Step-Down Controller Manages DDR/DDR2/DDR3 Memory July 18, 2008
To save board space, the MAX17000 Quick-PWM step-down controller for DDR, DDR2, and DDR3 memory integrates a step-down controller, source/sink linear regulator, and reference buffer, enabling it to generate all necessary VDDQ, VTT, and VTTR rails. The device supplies the VDDQ rail, providing a ±1% accurate output voltage over the line-and-load operating range. Its ±2A source/sink regulator generates the memory-termination VTT rail. Via a ±5 mV dead band, the regulator reduces output capacitance requirements and sources or sinks. An integrated VTTR reference buffer sources and sinks ±3 mA, providing the reference voltage for the memory controller and devices on the memory bus. Of note, the MAX17000 employs the company’s proprietary Quick-PWM architecture to support wide input/output voltage ratios while maintaining a relatively constant switching frequency. Other device features include three operating modes: a power-efficient skip mode, low-noise forced-PWM mode, and a standby mode that supports memory when the computer is in standby operation. Additionally, over-voltage, under-voltage, and thermal protection are on board. Available in a 24-pin TQFN package measuring 4 mm x 4 mm, prices start at $2.75 each/1,000. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.
