1

2

3

Dwg. PD-0xx

VR

VR

7.7 V

2

3

1

LOW-DROPOUT,

7.7 V PREREGULATOR

Designed specifically to meet the stringent requirements of automo-

tive 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 automo-

tive 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 dissipa-

tion.

ABSOLUTE MAXIMUM RATINGS

Input Voltage, V

30 V

Reverse Input Voltage, V

-120 V

Output Current, I

TBD*

Operating Temperature Range,

T

-40

Junction Temperature, T

+150

Storage Temperature Range,

T

-40

* 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)

April 5, 1996