Product Description

California Micro Devices SmartOR™ CMPWR150 is a low dropout regulator that delivers up to 500mA of load current at a fixed 3.3V output. An internal threshold level (typically 4.1V) is used to prevent the regulator from being operated below dropout voltage. The device continuously monitors the input supply and will automatically disable the regulator when VCC falls below the threshold level. When the regulator is disabled, the control signal "Drive" (Active Low) is enabled, which allows an external PMOS switch to power the load from an auxiliary 3.3V supply.

When VCC is restored to a level above the select threshold, the control signal for the external PMOS switch is disabled and the regulator is once again enabled.

All the necessary control circuitry needed to provide a smooth and automatic transition between the supplies has been incorporated. This allows VCC to be dynamically switched without loss of output voltage.

The CMPWR150 is available in either an 8-pin SOIC thermally enhanced package, ideal for space critical applications, or a 5-pin TO-263 package.

Features

• Automatic detection of VCC input supply

• Drive output logic to control external switch

• Glitch-free output during supply transitions

• 500mA output maximum load current

• Built-in hysteresis during supply selection

• Controller operates from either VCC or VOUT

• 8-pin SOIC Thermal or 5-pin TO-263 packages

Applications

• PCI adapter cards

• Network Interface Cards (NICs)

• Dual power systems

• Systems with standby capabilities

• See Application Note AP-211