advanced power electronics corp. 1.6x linear regulator for dc fan driver control features description low dropout voltage: 150mv@0.5a v o follows 1.6 times of v set enable/shutdown function stable with low esr ceramic capacitors current-limit and thermal shutdown protection sop-8 pb-free package data and specifications subject to change without notice 200808283 APE8873 typical application package ordering information 1 the APE8873 is a low dropout linear regulator which is designed to power a dc fan and delivers up to 500ma output current. the output voltage follows the 1.6 times of v set voltage and typical dropout voltage is only 150mv (typical) at 500ma output current. the v set voltage must be larger than 1v to guarantee v o 1.6 times of v set . an enable pin further reduces power dissipation while shut-down. the features of current limit (with fold back current) and over temperature protection protect the device against current over-loads and over temperature. the APE8873 is available in a sop-8 package. package type m : sop-8l APE8873x y ww sss 8873m part number id code: internal ww: 01~52 year: 8 : 2008 c1 2 .2uf vo =1 .6 x v set vin=5v u1 APE8873 2 5 ,6,7, 8 1 4 3 vin gnd vset en vo c2 2.2 uf vset fan
advanced power electronics corp. APE8873 absolute maximum ratings v in supply voltage (v in ) ??????????? ? -0.3 to 7 v en voltage (v en ) ?????????????? ? -0.3v to vin v set voltage (v set ) ????????????? ? -0.3v to vin power dissipation (p d ) ???????????? internally limited storage temperature range (t st ) ??????? -65 to +150c junction temperature range (t j ) ??????? ? -40 to 125c operating temperature range (t op ) ?????? -40 to +85c thermal resistance from junction to case (r thjc ) 20c/w 60c/w note: r thja is measured with the pcb copper area approximately 1.5 in 2 (multi-layer) package information electrical specifications ( v set = 2v, v in = 5v, i o = 0.5a, c in =c out =2.2uf, t a =25 unless otherwise specified) parameter sym test condition min typ max units v in supply voltage range v in 4.5 - 5.5 v quiescent current i ccq v o =5v, no load - 1 - ma standby current i stb v en =0v - 10 50 ua output voltage/v set voltage v o /v set v in =5.5v, v set =1v~3.2v 1.552 1.6 1.648 v/v line regulation vin=4.5v to 5.5v - 0.2 0.5 % load regulation i o =10ma ~ 0.5a - 0.2 0.5 % output resistance r ds(on) i o =0.5a, v set =3.4v - 300 400 m ? current limit i limt -1- a short circuit current i short vo<0.6v - 0.5 - a minimum v set voltage v set -1- v v set pin current i set - 80 200 na v en-h operating mode 2 - - v en-l shutdown mode - - 0.8 en pin pull-up current i en en=0v - 1.5 10 ua thermal shutdown temp t sd - 150 - c thermal shutdown hysteresis - 40 - c 2 en pin logic threshold voltage v thermal resistance from junction to ambient (r thja ) ( top view ) 1 2 3 4 8 7 6 5 vo vset sop-8l APE8873 en vin gnd gnd gnd gnd
advanced power electronics corp. APE8873 pin descriptions pin symbol pin description gnd gnd pin vin ic power supply pin vo output pin. its voltage is 1.6 times of v set this pin sets the output voltage. its voltage must be larger than 1v to guarantee v o 1.6 times of v set en this pin is pulling high inside. if en input < 0.8v, the ic is into shutdown mode. block diagram function description output voltage regulation current-limit short current protection thermal shutdown 3 vset the output voltage is set by vset voltage. vo output voltage follows the 1.6 times of vset voltage until it reaches vin voltage. the APE8873 monitors the current via the output pmos and limits the maximum current to prevent load and APE8873 from damages during overload or short circuit conditions. when the output voltage drops below 0.6v (typical), which is caused by over load or short circuit, the fold back current limit circuitry limits the output current to 500ma. the fold back current limit is used to reduce the power dissipation during short circuit condition. a thermal shutdown circuit limits the junction temperature of APE8873. when the junction temperature exceeds +150c, a thermal sensor turns off the output pmos, allowing the device to cool down. the regulator regulates the output again through initiation of a new soft-start cycle after the junction temperature cools by 40c, resulting in a pulsed output during continuous thermal overload conditions. current limit and short protection - + vin vo gnd error amp thermal shutdown enable vset en
advanced power electronics corp. APE8873 application information capacitor selection thermal considerations pcb layout 4 normally, use a 2.2uf capacitor on the input and a 2.2uf capacitor on the output of the a pe8873. in order to insure the circuit stability, the proper output capacitor value should be large r than 1uf. with x5r and x7r dielectrics, 2.2uf is sufficient at all operating temperatures. the APE8873 series can deliver a current of up to 500ma over the full operating junction temperature range. however, the maximum output current must be dated at higher ambient temperature to ensure the junction temperature does not exceed 125c. with all possible conditions, the junction temperature must be within the range specified under operating conditions. power dissipation can be calculated based on the output current and the voltage drop across regulator. p d = (v in - v o ) i o the final operating junction temperature for any set of conditions can be estimated by the following thermal equation: p d (max) = (t j (max) - t a ) / r thja where t j (max) is the maximum junction temperature of the die (125 c) and t a is the maximum ambient temperature. the junction to ambient thermal resistance (r thja ) for sop-8l package at recommended minimum footprint is 60c/w. visit our website in which ?recommended footprints for soldering surface mount packages? for detail. 1. please place the input capacitors close to the v in 2. ceramic capacitors for load must be placed near the load as close as possible 3. to place APE8873 and output capacitors near the load is good for performance. 4. large current paths that v in and output lines must have wide tracks. 5. gnd connect large copper area can reduced ic temperature.
millimeters symbols min nom max a 1.35 1.55 1.75 a1 0.10 0.18 0.25 b 0.33 0.41 0.51 c 0.19 0.22 0.25 d 4.80 4.90 5.00 e 5.80 6.15 6.50 e1 3.80 3.90 4.00 e g l 0.38 0.90 0.00 4.00 8.00 1.all dimension are in millimeters. 2.dimension does not include mold protrusions. part marking information & packing : so-8 1.27 typ 0.254 typ package outline : so-8 advanced power electronics corp. e b 1 34 5 6 7 8 2 d e1 a1 a g part number 8873 m ywwsss package code date code (ywwsss) y last digit of the year ww week sss sequence e
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