3A, 18V, 650kHz, ACOT® Synchronous Step-Down Converter

The RT6259A/B are high-performance 650kHz 3A step-down regulators with internal power switches and synchronous rectifiers. They feature quick transient response using their Advanced Constant On-Time (ACOT^TM) control architecture that provides stable operation with small ceramic output capacitors and without complicated external compensation, among other benefits. The input voltage range is from 4.5V to 18V and the output is adjustable from 0.765V to 7V. The proprietary ACOT^TM control improves upon other fast-response constant on-time architectures, achieving nearly constant switching frequency over line, load, and output voltage ranges. Since there is no internal clock, response to transients is nearly instantaneous and inductor current can ramp quickly to maintain output regulation without large bulk output capacitance. The RT6259A/B are stable with and optimized for ceramic output capacitors.

With internal 70mΩ switches and 70mΩ synchronous rectifiers, the RT6259A/B display excellent efficiency and good behavior across a range of applications, especially for low output voltages and low duty cycles. Cycle-by-cycle current limit, input under-voltage lockout, externally-adjustable soft-start, output under- and over-voltage protection, and thermal shutdown provide safe and smooth operation in all operating conditions.

The RT6259A and RT6259B are each available in the WQFN-16L 3x3 package, with exposed thermal pads.The RT6259B switches continuously even at light loads to avoid low-frequency interference while the RT6259A features a power-saving discontinuous operating mode at light loads.