Allegro A8178LLT, A8178LLR Datasheet

8178

Data Sheet

27468.22

PRODUCT PREVIEW

(Subject to change without notice)

April 5, 1996

3

VR

7.7 V

1

VR

2

7.7 V

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.

2 31

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.

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

LOW-DROPOUT,

7.7 V PREREGULATOR

ELECTRICAL CHARACTERISTICS over operating temperature range.

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Output Voltage V

Output Volt. Temp. Coeff. α
Line Regulation ∆V
Load Regulation ∆V
Quiescent Current I

Power Dissipation P
Thermal Resistance* R

O

VO

O(∆VI)

O(∆IO)

Q

d

θJA

6.9 V ≤ VI ≤ 24 V 6.5 7.7 8.8 V

2.5 V ≤ V
V

= 120 V, pulse test — — 11 V

I

≤ 6.9 V VI - 0.4 — — V

I

VI = 13.5 V, IO = 0 — — 2.5 mA

2.5 V ≤ V

≤ 8 V, IO = 0 — — 5.6 mA

I

VI = 13.5 V, IO = 15 mA — — 130 mW
A8178LLR — 575 — °C/W
A8178LLT — 200 — °C/W

Typical values are at T

*Mounted on 2.24" x 2.24" solder-coated copper-clad board in still air.

= +25°C and are given for circuit design information only.

A

— — TBD mV/°C
— — TBD mV
— — TBD mV

INTERNAL PROTECTIVE FEATURES

ISO

Pulse No. Test Test Conditions (at T

1 Inductive Turn Off (Negative) V

2 Inductive Turn Off (Positive) V
3a Capacitive/Inductive Coupling (Neg) V
3b Capacitive/Inductive Coupling (Pos) V

4 Reverse Battery V

5 Load Dump V

6 Ignition Coil Disconnect V

EXTERNAL PROTECTION REQ’D

7 Field Decay (Negative) V

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
Copyright © 1996 Allegro MicroSystems, Inc.

= -100 V, RS = 10 Ω, tr = 1 µs, td = 2 ms

S

= 100 V, RS = 10 Ω, tr = 1 µs, td = 50 µs, non-operating

S

= -150 V, RS = 50 Ω, tr = 50 ns, td = 100 ns

S

= 100 V, RS = 50 Ω, tr = 50 ns, td = 100 ns

S

= -14 V, td = 20 s, non-operating

S

= 86.5 V, RS = 0.5 Ω, tr = 5 ms, td = 400 ms

S

= -300 V, RS = 30 Ω, tr = 60 µs, td = 300 µs

S

= -80 V, RS = 10 Ω, tr = 5 ms, td = 100 ms

S

= +25°C)

A

8178

LOW-DROPOUT,

7.7 V PREREGULATOR

A8178LLR

Dimensions in Inches

(for reference only)

0.055

0.047

0.024

0.018

0.004

0.0005

0.020

0.015

0.120

0.110

3

1

2

0.1039

0.083

0.040

0.080

0.035

0.070

Dimensions in Millimeters

(controlling dimensions)

0.044

0.035

0.007

0.003

0.027

REF

Dwg. MA-010 in

3.04

2.80

0.51

0.37

1.40

1.20

1

0.60

0.45

2.05

1.78

0.10

0.013

NOTES: 1. Lead spacing tolerance is non-cumulative.

2.Exact body and lead configuration at vendor’s option within limits shown.

1.12

0.89

0.18

0.085

3

2.64

2

2.10

0.69

REF

1.03

0.89

Dwg. MA-010 mm

8178

LOW-DROPOUT,

7.7 V PREREGULATOR

A8178LLT

Dimensions in Inches

(for reference only)

0.155

0.167

0.035

0.047

0.059

BSC

1

0.173

0.181

0.064

0.072

0.090

23

0.102

0.014

0.019

0.017

0.022

0.118

BSC

Dimensions in Millimeters

(controlling dimensions)

4.40

4.60

1.62

1.83

0.055

0.063

0.014

0.017

0.084

0.090

Dwg. MA-009-3 in

1.40

1.60

0.35

0.44

3.94

4.25

1

23

0.89

1.20

1.50

BSC

3.00

BSC

NOTES: 1. Lead spacing tolerance is non-cumulative.

2.Exact body and lead configuration at vendor’s
option within limits shown.

2.29

2.60

2.13

2.29

0.36

0.48

0.44

0.56

Dwg. MA-009-3 mm

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 [phone]