PRODUCT PREVIEW (Subject to change without notice) April 5, 1996 7.7 V 3 VR 1 2 VR 1 2 7.7 V Data Sheet 27468.22 8178 LOW-DROPOUT, 7.7 V PREREGULATOR Designed specifically to meet the stringent requirements of automotive applications, the A8178LLR and A8178LLT provide an output voltage of 7.7 V ±15% for supply voltages greater than 6.9 V. They also provide a low-dropout tracking output for supply voltages down to 2.5 V. These regulators are 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. These 7.7 V preregulators will withstand all ISO pulses (ignition coil disconnect requires an external diode) and will continue to operate during positive power supply transients (noise). These devices are supplied in small-outline plastic transistor packages for surface-mount applications. The A8178LLR is supplied in the minimum footprint SOT-23/TO-236AB; the A8178LLT is furnished in the SOT-89/TO-243AA for increased allowable package power dissipation. 3 Dwg. PD-0xx ABSOLUTE MAXIMUM RATINGS Input Voltage, VI . . . . . . . . . . . . . . 30 V Reverse Input Voltage, VRI . . . . -120 V Output Current, IO . . . . . . . . . . . . TBD* Operating Temperature Range, TA . . . . . . . . . . . . -40°C to +150°C Junction Temperature, TJ . . . . +150 °C Storage Temperature Range, TS . . . . . . . . . . . . -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. This 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 LOW-DROPOUT, 7.7 V PREREGULATOR ELECTRICAL CHARACTERISTICS over operating temperature range. Limits Characteristic Symbol Test Conditions Min. Typ. Max. Units Output Voltage VO 6.9 V ≤ VI ≤ 24 V 6.5 7.7 8.8 V 2.5 V ≤ VI ≤ 6.9 V VI - 0.4 — — V — — 11 V αVO — — TBD mV/°C Line Regulation ∆VO(∆VI) — — TBD mV Load Regulation ∆VO(∆IO) — — TBD mV VI = 13.5 V, IO = 0 — — 2.5 mA 2.5 V ≤ VI ≤ 8 V, IO = 0 — — 5.6 mA VI = 13.5 V, IO = 15 mA — — 130 mW A8178LLR — 575 — °C/W A8178LLT — 200 — °C/W VI = 120 V, pulse test Output Volt. Temp. Coeff. Quiescent Current IQ Power Dissipation Pd Thermal Resistance* RθJA Typical values are at TA = +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 TA = +25°C) 1 Inductive Turn Off (Negative) VS = -100 V, RS = 10 Ω, tr = 1 µs, t d = 2 ms 2 Inductive Turn Off (Positive) VS = 100 V, RS = 10 Ω, tr = 1 µs, t d = 50 µs, non-operating 3a Capacitive/Inductive Coupling (Neg) VS = -150 V, RS = 50 Ω, tr = 50 ns, td = 100 ns 3b Capacitive/Inductive Coupling (Pos) VS = 100 V, RS = 50 Ω, tr = 50 ns, td = 100 ns 4 Reverse Battery VS = -14 V, td = 20 s, non-operating 5 Load Dump VS = 86.5 V, RS = 0.5 Ω, tr = 5 ms, td = 400 ms 6 Ignition Coil Disconnect EXTERNAL PROTECTION REQ’D VS = -300 V, RS = 30 Ω, tr = 60 µs, t d = 300 µs 7 Field Decay (Negative) VS = -80 V, RS = 10 Ω, tr = 5 ms, td = 100 ms 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1996 Allegro MicroSystems, Inc. 8178 LOW-DROPOUT, 7.7 V PREREGULATOR A8178LLR Dimensions in Inches (for reference only) 0.120 0.110 0.020 0.015 0.055 0.047 0.044 0.035 0.007 0.003 3 2 1 0.024 0.018 0.004 0.0005 0.1039 0.027 REF 0.083 0.040 0.035 0.080 0.070 Dwg. MA-010 in Dimensions in Millimeters (controlling dimensions) 3.04 2.80 1.12 0.89 0.51 0.37 1.40 1.20 0.18 0.085 3 2 1 0.60 0.45 0.10 0.013 2.05 1.78 2.64 2.10 0.69 REF 1.03 0.89 Dwg. MA-010 mm 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 A8178LLT Dimensions in Inches (for reference only) 0.173 0.181 0.064 0.072 0.155 0.167 1 2 0.055 0.063 3 0.090 0.102 0.014 0.017 0.084 0.090 0.014 0.019 0.017 0.022 0.035 0.047 0.059 BSC 0.118 BSC Dwg. MA-009-3 in Dimensions in Millimeters (controlling dimensions) 4.40 4.60 1.62 1.83 3.94 4.25 1 2 1.40 1.60 3 2.29 2.60 0.35 0.44 2.13 2.29 0.36 0.48 0.89 1.20 0.44 0.56 1.50 BSC 3.00 BSC Dwg. MA-009-3 mm NOTES: 1. Lead spacing tolerance is non-cumulative. 2. Exact body and lead configuration at vendor’s option within limits shown. 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. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000