IR3522 and IR3506 - IR Introduces High Efficiency Solution to Power 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, reducing board space, and overall system cost. The IR3522/IR3506 chipset enables accurate tracking with the additional flexibility of margining between the VDDQ and Vtt outputs through the I²C interface.

“The new 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. The IR3522 combines the best of both worlds: precision of analog control combined with programmability of power management functions via I²C to implement a simple but smart memory power supply,” said Omar Hassen, executive director, IR’s Multiphase Products, Enterprise Power Business Unit.

The IR3522 allows output voltage programming capability for both VDDQ and Vtt outputs through the I²C compatible interface with a VDDQ set point error of only +/-0.5 %. The IR3506 provides both source and sink capability to enable more accurate tracking of the Vtt output to VDDQ. In addition the IR3506 supports a power savings function (PSI) to maximize efficiency at light loads.

IR3522 Features

The IR3522’s I²C interface programs the Vtt tracking ratio ± 25 % and provides digital ON/OFF control. Four I²C addresses are selectable using 2 ADDR pins while four different VREF1 voltages are selectable using 2 VID pins if I²C communication is not available. Soft-stop turn-off to ensure VDDR and Vtt tracking is also featured in addition to a fault activated Crowbar pin to drive external NMOS devices for external output voltage protection. As with all Xphase ICs, the IR3522 features a comprehensive set of protection features including over-current, over-voltage, open remote sense, and open control.

IR3506 Features

The IR3506 phase IC features 7V/2A gate drivers (4A GATE L 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 also offers over-current protection during PSI assertion mode operation, integrated boot-strap synchronous PFET, debugging function, self-calibration of PWM ramp, current sense amplifier, and current share amplifier and single-wire bidirectional average current sharing.