General Description

The MAX1777/MAX1977/MAX1999 dual step-down, switch-mode power-supply (SMPS) controllers generate logic-supply voltages in battery-powered systems. The MAX1777/MAX1977/MAX1999 include two pulse-width modulation (PWM) controllers, adjustable from 2V to 5.5V or fixed at 5V and 3.3V. These devices feature two linear regulators providing 5V and 3.3V always-on outputs.

Features

♦ No Current-Sense Resistor Needed (MAX1999)

♦ Accurate Current Sense with Current-Sense

   Resistor (MAX1777/MAX1977)

♦ 1.5 Output Voltage Accuracy

♦ 3.3V and 5V 100mA Bootstrapped Linear

   Regulators

♦ Internal Soft-Start and Soft-Stop Output

   Discharge

♦ Quick-PWM with 100ns Load Step Response

♦ 3.3V and 5V Fixed or Adjustable Outputs

   (Dual Mode™)

♦ 4.5V to 24V Input Voltage Range

♦ Ultrasonic Pulse-Skipping Mode (25kHz min)

♦ Power-Good (PGOOD) Signal

♦ Overvoltage Protection Enable/Disable

Applications

   Notebook and Subnotebook Computers

   PDAs and Mobile Communication Devices

   3- and 4-Cell Li+ Battery-Powered Devices