MAX1858

The MAX1858 dual, synchronized, step-down controller generates two outputs from input supplies ranging from 4.75V to 23V. Each output is adjustable from sub-1V to 18V and supports loads of 10A or higher. Input voltage ripple and total RMS input ripple current are reduced by synchronized 180° out-of-phase operation.

The switching frequency is adjustable from 100kHz to 600kHz with an external resistor. Alternatively, the controller can be synchronized to an external clock generated to another MAX1875/MAX1876 or a system clock. One MAX1875/MAX1876 can be set to generate an inphase, or 90° out-of-phase, clock signal for synchronization with additional controllers. This allows two controllers to operate either as an interleaved two- or four-phase system with each output shifted by 90°. These devices also feature soft-start and soft-stop.

The MAX1858 eliminate the need for currentsense resistors by utilizing the low-side MOSFET's onresistance as a current-sense element. This protects the DC-DC components from damage during outputoverload conditions or when output short-circuit faults without requiring a current-sense resistor. Adjustable foldback current limit reduces power dissipation during short-circuit conditions. The MAX1876 includes a power-on reset output to signal the system when both outputs reach regulation.

The MAX1858 are available in a 24-pin QSOP package. An evaluation kit is available to speed designs.