RT8206A Datasheet, PDF (1/26 Pages) Richtek Technology Corporation – High-Efficiency, Main Power Supply Controllers for Notebook Computers

RT8206A/B
High-Efficiency, Main Power Supply Controllers
for Notebook Computers
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.
Applications
z Notebook and Sub-Notebook Computers
z 3-Cell and 4-Cell Li+ Battery-Powered Devices
Features
z Wide Input Voltage Range 6V to 25V
z Dual Fixed 5V/3.3V Outputs or Adjustable from 2V
to 5.5V, 1.5% Accuracy
z Secondary Feedback Input Maintains Charge Pump
Voltage (RT8206A)
z Independent Enable and Power Good
z 5V Fixed LDO Output : 70mA
z 2V Reference Voltage ±1% : 50uA
z Constant ON-Time Control with 100ns Load Step
Response
z Frequency Selectable via TON Setting
z R_DS(ON) Current Sensing and Programmable Current
Limit
z Selectable PWM, DEM or Ultrasonic Mode
z Internal Soft-Start with 5 Steps Current Limiting and
Soft-Discharge
z High Efficiency Up to 97%
z 5mW Quiescent Power Dissipation
z Thermal Shutdown
z RoHS Compliant and Halogen Free
Ordering Information
RT8206
Package Type
QW : WQFN-32L 5x5 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
A : With SECFB
B : Without SECFB
Richtek Green products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
DS8206A/B-04 March 2011
www.richtek.com
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