General Description

The MAX886/MAX888/MAX1863 power-management ICs are complete power systems for wireless and satellite handsets. The devices operate from 3- to 6-cell NiCd/NiMH batteries or from 1- or 2-cell lithium-ion (Li+) batteries. They incorporate a high-efficiency, step-down DC-DC converter, a regulated 5V charge pump, and four linear regulators. The regulators supply power to the SIM, LCD, BB, DSP, and RF sections of a cellular telephone handset. The step-down converter and linear regulator outputs are adjustable by internal 4-bit DACs, programmable through the I2C™-compatible serial interface. A pushbutton on/off scheme activates a 5µA low-power shutdown mode. The devices also feature a low-battery detector output and an internal startup timer.

Features

♦ 90 Efficient, 500mA Step-Down Converter

♦ Two 100mA DAC-Controlled LDOs

   One 200mA DAC-Controlled LDO

   One 20mA DAC-Controlled LDO

♦ 3- to 6-Cell NiCd or NiMH Operation

   1- or 2-Cell Li+ Operation

♦ +2.7V to +12V Input Voltage Range

♦ 250µA Standby (PFM) Quiescent Current

♦ 5µA Shutdown Current

♦ I2C-Compatible Serial Interface

♦ Selectable 375kHz, 535kHz, 670kHz, 925kHz

   (or Synchronizable) Switching Frequency

♦ Power-On Reset and Startup Timer

♦ Thermal Overload Protection

♦ Pushbutton On/Off Control

♦ Space-Saving 32-Pin TQFP Package (9mm x 9mm)

Applications

   Satellite Phones

   Private Mobile Radio (PMR)

   Wireless Handsets

   GSM Cellular/PCS Telephones