Step-Down Controllers with Prebias Startup, Lossless Sensing, Synchronization, and OVP

The MAX8543/MAX8544 current-mode, constant-frequency PWM buck controllers operate from a 3V to 13.2V input supply and generate adjustable 0.8V to 0.9 x VIN output voltages at loads up to 25A. They feature adjustable switching frequency and synchronization for noise-sensitive applications.

The MAX8543/MAX8544 can start with (or without) a preexisting bias on the output, without discharging the output. This feature simplifies tracking supply designs for core and I/O applications and redundant supply designs.

The MAX8543/MAX8544 use the DC resistance of the output inductor as the current-sense element for lossless, low-cost current sensing. The current-sense threshold can be set to four discrete levels to accommodate inductors with different DC resistance values.

The MAX8544 features a power-OK monitor and two MAX8544 controllers that can operate at 180° out-of-phase for dual-output applications.

Applications

* Networks and Telecom

* Servers

* Storage

* Wireless Base Stations

* Prebias Startup/Monotonic

* 1% Output Accuracy

* Ceramic, Polymer, or Electrolytic Capacitors

* 200kHz to 1MHz Adjustable Frequency

* 160kHz to 1.2MHz Synchronization

* Lossless, Foldback Current Limit

* Overvoltage Protection

* Enable (On/Off)

* Adjustable Soft-Start

* MAX8544

* Latch-Off/Autorecovery

* Power-OK Monitor

* Out-of-Phase Clock Output