8178
PRODUCT PREVIEW
(Subject to change without notice)
April 5, 1996
Data Sheet
27468.22
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.
3
VR
1
2
VR
7.7 V
1
2
Dwg. PD-0xx
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.
7.7 V
3
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
.
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
