Maxim Integrated Products' MAX8809A/MAX8810A are single-chip two-, three-, or four-phase controllers with integrated dual drivers, designed for next-generation Intel and AMD core power requirements.
The MAX8809A operates as a single-chip, 2-phase solution with integrated drivers, making it suitable for power requirements up to 65 W. It also easily scales to higher power requirements by including a 3rd-phase PWM output on-chip; just add the MAX8552 driver to support designs up to 90 A.
The MAX8810A also integrates a dual driver but adds two PWM outputs. Combine the MAX8810A with the MAX8523 to achieve a low-cost solution for four-phase designs up to 150 A.
A selection pin lets designers program the controller to support three different processors, including Intel VRD10.1 and next-generation CPUs from both Intel and AMD. Included is support for VID codes, VID signal thresholds, proper startup sequencing, and over-voltage protection (OVP) thresholds.
The MAX8809A/MAX8810A use a low input bias current (0.1 ΜA typical) differential amplifier to support remote output-voltage sensing at the processor die. This eliminates the effects of trace impedance in the output and return paths. Initial output voltage accuracy is +/-0.4% due to a high-accuracy DAC combined with precision current-sense amplifiers. The precision error amplifier ensures high voltage-positioning accuracy over the full load range.
The MAX8809A/MAX8810A utilizes peak current-mode control to provide fast transient response and inherent current sharing. Applications can use resistor current sensing, or take advantage of the inductor dc resistance to save cost and improve efficiency. Current-sharing mismatch is less than 5% between phases.
Current limiting is cycle-by-cycle and based on temperature-corrected average current. The MAX8809A/MAX8810A fold back current to 50% of the maximum value during an overcurrent event, thus reducing stress on input and output components. Other built-in protection mechanisms include over-temperature and over-voltage protection.
The MAX8809A is available in a lead-free, 5- by 5-mm, 40-pin thin QFN (TQFN) package, while the MAX8810A is available in a lead-free, 6- by 6-mm, 48-pin TQFN. Prices for the MAX8809A and MAX8810A start at $2.40 and $2.50, respectively for lots of 1000. A data sheet is available at www.maxim-ic.com/MAX8809A.