The ISL6271A is a versatile power management IC (PMIC)

designed for the Xscale type of processors. The device

integrates three regulators, two fault indicators and an I2C

bus for communication with a host microprocessor. Two of

the three regulators function as low power, low drop out

regulators, designed to power SRAM and phase-lock loop

circuitry internal to the Xscale processor. The third regulator

uses a proprietary switch-mode topology to power the

processor core and facilitate Dynamic Voltage Management

(DVM), as defined by Intel.

Since power dissipation inside a microprocessor is

proportional to the square of the core voltage, Intel XScale

processors implement DVM as a means to more efficiently

utilize battery capacity. To support this power saving

architecture, the ISL6271A integrates an I2C bus for

communication with the host processor. The processor, acting

as the bus master, transmits a “voltage level” and “voltage

slew rate” to the ISL6271A appropriate to the processing

requirements; higher core voltages support higher operating

frequencies and code execution. The bus is fully compliant

with the Phillips? I2C protocol and supports both standard

and fast data transmission modes. Alternatively, the output of

the core regulator can be programmed in 50mV increments

from 0.85V to 1.6V using the input Voltage ID (VID) pins. All

three regulators share a common enable pin and are

protected against overcurrent, over temperature and

undervoltage conditions. When disabled via the enable pin,

the ISL6271A enters a low power state that can be used to

conserve battery life while maintaining the last programmed

VID code and slew rate. An integrated soft-start circuit

transitions the ISL6271A output voltages to their default

values at a rate determined by an external soft-start capacitor.

Features

? Three Voltage Regulators (1 Buck, 2 LDOs)

? High-Efficiency, fully-Integrated synchronous buck

regulator with DVM

? 800mA DC output current for the buck regulator

? Proprietary ‘Synthetic Ripple’ Control Topology

? Greater than 1MHz Switching Frequency

? Diode emulation for light load efficiency

? I2C Interface Module for DVM from 0.85V to 1.6V

? Optional fixed 4-bit VID-control in lieu of DVM

? Small Output Inductor and Capacitor

? Battery Fault signal

? Input Supply Voltage Range: 2.76V-5.5V

? 4x4 mm QFN Package:

- Compliant to JEDEC PUB95 MO-220

QFN - Quad Flat No Leads - Package Outline

- Near Chip Scale Package footprint, which improves

PCB efficiency and has a thinner profile

? Pb-free Available (RoHS Compliant)

Applications

? PDA

? Cell Phone

? Tablet Devices

? Embedded Processors