LDO Regulator Pos 3.3V 1A 8-Pin SOIC T/R

The UCC381-3/-5/-ADJ family of positive linear series pass regulators istailored for low drop out applications where low quiescent power is important.Fabricated with a BiCMOS technology ideally suited for low input tooutput differential applications, the UCC381 will pass 1A while requiringonly 0.5V of input voltage headroom. Dropout voltage decreases linearlywith output current, so that dropout at 200mA is less than 100mV. Quiescentcurrent is always less than 650µA. 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 voltageis maintained as the input voltage drops until undervoltage lockout disablesthe regulator.UCC381-3 and UCC381-5 versions have on-chip resistor networks presetto regulate either 3.3V or 5.0V, respectively. Furthermore, remote sensingof the load voltage is possible by connecting the VOUTS pin directly at theload. The output voltage is then regulated to 1.5% at room temperature andbetter than 2.5% over temperature. The UCC381-ADJ version has a regulatedoutput voltage programmed by an external user-definable resistor ratio.Short circuit current is internally limited. The device respondsto a sustained overcurrent condition by turningoff after a TON delay. The device then stays off for a period,TOFF, that is 32 times the TON delay. The devicethen begins pulsing on and off at the TON /(TON+TOFF)duty cycle of 3%. This drastically reduces the power dissipationduring short circuit such that heat sinking, if at allrequired, must only accommodate normal operation. Onthe fixed output versions of the device TON is fixed at400µs - a guaranteed minimum. On the adjustable versionan external capacitor sets the on time. The off timeis always 32 times TON.The UCC381 can be shutdown to 25µA (max) by pullingthe CT pin low.Internal power dissipation is further controlled with thermaloverload protection circuitry. Thermal shutdown occursif the junction temperature exceeds 165°C. The chipwill remain off until the temperature has dropped 20°C.The UCC281 series is specified for operation over the industrialrange of -40°C to +85°C, and the UCC381 seriesis specified from 0°C to +70°C. These devices areavailable in the 8 pin DP surface mount power package.For other packaging options consult the factory.

• Precision Positive Linear Voltage Regulation
• 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
• Logic Shutdown Capability
• Short Circuit Power Limit of 3%
  • VIN
  • Current Limit
• Remote Load Voltage for Accurate Load Regulation