Single/Multiphase, Step-Down, DC-DC Converter Delivers Up to 25A Per Phase

The MAX8686 current-mode, synchronous PWM step-down regulator with integrated MOSFETs operates from a 4.5V to 20V input supply and generates an adjustable output voltage from 0.7V to 5.5V while delivering up to 25A per phase.

The MAX8686 employs a peak current-mode architecture that operates with an adjustable switching frequency from 300kHz to 1MHz. An adjustable current-limit threshold allows for optimization for different applications with different load currents. Inductor current sense is achieved either using an external sense resistor or using a lossless inductor current-sense scheme. The foldback and hiccup current limit reduces the power dissipation during overload or short-circuit conditions and allows for autorecovery when the fault condition is removed.

The MAX8686 offers the ability to start up monotonically even when there is a prebias output voltage. In addition, an adjustable soft-start capability allows for a controlled turn-on. The MAX8686 features an accurate 1% reference and offers a reference input that allows for a higher accuracy reference to be used for voltage tracking applications such as DDR memory.

The MAX8686 can be paralleled (up to eight) together in a true multiphase mode to deliver up to 200A of output current. When operating in this mode, this device achieves better than 10% current balance between phases at full load. The MAX8686 supports programmable phase shedding to improve system efficiency during light load conditions.

Other features include an enable input and a power-OK (POK) indicator used for power sequencing. The MAX8686 also features latch overvoltage protection that turns on the low-side MOSFET when the output voltage exceeds 120% of the nominal voltage. The MAX8686 is offered in a thermally enhanced 40-pin, 6mm x 6mm TQFN package.

Applications

* DDR Memory * Module Replacements * Networking Equipment * POL Power Supplies * Servers * Telecom Equipment

* Operating Range from 4.5V to 20V Input Supply

* 1% Reference Voltage Accuracy Over Temperature

* Reference Input (REFIN) for Output Tracking or System Reference Voltage

* Adjustable Switching Frequency from 300kHz to 1MHz

* Single/Multiphase Operation Delivers Up to 25A/200A with Integrated MOSFETs

* Adjustable Current Limit

* Monotonic Output Voltage at Startup (Prebias)

* Output Sink and Source Current Capability

* Adjustable Soft-Start

* Thermal-Overload Protection

* Output Overvoltage Protection

* Thermally Enhanced 6mm x 6mm TQFN Package (4W)