REG104
REG104
REG
104
SBVS025G – SEPTEMBER 2001 – REVISED SEPTEMBER 2005
DMOS
1A Low-Dropout Regulator
DESCRIPTION
FEATURES
The REG104 is a family of low-noise, low-dropout linear
regulators with low ground pin current. Its new DMOS topol-
ogy provides significant improvement over previous designs,
including low dropout voltage (only 230mV 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.
● NEW DMOS TOPOLOGY:
Ultra Low Dropout Voltage:
230mV typ at 1A and 3.3V Output
Output Capacitor NOT Required for Stability
● FAST TRANSIENT RESPONSE
● VERY LOW NOISE: 33µVRMS
● HIGH ACCURACY: ±2% max
● HIGH EFFICIENCY:
Typical ground pin current is only 1.7mA (at IOUT = 1A) and
drops to 0.5µA in not enabled mode. Unlike regulators with
PNP pass devices, quiescent current remains relatively con-
stant over load variations and under dropout conditions.
IGND = 1.7mA at IOUT = 1A
Not Enabled: IGND = 0.5µA
● 2.5V, 2.7V, 3.0V, 3.3V, 5.0V AND
ADJUSTABLE OUTPUT VERSIONS
The REG104 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 main-
tained over temperature, line, and load variations. Key pa-
rameters are tested over the specified temperature range
(–40°C to +85°C).
● THERMAL PROTECTION
● SMALL SURFACE-MOUNT PACKAGES:
SOT223-5, DDPAK-5
APPLICATIONS
● PORTABLE COMMUNICATION DEVICES
● BATTERY-POWERED EQUIPMENT
● MODEMS
The REG104 is well protected—internal circuitry provides a
current limit which protects the load from damage. Thermal
protection circuitry keeps the chip from being damaged by
excessive temperature. The REG104 is available in the
DDPAK-5 and the SOT223-5.
● BAR-CODE SCANNERS
● BACKUP POWER SUPPLIES
Enable
Enable
VOUT
VIN
VOUT
VIN
REG104
(Fixed Voltage
Versions)
+
R1
Adj
R2
+
+
+
0.1µF
(1)
(1)
COUT
REG104-A
COUT
0.1µF
NR
Gnd
Gnd
NR = Noise Reduction
NOTE: (1) Optional.
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.
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 © 2001-2005, Texas Instruments Incorporated
www.ti.com
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