General Description

The MAX1534 is a high-efficiency, triple-output power supply for keep-alive (always on) voltage rails. The 500mA buck regulator with an internal current-limited 0.5Ω PMOS steps down the battery or wall adapter supply rail to a fixed 5V or an adjustable output voltage. Two integrated low-voltage linear regulators follow this output and provide two independent preset output voltages of 3.3V and 1.8V, or adjustable output voltages.

Features

♦ One Switching and Two Linear Regulators

♦ Switching Regulator

    +4.5V to +24V Input Voltage Range

    Over 95 Efficiency

    Up to 500mA Output Current

    Up to 200kHz Switching Frequency

    Fixed 5V or Adjustable Output Voltage

    Internal 0.5Ω PMOS Switch

    100 Maximum Duty Cycle for Low-Dropout Operation

♦ Two Low-Dropout Linear Regulators

    Up to 160mA Output Current (Each)

    3.3V/Adj Output Voltage for OUT1

    1.8V/Adj Output Voltage for OUT2

♦ ±1.5 Accurate Output Voltage

♦ ±4 Accurate Shutdown for Low Battery Detection

♦ Thermal Shutdown Protection

♦ POK Output

♦ 1mW Typical Standby Power