General Description
The RT8206A/B dual step-down, Switch Mode Power Supply (SMPS) controller generates logic supply voltages in battery powered systems. The RT8206A/B includes two Pulse Width Modulation (PWM) controllers fixed at 5V/3.3V or adjustable from 2V to 5.5V. An optional external charge pump can be monitored through SECFB (RT8206A). This device also features a linear regulator providing a fixed 5V output. The linear regulator provides up to 70mA output current with automatic linear regulator bootstrapping to the BYP input. The RT8206A/B includes on-board power up sequencing, the power good outputs, internal soft-start, and internal soft-discharge output that prevents negative voltages on shutdown.
A constant on-time PWM control scheme operates without sense resistors and provides 100ns response to load transients while maintaining a relatively constant switching frequency. The unique ultrasonic mode maintains the switching frequency above 25kHz, which eliminates noise in audio applications. Other features include Diode Emulation Mode (DEM), which maximizes efficiency in light load applications, and fixed frequency PWM mode, which reduces RF interference in sensitive application.
The RT8206A/B is available in the WQFN-32L 5x5 package.

Features
● Wide Input Voltage Range 6V to 25V
● Dual Fixed 5V/3.3V Outputs or Adjustable from 2V
   to 5.5V, 1.5% Accuracy
● Secondary Feedback Input Maintains Charge Pump
   Voltage (RT8206A)
● Independent Enable and Power Good
● 5V Fixed LDO Output : 70mA
● 2V Reference Voltage ±1% : 50μA
● Constant ON-Time Control with 100ns Load Step
   Response
● Frequency Selectable via TON Setting
● RDS(ON) Current Sensing and Programmable Current
   Limit
● Selectable PWM, DEM or Ultrasonic Mode
● Internal Soft-Start with 5 Steps Current Limiting and
   Soft-Discharge
● High Efficiency Up to 97%
● 5mW Quiescent Power Dissipation
● Thermal Shutdown
● RoHS Compliant and Halogen Free

Applications
● Notebook and Sub-Notebook Computers
● 3-Cell and 4-Cell Li+ Battery-Powered Devices