Allegro A8187SLT Datasheet

VR

2

3.3 V

31

27468.16A

8187

LOW-DROPOUT, 3.3 V REGULATOR

— HIGH EFFICIENCY

Designed specifically to meet the requirement for extended opera­tion of battery-powered equipment such as cordless and cellular
telephones, the A8187SLT voltage regulator offers the reduced dropout
voltage and quiescent current essential for maximum battery life.
Applicable also to palmtop computers and personal data assistants, the
device delivers a regulated, continuous 3.3 V output at up to 75 mA
under normal operating conditions, or to 150 mA (transient) under
worst-case conditions.

A PMOS pass element provides a typical dropout voltage of only
85 mV at 60 mA of load current. The low dropout voltage permits
deeper battery discharge before output regulation is lost. Furthermore,
quiescent current does not increase as the dropout voltage is ap­proached, an ideal feature in standby/resume power systems where
data integrity is crucial. Regulator accuracy and excellent temperature
characteristics are provided by a bandgap reference.

Data Sheet

IN

GND

ABSOLUTE MAXIMUM RATINGS

Input Voltage, VI. . . . . . . . . . . . . . 10 V

Output Current, IO. . . . . . . . . 150 mA*

Operating Temperature Range,

TA. . . . . . . . . . . . . -20°C to +85°C

Junction Temperature, TJ. . . +150°C

Storage Temperature Range,

* Output current rating is limited by input voltage,

† Fault conditions that produce excessive junction

DISCONTINUED PRODUCT

TS. . . . . . . . . . . . -40°C to +150°C

duty cycle, and ambient temperature. Under
any set of conditions, do not exceed a junction
temperature of +150°C. See next page.

temperature will activate device thermal
shutdown circuitry. These conditions can be
tolerated but should be avoided.

— FOR REFERENCE ONLY

OUT

Dwg. PS-022-1

This device is supplied in a small-outline plastic transistor package
(SOT-89/TO-243AA) for surface-mount applications. The A8187SLT is
rated for operation over a temperature range of -20°C to +85°C. A
similar device with an ENABLE input for control over sequential power
up, standby, or power down is the A8186SLU.

FEATURES AND BENEFITS

■ High Efficiency Provides Extended Battery Life

■ 85 mV Typical Dropout Voltage at IO = 60 mA

■ 45 µA Typical Quiescent Current at VI = 6 V

■ Up to 150 mA Output Current

■ Internal Thermal Protection

■ Surface-Mount Package

†

APPLICATIONS

■ Cordless and Cellular Telephones

■ Personal Data Assistants

■ Personal Communicators

■ Palmtop Computers

Always order by complete part number: A8187SLT .

8187

LOW-DROPOUT,

3.3 V REGULATOR

FUNCTIONAL BLOCK DIAGRAM

IN

GND

1

BIAS

DRIVE

ERROR

3

OUT

AMP

BANDGAP

THERMAL

PROTECT.

2

REF.

TAB

Dwg. FS-012-4

MAXIMUM ALLOWABLE OUTPUT CURRENT with device mounted on 2.24" x 2.24"
(56.9 mm x 56.9 mm) solder-coated copper-clad board in still air.

Maximum Allowable Output Current in Milliamperes with VI = 8 V, TJ = 150°C, Period ≤10 s*

dc (Duty Cycle)

T

A

25°C 100 115 125 145 150 150 150 150 150

50°C 80 90 100 115 135 150 150 150 150

70°C 65 70 80 90 110 130 150 150 150

85°C 50 60 65 75 85 105 130 150 150

*IO = (TJ - TA)/([VI - VO] R

Output current rating can be increased (to 150 mA maximum) by heat sinking or reducing the input voltage. Conditions that produce excessive
junction temperature will activate device thermal shutdown circuitry. These conditions can be tolerated but should be avoided.

100% 90% 80% 70% 60% 50% 40% 30% 20%

• dc) = (150 - TA)/(4.7 • 258 • dc)

θJA

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
Copyright © 1995, 2000 Allegro MicroSystems, Inc.

8187

LOW-DROPOUT,

3.3 V REGULATOR

ELECTRICAL CHARACTERISTICS at TA = +25°C (unless otherwise noted).

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Output Voltage V

Output Volt. Temp. Coeff. α

Line Regulation ∆V

Load Regulation ∆V

O

VO

O(∆VI)

O(∆IO)

4 V ≤ VI ≤ 8 V, TA = +25°C 3.25 3.30 3.35 V

10 µA ≤ I

= 3.3 V, IO = 60 mA*, -20°C ≤ TA ≤ +85°C 3.00 — — V

V

I

≤ 100 mA* -20°C ≤ TA ≤ +85°C 3.20 3.30 3.40 V

O

VI = 6 V, IO = 10 mA — — ±1.0 mV/°C

6 V ≤ VI ≤ 8 V, IO = 1 mA — 8.0 12 mV

4 V ≤ V

≤ 6 V, IO = 1 mA — 10 20 mV

I

1 mA ≤ IO ≤ 100 mA*, VI = 8 V — 20 30 mV

1 mA ≤ IO ≤ 100 mA*, VI = 6 V — 13 25 mV

≤ 100 mA*, VI = 4 V — 8.0 20 mV

O

Dropout Voltage V

1 mA ≤ I

min - VOIO = 60 mA* — 85 150 mV

I

IO = 125 mA* — 190 300 mV

Quiescent Current I

Q

(GND terminal current) V

Thermal Shutdown Temp. T

Thermal Resistance R

J

θJA

VI = 6 V, 1 mA ≤ IO ≤ 100 mA* — 45 60 µA

= 8 V, 1 mA ≤ IO ≤ 100 mA* — 50 65 µA

I

Mounted on 2.24" x 2.24" solder-coated — 258 — °C/W
copper-clad board in still air

Typical values are at TA = +25°C and are given for circuit design information only.

* Pulse test (≤20 ms). See previous page for duty cycle limitations.

150 — — °C