[MAXIM INTEGRATED PRODUCTS]

Device Description

General

The MAX8538 is configured as a dual out-of-phase controller for point-of-load supplies. Each buck controller can source or sink up to 25A of current, while the termination reference can supply up to 15mA output.

The MAX8538 uses constant-frequency voltage-mode architecture with operating frequencies of 200kHz to 1.4MHz.

An internal high- bandwidth (25MHz) operational amplifier is used as an error amplifier to regulate the output voltage This allows fast transient response, reducing the number of output capacitors. An all-N-FET design optimizes efficiency and cost. The MAX8538 has a 1 accurate reference.

The controller uses a high-side current-sense architecture for current limiting. ILIM pins allow the setting of an adjustable, lossless current limit for different combinations of load current and RDSON. Alternately, more accurate overcurrent limit is achieved by using a sense resistor in series with the high-side FET. Overvoltage protection is achieved by latching off the high-side MOSFET and latching on the low-side MOSFET when the output voltage exceeds 17 of its set output. Independent enable, power-good, and soft-start features enhance flexibility.