Buck controller for non-isolated step-down rails
The MAX1651CSA+ is a step-down (buck) PWM controller from Analog Devices, designed for non-isolated DC-DC conversion. It drives an external transistor switch (no synchronous rectifier), operates from a 3V to 16V supply, and switches at up to 300 kHz. The single output is positive, with a maximum duty cycle of 96.5%, allowing near-dropout operation. Control features include an enable pin. The part is housed in an 8-SOIC surface-mount package and rated for the commercial temperature range of 0°C to 70°C. Typical applications include point-of-load regulation in telecom, networking, and industrial equipment where a simple, cost-effective buck controller is needed.
Switching frequency and supply range — what they mean for your rail design
The 300 kHz maximum switching frequency sets the inductor size and output ripple. The 3V to 16V supply range covers standard 5V, 12V, and 15V rails. The 96.5% max duty cycle allows the output to approach the input voltage within a few hundred millivolts.
Active lifecycle — no obsolescence concern
The MAX1651CSA+ carries an Active lifecycle status and is ROHS3 compliant. There is no last-time-buy or end-of-life notice on record.
Package and mounting — 8-SOIC, surface-mount, tube delivery
The part comes in an 8-SOIC package (0.154" body width, 3.90 mm width), surface-mount. It ships in a tube. The 8-SOIC footprint is common and easy to route on a two-layer PCB. No special thermal pad or exposed die attach — standard soldering profile applies.