General Description

The MAX886/MAX888 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 Li-Ion 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 start-up 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-Ion 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 Start-Up Timer
♦ Thermal Overload Protection
♦ Pushbutton On/Off Control
♦ Space-Saving 32-Pin TQFP Package (7mm x 7mm)

Applications

Satellite Phones
Private Mobile Radio (PMR)
Wireless Handsets
GSM Cellular/PCS Telephones