General Description

The MAX8686 current-mode, synchronous PWM stepdown 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 thresh old 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.

Features

♦ Operating Range from 4.5V to 20V Input Supply

♦ 1 Reference Voltage Accuracy Over Temperatu

♦ 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)

Applications

  POL Power Supplies

  Module Replacements

  Telecom Equipment

  Networking Equipment

  Servers

  DDR Memory