4.5V to 60V, Synchronous Step-Down Controller

The MAX17557 is a synchronous step-down controller that drives nMOSFETs. The device uses a constant-frequency, peak-current-mode architecture.

The IC supports current sensing using either an external current-sense resistor for accuracy or an inductor DCR for improved system efficiency. Current foldback limits MOSFET power dissipation under short-circuit conditions.

The IC can start up monotonically into a prebiased output. The device can be operated in forced pulse-width modulation (PWM), or discontinuous-conduction mode (DCM) to enable high efficiency under full-load and light-load conditions. The device features a programmable soft-stop enable (SSTPEN) or disable function.

The IC operates over the -40°C to +125°C temperature range and is available in a lead (Pb)-free, 20-pin TQFN, 4mm x 4mm package with an exposed pad.

Applications

* Computerized Numerical Control * Distributed DC Power Systems * Industrial Power Supplies * Motion Control * Programmable Logic Controllers

* Wide Range of Operation

* Wide 4.5V to 60V Input Voltage Range

* Wide 0.8V to 24V Output Voltage Range

* RSENSE or Inductor DCR Current-Sensing

* 100kHz to 2.2MHz Adjustable Frequency with External Clock Synchronization

* Available in a Lead (Pb)-Free 20-Pin, 4mm x 4mm TQFN-EP Package

* Enhances Power Efficiency

* Low-Impedance Gate Drives for High Efficiency

* DCM Operation at Light Loads

* Auxiliary Bootstrap LDO

* Operates Reliably in Adverse Industrial Environments

* Programmable Soft-Stop Enable or Disable Function

* Adjustable Soft-Start

* Current Foldback Limits MOSFET Heat Dissipation During a Short-Circuit Condition

* Overtemperature Protection

* High Industrial Ambient Operating Temperature Range (-40°C to +125°C) and Junction Tempera- ture Range (-40°C to +150°C)