Document
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.
Features
z
z z z
z z z z z
z z z z z z
Constant On-time Control with 100ns Load Step Response Wide Input Voltage Range : 6V to 25V Dual Adjustable Outputs from 2V to 5.5V Secondary Feedback Input Maintains Charge Pump Voltage (RT8205M) Fixed 3.3V and 5V LDO Output : 100mA 2V Reference Voltage Frequency Selectable via TONSEL Setting 4700ppm/°C RDS(ON) Current Sensing Programmable Current Limit Combined with Enable Control Selectable PWM, DEM, or Ultrasonic Mode Internal Soft-Start and Soft-Discharge High Efficiency up to 97% 5mW Quiescent Power Dissipation Thermal Shutdown RoHS Compliant and Halogen Free
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Applications
z z
Notebook and Sub-Notebook Computers 3-Cell and 4-Cell Li+ Battery-Powered Devices
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 :
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RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes.
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DS8205L/M-05 June 2011
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datasheet pdf - http://www.DataSheet4U.net/
RT8205L/M
Marking Information
RT8205LGQW EM= : Product Code RT8205MGQW EN= : Product Code YMDNN : Date Code
EM=YM DNN
EN=YM DNN
YMDNN : Date Code
RT8205LZQW EM : Product Code
RT8205MZQW EN : Product Code YMDNN : Date Code
EM YM DNN
EN YM DNN
YMDNN : Date Code
Pin Configurations
(TOP VIEW)
VOUT1 PGOOD BOOT1 UGATE1 PHASE1 LGATE1 VOUT1 PGOOD BOOT1 UGATE1 PHASE1 LGATE1
24 23 22 21 20 19 18 17 16 15 25 7 8 9 10 11 12 14 13
24 23 22 21 20 19
ENTRIP1 FB1 REF TONSEL FB2 ENTRIP2
1 2 3 4 5 6
GND
NC VREG5 VIN GND SKIPSEL EN
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ENTRIP1 FB1 REF TONSEL FB2 ENTRIP2
1 2 3 4 5 6 7 8 9 10 11 12
18 17 16 15 25 14 13
GND
SECFB VREG5 VIN GND SKIPSEL EN
VOUT2 VREG3 BOOT2 UGATE2 PHASE2 LGATE2
WQFN-24L 4x4 RT8205L
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VOUT2 VREG3 BOOT2 UGATE2 PHASE2 LGATE2
WQFN-24L 4x4 RT8205M
DS8205L/M-05 June 2011
datasheet pdf - http://www.DataSheet4U.net/
RT8205L/M
Typical Application Circuit
C1 10µF R8 3.9 C10 0.1µF VIN 6V to 25V
RT8205L 16 VIN UGATE2 10 BOOT2 21 UGATE1 22 BOOT1 20 PHASE1 19 LGATE1
R10 0
9 RBOOT2 0
C11 0.1µF
Q2 BSC119 N03S
C13 10µF
C12 10µF
Q1 BSC119 N03S
L1 6.8µH R5 C4 C18 C19 0.1µF
R4 0 RBOOT1 0 C2 0.1µF
PHASE2 11 LGATE2 12 GND 15 VOUT2 7 5 FB2 ENTRIP1 1 ENTRIP2 6
L2 4.7µH
Q4 BSC119 N03S
VOUT2 3.3V C17 220µF
R11 C14
VOUT1 5V C3 220µF
Q3 BSC119 N03S
RILIM1 150k RILIM2 150k
R14 6.5k R15 10k
C21 C20 0.1µF
24 VOUT1
R12 15k R13 10k
VREF 2V
Frequency Control PWM/DEM/Ultrasonic
C15 0.22µF
2 FB1 3 REF 4 TONSEL 14 SKIPSEL 13 EN
GND
25 (Exposed Pad)
5V Always On R6 100k PGOOD Indicator C16 4.7µF 3.3V Always On
VREG5 17 PGOOD 23 VREG3 8
C9 4.7µF
ON OFF
C1 10µF
R8 3.9 C10 0.1µF
VIN 6V to 25V
RT8205M 16 VIN UGATE2 10
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R10 0
BOOT2 21 UGATE1 22 BOOT1 20 PHASE1 19 LGATE1
9 RBOOT2 0
C11 0.1µF
Q2 BSC119 N03S
C13 10µF
C12 10µF
Q1 BSC119 N03S
L1 6.8µH R5 C4 C18 C19 0.1µF
R4 0 RBOOT1 0 C2 0.1µF
PHASE2 11 LGATE2 12 GND 15 VOUT2 7 5 FB2 ENTRIP1 1 ENTRIP2 GND 6
L2 4.7µH
Q4 BSC119 N03S
VOUT2 3.3V C17 220µF
R11 C14
VOUT1 5V C3 220µF
Q3 BSC119 N03S
RILIM1 150k RILIM2 150k
R14 6.5k R15 10k
C21 C20 0.1µF
24 VOUT1
R12 15k R13 10k C6 0.1µF D2 D3 D4 C8 0.1µF BAT254 R6 200k R7 39k C7 0.1µF D1 C5 0.1µF
2 FB1
25 (Exposed Pad)
VREG5 17 PGOOD 23 18 VREG3 8 SECFB REF 3 TONSEL 4 SKIPSEL 14
C9 4.7µF
5V Always On R6 100k PGOOD Indicator 3.3V Always On
C16 4.7µF C15 0.22µF
CP
VREF 2V
Frequency Control PWM/DEM/Ultrasonic
ON OFF
13 EN
DS8205L/M-05 June 2011
www.richtek.com 3
datasheet pdf - http://www.DataSheet4U.net/
RT8205L/M
Fun.