IR3505ZMTRPBF Power Management Specialized - PMIC Xphase3 IR3505Z AMD PVID CTRL IC

DESCRIPTION

The IR3505Z Phase IC combined with an IR XPhase3TM Control IC provides a full featured and

flexible way toimplement power solutions for the latest high performance CPUs and AS ICs. The

“Control” IC providesoverall system control and interfaces with any number of “Phase” ICs which

each drive and monitor a singlephase of a multiphase converter. The XPhase3TM architecture results

in a power supply that is smaller, lessexpensive, and easier to design while providing higher efficiency

than conventional approaches.

FEATURES

• 7V/2A gate drivers (4A GATEL sink current)• Support

converter output voltage up to 5.1 V (Limited to VCCL-1.4V)• Support loss-less inductor current sensing•

Feed-forward voltage mode control• Integrated boot-strap synchronous PFET• Only four IC related external

components per phase• 3 wire analog bus connects Control and Phase ICs (VDAC, Error Amp, ISHARE)•

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

16L 3 x 3mm MLPQ package• RoHS compliant

Frequency and Phase Timing ControlThe oscillator is located in the Control IC and the system clock frequency

is programmable from 250kHz to 9MHZ by anexternal resistor. The control IC system clock signal (CLKOUT) is

connected to CLKIN of all the phase ICs. The phasetiming of the phase ICs is controlled by the daisy chain loop,

where control IC phase clock output (PHSOUT) isconnected to the phase clock input (PHSIN) of the first phase IC,

and PHSOUT of the first phase IC is connected toPHSIN of the second phase IC, etc. and PHSOUT of the last

phase IC is connected back to PHSIN of the control IC.During power up, the control IC sends out clock signals

from both CLKOUT and PHSOUT pins and detects thefeedback at PHSIN pin to determine the phase number and

monitor any fault in the daisy chain loop. Figure 2 shows thephase timing for a four phase converter. The switching

frequency is set by the resistor ROSC. The clock frequencyequals the number of phase times the switching frequency.