Product details


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 Load capacitance (Min) (µF) 10 Rating Catalog 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) 0 to 70 open-in-new Find other Linear regulators (LDO)

Package | Pins | Size

TO-220 (KC) 5 86 mm² 8.51 x 10.16 TO-263 (KTT) 5 155 mm² 10.16 x 15.24 TO-263 (KTT) 3 155 mm² 10.16 x 15.24 open-in-new Find other Linear regulators (LDO)


  • 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.

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Technical documentation

= Top documentation for this product selected by TI
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Type Title Date
* Datasheet UCC283-x, UCC383-x: Low-Dropout 3-A Linear Regulator Family datasheet (Rev. B) Feb. 23, 2004
Technical articles LDO basics: capacitor vs. capacitance Aug. 01, 2018
Technical articles LDO Basics: Preventing reverse current Jul. 25, 2018
Technical articles LDO basics: introduction to quiescent current Jun. 20, 2018
Application notes LDO Noise Demystified (Rev. A) Aug. 09, 2017
Application notes LDO PSRR Measurement Simplified (Rev. A) Aug. 09, 2017
Technical articles LDO basics: noise – part 1 Jun. 14, 2017
User guides DEM-TO263LDO Demonstration Fixture Oct. 15, 2003
Application notes High Current LDO Linear Reglators (UCCx81-ADJ, UCx82-ADJ, UCCx83-ADJ, UCx85-AD May 07, 2002
Application notes Using LDOs and Power Managers in Systems with Redundant Power Supplies Nov. 29, 2000

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CAD/CAE symbols

Package Pins Download
DDPAK/TO-263 (KTT) 3 View options
DDPAK/TO-263 (KTT) 5 View options
TO-220 (KC) 5 View options

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