Allegro A8405SLH-50, A8405SLH-40, A8405SLH-38, A8405SLH-36, A8405SLH-33 Datasheet

DISCONTINUED PRODUCT

— FOR REFERENCE ONLY

Designed specifically to meet the requirement for extended opera­tion of battery-powered equipment such as cordless and cellular tele­phones, the A8405SLH voltage regulators offer the reduced dropout
voltage and quiescent current essential for maximum battery life.
Applicable also to palmtop computers and personal data assistants,
these devices deliver a regulated output at up to 200 mA (transient),
which is internally limited, providing short-circuit protection. Regu­lated output voltages of 2.7, 2.8, 3.0, 3.2, 3.3, 3.6, 3.8, 4.0, and 5.0 V
are currently provided. Other voltages, down to 2.0 volts, are available
on special order.

A PMOS pass element provides a typical dropout voltage of only
100 mV at 100 mA of load current. The low dropout voltage permits
deeper battery discharge before output regulation is lost. Quiescent
current does not increase significantly 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. The A8405SLH
includes an ENABLE input to give the designer complete control over
power up, standby, or power down.

These devices are supplied in a thermally enhanced 5-lead small­outline plastic package similar to the SOT-23, and fitting the SC-74A
footprint. All devices are rated for operation over a temperature range
of -20°C to +85°C.

FEATURES AND BENEFITS

■ High Efficiency Provides Extended Battery Life

■ 100 mV Typical Dropout Voltage at I

O

= 100 mA

■ 80 µA Typical Quiescent Current

■ Low Output Noise

■ 200 mA Current-Limited Output

■ Improved PSRR and Transient Performance

APPLICATIONS

■ Cordless/Cellular/GSM/PHS Telephones

■ Personal Data Assistants

■ Personal Communicators

■ Palmtop Computers

■ GPS

■ Pagers

LOW-DROPOUT REGULATORS

— HIGH EFFICIENCY

Data Sheet

27468.22

PRELIMINARY INFORMATION

(subject to change without notice)

June 25, 1999

Always order by complete part number, e.g., A8405SLH-xx , where “xx”
is the required output voltage in tenths or “ADJ” for adjustable.

ABSOLUTE MAXIMUM RATINGS

Input Voltage, VI. . . . . . . . . . . . . . . 7 V

Peak Output Current,

IOM. . . . . . . . . . . . . . . . . . 200 mA*

Enable Input Voltage, VE. . . . . . . . . . V

I

Operating Temperature Range,

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

Junction Temperature, TJ. . . . +150°C

Storage Temperature Range,

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

8405

Dwg. PS-021-6

VR

2

GND

3

BYPASS

OR

ADJ*

1

ENABLE

5

IN

OUT

4

*BYPASS (fixed regulators) or

ADJUST (A8405SLH-ADJ only).

8405

LOW-DROPOUT
REGULATORS

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

FUNCTIONAL BLOCK DIAGRAM

Copyright © 1999, 2000 Allegro MicroSystems, Inc.

A8405SLH Maximum Allowable Average 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.

Allowable Total Average (10 ms) Output Current in Milliamperes with TJ = 150°C, Duty Cycle = 100%†

VI - V

O

T

A

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0* 4.5*

25°C 200 200 200 200 200 189 162 142 126

50°C 200 200 200 200 182 152 130 114 101

70°C 200 200 200 182 145 121 104 91 81

85°C 200 200 197 148 118 98 84 74 66

* Absolute maximum peak output current rating is 200 mA; absolute maximum input voltage is 7 V.

† IO = (TJ – TA)/([VI – VO] R

θJA

x dc) = (150 – TA)/([VI – VO] x 220 x 1.00)

Output current rating can be increased (to 200 mA maximum) by additional heat sinking or reducing the duty cycle.

OVERCURRENT

PROTECTION

THERMAL

PROTECT.

DRIVE

BANDGAP

REF.

ERROR

AMP

Dwg. FS-012-7

BIAS

ENABLE

IN

ENABLE

OUT

1 5

3

2

GND

BYPASS

(FIXED REG'S)

4

OUT

5

ADJUST

(SUFFIX
"-ADJ" ONLY)

4

8405

LOW-DROPOUT

REGULATORS

www.allegromicro.com

ELECTRICAL CHARACTERISTICS

at TA = +25°C, VE ≥ 2.0 V, C

BYPASS

= TBD (unless otherwise noted).

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Output Voltage V

O

VI ≥ V

O(nom)

+ 1 V, 1 mA ≤ IO ≤ 150 mA* — ±0.5 — %

(reference specified V

O(nom)

)

VI ≥ V

O(nom)

+ 1 V, 1 mA ≤ IO ≤ 150 mA*,

over operating temperature range — — ±2.0 %

VI = V

O(nom)

, IO = 50 mA — — -0.25 V

Output Volt. Temp. Coeff. a

VO

VI = 6 V, IO = 10 mA, TJ ≤ 125°C — TBD — mV/°C

Output Short-Circuit Current I

OM

200 — — mA

Line Regulation ∆V

O(∆VI)

at VI = V

O(nom)

+ 1 V, IO = 3 mA

and VI = 7 V, IO = 3 mA — 1.0 2.0 mV

Load Regulation ∆V

O(∆IO)

at VI = V

O(nom)

+ 1 V, IO = 1 mA

and VI = V

O(nom)

+ 1 V , IO = 150 mA* — 2.0 — mV

at VI = 7 V, IO = 1 mA
and VI = 7 V, IO = 150 mA* — 2.0 — mV

Dropout Voltage VImin - VOIO = 100 mA — 100 — mV

Ground Terminal Current I

GND

VI = V

O(nom)

+ 1 V, IO = 1 mA — 80 100 µA

VI = V

O(nom)

+ 1 V, IO = 150 mA* — 80 100 µA

VI = 7 V, IO = 1 mA — 80 100 µA

VI = 7 V, IO = 150 mA* — 80 100 µA

I

Q

VI ≤ 7 V, VE ≤ 0.8 V, IO = 0 mA — — 1.0 µA

ENABLE Input Voltage V

EH

VI ≥ V

O(nom)

+ 1 V, Output ON 2.0 — — V

V

EL

VI ≥ V

O(nom)

+ 1 V, Output OFF — — 0.4 V

ENABLE Input Current I

E

VE = VI = 7 V — — ±1.0 µA

Internal Reference Voltage V

REF

—1.26— V

ADJUST Input Current I

ADJ

A8405SLH-ADJ only — 0.10 — µA

Rejection Ratio PSRR VI = V

O(nom)

+ 1.5 V, Vi = 100 mV,

IO = 30 mA, f = 60 Hz — 70 — dB

Output Noise e

n

10 Hz ≤ f ≤ 100 kHz, IO = 10 mA, CO = 10 µF

—0.2—µV/√Hz

Thermal Shutdown T

J

— 170 — °C

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.