CMPWR280

• Selects from 3 input voltages and provides 3.3V output
• Automatic selection of VCC, VSBY or VAUX
• Drive control signal for external VAUX switch
• Glitch-free 3.3V output during supply transitions
• Built-in hysteresis for supply selection
• VCC regulates up to 1.5A output current
• VSBY regulates up to 375mA output current
• Foldback current limiting
• Thermal shutdown with hysteresis
• Standard 5-lead TO-263 package
• Lead-free version available

The California Micro Devices&prime SmartOR™ CMPWR280 is a fully protected Dual-Input low-dropout CMOS regulator that also provides the necessary control signal for driving an external auxiliary P-channel MOSFET switch. The SmartOR™ device automatically selects one of three possible inputs on a priority basis: VCC (1.5A), VSBY (375mA) or VAUX via the drive signal used to control an external switch.

VCC is given first priority. In the event of the VCC supply being powered down, CMPWR280 will automatically deselect the VCC prior to regulator dropout and immediately select VSBY (second priority) as its power source.

If neither VCC nor VSBY are present the drive control output will turn-on an external P-channel MOSFET switch from an auxiliary 3.3V supply VAUX to VOUT.

All the necessary control circuitry CMPWR280 needed to provide a smooth and automatic transition between all three supplies has been incorporated. This allows VCC to be dynamically switched without loss of output voltage.

The CMPWR280 is internally protected against output short-circuits, current overload and thermal overload.

The CMPWR280 is housed in a standard, 5-lead TO-263 package and is available with optional lead-free finishing.