IR3508Z Datasheet, PDF (1/19 Pages) International Rectifier – XPHASE3TM PHASE IC

IR3508Z
DATA SHEET
XPHASE3^TM PHASE IC
DESCRIPTION
The IR3508Z Phase IC combined with any IR XPhase3^TM Control IC provides a full featured and flexible way
to implement a power solution for the latest high performance CPUs and ASICs. The “Control” IC provides
overall system control and interfaces with any number of “Phase” ICs which each drive and monitor a single
phase of a multiphase converter. The XPhase3^TM architecture results in a power supply that is smaller, less
expensive, and easier to design while providing higher efficiency than conventional approaches.
The IR3508Z disables its current sense amplifiers when entering power savings mode. The recommended
use for these Phase ICs is for applications without adaptive voltage positioning where two or more power
stages will be operating in power savings mode.
FEATURES IR3508Z PHASE IC
• Power State Indicator (PSI) interface provides the capability to maximize the efficiency at light loads.
• Anti-bias circuitry
• 7V/2A gate drivers (4A GATEL sink current)
• Support converter output voltage up to 5.1 V (Limited to VCCL-1.4V)
• Loss-less inductor current sensing
• Phase delay DFF bypassed during PSI assertion mode to improve output ripple performance
• Over-current protection during PSI assertion mode operation
• Feed-forward voltage mode control
• Integrated boot-strap synchronous PFET
• Only four external components per phase
• 3 wire analog bus connects Control and Phase ICs (VID, Error Amp, IOUT)
• 3 wire digital bus for accurate daisy-chain phase timing control without external components
• Debugging function isolates phase IC from the converter
• Self-calibration of PWM ramp, current sense amplifier, and current share amplifier
• Single-wire bidirectional average current sharing
• Small thermally enhanced 20L 4 X 4mm MLPQ package
• RoHS compliant
APPLICATION CIRCUIT
Page 1 of 19
Figure 1 Application Circuit
Jan 09, 2009