| Output options | Adjustable Output, Fixed Output |
| Iout (Max) (A) | 3 |
| Vin (Max) (V) | 9 |
| Vin (Min) (V) | 2.8 |
| Vout (Max) (V) | 8.5 |
| Vout (Min) (V) | 1.2 |
| Fixed output options (V) | 3.3, 5 |
| Iq (Typ) (mA) | 0.4 |
| Thermal resistance θJA (°C/W) | 70 |
| Rating | Catalog |
| Load capacitance (Min) (μF) | 10 |
| Regulated outputs (#) | 1 |
| Features | Reverse current protection |
| Accuracy (%) | 2.5 |
| PSRR @ 100 KHz (dB) | 18 |
| Dropout voltage (Vdo) (Typ) (mV) | 400 |
| Operating temperature range (C) | -40 to 85 |
- 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
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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.
