CALIFORNIA MICRO DEVICES
CMPWR280
1.5A SmartORTM Dual Regulator with VAUX Drive
Features
Automatic selection of VCC or VSBY
Pin Diagram
Drive control signal for external VAUX switch
Continuous 3.3V output supply
Glitch-free 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
On-chip controller operates from VCC, VSBY or VOUT
Applications
Peripheral Component Interface (PCI) Adapter Cards
Network Interface Cards (NICs)
Multiple Powered Systems
Typical Application Circuit
Systems with Standby Capabilities
Product Description
The California Micro Devices SmartORTM CMPWR280 is a fully
protected Dual-Input low dropout CMOS regulator that also
provides the necessary control signal for driving an external
auxiliary Pchannel MOSFET switch. The SmartORTM device au-
tomatically 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, the device will automatically deselect the VCC
prior to regulator dropout and immediately select VSBY (second
priority) as its power source.
Simplified Electrical Schematic
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 needed to provide a smooth
and automatic transition between all three supplies has been
incorporated. This allows VCC to be dynamically switched with-
out loss of output voltage.
The CMPWR280 is internally protected against output
short-circuits, current overload and thermal overload.
S TA N D A R D P A R T O R D E R IN G IN F O R M A TIO N
Package
Ordering Part Num ber
Part Marking
Pins
Style
5
TO263
CMPWR280TO
When placing an order please specify desired shipping: Tubes or Tape & Reel.
C0660200
© 2000 Calirornia Micro Devices Corp. All rights reserved.
CMPWR300 is a trademark of California Micro Devices Corp.
3/00
215 Topaz Street, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
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