UCC281-3/-5/-ADJ
UCC381-3/-5/-ADJ Low Dropout 1 Ampere Linear Regulator Family
FEATURES DESCRIPTION Precision Positive Linear Voltage
Regulation The UCC381-3/-5/-ADJ family of positive linear series pass regulators is
tailored for low drop out applications where low quiescent power is important. Fabricated with a BiCMOS technology ideally suited for low input to
output differential applications, the UCC381 will pass 1A while requiring
only 0.5V of input voltage headroom. Dropout voltage decreases linearly
with output current, so that dropout at 200mA is less than 100mV. Quiescent current is always less than 650ВµA. To prevent reverse current conduction, on-chip circuitry limits the minimum forward voltage to typically 50mV.
Once the forward voltage limit is reached, the input-output differential voltage is maintained as the input voltage drops until undervoltage lockout disables the regulator. 0.5V Dropout at 1A Guaranteed Reverse Input/ Output
Voltage Isolation with Low Leakage Low Quiescent Current Irrespective of
Load Adjustable Output Voltage Version Fixed Versions for 3.3V and 5V
Outputs UCC381-3 and UCC381-5 versions have on-chip resistor networks preset
to regulate either 3.3V or 5.0V, respectively. Furthermore, remote sensing
of the load voltage is possible by connecting the VOUTS pin directly at the
load. The output voltage is then regulated to 1.5% at room temperature and
better than 2.5% over temperature. The UCC381-ADJ version has a regulated output voltage programmed by an external user-definable resistor ratio. Logic Shutdown Capability Short Circuit Power Limit of
3% VIN Current Limit Remote Load Voltage for Accurate
Load Regulation (continued) BLOCK DIAGRAM VIN 8
VPUMP
VOLTAGE
AMPLIFIER CURRENT
LIMIT
1.3/2.1A …
