Analog Devices MAX8792

Description

The MAX8792 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-voltagecore or chipset/RAM bias supplies in notebook computers. The output voltage can be dynamically controlled using the dynamic REFIN, which supports input voltages between 0 to 2V. The REFIN adjustability combinedwith a resistive voltage-divider on the feedback input allows the MAX8792 to be configured for any output voltage between 0 to 0.9VIN.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 toload transients while maintaining a relatively constant switching frequency. Strong drivers allow the MAX8792 to efficiently drive large synchronous-rectifier MOSFETs.The controller senses the current across the synchronous rectifier to achieve a low-cost and highly efficient valley current-limit protection. The adjustable currentlimit threshold provides a high degree of flexibility, allowing thermally compensated protection using an NTC or foldback current-limit protection using a voltage- divider derived from the output.The MAX8792 includes a voltage-controlled soft-start and soft-shutdown in order to limit the input surge current, provide a monotonic power-up (even into a precharged output), and provide a predictable powerup time. The controller also includes output fault protection—undervoltage and overvoltage protection—as well as thermal-fault protection.The MAX8792 is available in a tiny 14-pin, 3mm x 3mm TDFN package. For space-constrained applications, refer to the MAX17016 single step-down with 10A, 26V internal MOSFETs available in a small 40-pin, 6mm x6mm TQFN package.

Features

• Quick-PWM with Fast Transient Response
• Supports Any Output Capacitor
• No Compensation Required withPolymers/Tantalum
• Stable with Ceramic Output Capacitors Using External Compensation
• Precision 2V ±10mV Reference
• Dynamically Adjustable Output Voltage (0 to 0.9VIN Range)
• Feedback Input Regulates to 0 to 2V REFIN Voltage
• 0.5% VOUT Accuracy Over Line and Load
• 26V Maximum Input Voltage Rating
• Adjustable Valley Current-Limit Protection
• Thermal Compensation with NTC
• Supports Foldback Current Limit
• Resistively Programmable Switching Frequency
• Overvoltage Protection
• Undervoltage/Thermal Protection
• Voltage Soft-Start and Soft-Shutdown
• Monotonic Power-Up with Precharged Output
• Power-Good Window Comparator

Typical applications

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

More information

• Datasheet
• IC product information