Single Quick-PWM Step-Down Controller with Dynamic REFIN

The MAX17024 pulse-width modulation (PWM) controller provides high efficiency, excellent transient response, and high DC-output accuracy needed for stepping down high-voltage batteries to generate low-voltage core or chipset/RAM bias supplies in notebook computers. The output voltage can be controlled using the dynamic REFIN, which supports input voltages between 0 to 2V. The REFIN adjustability combined with a resistive voltage-divider on the feedback input allows the MAX17024 to be configured for any output voltage between 0 to 0.9 x VIN.

Maxim's proprietary Quick-PWM™ quick-response, constant-on-time PWM control scheme handles wide input/output voltage ratios (low-duty-cycle applications) with ease and provides 100ns "instant-on" response to load transients while maintaining a relatively constant switching frequency. Strong drivers allow the MAX17024 to efficiently drive large synchronous-rectifier MOSFETs.

The controller senses the current across the sense resistor series with the synchronous rectifier to achieve highly accurate valley current-limit protection.

The MAX17024 includes a voltage-controlled soft-start and soft-shutdown to limit the input surge current, provide a monotonic power-up (even into a precharged output), and provide a predictable power-up time. The controller also includes output undervoltage and thermal-fault protection.

The MAX17024 is available in a tiny 14-pin, 3mm x 3mm TDFN package. For space-constrained applications, refer to the MAX17016 single step-down with 26V internal MOSFETs capable of supporting 10A continuous load. The MAX17016 is available in a small 40-pin, 6mm x 6mm TQFN package.

Applications

* DDR Memory-VDDQ or VTT * GPU Core Supply * I/O and Chipset Supplies * Notebook Computers * Point-of-Load Applications * Step-Down Power Supply

* Quick-PWM with Fast Transient Response

* Supports Any Output Capacitor

* No Compensation Required with Polymers/Tantalum

* Stable with Ceramic Output Capacitors Using External Compensation

* Precision 2V ±10mV Reference

* Dynamically Adjustable Output Voltage (0 to 0.9 x VIN Range)

* Feedback Input Regulates to 0 to 2V REFIN Voltage

* 0.5% VOUT Accuracy Over Line and Load

* 26V Maximum Input Voltage Rating

* Resistively Programmable Switching Frequency

* Undervoltage/Thermal Protection

* Voltage Soft-Start and Soft-Shutdown

* Monotonic Power-Up with Precharged Output

* Power-Good Window Comparator