UCC284-EP Datasheet, PDF (1/20 Pages) Texas Instruments – LOW-DROPOUT 0.5-A NEGATIVE LINEAR REGULATOR

UCC284-EP
www.ti.com ....................................................................................................................................... SLVS862A – NOVEMBER 2008 – REVISED NOVEMBER 2008
LOW-DROPOUT 0.5-A NEGATIVE LINEAR REGULATOR
FEATURES
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• Precision Negative Series Pass Voltage
Regulation
• 0.2-V Dropout at 0.5 A
• Wide Input Voltage Range –3.2 V to –15 V
• Low Quiescent Current Irrespective of Load D
Simple Logic Shutdown Interfacing
• –5 V, –12 V, and Adjustable Output
• 2.5% Duty Cycle Short Circuit Protection
SUPPORTS DEFENSE, AEROSPACE AND
MEDICAL APPLICATIONS
• Controlled Baseline
• One Assembly/Test Site
• One Fabrication Site
• Available in S-Temp (–55°C/100°C)
Temperature Range⁽¹⁾
• Extended Product Life Cycle
• Extended Product-Change Notification
• Product Traceability
(1) Additional temperature ranges are available – contact factory.
D PACKAGE
(FRONT VIEW)
VOUTS 1
8 SD/CT
VIN 2
7 VIN
VIN ³
GND 4
6 VIN
5 VOUT
DESCRIPTION
The UCC284-x family of negative linear-series pass regulators is tailored for low-dropout applications where
low-quiescent power is important. Fabricated with a BCDMOS technology ideally suited for low input-to-output
differential applications, the UCC284-x passes 0.5 A while requiring only 0.2 V of input-voltage headroom.
Dropout voltage decreases linearly with output current, so that dropout at 50 mA is less than 20 mV.
Quiescent current consumption for the device under normal (non-dropout) conditions is typically 200 µA. An
integrated charge pump is internally enabled only when the device is operating near dropout with low VIN. This
ensured that the device meets the dropout specifications even for maximum load current and a VIN of –3.2 V
with only a modest increase in quiescent current. Quiescent current is always less than 360 µA, with the charge
pump enabled. The quiescent current of the UCC284 does not increase with load current.
Short-circuit current is internally limited. The device responds to a sustained overcurrent condition by turning off
after a t_ON delay. The device then stays off for a period, t_OFF, that is 40 times the t_ON delay. The device then
begins pulsing on and off at the t_ON/t_OFF duty cycle of 2.5%. This drastically reduces the power dissipation during
short circuit such that heat sinking, if at all required, must only accommodate normal operation. An external
capacitor sets the on time. The off time is always 40 times t_ON.
The UCC284-x can be shutdown to 45 µA (maximum) by pulling the SD/CT pin more positive than –0.7 V. To
allow for simpler interfacing, the SD/CT pin may be pulled up to 6 V above the ground pin without turning on
clamping diodes.
Internal power dissipation is further controlled with thermal-overload protection circuitry. Thermal shutdown
occurs if the junction temperature exceeds 140°C. The chip remains off until the temperature has dropped 20°C
(T_J = 120°C).
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008, Texas Instruments Incorporated