RT8245C Datasheet | Richtek

® RT8245A/B/C High Efficiency, Main Power Supply Controller for Notebook puters General Description The RT8245A/B/C is a dual step down, Switch Mode Power Supply (SMPS) controller which generates logic supply voltages for battery powered systems. It includes two Pulse Width Modulation (PWM) controllers adjustable from 2V to 5.5V and also two fixed 5V/3.3V linear regulators. One of the controllers (LDO5) provides automatic switch over to the BYP1 input connected to the main SMPS1 output for maximized efficiency. An optional external charge pump can be monitored through SECFB (RT8245B/C). Other Features include on board power up sequencing, a power good output, internal softstart, and a soft discharge output that prevents negative voltage during shutdown. A constant on-time PWM control scheme operates without sense resistors and assures fast load transient response while maintaining nearly constant switching frequency. To eliminate noise in audio applications, an ultrasonic mode is included, which maintains the switching frequency above 25k Hz. Moreover, a diode emulation mode maximizes efficiency for light load applications. The SMPS1/SMPS2 switching frequency can be adjustable from 200k Hz/233k Hz to 400k Hz/466k Hz respectively. The RT8245A/B/C is available in a WQFN-20L 3x3 package, and operates over an extended temperature range from - 40°C to 85°C. Features z 5.5V to 25V Input Voltage Range z 2V to 5.5V Output Voltage Range z No Current Sense Resistor Needed z 5V/3.3V Linear Regulators z 4700ppm/°C RDS(ON) Current Sensing z Internal Current Limit Soft-Start and Soft Discharge Output z Built In OVP/UVP/OCP z Selectable Operation Mode with Switcher Enable Control (RT8245A) z SECFB Input Maintains Charge Pump Voltage (RT8245B/C) z Power Good Indicator (RT8245B/C includes SECFB) z Ro HS pliant and Halogen Free Applications z Notebook puters z System Power Supplies z 3- and 4- Cell Li+ Battery-Powered Device Ordering Information RT8245A/B/C Package Type QW :...