XPhase chipset powers DDR3 memory modules

The IR3522 dual-output PWM controller with built-in I2C interface provides overall system control for both the DDR3 VDDQ and VTT rails.

The device interfaces with any number of IR3506 phase ICs to drive as many phases as needed to power any number of DDR3 dual in-line memory modules (DIMMS), simplifying layout and reducing board space.

The IR3522/IR3506 chipset enables accurate tracking with the additional flexibility of margining between the VDDQ and VTT outputs through the I2C interface.

The Xphase solution for DDR3 applications delivers a power supply that is smaller, more flexible and easier to design while providing higher efficiency from light load to full load when compared to conventional approaches, according to International Rectifier.

The IR3522 combines the precision of analogue control with programmability of power management functions via I2C.

It allows output voltage programming capability for both VDDQ and VTT outputs through the I2C compatible interface with a VDDQ set point error of +/-0.5 per cent.

The IR3506 provides both source and sink capability to enable more accurate tracking of the VTT output to VDDQ.

It supports a power-saving function (PSI) to maximise efficiency at light loads.

The IR3522's I2C interface programs the VTT tracking ratio +/- 25 per cent and provides digital on/off control.

Four I2C addresses are selectable using two ADDR pins, while four different VREF1 voltages are selectable using two VID pins if I2C communication is not available.

Soft-stop turn-off to ensure VDDR and VTT tracking is also featured, as well as a fault activated Crowbar pin to drive external NMOS devices for external output voltage protection.

As with all Xphase ICs, the IR3522 features protection against over-current, over-voltage, open remote sense and open control.

The IR3506 phase IC features 7V/2A gate drivers (4A GATEL sink current) and supports loss-less inductor current sensing.

The device also features a soft-stop turn-off to ensure VDDR and VTT tracking.

The IR3506 offers over-current protection during PSI assertion mode operation, integrated bootstrap synchronous PFET, debugging function, self-calibration of PWM ramp, current sense amplifier and current share amplifier and single-wire bidirectional average current sharing.