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