RT8205L Datasheet, PDF (1/26 Pages) Richtek Technology Corporation – High Efficiency, Main Power Supply Controller for Notebook Computer

RT8205L/M
High Efficiency, Main Power Supply Controller
for Notebook Computer
General Description
The RT8205L/M is a dual step-down, switch mode power
supply controller generating logic-supply voltages in
battery powered systems. It includes two Pulse-Width
Modulation (PWM) controllers adjustable from 2V to 5.5V,
and also features fixed 5V/3.3V linear regulators. Each
linear regulator provides up to 100mA output current with
automatic linear regulator bootstrapping to the PWM
outputs. An optional external charge pump can be
monitored through SECFB (RT8205M). The RT8205L/M
includes on-board power up sequencing, a power good
output, internal soft-start, and internal soft-discharge
output that prevents negative voltage during shutdown.
The constant on-time PWM control scheme operates
without sense resistors and provides 100ns response to
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 25kHz. Moreover,
the diode-emulation mode maximizes efficiency for light
load applications. The RT8205L/M is available in a
WQFN-24L 4x4 package.
Ordering Information
RT8205
Package Type
QW : WQFN-24L 4x4 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)
Pin Function
L : Default
M : With SECFB
Note :
Richtek 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.
Features
z Constant On-time Control with 100ns Load Step
Response
z Wide Input Voltage Range : 6V to 25V
z Dual Adjustable Outputs from 2V to 5.5V
z Secondary Feedback Input Maintains Charge Pump
Voltage (RT8205M)
z Fixed 3.3V and 5V LDO Output : 100mA
z 2V Reference Voltage
z Frequency Selectable via TONSEL Setting
z 4700ppm/°C R_DS(ON) Current Sensing
z Programmable Current Limit Combined with
Enable Control
z Selectable PWM, DEM, or Ultrasonic Mode
z Internal Soft-Start and Soft-Discharge
z High Efficiency up to 97%
z 5mW Quiescent Power Dissipation
z Thermal Shutdown
z RoHS Compliant and Halogen Free
Applications
z Notebook and Sub-Notebook Computers
z 3-Cell and 4-Cell Li+ Battery-Powered Devices
DS8205L/M-05 June 2011
www.richtek.com
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