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| ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 1 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated 30v 350ma led driver with 1000:1 pwm dimming and aec-q100 description the ZXLD1352 is a continuous mode inductive step-down converter with integrated switch and high side current sense. it operates from an input supply from 7v to 30v driving single and multiple series connected leds effciently externally adjustable output current up to 350ma. the ZXLD1352 has been qua lified to aec-q100 grade 2 allowing it to operate at ambient temperatures from -40 to 105c. dc voltage or a pwm waveform. 1000:1 adjustment of output current is possible using pwm control. applying a voltage of 0.2v or lower to the adj pin turns the output off and switches the device into a low current standby state. pin assignments features ? simple low parts count ? single pin on/off and brightness control using dc voltage or pwm ? 1000:1 pwm dimming range ? high efficiency (up to 95%) * ? wide input voltage range: 7v to 30v ? 40v transient capability ? up to 1mhz switching frequency ? typical 4% output current accuracy ? qualified to aec-q100 grade 2 ? available in green molding (no br, sb) with lead free finish/rohs compliant applications ? low voltage halogen replacement leds ? automotive lighting ? low voltage industrial lighting ? led back-up lighting ? illuminated signs typical application circuit * using standard external components as specified under electrical characteristics. efficiency is dependent upon the number of leds driven and on external component types and values. i sense v in adj gnd lx tsot23-5 top view v in i sense lx gnd ZXLD1352 adj v in (12v - 30v) rs 0.33 1 f c1 gnd d1 zlls1000 47mh l1 pw m
ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 2 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated block diagram figure 1. block diagram pin description name pin no. description lx 1 drain of ndmos switch gnd 2 ground (0v) adj 3 multi-function on/off and br ightness control pin: ? leave floating for normal operation. (v adj = v ref =1.25v giving nominal average output current i outnom =0.1/r s ) ? drive to voltage below 0.2v to turn off output current ? drive with dc voltage (0.3v ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 4 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated electrical characteristics (test conditions: v in = 12v, t amb = 25c, unless otherwise specified.) symbol paramete r conditions min. typ. max. unit v su internal regulator start-up threshold v in rising 4.8 v i inqoff quiescent supply current with output off adj pin grounded 20 30 a i inqon quiescent supply current with output switching adj pin floating f = 250khz 250 500 a v sense mean current sense threshold voltage (defines led current setting accuracy) measured on i sense pin with respect to v in v adj =1.25v 95 100 105 mv v sensehys sense threshold hysteresis 15 % i sense i sense pin input current v sense = v in -0.1 1.25 10 a v ref internal reference voltage measured on adj pin with pin floating 1.21 1.25 1.29 v v ref / t temperature coefficient of v ref 50 ppm/c v adj external control voltage range on adj pin for dc brightness control 1 0.3 2.5 v v adjoff dc voltage on adj pin to switch device from active (on) state to quiescent (off) state v adj falling 0.15 0.2 0.25 v v adjon dc voltage on adj pin to switch device from quiescent (off) state to active (on) state v adj rising 0.2 0.25 0.3 v r adj resistance between adj pin and v ref 35 65 k ? i lxmean continuous lx switch current 0.37 a r lx lx switch ?on? resistance 1.5 2 ? i lx ( leak ) lx switch leakage current 1 a d pwm(lf) duty cycle range of pwm signal applied to adj pin during pwm dimming mode pwm frequency 100hz ? 1khz pwm amplitude = v ref measured on adj pin 0.001 1 brightness control range 1000:1 f lx operating frequency (see graphs for more detail) adj pin floating l=100h (0.82v) i out =350ma @ v led =3.4v driving 1 led 250 khz t pd internal comparator propagation delay 50 ns notes: 1. production testing of the device is performed at 25c. functional o peration of the device and parameters specified ov er a -40c to +105c temperature range, are guaranteed by design, characterization and process control. 2. 100% brightness corresponds to v adj = v adj(nom) = v ref . driving the adj pin above v ref will increase the v sense threshold and output current proportionally. ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 5 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated device description the device, in conjunction with the coil ( l1) and current sense resistor (rs), forms a self-oscillating continuous-mode buck converter device operation (refer to block diagram and figure 1 - operating waveforms) operation can be best understood by assuming that the adj pin of the device is unconnected and the voltage on this pin (v adj ) appears directly at the (+) input of the comparator. when input voltage v in is first applied, the initial current in l1 and r s is zero and there is no output from the current sense circuit. under this condition, the (-) input to the comparator is at ground and its output is high. this turns mn on and switches the lx pin low, causing current to flow from v in to ground, via r s , l1 and the led(s). the current rises at a rate determined by v in and l1 to produce a voltage ramp (v sense ) across r s . the supply referred voltage v sense is forced across internal resistor r1 by the current sense circuit and produces a proportional current in internal resist ors r2 and r3. this produces a ground referr ed rising voltage at the (-) input of the comparat or. when this reaches the threshold voltage (v adj ), the comparator output switches low and mn turns off. the comparator output also drives another nmos switch, which by passes internal resistor r3 to provide a controlled amount of hysteresis. the hysteres is is set by r3 to be nominally 15% of v adj . when mn is off, the current in l1 continues to flow via d1 and the led(s) back to v in . the current decays at a rate determined by the led and diode forward voltages to produce a falling voltag e at the input of the comparator. when this voltage returns to v adj , the comparator output switches high again. this cycle of events repeats, with the comparator input ramping between limits of v adj 15%. switching thresholds with v adj =v ref , the ratios of r1, r2 and r3, define an average v sense switching threshold of 100mv (measured on the i sense pin with respect to v in ). the average output current i outnom is then defined by this voltage and rs according to: i outnom =100mv/r s nominal ripple current is 15mv/r s adjusting output current the device contains a low pass filter for noise suppression bet ween the adj pin and the threshold comparator and an internal current limiting resistor (50k nom) between adj and the internal re ference voltage. this allows the adj pin to be overdriven wi th either dc or pwm signals to adjust the outpu t current. the filter is first order, comp rising one section with a cut-off frequen cy of nominally 600khz. details of the different modes of adjusting output current are give n in the applications section. output shutdown the adj pin drives the shutdown circuit. when the input voltage to this circuit falls below the threshold (0.2v nom), the inter nal regulator and the output switch are turn ed off. the voltage reference remains powere d during shutdown to provide the bias current for the shutdown circuit. quiescent supply current during shutdown is nominally 20ma and switch leakage is below 1ma. ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 6 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated device description figure 2. operating waveforms 0v v in 100mv 115mv 0v sense voltage v sense+ v sense- to f f to n 85mv 0v 5v v in 0.15v adj 0.15v adj i outnom i outnom +15% i outnom -15% v adj lx voltage coil current comparator input voltage comparator output ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 7 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated typical operating waveforms [v in = 12v, r s = 0.3 ? , l = 100h] normal operation. output current (ch3) and lx voltage (ch1) start-up waveforms. output current (ch3), lx voltage (ch2) 2 3 ch3 100ma ch 2 20.0v m 400 s5.0s/s ach2 \ 12.0 v 200 ns/pt ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 8 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated typical characteristics for typical application circuit driving 1w luxeon ? white led(s) at v in =12v and t amb =25c unless otherwise stated. sdelfo.onsvycneiciffe smho33.0=sr,hu001=l 07 57 08 58 09 59 001 03 52 02 51 01 5 )v(niv efficiency (%) del1 del2 del3 del4 del5 del6 del7 del8 egatlovtupnisvelcycytud smho33.0=sr,hu001=l 0 2.0 4.0 6.0 8.0 1 2.1 03 52 02 51 01 5 )v(niv duty cycle del1 del2 del3 del4 del5 del6 del7 del8 egatlovtupnisvycneuqerfgnitarepo smho33.0=sr,hu001=l 0 001 002 003 004 005 006 03 52 02 51 01 5 )v(niv frequency (khz) del1 del2 del3 del4 del5 del6 del7 del8 egatlovylppushtiwnoitairavtnerructuptuo smho33.0=sr,hu001=l 8- 6- 4- 2- 0 2 4 6 8 03 52 02 51 01 5 )v(niv deviation from nominal set current (%) del1 del2 del3 del4 del5 del6 del7 sdelfo.onsvycneiciffe smho33.0=sr,hu74=l 07 57 08 58 09 59 001 0352025101 5 )v(niv efficiency (%) del1 del2 del3 del4 del5 del6 del7 egatlovtupnisvelcycytud smho33.0=sr,hu74=l 0 2.0 4.0 6.0 8.0 1 0352025101 5 )v(niv duty cycle del1 del2 del3 del4 del5 del6 del7 egatlovtupnisvycneuqerfgnitarepo smho33.0=sr,hu74=l 0 001 002 003 004 005 006 007 008 0352025101 5 )v(niv frequency (khz) del1 del2 del3 del4 del5 del6 del7 egatlovylppussvnoitairavtnerructuptuo smho33.0=sr,hu74=l 51- 01- 5- 0 5 01 51 02 0352025101 5 )v(niv deviation from nominal set current (%) del 1 del2 del3 del4 del5 del6 del7 ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 9 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated typical characteristics (cont.) sdelfo.onsvycneiciffe smho33.0=sr,hu022=l 57 08 58 09 59 001 03 52 02 51 01 5 )v(niv efficiency (%) del1 del2 del3 del4 del5 del6 del7 del8 egatlovtupni s velcyc y tud smho33.0=sr,hu022=l 0 2.0 4.0 6.0 8.0 1 03 52 02 51 01 5 )v(niv duty cycle del1 del2 del3 del4 del5 del6 del7 del8 egatlovtupnisvycneuqerfgnitarepo smho33.0=sr,hu022=l 0 05 001 051 002 052 003 053 03 52 02 51 01 5 )v(niv frequency (khz) del1 del2 del3 del4 del5 del6 del7 del8 egatlovtupnisvnoitairavtnerructuptuo smho33.0=sr,hu022=l 6- 5- 4- 3- 2- 1- 0 1 2 03 52 02 51 01 5 )v(niv deviation from nominal set current (%) del1 del2 del3 del4 del5 del6 del7 del8 ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 10 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated typical characteristics (cont.) vref vs vin at low supply voltage 0 0.2 0.4 0.6 0.8 1 1.2 1.4 012345678910 vin (v) vref (v) egnaregatlovylppuslanimonrevonivsvferv 5142.1 242.1 5242.1 03 52 02 51 01 5 )v(niv vref (v) jdavsvtnerructuptuo 0 05 001 051 002 052 003 053 3 5.2 2 5.1 1 5.0 0 )v(jdav iout mean (ma) mho65.0=sr mho3.0=sr mho1=sr )gnitarepo(nivsvtnerrucylppus 0 001 002 003 004 005 03 52 02 51 01 5 0 )v(niv iin (ua) )tnecseiuq(nivsvtnerrucylppus 0 5 01 51 02 03 52 02 51 01 5 0 )v(niv iin (ua) ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 11 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated typical characteristics (cont.) ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 12 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated application information setting nominal average output current with external resistor r s the nominal average output current in the led(s) is determi ned by the value of the external current sense resistor (r s ) connected between v in and i sense and is given by: i outnom = 0.1/r s for r s >0.27 the table below gives values of nominal average output current for several preferred values of current setting resistor (r s ) in the typical application circuit shown on page 1: r s ( ) nominal average output current (ma) 0.27 370 0.3 333 0.33 300 0.39 256 the above values assume that the adj pin is floating and at a nominal voltage of v ref (=1.25v). note that r s =0.27 is the minimum allowed value of sense resistor under these conditions to maintain switch current below the specified maximum value. it is possible to use different values of r s if the adj pin is driven from an exte rnal voltage. (see next section). output current adjustment by external dc control voltage the adj pin can be driven by an external dc voltage (v adj ), as shown, to adjust the output current to a value above or below the nominal average value defined by r s . the nominal average output current in this case is given by: i outdc = 0.08*v adj /r s [for 0.3< v adj <2.5v] note that 100% brightness setting corresponds to v adj = v ref . when driving the adj pin above 1.25v, r s must be increased in proportion to prevent i outdc exceeding 370ma maximum. the input impedance of the adj pin is 50k 25%. gnd ZXLD1352 adj gnd + dc ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 13 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated application information (continued) output current adjustment by pwm control directly driving adj input a pulse width modulated (pwm) signal with duty cycle d pwm can be applied to the adj pin, as shown below, to adjust the output current to a value above or below t he nominal average value set by resistor r s : driving the adj input via open collector transistor the recommended method of driving the adj pin and controlling the amplitude of the pwm waveform is to use a small npn switching transistor as shown below: this scheme uses the 50k resistor between the adj pin and the internal voltage reference as a pull-up resistor for the external transistor eg mmbt3904. driving the adj input from a microcontroller another possibility is to drive the device from the open drain output of a microcontroller. the diagram below shows one method of doing this: if the nmos transistor within the microcontro ller has high gate / drain capacitance, this arrangement can inject a negative spi ke into adj input of the ZXLD1352 and cause erratic operati on but the addition of a schottky clamp diode (eg diodes inc. sd103cws) to ground and inclusion of a series resistor (3.3 k) will prevent this. see the section on pwm dimming for more details of the various modes of control using high frequency and low frequency pwm signals. ? pwm gnd 0v v adj gnd ZXLD1352 adj gnd ZXLD1352 adj mcu 10k pwm gnd ZXLD1352 adj gnd ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 14 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated application information (continued) shutdown mode taking the adj pin to a voltage below 0.2v will turn off the output and supply current will fall to a low standby level of 20a nominal. note that the adj pin is not a logic input. taking the adj pin to a voltage above v ref will increase output current above the 100% nominal average value. (see graphs for details). soft-start an external capacitor from the adj pin to ground will provide soft-start delay, by increasing the time taken for the voltage on this pin to rise to the turn-on threshold and by slowing down the ra te of rise of the control volt age at the input of the comparator . the graph below shows the variation of soft-star t time for different values of capacitor. inherent open-circuit led protection if the connection to the led(s) is open-circui ted, the coil is isolated fr om the lx pin of the chip , so the device will not be damaged, unlike in many boost converters, where the back emf may damage the internal switch by forcing the drain above its breakdown voltage. capacitor selection a low esr capacitor should be used for input decoupling, as the esr of this capacitor appears in series with the supply source impedance and lowers overall efficiency. this capacitor has to s upply the relatively high peak current to the coil and smooth t he current ripple on the input supply. a minimum value of 1f is acceptable if the input source is close to the device, but higher values will improve performance at lower input voltages, especially when the source impedance is high. the input capacitor should be placed as close as possible to the ic. for maximum stability over temperature and voltage, capacitors with x7r, x5r, or better dielectric are recommended. capacitors with y5v dielectric are not suitable for decoupling in this application and should not be used. a table of recommended manufacturers is provided below: manufacture r website murata www.murata.com taiyo yuden www.t-yuden.com kemet www.kemet.com avx www.avxcorp.com ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 15 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated application information (continued) inductor selection recommended inductor values for the ZXLD1352 are in the range 47h to 220h. higher values of inductance are recommended at higher supply volt ages in order to minimize errors due to switching delays, which result in increased ripple and lower efficiency. higher va lues of inductance also result in a smaller change in output cu rrent over the supply voltage range. (see graphs). the inductor shou ld be mounted as close to the device as possible with low resistance connections to the lx and v in pins. the chosen coil should have a saturation current higher than the peak output current and a continuous current rating above the required mean output current. suitable coils for use with the ZXLD1352 are listed in the table below: part no. l ( h) dcr ( : ) i sat (a) manufacturer do1608c 47 0.64 0.5 coilcraft mss6132ml 47 0.38 0.56 68 0.58 0.47 100 0.82 0.39 cd104-mc 220 0.55 0.53 sumida np04sb470m 47 0.27 0.38 taiyo yuden the inductor value should be chosen to maintain operating duty cy cle and switch 'on'/'off' times within the specified limits ov er the supply voltage and load current range. the following equations can be used as a guide, wi th reference to figure 1 - operating waveforms. lx switch 'on' time t on l ' i v in v led ? i avg r s rl r lx ++ ? --------------------------------------------------------------------------------------- - = note: t onmin >200ns lx switch 'off' time t off l ' i v led vd i avg r s rl + ++ ---------------------------------------------------------------------- - = note: t offmin >200ns where: l is the coil inductance (h) rl is the coil resistance ( : ) i avg is the required led current (a) di is the coil peak-peak ripple curr ent (a) {internally set to 0.3 x i avg } v in is the supply voltage (v) v led is the total led forward voltage (v) r lx is the switch resistance ( : ) vd is the diode forward voltage at the required load current (v) ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 16 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated application information (continued) example for v in =12v, l=47 h, rl=0.64 : , v led =3.4v, i avg =350ma and vd =0.36v t on = (47e-6 x 0.105)/(12 - 3.4 - 0.672) = 0.622 s t off = (47e-6 x 0.105)/(3. 4 + 0.36 + 0.322)= 1.21 s this gives an operating frequency of 546khz and a duty cycle of 0.34. these and other equations are available as a spreads heet calculator from the zetex website. go to www.diodes.com/ZXLD1352 note that in practice, the duty cycle and operating frequency w ill deviate from the calculated values due to dynamic switching delays, switch rise/fall times and losses in the external components. optimum performance will be achieved by setting the duty cycle close to 0.5 at the nominal supply voltage. this helps to equalize the undershoot and overshoot and improves temperature stability of the output current. diode selection for maximum efficiency and performance, the rectifier (d1) should be a fast low capacitance schottky diode with low reverse leakage at the maximum operating voltage and temperature. the recommended diode for use with this part is the zlls1000. this has approximately ten times lower leakage than standard scho ttky diodes, which are unsuitable for use above 85c. it also provides better efficiency than silicon diodes, due to a combination of lower forward voltage and reduced recovery time. the table below gives the typical characteristics for the zlls1000: diode forward voltage at 100ma (mv) continuous current (ma) reverse leakage at 30v 85oc ( a) package zlls1000 310 1000 300 tsot23-5 if alternative diodes are used, it is impor tant to select parts with a peak curre nt rating above the peak coil current and a continuous current rating higher than the maximum output load cu rrent. it is very important to consider the reverse leakage of the diode when operating above 85c. excess leakage wi ll increase the power dissipation in the device. the higher forward voltage and overshoot due to reverse recovery time in silicon diodes will increase the peak voltage on the l x output. if a silicon diode is used, care should be taken to ensure that the total voltage appearing on the lx pin including sup ply ripple, does not exceed the specified maximum value. ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 17 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated application information (continued) reducing output ripple peak to peak ripple current in the led can be re duced, if required, by shunting a capacitor c led across the led(s) as shown below: a value of 1f will reduce nominal ripple current by a factor three (approx.). proportionally lower ripple can be achieved with higher capacitor values. note that the capacitor will not affe ct operating frequency or efficienc y, but it will increase start- up delay, by reducing the rate of rise of led voltage. operation at low supply voltage the internal regulator disables the drive to the switch until the supply has risen above the start-up threshold (v su ). above this threshold, the device will start to operate. however, with th e supply voltage below the specified minimum value, the switch dut y cycle will be high and the device power dissipation will be at a maximum. care should be taken to avoid operating the device under such conditions in the application, in order to minimize the risk of exceeding the maximum allowed die temperature. (see next section on thermal considerations). note that when driving loads of two or more leds, the forw ard drop will normally be sufficient to prevent the device from switching below approximately 6v. this will minimize the risk of damage to the device. thermal considerations when operating the device at high ambient tem peratures, or when driving maximum load current, care must be taken to avoid exceeding the package power dissipation limits. the graph below gives details for power derating. this assumes the device to be mounted on a 25mm 2 pcb with 1oz copper standing in still air. ? v in v in i sense lx ZXLD1352 rs l1 cled led d1 ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 18 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated application information (continued) note that the device power dissipation will most often be a maximum at minimum supply voltage. it will also increase if the efficiency of the circuit is low. this may result from the us e of unsuitable coils, or excessive parasitic output capacitance o n the switch output. thermal compensation of output current high luminance leds often need to be supplied with a temper ature compensated current in order to maintain stable and reliable operation at all drive levels. the leds are usually mounted remotely from the device, so for this reason, the temperature coefficients of the internal circuits for the zxld 1352 have been optimized to minimize the change in output curren t when no compensation is employed. if output current compensation is required, it is possible to use an external temperature sensing network - normally using negative temperature coefficient (ntc) thermistors and/or diodes, mounted very close to the led(s). the output of the sensing network can be used to driv e the adj pin in order to reduce output current with increasing temperature. layout considerations lx pin the lx pin of the device is a fast switch ing node, so pcb tracks should be kept as short as possible. to minimize ground 'bounce', the ground pin of the device should be soldered directly to the ground plane. coil and decoupling capacitors it is particularly important to mount the coil and the input dec oupling capacitor close to the device to minimize parasitic resistance and inductance, which will degrade efficiency. it is also important to take account of any track resistance in serie s with current sense resistor r s . adj pin the adj pin is a high impedance input, so when left floating, pcb tracks to this pin should be as short as possible to reduce noise pickup. a 100nf capacitor from the adj pin to ground will reduce frequency modulation of the output under these conditions. an additional series 10k ? resistor can also be used when driving the adj pin from an external circuit (see below). this resistor will provide filtering for low frequency noise and provide prot ection against high voltage transients. high voltage tracks avoid running any high voltage tr acks close to the adj pin, to reduce the risk of leakage due to board contaminat ion. any such leakage may raise the adj pin voltage and cause excessive ou tput current. a ground ring placed around the adj pin will minimize changes in output current under these conditions. gnd ZXLD1352 adj 10k 100nf gnd ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 19 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated dimming output current using pwm when the adj pin is driven with a low frequency pwm signal (eg 100hz), with a high level voltage v adj and a low level of zero, the output current will be switched on and off at the pwm frequency, resulting in an average output current i outavg proportional to the pwm duty cycle. (see figure 2) figure 3. low frequency pwm operating waveforms the average value of output current in this mode is given by: the average value of output current is given by: i outavg = 0.1d pwm /r s for d pwm >0.01 pwm dimming is preferable to dc dimming if optimum led 'whi teness' is required. it will also provide the widest possible dimming range (approx. 1000:1) and higher efficiency at the expense of greater output ripple. v adj pwm voltage to n ioutavg 0v 0 to ff 0.1/rs ioutnom output current ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 20 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated ordering information device package reel size (mm) tape width (mm) quantity (per reel) part marking ZXLD1352et5ta tsot23-5 180 8 3000 1352 package outline dimensions tsot23-5 ZXLD1352 ZXLD1352 document number: ds33469 rev. 3 - 2 21 of 21 www.diodes.com december 2010 ? diodes incorporated a product line o f diodes incorporated important notice diodes incorporated makes no warranty of any kind, express or implied, with regards to this document, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose (and their equivalents under the laws of any jurisdiction). diodes incorporated and its subsidiaries reserve the right to ma ke modifications, enhancements, im provements, corrections or ot her changes without further notice to this document and any product described herein. diodes incorporated does not assume any liability ari sing out of the application or use of this document or any product described herein; neither does diodes incorporated convey any license under its patent or trademark rights, nor the rights of others. any customer or user of this document or products described herein in such applica tions shall assume all risks of such use and will agree to hold diodes incorporat ed and all the companies whose products are represented on diodes incorporated website, harmless against all damages. diodes incorporated does not warrant or accept any liability wh atsoever in respect of any products purchased through unauthoriz ed sales channel. should customers purchase or use diodes inco rporated products for any unintended or unauthorized application, customers shall i ndemnify and hold diodes incorporated and its representat ives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death a ssociated with such unintended or unauthorized application. products described herein may be covered by one or more united states, international or foreign patents pending. product names and markings noted herein may also be covered by one or more united states, international or foreign trademarks. life support diodes incorporated products are specifically not authorized for use as critical comp onents in life support devices or systems without the express written approval of the chief executive offi cer of diodes incorporated. as used herein: a. life support devices or syst ems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when proper ly used in accordance with inst ructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. b. a critical component is any component in a life support devic e or system whose failure to perform can be reasonably expect ed to cause the failure of the life support device or to affect its safety or effectiveness. customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support dev ices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning the ir products and any use of diodes incorporated products in such safety-critica l, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by diodes incorporated. further, customers must fully indemnify diodes incorporate d and its representatives against any damages arising out of the use of diodes incorporated products in such safety-critical, life suppor t devices or systems. copyright ? 2010, diodes incorporated www.diodes.com |
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