DMOS

500mA Low-Dropout Regulator

FEATURES

q NEW DMOS TOPOLOGY:

Ultra Low Dropout Voltage:

115mV Typ at 500mA and 3.3V Output

Output Capacitor NOT Required for Stability

q FAST TRANSIENT RESPONSE

q VERY LOW NOISE: 33

µVrms

q HIGH ACCURACY:

±2% max

q HIGH EFFICIENCY:

IGND = 1mA at IOUT = 500mA

Not Enabled: IGND = 0.5µA

q 2.5V, 2.7V, 3.0V, 3.3V, 5.0V, AND ADJUSTABLE

OUTPUT VERSIONS

q FOLDBACK CURRENT LIMIT

q THERMAL PROTECTION

q OUTPUT VOLTAGE ERROR INDICATOR(1)

q SMALL SURFACE-MOUNT PACKAGES:

SOT223-5, DDPAK-5, SO-8

APPLICATIONS

q PORTABLE COMMUNICATION DEVICES

q BATTERY-POWERED EQUIPMENT

q PERSONAL DIGITAL ASSISTANTS

q MODEMS

q BAR-CODE SCANNERS

q BACKUP POWER SUPPLIES

DESCRIPTION

The REG103 is a family of low-noise, low-dropout, linear

regulators with low ground pin current. Its new DMOS

topology provides significant improvement over previous

designs, including low-dropout voltage (only 115mV typ at

full load), and better transient performance. In addition, no

output capacitor is required for stability, unlike conventional

low-dropout regulators that are difficult to compensate and

require expensive low ESR capacitors greater than 1

µF.

Typical ground pin current is only 1mA (at IOUT = 500mA)

and drops to 0.5

µA in not enabled mode. Unlike regulators

with PNP pass devices, quiescent current remains relatively

constant over load variations and under dropout conditions.

The REG103 has very low output noise (typically 33

µVrms

for VOUT = 3.3V with CNR = 0.01µF), making it ideal for use

in portable communications equipment. On-chip trimming

results in high output voltage accuracy. Accuracy is main-

tained over temperature, line, and load variations. Key

parameters are tested over the specified temperature range

(–40

°C to +85°C).

The SO-8 version of the REG103 has an ERROR pin that

provides a power good flag, indicating the regulator is in

regulation. The REG103 is well protected—internal cir-

cuitry provides a current limit that protects the load from

damage. Thermal protection circuitry keeps the chip from

being damaged by excessive temperature. In addition to the

SO-8 package, the REG103 is also available in the DDPAK

and the SOT223-5.

REG103

(Fixed Voltage

Versions)

ENABLE

Gnd

0.1

µF

C

OUT

(2)

+

+

V

OUT

V

IN

NR

NR = Noise Reduction

ERROR(1)

ERROR1)

REG103-A

Gnd

ENABLE

0.1

µF

+

C

OUT

(2)

+

V

OUT

V

IN

R

2

R

1

Adj

REG103

REG1

03

REG1

03

REG103

SBVS010D – JANUARY 2000 – REVISED SEPTEMBER 2005

www.ti.com

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

Copyright © 2000-2005, Texas Instruments Incorporated

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

All trademarks are the property of their respective owners.

NOTE: (1) SO-8 Package Only. (2) Optional.