lr8 features 13.2 - 450v input voltage range adjustable 1.20 - 440v output regulation 5% output voltage tolerance output current limiting 10a typical adj current internal junction temperature limiting applications off-line smps startup circuits adjustable high voltage constant current source industrial controls motor controls battery chargers power supplies ? ? ? ? ? ? ? ? ? ? ? ? general description the supertex lr8 is a high voltage, low output current, adjustable linear regulator. it has a wide operating input voltage range of 13.2 - 450v. the output voltage can be adjusted from 1.20 - 440v provided that the input voltage is at least 12v greater than the output voltage. the output voltage can be adjusted by means of two external resistors r1 and r2 as shown in the typical application circuits. the lr8 regulates the voltage difference between vout and adj pins to a nominal value of 1.20v. the 1.20v is ampli?ed by the external resistor ratio r1 and r2. an internal constant bias current of typically 10a is connected to the adj pin. this increases v out by a constant voltage of 10a times r2. the lr8 has current limiting and temperature limiting. the output current limit is typically 20ma and the minimum temperature limit is 125c. an output short circuit current will therefore be limited to 20ma. when the junction temperature reaches its temperature limit, the output current and/or output voltage will decrease to keep the junction temperature from exceeding its temperature limit. for smps start-up circuit applications, the lr8 turns off when an external voltage greater than the output voltage of the lr8 is applied to vout of the lr8. to maintain stability, a bypass capacitor of 1.0f or larger and a minimum dc output current of 500a are required. the device is available in to-243aa (sot-89), to-252 (d- pak), and to-92 packages. typical application circuit high input voltage, adjustable 3-terminal linear regulator lr8 v in * *required for conditions where v in is less than v out . r1 r2 c2 c1 r load v out vout adj vin
2 lr8 ordering information device package options to-252 (d-pak) to-92 to-243aa (sot-89) lr8 lr8k4-g lr8n3-g lr8n8-g -g indicates package is rohs compliant (green) absolute maximum ratings parameter value v in input voltage (voltages ref to adj) -0.5v to +480v output voltage range -0.5v to +470v operating ambient temperature range -40c to +85c operating junction temperature range -40c to +125c storage temperature range -65c to +150c stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the speci?cations is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. electrical characteristics (test conditions unless otherwise speci?ed: -40c < t a < 85c.) sym parameter min typ max units conditions v in - v out input to output voltage difference 12 - 450 v --- v out overall output voltage regulation 1.14 1.20 1.26 v 13.2v < v in < 400v, r1 = 2.4k, r2 = 0 v out overall output voltage regulation 375 400 425 v r1 = 2.4k, r2 = 782k v out line regulation - 0.003 0.01 %/v 17v < v in < 400v, v out = 5v, i out = 0.5ma v out load regulation - 1.4 3.0 % v in = 17v, v out = 5v, 0.5ma 3 lr8 thermal characteristics package power dissipation @ t a = 25c jc c/w ja c/w to-92 0.74w 125 170 to-243aa 1.6w 15 78 ? to-252 2.5w 6.25 50 ? note: ? ounte on oar x x .. functional block diagram overtemp & overcurrent 10a 1.2v vin vout adj lr8 pass element sym parameter min typ max units conditions i out output current limit 10 - 30 ma t j < 85c, v in - v out = 12v i out output current limit - - 0.5 ma t j > 125c, v in - v out = 450v i out minimum output current - 0.3 0.5 ma includes r1 and load current i adj adjust output current 5.0 10 15 a --- c2 minimum output load capacitance 1.0 - - f --- dv out /dv in ripple rejection ratio 50 60 - db 120hz, v out = 5v t limit junction temperature limit 125 - - c --- electrical characteristics (cont.) (test conditions unless otherwise speci?ed: -40c t a 85c.)
4 lr8 typical application circuits figure 2: smps start-up circuit figure 3: high voltage adjustable constant current source pwm ic lr8 v out 1 v out 2 + + - - v cc v auxiliar y v in = (v out + 12v) to 450v vout adj vin fb lr8 v in = (v out + 12v) to 450v r load i out = 1.20v r + - 1.0f vout adj vin lr8 v in = 17v to 450v vout adj vin * r1 6.04k 1% c2 1.0f c1 r load 16.5k v out = 5.0v v out = 1.20v 1+ r2 r1 + i adj r2 r2 18.2k 1% * required for conditions where v in is less than v out figure 1: high input voltage, 5.0v output linear regulator
5 lr8 typical performance curves 12v adj v in 2.4k 1.0f v out = 1.2v 12 v, 200 v, 400 v ad j v in 2.4k 1.0f v out = 1.2v i adj v t u o ) v ( t(junction) ( o c) te mperature va ri atio n -5 0 - 25 0 2 5 5 0 7 5 1 00 12 5 1.00 1.05 1.10 1.15 1.20 1.25 1.30 adjustment current i ad j ( ) a t(junction) ( o c) -5 0 - 25 0 2 5 5 0 7 5 1 00 12 5 6 7 8 9 10 11 12 v in = 400v v in = 12v v in = 200v v ou t ) v ( i out (ma ) load regulation 0 2 4 6 8 1 0 4. 8 4. 9 5. 0 5. 1 5. 2 adj v in 6.04k 1% 18.2k 1% 1.0f r lo ad v out = 5.0v 25v i out lr8 lr8 lr8
6 lr8 typical performance curves (cont.) adj v in 6.04k 1% 18.2k 1% 1.0 f 1k v out = 5.0v 0v to 50 v v out vs . v in v ou t ) v ( v in (v) 0 1 0 2 0 3 0 4 0 5 0 0 1 2 3 4 5 6 ripple rejectio n ) b d ( o i t a r n o i t c e j e r e l p p i r i out (ma) 0 2 4 6 8 1 0 -6 0 -6 1 -6 2 -6 3 -6 4 -6 5 adj v in 6.04k 1% 18.2k 1% 1.0f r lo ad v out = 5.0v 65v i out 20v p- p @ 60hz 30 25 20 15 10 -4 0 - 20 0 2 0 4 0 6 0 8 0 100 te mperature ( c ) ) a m ( l c l lr8 lr8
7 lr8 typical performance curves (cont.) ? ? ? ? ? ? ? load tr ansient respons e line t ransient response line power up t ransient line power down tr ansient lr8 lr8
8 lr8 3-lead to-252 d-pak package outline (k4) note: ltoug terinal locations are sown onl are unctional. ea nuer was reoe. . 1 2 3 4 l4 l5 b b2 e d1 e1 l1 l seating plane a1 gauge plane d e vi ew b front v iew side v iew rear v iew vi ew b 1 h c2 a l3 l2 b3 note 1 symbol a a1 b b2 b3 c2 d d1 e e1 e h l l1 l2 l3 l4 l5 1 dimension (inches) min .086 - .025 .030 .195 .018 .235 .205 .250 .170 .090 bsc .370 .055 .108 ref .020 bsc .035 - .045 0 o 0 o nom - - - - - - .240 - - - - .060 - - - - - max .094 .005 .035 .045 .215 .035 .245 - .265 - .410 .070 .050 .040 .060 10 o 15 o mfhr0585ddhmh53371 drawings not to scale. supertex doc. #: dsd ersion d.
9 lr8 3-lead to-92 package outline (n3) symbol a b c d e e1 e e1 l dimensions (inches) min .170 .014 ? .014 ? .175 .125 .080 .095 .045 .500 nom - - - - - - - - - max .210 .022 ? .022 ? .205 .165 .105 .105 .055 .610* jedec registration to-92. * this dimension is not speci?ed in the original jedec drawing. the value listed is for reference only. ? this dimension is a non-jedec dimension. drawings not to scale. supertex doc.#: dspd-3to92n3, version d080408. seating plane 1 2 3 front v iew side v iew bottom v iew e1 e d e1 l e c 1 2 3 b a
supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such appl ications unless it receives an adequate product liability indemnification insurance agreement. supertex inc. does not assume responsibility for use of devices described, and limits its liability to the replacement of the devices determined defective due to workmanship. no responsibility is assumed for possible omissions and inaccuracies. circuitry and specifications are subject to change without notice. for the latest product specifications refer to the supertex inc. website: http//www .supertex.com . ?2008 all rights reserved. unauthorized use or reproduction is prohibited . 1235 bordeaux drive, sunnyvale, ca 9408 9 te l: 408-222-8888 www .supertex.com 10 lr8 (the package drawing(s) in this data sheet may not re?ect the most current speci?cations. for the latest package outline information go to http://www.supertex.com/packaging.htm l .) doc.# dsfp-lr8 a091208 3-lead to-243aa (sot-89) package outline (n8) symbol a b b1 c d d1 e e1 e e1 h l dimensions (mm) min 1.40 0.44 0.36 0.35 4.40 1.62 2.29 2.13 1.50 bsc 3.00 bsc 3.94 0.89 nom - - - - - - - - - - max 1.60 0.56 0.48 0.44 4.60 1.83 2.60 2.29 4.25 1.20 jedec registration to-243, variation aa, issue c, july 1986. drawings not to scale . supertex doc. #: dspd-3to243aan8, version d070908. b b1
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