FEATURES

NEW DMOS TOPOLOGY:

Ultra Low Dropout Voltage:

115mV Typ at 500mA and 3.3V Output

Output Capacitor NOT Required for Stability

FAST TRANSIENT RESPONSE

VERY LOW NOISE: 33μVrms

HIGH ACCURACY: ±2% max

HIGH EFFICIENCY:

IGND = 1mA at IOUT = 500mA

Not Enabled: IGND = 0.5μA

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

OUTPUT VERSIONS

FOLDBACK CURRENT LIMIT

THERMAL PROTECTION

OUTPUT VOLTAGE ERROR INDICATOR(1)

SMALL SURFACE-MOUNT PACKAGES:

SOT223-5, DDPAK-5, SO-8

APPLICATIONS

PORTABLE COMMUNICATION DEVICES

BATTERY-POWERED EQUIPMENT

PERSONAL DIGITAL ASSISTANTS

MODEMS

BAR-CODE SCANNERS

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 1μF.

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

and drops to 0.5μA 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 33μVrms

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 maintained

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 circuitry

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.