data sheet 27468.23 low-dropout, 7.7 v preregulator designed specifically to meet the stringent requirements of automo- tive applications, the A8178llt provides an output voltage of 7.7 v 15% for supply voltages greater than 6.9 v. this device also provide a low-dropout tracking output for supply voltages down to 2.5 v. this regulator is intended to be used with sensitive automotive electronics systems that do not have the capability of low dropout operation and cannot withstand the high-voltage transients typical of automotive applications. this 7.7 v preregulator will withstand all iso pulses (ignition coil disconnect requires an external diode) and will continue to operate during positive power supply transients (noise). this device is supplied in a small-outline plastic transistor package for surface-mount applications. the A8178llt is furnished in the sot- 89/to-243aa for increased allowable package power dissipation. absolute maximum ratings input voltage, v i . . . . . . . . . . . . . . 30 v reverse input voltage, v ri . . . . -120 v output current, i o . . . . . . . . . . . . tbd* operating temperature range, t a . . . . . . . . . . . . -40 c to +150 c junction temperature, t j . . . . +150 c storage temperature range, t s . . . . . . . . . . . . -40 c to +170 c * output current rating is limited by input voltage, duty cycle, and ambient temperature. under any set of conditions, do not exceed a junction temperature of +150 c. see next page. t his document contains information on a product under development. allegro microsystems, inc. reserves the right to change or discontinue this product without notice. always order by complete part number: A8178llt . 8178 product preview (subject to change without notice) october 9, 2001 dwg. pd-0xx vr 7.7 v 2 3 1
8178 low-dropout, 7.7 v preregulator 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 electrical characteristics over operating temperature range. limits characteristic symbol test conditions min. typ. max. units output voltage v o 6.9 v v i 24 v 6.5 7.7 8.8 v 2.5 v v i 6.9 v v i - 0.4 v v i = 120 v, pulse test 11 v output volt. temp. coeff. vo tbd mv/ c line regulation ? v o( ? vi) tbd mv load regulation ? v o( ? io) tbd mv quiescent current i q v i = 13.5 v, i o = 0 2.5 ma 2.5 v v i 8 v, i o = 0 5.6 ma power dissipation p d v i = 13.5 v, i o = 15 ma 130 mw thermal resistance* r ja 200 c/w typical values are at t a = +25 c and are given for circuit design information only. * mounted on 2.24" x 2.24" solder-coated copper-clad board in still air. internal protective features iso pulse no. test test conditions (at t a = +25 c) 1 inductive turn off (negative) v s = -100 v, r s = 10 ? , t r = 1 s, t d = 2 ms 2 inductive turn off (positive) v s = 100 v, r s = 10 ? , t r = 1 s, t d = 50 s, non-operating 3a capacitive/inductive coupling (neg) v s = -150 v, r s = 50 ? , t r = 50 ns, t d = 100 ns 3b capacitive/inductive coupling (pos) v s = 100 v, r s = 50 ? , t r = 50 ns, t d = 100 ns 4 reverse battery v s = -14 v, t d = 20 s, non-operating 5 load dump v s = 86.5 v, r s = 0.5 ? , t r = 5 ms, t d = 400 ms 6 ignition coil disconnect v s = -300 v, r s = 30 ? , t r = 60 s, t d = 300 s external protection req? 7 field decay (negative) v s = -80 v, r s = 10 ? , t r = 5 ms, t d = 100 ms copyright ?2001 allegro microsystems, inc.
dwg. ma-009-3 in 1 23 0.064 0.072 0.155 0.167 0.059 bsc 0.014 0.019 0.035 0.047 0.090 0.102 0.055 0.063 0.014 0.017 0.084 0.090 0.017 0.022 0.118 bsc 0.173 0.181 dimensions in millimeters (controlling dimensions) dwg. ma-009-3 mm 1 23 4.40 4.60 1.62 1.83 3.94 4.25 1.50 bsc 0.36 0.48 0.89 1.20 2.29 2.60 1.40 1.60 0.35 0.44 2.13 2.29 0.44 0.56 3.00 bsc A8178llt dimensions in inches (for reference only) notes: 1. lead spacing tolerance is non-cumulative. 2. exact body and lead configuration at vendor s option within limits shown.
8178 low-dropout, 7.7 v preregulator 115 northeast cutoff, box 15036 worcester, massachusetts 01615-0036 (508) 853-5000 allegro microsystems, inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of its products. the information included herein is believed to be accurate and reliable. however, allegro microsystems, inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
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