13107 ms im b8-8794 no.8273-1/5 LA5771mp overview the LA5771mp is a separately-excited step-down switching regulator (3.3v). features ? high efficiency ? four external parts ? time-base generator (160khz) incorporated ? current limiter incorporated ? thermal shutdown circuit incorporated ? soft start circuit incorporated specifications absolute maximum ratings at ta = 25 c parameter symbol conditions ratings unit input voltage v in max 30 v output current i o max 3a sw pin application reverse voltage vsw -1 v allowable power dissipation pd max mounted on the specified board * 3.9 w operating temperature topr -30 to +125 c storage temperature tstg -40 to +150 c * mounted on a specified board: 114.3mm 76.1mm 1.6mm, copper foil ratio 60% fr4 recommended operating conditions at ta = 25 c parameter symbol conditions ratings unit input voltage range v in 5.5 to 28 v ordering number : en8273a monolithic linear ic separately-excited step-down switching regulator (3.3v) specifications of any and all sanyo semiconductor co.,l td. products described or contained herein stipulate the performance, characteristics, and functions of the described products in the independent state, and are not guarantees of the performance, characteristics, and functions of the described products as mounted in the customer ' s products or equipment. to verify symptoms and states that cannot be evaluated in an independent device, the customer should always evaluate and test devices mounted in the customer ' sproductsor equipment. any and all sanyo semiconductor co.,ltd. products described or contained herein are, with regard to "standard application", intended for the use as general electronics equipment (home appliances, av equipment, communication device, office equipment, industrial equ ipment etc.). the products mentioned herein shall not be intended for use for any "special application" (medica l equipment whose purpose is to sustain life, aerospace instrument, nuclear control device, burning appliances, t ransportation machine, traffic signal system, safety equipment etc.) that shall require extremely high level of re liability and can directly threaten human lives in case of failure or malfunction of the product or may cause har m to human bodies, nor shall they grant any guarantee thereof. if you should intend to use our products for app lications outside the standard applications of our customer who is considering such use and/or outside the scope of our intended standard applications, please consult with us prior to the intended use. if there is n o consultation or inquiry before the intended use, our customer shall be solely responsible for the use.
LA5771mp no.8273-2/5 electrical characteristics at ta = 25 c ratings parameter symbol conditions min typ max unit output voltage v o v in =15v, i o =1.0a 3.17 3.30 3.43 v efficiency v in =15v, i o =1.0a 79 % switching frequency f v in =15v, i o =1.0a 128 160 192 khz line regulation ? voline v in =8 to 20v, i o =1.0a 25 80 mv load regulation ? voload v in =15v, i o =0.5 to 1.5a 10 30 mv output voltage temperature coefficient ? vo/ ? ta designeed target value* 0.5 mv/ c ripple attenuation factor rrej f=100 to 120hz 45 db current limiter operating voltage is v in =15v 3.1 a thermal shutdown operating temperature tsd designed target value* 165 c thermal shutdown hysteresis width ? tsd designed target value* 15 c * designed target value: no measurement made. package dimensions unit : mm (typ) 3275 pin assignment c vin d swout e gnd f vos g ss sanyo : smp5 1.5 10.0 9.9 1.2 4.5 (8.8) 1.3 4.5 2.7 0.4 1.7 (1.6) 0.9 15 0.2 ila07131 ambient temperature, ta - c allowable power dissipation, pd max - w pd max - ta 3.0 3.90 3.5 2.5 2.0 1.5 1.0 0.5 0 4.5 4.0 -30 160 0 20 40 60 80 100 120 140 mounted on a specified board: 114.3mm 76.1mm 1.6mm, copper foil ratio 60% fr4
LA5771mp no.8273-3/5 block diagram application circuit example notes: c3 is for the soft start function. delete c3 and k eep the ss pin open when the soft function is not necessary. c1: 220 f/35v c2: 1000 f/6.3v c3: 1 f/50v d1: sbd l1: 68 h v in 1 2 swou t 4 vos 5 ss reg. comp. amp. + - osc reset vref tsd drive ocp 3 gnd v in LA5771mp d1 swout vos ss gnd c1 c3 c2 l1
LA5771mp no.8273-4/5 description of functional settings 1.start delay function the ss pin has the internally-connected 22 a (typ) constant-current supply. when the voltage of ss pin exceeds the threshold voltage, the regulator starts operation. as the thre shold is 0.62v(typ), the start delay time can be calculated as follows: ex. for setting at 1 f 2.soft start function the internal pwm waveform has the voltage value as shown in the right. if down-conversion from the voltage of v in =15v to 3.3v output is to be made, for example, the pwm-on duty has the value as shown below. (note that calculation is made with vsat=1v and vf=0.2v) the output voltage of error amplifier, which is 3.3v, is th e value with pwm=23%, as calcu lated in the above equation, so that this voltage is determined as follows: ver=( ? vpwm) pwmduty+vpwml=0.88v 0.23+0.62v=0.82v ( ? vpwm is the pwm amplitude value or 0.88v(typ) while vpwml is the lower limit voltage of pwm waveform or 0.62v(typ)) ss pin and error amplifier output voltages are designed to prefer the lower voltages, so that v out will reach the designed regulation voltage in timing when the ss pin voltage exceeds the error amplifier output. therefore, the soft strt time is calculated as follows: for the set conditions of c=1 f and pwmduty=23%: 28.2ms 22 62v01 i vc td = ? . = = 23% vfvsat- in v out v pwmduty = + = a22 pwmduty 88v0c i pwmduty vpwm c tss . = ? = ms2.9 a22 088v01 tss = . 23. = 1.5v 0.62v pwm wave
LA5771mp no.8273-5/5 timing chart ps v in swout v out td tss this catalog provides information as of january, 2007. specifications and information herein are subject to change without notice. sanyo semiconductor co.,ltd. assumes no responsib ility for equipment failures that result from using products at values that exceed, even momentarily, rate d values (such as maximum ra tings, operating condition ranges, or other parameters) listed in products specif ications of any and all sanyo semiconductor co.,ltd. products described or contained herein. sanyo semiconductor co.,ltd. strives to supply high-qual ity high-reliability products, however, any and all semiconductor products fail or malfunction with some probabi lity. it is possible that these probabilistic failures or malfunction could give rise to acci dents or events that could endanger human lives, trouble that could give rise to smoke or fire, or accidents that could cause dam age to other property. when designing equipment, adopt safety measures so that these kinds of accidents or e vents cannot occur. such measures include but are not limited to protective circuits and error prevention c ircuits for safe design, redundant design, and structural design. upon using the technical information or products descri bed herein, neither warranty nor license shall be granted with regard to intellectual property rights or any other rights of sanyo semiconductor co.,ltd. or any third party. sanyo semiconductor co.,ltd. shall not be liable for any claim or suits with regard to a third party's intellctual property rights which has resulted from the use of the technical information and products mentioned above. information (including circuit diagr ams and circuit parameters) herein is for example only; it is not guaranteed for volume production. any and all information described or contained herein are subject to change without notice due to product/technology improvement, etc. when designing equi pment, refer to the "delivery specification" for the sanyo semiconductor co.,ltd. product that you intend to use. in the event that any or all sanyo semiconductor co.,ltd. products described or contained herein are controlled under any of applicable local export control laws and regulations, such products may require the export license from the authorities conc erned in accordance with the above law. no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, or any information storage or retrieval system, or otherwise, without the prior written consent of sanyo semiconductor co.,ltd.
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