UCC283TDTR-3

The UCC283-3/-5/-ADJ family of positive linear series pass voltage regulators are 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 UCC283-5 passes 3 A while requiring only 0.45 V of typical input voltage headroom (ensured 0.6 V dropout). These regulators include reverse voltage sensing that prevents current in the reverse direction. Quiescent current is always less than 650 μA. These devices have been internally compensated in such a way that the need for a minimum output capacitor has been eliminated. UCC283-3 and UCC283-5 versions are in 3-lead packages and have preset outputs at 3.3 V and 5.0 V respectively. The output voltage is regulated to 1.5% at room temperature. The UCC283-ADJ version, in a 5-lead package, regulates the output voltage programmed by an external resistor ratio. Short-circuit current is internally limited. The device responds to a sustained overcurrent condition by turning off after a toN time delay. The device then stays off for a period, toFF, that is 32 times the toN delay. The device then begins pulsing on and off at the tON/(tON + tOFF) duty cycle of 3%. This drastically reduces the power dissipation during short-circuit and means heat sinks need only accommodate normal operation. On the 3-leaded versions of the device toN is fixed at 750 μs, on the adjustable 5-leaded versions an external capacitor sets the on time. The off time is always 32×tON. The external timing control pin, CT, on the 5-leaded versions also serves as a shutdown input when pulled low. Internal power dissipation is further controlled with thermal overload protection circuitry. Thermal shutdown occurs if the junction temperature exceeds 165°C. The chip remains off until the temperature has dropped 20°C. The UCC283 series is specified for operation over the industrial range of -40°C to 85°C and the UCC383 series is specified from 0°C to 70°C. These devices are available in 3- and 5-pin TO-220 and TO-263 power packages.

Key features

• Precision Positive Linear Series Pass Voltage Regulation
• 0.45 V Dropout at 3 A
• 50 mV Dropout at 10 mA
• Quiescent Current Under 650 μA Irrespective of Load
• Adjustable (5-Lead) Output Voltage Version
• Fixed (3-Lead) Versions for 3.3-V and 5-V Outputs
• Logic Shutdown Capability
• Short-Circuit Power Limit of (3%×VIN×ISHORT)
• Low Vout to VIN Reverse Leakage
• Thermal Shutdown