Wide-input external-FET buck controller
The MAX17557ATP+T is an external-FET step-down controller from Analog Devices, designed for applications requiring a 4.5V to 60V input range and a single positive output up to 2.2 MHz switching frequency. Synchronous rectification is built in, which improves efficiency by replacing the freewheeling diode with a low-Rds(on) FET — the controller drives both the high-side and low-side external MOSFETs. The 100 kHz to 2.2 MHz programmable switching range lets the designer balance inductor size against switching losses; a higher frequency shrinks the magnetics but increases FET gate-drive losses.
Temperature grade and package for industrial use
Housed in a 20-lead TQFN with exposed pad (4x4 mm), the package provides a low thermal resistance path to the PCB copper plane — essential for dissipating heat from the internal gate-drive circuitry and the external FET switching losses. Surface-mount assembly with the exposed pad soldered to a thermal land on the PCB; the datasheet layout recommendation specifies a 4x4 mm pad with via array to the inner ground plane.
Available in tape-and-reel (TR) or cut-tape (CT) quantities, the part is suited for both prototype builds and production reels.