REG101
REG101
www.ti.com
DMOS
100mA Low-Dropout Regulator
DESCRIPTION
FEATURES
The REG101 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 60mV typ at full load), and better transient
performance. In addition, no output capacitor is re-
quired for stability, unlike conventional low dropout
regulators that are difficult to compensate and require
expensive low ESR capacitors greater than 1µF.
● NEW DMOS TOPOLOGY:
Ultra Low Dropout Voltage:
60mV typ at 100mA
Output capacitor NOT required for stability
● FAST TRANSIENT RESPONSE
●
VERY LOW NOISE: 23µVrms
● HIGH ACCURACY: ±1.5% max
● HIGH EFFICIENCY:
Typical ground pin current is only 500µA (at IOUT
=
IGND = 500µA at IOUT = 100mA
Not Enabled: IGND = 10nA
100mA) and drops to 10nA when not enabled mode.
Unlike regulators with PNP pass devices, quiescent
current remains relatively constant over load variation
and under dropout conditions.
● 2.5V, 2.8V, 2.85V, 3.0V, 3.3V, 5.0V AND
ADJUSTABLE OUTPUT VERSIONS
The REG101 has very low output noise (typically
23µVrms for VOUT = 3.3V with CNR = 0.01µF),
making it ideal for use in portable communications
equipment. Accuracy is maintained over temperature,
line, and load variations. Key parameters are guaran-
teed over the specified temperature range
(–40°C to +85°C).
● OTHER OUTPUT VOLTAGES AVAILABLE
UPON REQUEST
● FOLDBACK CURRENT LIMIT
● THERMAL PROTECTION
● SMALL SURFACE-MOUNT PACKAGES:
SOT23-5 and SO-8
The REG101 is well protected—internal circuitry pro-
vides a current limit which protects the load from
damage. Thermal protection circuitry keeps the chip
from being damaged by excessive temperature. The
REG101 is available in the SOT23-5 and the SO-8
packages.
APPLICATIONS
● PORTABLE COMMUNICATION DEVICES
● BATTERY-POWERED EQUIPMENT
● PERSONAL DIGITAL ASSISTANTS
● MODEMS
● BAR-CODE SCANNERS
● BACKUP POWER SUPPLIES
Enable
Enable
VOUT
VIN
VOUT
VIN
REG101
(Fixed Voltage
Versions)
+
R1
Adj
R2
+
+
+
0.1µF
(1)
(1)
COUT
REG101-A
COUT
0.1µF
NR
Gnd
Gnd
NR = Noise Reduction
NOTE: (1) Optional.
Copyright © 2000, Texas Instruments Incorporated
SBVS026B
Printed in U.S.A. February, 2001