RT2859A Datasheet | Richtek

Description The RT2859A/B are high-performance 650k Hz 3A step-down regulators with internal power switches and synchronous rectifiers. They feature quick transient response using their Advanced Constant On-Time (ACOT® ) control architecture that provides stable operation with small ceramic output capacitors and without plicated external pensation, 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® 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 RT2859A/B are stable with and optimized for ceramic output capacitors. With internal 70m switches and 70m synchronous rectifiers, the RT2859A/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 underand over-voltage protection, and thermal shutdown provide safe and smooth operation in all operating conditions. The RT2859A and RT2859B are each available in the WQFN-16L 3x3 package, with exposed thermal pads. The RT2859B switches continuously even at light loads to avoid low-frequency interference while the RT2859A features a power-saving discontinuous operating mode at light loads. The remended junction temperature range is - 40C to 125C and ambient temperature range is - 40C to 85C. 2 Features - Fast Transient Response - Steady 650k Hz Switching Frequency at all Load Current (RT2859B) - Discontinuous Operating Mode at Light Load (RT2859A) - 3A Output Current - Advanced Constant On-Time (ACOT® Control - Optimized for Ceramic Output Capacitors - 4.5V to...