UCC283 Datasheet, PDF (1/8 Pages) Texas Instruments – Low Dropout 3 Ampere Linear Regulator Family

UCC283-3/-5/-ADJ
UCC383-3/-5/-ADJ
Low Dropout 3 Ampere Linear Regulator Family
FEATURES
DESCRIPTION
• Precision Positive Series Pass The UCC283-3/-5/-ADJ family of positive linear series pass regulators are tailored
Voltage Regulation
for low drop out applications where low quiescent power is important. Fabricated
• 0.45V Dropout at 3A
• 50mV Dropout at 10mA
with a BiCMOS technology ideally suited for low input to output differential applica-
tions, the UCC283-5 will pass 3A while requiring only 0.45V of typical input voltage
headroom (guaranteed 0.6V dropout). These regulators include reverse voltage
• Quiescent Current Under
650µA Irrespective of Load
• Adjustable (5 Lead) Output
Voltage Version
• Fixed (3 Lead) Versions for
3.3V and 5V Outputs
sensing that prevents current in the reverse direction. Quiescent current is always
less than 650µA. These devices have been internally compensated in such a man-
ner 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 3.3V and 5.0V respectively. The output voltage is regulated to 1.5% at room tem-
perature. The UCC283-ADJ version, in a 5 lead package, regulates the output volt-
age programmed by an external resistor ratio.
• Logic Shutdown Capability
• Short Circuit Power Limit of
3% •V_IN • I_SHORT
• Low V_OUT to V_IN Reverse
Leakage
• Thermal Shutdown
Short circuit current is internally limited. The device responds to a sustained over-
current condition by turning off after a T_ON delay. The device then stays off for a pe-
riod, T_OFF, that is 32 times the T_ON delay. The device then begins pulsing on and off
at the T_ON/(T_ON+T_OFF) duty cycle of 3%. This drastically reduces the power dissipa-
tion during short circuit and means heat sinks need only accommodate normal op-
eration. On the 3 leaded versions of the device T_ON is fixed at 750µs, on the
adjustable 5 leaded versions an external capacitor sets the on time — the off time
is always 32 times T_ON. The external timing control pin, CT, on the five leaded ver-
sions also serves as a shutdown input when pulled low.
Internal power dissipation is further controlled with thermal overload protection cir-
cuitry. Thermal shutdown occurs if the junction temperature exceeds 165°C. The
chip will remain off until the temperature has dropped 20°C.
BLOCK DIAGRAM
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.
SLUS215 - OCTOBER 1998
UDG-98133