UCC3830-4/-5/-6

02/99

FEATURES

• 5-Bit Digital-to-Analog Converter

(DAC)

• Supports 4-Bit and 5-Bit

Microprocessor VID Codes

• Combined DAC/Voltage Monitor

and PWM Functions

• 1% DAC/Reference

• Current Sharing

• 100kHz, 200kHz, 400kHz

Oscillator Frequency Options

• Foldback Current Limiting

• Overvoltage and Undervoltage

Fault Windows

• Undervoltage Lockout

• 4Ω Totem Pole Output

• Chip Disable Function

5-Bit Microprocessor Power Supply Controller

BLOCK DIAGRAM

UDG-96188-2

DESCRIPTION

The UCC3830-4/-5/-6 is a fully integrated single chip solution ideal for power-

ing high performance microprocessors. The chip includes an average current

mode PWM controller, has a fully integrated 5-Bit DAC, and includes an

on-board precision reference and voltage monitor circuitry. The UCC3830-x

converts 5VDC to an adjustable output, ranging from 3.5VDC down to 1.8VDC

with 1% DC system accuracy (see Table 1). The UCC3830-x fully supports

Intel’s 4-bit Pentium® Pro and 5-bit Pentium® II VID codes.

The accuracy of the DAC/reference combination is 1%. The overvoltage and

undervoltage comparators monitor the system output voltage and indicate

when it rises above or falls below its programmed value by more than 8.5%. A

second overvoltage protection comparator pulls the current amplifier output

voltage low to force zero duty cycle when the system output voltage exceeds

its designed value by more than 17.5%. This comparator also terminates the

cycle. Undervoltage lockout circuitry assures the correct logic states at the

outputs during powerup and powerdown. The gate output can be disabled by

bringing the CAO/ENBL pin to below 0.8V.

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