LP3927

Cellular/PCS System Power Management IC

General Description

The LP3927 system power management IC is designed for

cellular/PCS handsets as well as other portable systems that

require intelligent power management. Each device contains

five low-dropout linear regulators (LDO’s), a reset timer, a

power-up control logic, a general-purpose open drain output

that can be used to light LEDs, and a CMOS rail-to-rail

input/output operational amplifier.

Each linear regulator features an extremely low dropout

voltage of 100 mV (typ) at maximum output current. LDO1

and LDO2 are powered on and off by either the KYBD or the

VEXT pin. LDO3, LDO4 and LDO5 each have its indepen-

dent enable pin. LDO1 and LDO4 are rated at 150 mA each,

LDO2 and LDO5 are rated at 200 mA each and LDO3 is

rated at 100 mA. All LDO’s are optimized for low noise and

high isolation.

The open drain output current sink can be programmed up to

150 mA by using an external low cost resistor.

A single supply, low voltage operational amplifier has rail to

rail input and output with 600 kHz of gain-bandwidth product.

Key Specifications

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3.0V to 5.5V Input Voltage Range

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Two 200 mA, Two 150 mA and One 100 mA LDO’s

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MAX

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150 mA General-Purpose Open-drain programmable

current sink for back light LED

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Low Voltage Rail to Rail Input/Output Operational

Amplifier

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28 pin LLP package

Applications

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Cellular/PCS handsets

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PDA’s, Palmtops, and portable terminals

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Single–Cell Li+ Systems

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2- or 3- Cell NiMH, NiCd or Alkaline System

Typical Application Circuit

20037901

V

August 2002

© 2002 National Semiconductor Corporation

DS200379

www.national.com