miniature, smt constant current output dc/dc led drivers key features: ? 300 - 700 ma output current ? constant current output ? miniature smtcase ? pwm & analog dimming ? wide 5.5v to 48v input range ? ef? ciency to 96% ? 2.0 mhrs mtbf ? low, low cost! series input parameter conditions min. typ. max. units input voltage range 5.5 24.0 48.0 vdc max input voltage see note 1 55.0 vdc input filter internal capacitor output parameter conditions min. typ. max. units output current accuracy vin = 24v 2.0 3.0 % output current stability vin = 48v 1.0 % output capacitive load 1,000 f ripple & noise 120 mv p-p temperature coef? cient 0.015 %/ o c output short circuit continuous environmental parameter conditions min. typ. max. units operating temperature range, ambient 300 ma, 350 ma output models -40 +25 +85 o c all other models -40 +25 +71 operating temperature range, case case +100 o c storage temperature range -55 +125 o c cooling free air convection humidity rh, non-condensing 95 % lead temperature 1.5 mm from case for 10 sec 260 oc physical case size 0.94 x 0.54 x 0.295 inches (23.86 x 13.70 x 7.50 mm) case material non-conductive black plastic (ul94-v0) weight 0.212 oz (6.0g) remote on/off control parameter conditions min. typ. max. units dc/dc on open or 2.8 vdc < 6.0 vdc dc/dc off <0.6 vdc remote pin drive current vcont = 5.0 vdc 1 ma quiescent input current (shutdown mode) vin = 24v, vcont = <0.6 vdc 400 a pwm dimming parameter conditions min. typ. max. units operation frequency 0.2 10 khz reliability speci? cations parameter conditions min. typ. max. units mtbf mil hdbk 217f, 25 o c, gnd benign 2.0 mhours micropower direct 292 page street suite d stoughton, ma 02072 usa t: (781) 344-8226 f: (781) 344-8481 e: sales@micropowerdirect.com w: www.micropowerdirect.com www.micropowerdirect.com electrical speci? cations speci cations typical @ +25?, nominal input voltage & rated output current, unless otherwise noted. speci cations subject to change without notice. s ldf24e-xx-xxx connection notes: 1. input lter components (c 1 , l 1 & c 2 ) are used to help meet the conducted emissions requirements (en 55022 b) for the unit. recommended values are: c 2 - 2.2 f l 1 - 1.25 mh c 3 - 1.0 f other components added to the circuit include an input storage capacitor to help prevent problems due to input line sags and an output capacitor to improve performance. recommended values are: c 1 - 470 f c 4 - 1.0 f 2. to comply with en61000-4-5, a tvs should be installed before the input lter compo- nents. a smcg51 is recommended. 2 typical connection: ac input typical connection: dc input
output current may be adjusted by using a pulse width modu- lated (pwm) signal. by varying the signal duty cycle (as shown at right) the output current is adjusted up or down. output current may be calcu- lated by using the formula: i out = (dt - 0.6) x i rated t where i out = required output current i rated = full rated output current for the unit d = pulse width of the he control signal t = cycle of the control signal the t on of the driver signal must be greater than 0.7 ms. an audible noise may be generated during the digital dimming process of the driver, since the control circuit frequency is within the is within the range of human hearing (20 hz - 20 khz). speci? cation notes: 1. exceeding 55v on the unit input could damage the unit. 2. no connection should be made between input ground and the output. 3. these are step-down devices, the maximum output open voltage is equal to the input voltage. 4. when not used, the pwm/cont input (pin 3) or should be left open if not used. 5. exceeding the speci ed maximum output power could cause damage to the unit. pwm output current control analog dimming is accomplished by using a simple resistor divider network, as illustrated above. the output current is varied by changing the voltage level pres- ent at pin 10. the amount varia- tion is shown in chart at right. the maximum voltage level that can be applied to pin 10 is 15v. exceeding this may damage the driver. analog and pwm control of the driver should not be attempted at the same time. the control pin not being used should be left open. mechanical dimensions www.micropowerdirect.com micropower direct we power your success - for less! 292 page street ste d stoughton, ma 02072 ? tel: (781) 344-8226 ? fax: (781) 344-8481 ? e-mail: sales@micropowerdirect.com notes: all dimensions are typical in inches (mm) tolerance x.xx = ?.01 (?.25) pin 1 is marked by a ?ot or indentation on the top of the unit pin connections pin function pin function 1 gnd 9 +v out 7 pwm, on/off 10 analog dimming 8-v out 16 +v in typical connection: parallel output model number input output dimming control ef? ciency (%, max) voltage (vdc) voltage (vdc) current (ma) nominal range ldf24e-10-300 24 5.5 - 48.0 3.3 - 36.0 0.0 - 300 pwm/analog 96 ldf24e-12-350 24 5.5 - 48.0 3.3 - 36.0 0.0 - 350 pwm/analog 96 ldf24e-18-500 24 5.5 - 48.0 3.3 - 36.0 0.0 - 500 pwm/analog 96 ldf24e-21-600 24 5.5 - 48.0 3.3 - 36.0 0.0 - 600 pwm/analog 96 ldf24e-25-700 24 5.5 - 48.0 3.3 - 36.0 0.0 - 700 pwm/analog 96 model selection guide connection notes: 1. a positive temperature coef cient ptc is connected to each parallel channel for protection. analog output current control solder layout analog control vs output
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