ksd-i6t002-000 1 SN8500D switching type (buck) led driver ic ? description the SN8500D is a high power pwm led driver ic using a bu ck converter topology that is capable of driving up to 1.5a of output current. it operates from an input volta ge range of 3vdc to 40vdc and generates a regulated programmable constant output current for high power led s. external resistor controlled the maximum output current to single led or a led string. ? features ? operation from 3.0v to 40v input. ? low standby current ? high efficiency ? output switch current to 1.5a ? halogen-free package is available ? application ? automotive and marine lighting ? high power led driver ? constant current source package type device name marking to-252-5l SN8500D sn8500---(1) yyww---(2) (1) device code, (2) year & week code pin symbol description 1 vcc input voltage 2 cs peak current sense pin 3 gnd ground 4 out output pin 5 osc oscillator timing pin ? pin assignment & description (top view) package : to-252-5l ? ordering information 1 2 3 4 5 vcc cs gnd out osc s s e e m m i i c c o o n n d d u u c c t t o o r r http:// www.auk.co.kr
ksd-i6t002-000 2 SN8500D ? absolute maximum ratings [ta=25 ] characteristic symbol rating unit power supply voltage v cc(max) 40 v output current i out(max) 1.5 a thermal resistance junction-ambient rth(j-a) * 96.1 /w power dissipation p d * 1.3 w operating temperature range t opr -40 ~ +85 storage temperature range t stg -55 ~ +150 * mounted on a glass epoxy circuit board of 30x30mm pad dimension of 50mm 2 ? recommended operating conditions characteristic symbol rating unit min max power supply voltage v cc 7 40 v output current i out - 1.5 a dimming frequency f dim - 10 khz ? electrical characteristics (ta=25 , unless otherwise noted.) characteristic symbol condition min. typ. max. unit supply current 1 i cc1 v cc =4v, out=open - 2.0 4.0 ma supply current 2 i cc2 v cc =40v, out=open - 2.0 4.0 ma dropout voltage vdrop v cc =10v, iout=1a - 1 1.3 v current sense voltage v cs v cc =10v, rout=820k ? 270 300 330 mv maximum duty cycle t dc - - 85 - % current sense off current i cs(off) v cc =40v, v osc =1.5v - 200 1000 a osc on voltage v osc (on) v cc =4v~40v - - 0.5 v osc off voltage v osc (off) v cc =4v~40v 1.5 - - v osc charge current i ch vcc=5v, v osc =0.5v 24 35 42 a osc discharge current i dch vcc=5v, v osc =1.5v 140 180 260 a
ksd-i6t002-000 3 s8500d ? functional block diagram out gnd vcc cs osc driver - + control osc sn8500 0.3v ? typical application + supply voltage 7~40v c in r sense c t l sn8500 power led cs vcc osc gnd out d f
ksd-i6t002-000 4 SN8500D ? application information 1) input capacitor the input capacitor (c in ) reduces the ripple of the input cu rrent drawn from the input supply and reduces noise injection into the ic. the refl ected ripple voltage will be smaller when an input capacitor with larger capacitance is used. the capacitors should be placed close to the v cc and gnd. 2) current-sense resistor the snese resistor rsense can be obtained as follows rsense = 300mv / (i avg + 0.5 x i ripple ) thus target average led current 700ma and ripple current 100ma then the result rsense= 300mv/ (700ma + 0.5 x 100ma) = 0.4 ? when selecting the sense resistor, low?inductanc e resistors, such as surface?mount metal film resistors, are preferred. 3) output inductor the value of the inductor is not fixed and can be adjusted freely in order to make tradeoffs among size, cost, and efficiency. although lower inductor values will minimize size and cost, they will also reduce efficiency due to hi gher peak currents. on the other hand, higher inductor values will increase efficiency, but at some point the resistive losses due to the extra turns of wire will exceed the benefit gained from lower ac current levels. also, high inductor values can affect the load?t ransient response of the converter. 4) freewheeling diode the schottky barrier diode sdb30a40(40v, 3a ) was recommended for freewheeling diode
ksd-i6t002-000 5 SN8500D ? application guide + supply voltage 7~40v c in =47uf r sense c t =470pf l=220uh sn8500 power led x n cs vcc osc gnd out d f (sdb30a40) + supply voltage 7~40v c in =47uf r sense c t =470pf l=220uh sn8500 power led x n cs vcc osc gnd out d f (sdb30a40)
ksd-i6t002-000 6 SN8500D ? application guide + supply voltage 7~40v c in =47uf r sense d f (sdb30a40) c t =470pf l=220uh cs vcc osc gnd out enable sds511 sn8500 power led + supply voltage 12vac c in= 47uf r sense d f (sdb30a40) c t= 470pf l=220uh sn8500 power led (mr16) ipk vcc ct gnd out sdb30a40
ksd-i6t002-000 7 SN8500D 0 50 100 150 200 250 300 350 0 20406080100 vcc=15v f dim =1khz c t =470pf l=220uh rs=0.99 ? 0.0 0.5 1.0 1.5 2.0 2.5 3.0 -50 -25 0 25 50 75 100 125 150 v cc =10v i out =1a 0 1 2 3 4 5 -50 -25 0 25 50 75 100 125 150 v cc =5v -20 -16 -12 -8 -4 0 4 8 12 16 20 -50 -25 0 25 50 75 100 125 150 v cc =10v ? electrical characteristic curves fig.1 v cs vs t a current sense voltage change ? v cs [%] ambient temperature - t a [ ] supply current ? i cc [ma] ambient temperature - t a [ ] fig.2 i cc vs t a fig.3 dropout voltage vs t a dropout voltage- v drop [v] ambient temperature - t a [ ] fig.4 led current vs pwm duty led current- i led [ma] pwm duty cycle [ %]
ksd-i6t002-000 8 SN8500D ? electrical characteristic curves ch1 ? ch2 ? ch3 ? ch4 ? fig.5 start-up waveform fig.6 normal operating waveform ch1 ? ch2 ? ch3 ? ch4 ? ch1 : osc, 2v/div ch2 : i in , 80ma/div ch3 : v out , 10v/div ch4 : i out , 200ma/div ch1 : osc, 2v/div ch2 : i in , 50ma/div ch3 : v out , 10v/div ch4 : i out , 200ma/div v cc =15v v cc =15v ch1 ? ch2 ? ch3 ? ch4 ? fig.7 dimming waveform ch1 : osc, 5v/div ch2 : i in , 80ma/div ch3 : v led , 3v/div ch4 : i led , 200ma/div fosc=100hz
ksd-i6t002-000 9 SN8500D ? to-252-5l outline dimension (unit : mm) recommend pcb solder land [unit: mm] 5 . 6 0 5.60 2 . 0 0 1.27 0.60 7 . 2 0 1 1 . 0 0
ksd-i6t002-000 10 SN8500D the auk corp. products are intended for the use as components in general electronic equipment (office and communication e quipment, measuring equipment, home appliance, etc.). please make sure that you consult with us before you use these auk corp. products in equipments which require high quality and / or reliability, and in equipments which could have major impact to the welfare of human life(atomic energy control, airplane, spaceship, transportation, combustion control, all types of safet y device, etc.). auk corp. cannot accept liability to any damage which may occur in case these auk corp. products were used in the mentioned equi pments without prior consultation with auk corp.. specifications mentioned in this publicati on are subject to change without notice.
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