RT6338 Series: 8 A, 23 Vin, Synchronous ACOT® Buck Converter

Richtek's RT6338 family are high efficiency synchronous step-down DC-DC converters with pseudo-constant switching frequency 500 kHz and deliver up to 8 A output current. The RT6338A, RT6338AH, RT6338B, and RT6338BH operate from 4.5 V to 23 V input voltage. The output voltage of the RT6338A and RT6338AH is programmed between 0.6 V to 5.5 V, and RT6338B and RT6338BH are fixed to 3.3 V output voltage. The input voltage of RT6338C and RT6338CH ranges from 5.2 V to 23 V, and the output voltage of RT6338C and RT6338CH is fixed to 5.1 V.

The RT6338 adopts Advanced Constant On-Time (ACOT) control architecture, providing ultra-fast transient response and reducing the external component count. In steady states, ACOT operates at nearly constant switching frequency over line, load, and output voltage ranges, making the EMI filter design easier.

By setting the voltage of the EN/MODE pin, RT6338 operates either in diode emulation mode (DEM) or ultrasonic mode (USM) at light load. The USM maintains an operation frequency above 25 kHz, eliminating acoustic noise. In the DEM, RT6338 provides the best light-load efficiency and improves acoustic noise with a spread spectrum function.

RT6338 provides a PGOOD indicator for easy system sequence control. Full protection features are also integrated into the device, including the cycle-by-cycle current limit, overvoltage protection (OVP), undervoltage protection (UVP), input undervoltage lockout (UVLO), and overtemperature protection (OTP).

All the above functions are integrated in a UQFN-23L 3x3 (FC) package.