from rtct to agnd set the oscillator frequency. 30 cs pwm controller current-sense input 33 agnd analog ground 34 out mosfet driver output out. connects to the gate of the external n-channel mosfet. 35 v cc power-supply input. bypass v cc to agnd with a 0.1? ceramic capacitor or a parallel combination of a 0.1? and a higher value ceramic capacitor. 37 ref 5v reference output. bypass ref to agnd with a 0.1? ceramic capacitor. ?p exposed paddle. connect to the ground plane for improved power dissipation. do not use as the only ground connection.
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 12 ______________________________________________________________________________________ cathode of a string of leds connected in series. the constant-current capability is up to 55ma per output, set for all 16 outputs by an external resistor, r set . the devices can operate in a stand-alone mode (see the typical operating circuits ). the max16810 includes circuitry that automatically detects open-circuit leds. fault status is loaded into the serial-interface shift register when le goes high and is automatically shifted out on dout when the next data transmission is shifted in. the max16810 also features a watchdog that monitors activity on the clk, din, and le inputs (see the watchdog (max16810) section). the number of channels can be expanded by using the max6970 and max6971 family in conjunction with the max16809 and max16810. 2r r 26.5v en_ref bg sns 300mv uvlo i lim vea cpwm voltage- divider v dd thermal shutdown voltage divider osc clk prereg 5v reg_ok 5v reg reference 2.5v delay s r q q v cc v+ current reference power-on reset thermal shutdown agnd cs v cc ref out rtct dout v+ set fb comp clk din le oe d0 d1 d2 d3 d4 d5 d6 d7 d0 d1 d2 d3 d4 d5 d6 d7 d0 d1 d2 d3 d4 d5 d6 d7 out0 out1 out2 out3 out4 out5 out6 out7 d8 d9 d10 d11 d12 d13 d14 d15 d8 d9 d10 d11 d12 d13 d14 d15 d8 d9 d10 d11 d12 d13 d14 d15 out8 out9 out10 out11 out12 out13 out14 out15 pgnd max16809 serial-to-parallel shift register output latches constant-current sink figure 1a. internal block diagram (max16809)
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller ______________________________________________________________________________________ 13 2r r 26.5v en_ref bg sns 300mv uvlo i lim vea cpwm voltage- divider v dd thermal shutdown voltage divider osc clk prereg 5v reg_ok 5v reg reference 2.5v delay s r q q v cc v+ current reference power-on reset thermal shutdown agnd cs v cc ref out rtct dout v+ set fb comp clk din le oe d0 d1 d2 d3 d4 d5 d6 d7 d0 d1 d2 d3 d4 d5 d6 d7 d0 d1 d2 d3 d4 d5 d6 d7 out0 out1 out2 out3 out4 out5 out6 out7 d8 d9 d10 d11 d12 d13 d14 d15 d8 d9 d10 d11 d12 d13 d14 d15 d8 d9 d10 d11 d12 d13 d14 d15 out8 out9 out10 out11 out12 out13 out14 out15 pgnd max16810 watchdog serial-to-parallel shift register output latches constant-current sink fault detection (max16810 only) figure 1b. internal block diagram (max16810)
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 14 ______________________________________________________________________________________ switch-mode controller current-mode control loop the advantages of current-mode control over voltage- mode control are twofold. first, there is the feed-for- ward characteristic brought on by the controller? ability to adjust for variations in the input voltage on a cycle- by-cycle basis. second, the stability requirements of the current-mode controller are reduced to that of a sin- gle-pole system unlike the double pole in the voltage- mode control scheme. the max16809/max16810 use a current-mode control loop where the output of the error amplifier is compared to the current-sense voltage (v cs ). when the current-sense signal is lower than the inverting input of the cpwm comparator, the output of the comparator is low and the switch is turned on at each clock pulse. when the current-sense signal is higher than the inverting input of the cpwm compara- tor, the output is high and the switch is turned off. undervoltage lockout (uvlo) the turn-on supply voltage for the max16809/ max16810 is 8.4v (typ). once v cc reaches 8.4v, the reference powers up. there is a 0.8v of hysteresis from the turn-on voltage to the uvlo threshold. once v cc reaches 8.4v, the max16809/max16810 operate with v cc down to 7.6v. once v cc goes below 7.6v (typ), the device is in uvlo. when in uvlo, the quiescent supply current into v cc falls back to 32? (typ), and out and ref are pulled low. mosfet driver out drives an external n-channel mosfet and swings from agnd to v cc . ensure that v cc remains below the absolute maximum v gs rating of the external mosfet. out is a push-pull output with the on-resistance of the pmos typically 3.5 ? and the on-resistance of the nmos typically 4.5 ? . the driver can source 2a and sink 1a typi- cally. this allows for the max16809/max16810 to quickly turn on and off high gate-charge mosfets. bypass v cc with one or more 0.1? ceramic capacitors to agnd, placed close to v cc . the average current sourced to drive the external mosfet depends on the total gate charge (q g ) and operating frequency of the converter. the power dissipation in the max16809/max16810 is a function of the average output drive current (i drive ). use the following equation to calculate the power dissipation in the device due to i drive : i drive = (q g x f sw ) pd = (i drive + i cc ) x v cc where i cc is the operating supply current. see the typical operating characteristics for the operating supply current at a given frequency. error amplifier the max16809/max16810 include an internal error amplifier. the inverting input is at fb and the noninvert- ing input is internally connected to a 2.5v reference. set the output voltage using a resistive divider between output of the converter v out , fb, and agnd. use the following formula to set the output voltage: where v fb = 2.5v. oscillator the oscillator frequency is programmable using an external capacitor and a resistor at rtct (see rtct in the typical operating circuits ). r t is connected from rtct to the 5v reference (ref), and c t is connected from rtct to agnd. ref charges c t through r t until its voltage reaches 2.8v. c t then discharges through an 8.3ma internal current sink until c t ? voltage reach- es 1.1v, at which time c t is allowed to charge through r t again. the oscillator? period is the sum of the charge and discharge times of c t . calculate the charge time as follows: t c = 0.57 x r t x c t where t c is in seconds, r t in ohms ( ? ), and c t in farads (f). the discharge time is then: t d = (r t x c t x 1000) / [(4.88 x r t ) - (1.8 x 1000)] where t d is in seconds, r t in ohms ( ? ), and c t in farads (f). v r r xv out fb =+ ? ? ? ? ? ? 1 1 2 v+ w/l out_ _ 68w/l 945r r est 1.23 r 1.23v pgnd set figure 1c. out_ _ driver internal diagram
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller ______________________________________________________________________________________ 15 the oscillator frequency is then: reference output ref is a 5v reference output that can source 20ma. bypass ref to agnd with a 0.1? capacitor. current limit the max16809/max16810 include a fast current-limit comparator to terminate the on cycle during an over- load or a fault condition. the current-sense resistor, r cs , connected between the source of the external mosfet and agnd, sets the current limit. the cs input has a voltage trip level (v cs ) of 0.3v. use the fol- lowing equation to calculate r cs : i p-p is the peak current that flows through the mosfet. when the voltage produced by this current (through the current-sense resistor) exceeds the current-limit com- parator threshold, the mosfet driver (out) turns the switch off within 60ns. in most cases, a small rc filter is required to filter out the leading-edge spike on the sense waveform. set the time constant of the rc filter at 50ns. buck-boost (sepic) operation figure 2 shows a buck-boost application circuit using the max16809/max16810 in a stand-alone mode of operation. sepic topology is necessary when the total forward voltage of the leds in a string is such that v out can be below or above v in . r v i cs cs pp = ? f tt osc cd = + () 1 max16809 max16810 out0 fb out1 out2 out3 out4 out5 out6 out7 out8 out9 out10 out11 out12 out13 out14 out15 external dim input external clock input set le din pgnd v cc v+ oe dout clk ref rtct c ref c in r set r cs c 1 c c2 c c1 out cs agnd comp r c1 r2 r1 c out c byp r t c t 3v to 5.5v v in v out q1 d l1 l2 figure 2. buck-boost (sepic) operation
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 16 ______________________________________________________________________________________ led driver 4-wire interface the max16809/max16810 also operate in a stand- alone mode (see the typical operating circuits ). for use with a microcontroller, the max16809/max16810 feature a 4-wire serial interface using din, clk, le, oe inputs and dout as a data output. this interface is used to write the led channels?data to the max16809/ max16810. the serial-interface data word length is 16 bits, d0?15. see figure 3. the functions of the five interface pins are as follows: din is the serial-data input, and must be stable when it is sampled on the rising edge of clk. data is shifted in msb first. this means that data bit d15 is clocked in first, followed by 15 more data bits, finishing with the lsb, d0. clk is the serial-clock input that shifts data at din into the max16809/max16810? 16-bit shift register on its rising edge. le is the latch-enable input of the max16809/max16810 that transfers data from the 16-bit shift register to its 16- bit output latches (transparent latch). the data latches on the falling edge of le (figure 4). the fourth input ( oe) provides output-enable control of the output drivers. when oe is driven high, the outputs (out0?ut15) are forced to high impedance without altering the contents of the output latches. driving oe low enables the outputs to follow the state of the output latches. oe is independent of the serial interface operation. data can be shifted into the serial-interface shift register and latched, regardless of the state of oe . dout is the serial-data output that shifts data out from the max16809/max16810? 16-bit shift register on the rising edge of clk. data at din propagates through the shift register and appears at dout 16 clock cycles later. table 1 shows the 4-wire serial-interface truth table. table 1. 4-wire serial-interface truth table clock input shift register contents load input latch contents blanking input output contents current at out_ _ serial data input din clk d0 d1 d2 dn-1 dn le d0 d1 d2 dn-1 dn oe d0 d1 d2 dn-1 dn h h r0 r1 rn-2 rn-1 l l r0 r1 rn-2 rn-1 x r0 r1 r2 rn-1 rn x x x x x l r0 r1 r2 rn-1 rn p0 p1 p2 pn-1 pn h p0 p1 p2 pn-1 pn l p0 p1 p2 pn-1 pn xxxx x h lll l l l = low logic level h = high logic level x = don? care p = present state (shift register) r = previous state (latched)
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller ______________________________________________________________________________________ 17 watchdog (max16810) the max16810 includes a watchdog circuit that moni- tors the clk, din, and le inputs. if there is no transi- tion on any one of these inputs for nominally 1s, the output latches are cleared and outputs out0?ut15 go high impedance like the initial power-up condition. this turns off all leds connected to the outputs. the shift-register data does not change, just the output- latch data. when the watchdog triggers, the outputs remain off until the driver output latches are updated with data turning them on. recovery is therefore auto- matic if the transmission failure is temporary because the max16810 does not lock up in the watchdog timeout state. the max16810 operates correctly when the serial interface is next activated, and the watchdog circuit is reset and starts monitoring the serial interface again. the watchdog function requires no software change to the application driving the max16810. the rise time for clk, din, and le should be less than 10?. d15 d14 t ds t dh t cl t cp t do t oew t oef t f t r t oer t ls t lw t ch d1 d0 d15 le clk din dout oe out_ _ 80% 20% figure 3. 4-wire serial-interface timing diagram le out_ _ le out_ _ clk out_ _ clk out_ _ t crr t crf t lrr t lrf figure 4. le and clk to out_ _ timing
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 18 ______________________________________________________________________________________ led fault detection (max16810) the max16810 includes circuitry that detects open-cir- cuit leds automatically. an open-circuit fault occurs when an output is sinking current less than approxi- mately 50% of the programmed current flows. open cir- cuits are checked just after the falling edge of oe . the fault data is latched on the rising edge of le and is shift- ed out when new led data is loaded into the output latches from the shift register. if one or more output ports are detected with an open-circuit fault, the d14 and d13 bits of dout go high. if no open-circuit faults are detected, d14 and d13 are set to low. the data in the other 14 bit positions in dout are not altered. fault status is shifted out on dout for the first two rising edges of the clock after the falling edge of le (see figure 5). le is normally taken high after all 16 bits of new led data have been clocked into the shift regis- ter(s), and then dout outputs data bit d15. a typical fault-detecting application tests all the shifted out data. bits d0?12 and d15 are checked against the originally transmitted data to check data-link integrity. bits d13 and d14 are checked first to see that they contain the same data (validating the status), and second, whether faults are reported or not by the actual logic level. selecting external component r set to set led output current the max16809/max16810 use an external resistor, r set , to set the led current for outputs out0?ut15. the minimum allowed value of r set is 311 ? , which sets the output currents to 55ma. the maximum allowed value of r set is 5k ? (i out_ _ = 3.6ma) and maximum allowed capacitance at set is 100pf. use the following formula to set the output current: where i out_ _ is the desired output current in milliamps and the value for r set is in ohms. overtemperature cutoff the max16809/max16810 contain an internal tempera- ture sensor that turns off all outputs when the die temper- ature exceeds +165?. the outputs are enabled again when the die temperature drops below +140?. register contents are not affected, so when a driver is overdissi- pating, the external symptom is the load leds cycling on and off as the driver repeatedly overheats and cools, alternately turning itself off and then back on again. stand-alone operation in stand-alone operation, the max16809/max16810 does not use the 4-wire interface (see the typical operating circuits ). connect din and le to v+ and provide at least 16 external clock pulses to clk to enable 16 output ports. this startup pulse sequence can be provided either using an external clock or the pwm signal. the external clock can also be generated using the signal at rtct and an external comparator. r v i set out , _ _ = 17 100 oe le clk dout d15 d14 d13 d12 fault status bits figure 5. fault timing
led dimming pwm dimming all the output channels can be dimmed simultaneously by applying a pwm signal (50hz to 30khz) to oe . this allows for a wide range of dimming up to a 5000:1 ratio. each channel can be independently turned on and off using a 4-wire serial interface. the dimming is propor- tional to the pwm duty cycle. led current amplitude adjustment using an analog or digital potentiometer as r set allows for led current amplitude adjustment and linear dimming. computing power dissipation use the following equation to estimate the upper limit power dissipation (pd) for the max16809/max16810: where: v+ = supply voltage i+ = v+ operating supply current duty = pwm duty cycle applied to oe v outi = max16809/max16810 port output voltage when driving load led(s) i outi = led drive current programmed by r set pd = power dissipation pcb layout guidelines careful pcb layout is critical to achieve low switching losses and clean, stable operation. use a multilayer board whenever possible for better noise immunity. protect sensitive analog grounds by using a star ground configuration. minimize ground noise by con- necting agnd, pgnd, the input bypass-capacitor ground lead, and the output-filter ground lead to a sin- gle point (star ground configuration). also, minimize trace lengths to reduce stray capacitance, trace resis- tance, and radiated noise. the trace between the out- put voltage-divider and the fb pin must be kept short, as well as the trace between agnd and pgnd. pd duty v x i v x i vxi outi i i outi cc cc ( ) ( ) =+++ ? ? ? ? ? ? ? ? + = = 0 15 max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller ______________________________________________________________________________________ 19
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 20 ______________________________________________________________________________________ max16809 max16810 fb pgnd v cc v+ oe le dout din clk sclk mosi miso c load enable r cs c c2 c c1 out cs agnd comp leds operation with microcontroler r c1 r2 r1 c out 3v to 5.5v v in v out l out0 out1 out2 out3 out4 out5 out6 out7 out8 out9 out10 out11 out12 out13 out14 out15 set ref rtct c ref r set r t c t c in c byp d typical operating circuits (continued)
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller ______________________________________________________________________________________ 21 top view max16809 max16810 tqfn + 13 14 15 16 17 18 19 dout set v+ pgnd pgnd din clk 38 37 36 35 34 33 32 123456789101112 n.c. ref n.c. v cc out agnd n.c. oe out15 out14 out13 out12 out11 out10 out9 out8 comp fb n.c. 31 30 29 28 27 26 25 24 23 22 21 20 le out0 out1 out2 out3 out4 out5 out6 out7 rtct cs n.c. pin configuration chip information process: bicmos
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 22 ______________________________________________________________________________________ package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .) 38l thin qfn.eps
max16809/max16810 integrated 16-channel led drivers with switch-mode boost and sepic controller 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 ____________________ 23 2006 maxim integrated products is a registered trademark of maxim integrated products, inc. 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 ____________________ 23 2006 maxim integrated products is a registered trademark of maxim integrated products, inc. package information (continued) (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .)

▲Up To Search▲

Price & Availability of MAX16810ATU

	To Download MAX16810ATU Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .