Richtek RT8020AGQW, RT8020APQW, RT8020BGQW, RT8020BPQW, RT8020CGQW, RT8020CPQW, RT8020DPQW, RT8020GQW, RT8020PQW Schematic [ru]
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®
RT8020
Dual High-Efficiency PWM Step-Down DC/DC Converter
General Description
The RT8020 is a dual high-efficiency Pulse-Width- Modulated (PWM) step-down DC/DC converter. It is capable of delivering 1A output current over a wide input voltage range from 2.5V to 5.5V, the RT8020 is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources within the range such as cellular phones, PDAs and other handheld devices.
Two operational modes are available : PWM/Low-Dropout auto-switch and shutdown modes. Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical application.
The RT8020 enters Low-Dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper PMOS. The RT8020 enter shutdown mode and consumes less than 0.1μAwhen ENpin is pulled low.
The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operation frequency of 1.5MHz. This along with small WDFN-12L 3x3 package provides small PCB area application. Other features include soft start, lower internal reference voltage with 2% accuracy, over temperature protection, and over current protection.
Pin Configurations
(TOP VIEW)
VIN2 |
1 |
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12 |
EN2 |
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LX2 |
2 |
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11 |
NC2 |
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GND 3 |
GND |
10 |
FB2 |
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FB1 4 |
9 |
GND |
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NC1 |
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8 |
LX1 |
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EN1 |
6 |
13 7 |
VIN1 |
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WDFN-12L 3x3
Features
2.5V to 5.5V Input Range Adjustable Output From 0.6V to VIN
1.2V, 1.3V, 1.8V, 2.5V and 3.3V Fixed/ Adjustable Output Voltage
1A Output Current
95% Efficiency
No Schottky Diode Required
50uA Quiescent Current per Channel 1.5MHz Fixed Frequency PWM Operation Small 12-Lead WDFN Package
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Mobile Phones
Personal Information Appliances
Wireless and DSL Modems
MP3 Players
Portable Instruments
Ordering Information
RT8020 
Package Type
QW : WDFN-12L 3x3 (W-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Output Voltage : VOUT1/VOUT2
Default : Adjustable
A : 3.3V/1.8V
B : 3.3V/1.3V
C : 3.3V/1.2V
D : 2.5V/1.8V
Note :
Richtek products are :
`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes.
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8020-06 March 2012 |
www.richtek.com |
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1 |
RT8020
Marking Information
RT8020APQW |
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RT8020CPQW |
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C2- : Product Code |
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C4- : Product Code |
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C2-YM |
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YMDNN : Date Code |
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C4-YM |
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YMDNN : Date Code |
DNN |
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DNN |
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RT8020AGQW |
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RT8020CGQW |
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C2= : Product Code |
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C4= : Product Code |
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C2=YM |
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YMDNN : Date Code |
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C4=YM |
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YMDNN : Date Code |
DNN |
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DNN |
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RT8020BPQW |
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RT8020DPQW |
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C3- : Product Code |
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C5- : Product Code |
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C3-YM |
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YMDNN : Date Code |
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C5-YM |
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YMDNN : Date Code |
DNN |
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DNN |
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RT8020BGQW |
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RT8020DGQW |
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C3= : Product Code |
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C5=: Product Code |
C3=YM |
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YMDNN : Date Code |
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C5=YM |
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YMDNN : Date Code |
DNN |
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DNN |
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Typical Application Circuit
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VIN2 |
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1 |
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CIN2 |
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4.7µF |
3, Exposed Pad (13) |
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R12 |
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5 |
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C11 |
R11 |
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22pF |
850k |
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VOUT1 |
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= VREF ×(1+ Rx1) |
COUT1 |
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VOUTx |
4.7µF |
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Rx2 |
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L2 |
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COUT2 |
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4.7µF |
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2.2µH |
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VOUT2 |
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RT8020 |
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VIN2 |
EN2 |
12 |
R21 |
C21 |
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11 |
850k |
22pF |
LX2 |
NC2 |
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GND |
FB2 |
10 |
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FB1 |
GND |
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R22 |
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8 |
CIN1 |
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NC1 |
LX1 |
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EN1 |
VIN1 |
7 |
4.7µF |
VIN1 |
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L1 |
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2.2µH |
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Figure 1. Adjustable Voltage Regulator
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8020-06 March 2012 |
2 |
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RT8020
L2
2.2µH
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VIN2 |
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VOUT2 |
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RT8020 |
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COUT2 |
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1 |
VIN2 |
EN2 |
12 |
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CIN2 |
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2 |
11 |
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4.7µF |
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LX2 |
NC2 |
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4.7µF |
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10 |
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3, Exposed Pad (13) |
GND |
FB2 |
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FB1 |
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NC1 |
LX1 |
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CIN1 |
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4.7µF |
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EN1 |
VIN1 |
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VIN1 |
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L1 |
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VOUT1 |
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2.2µH |
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COUT1 |
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4.7µF |
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VOUTx = 1.2V, 1.3V, 1.8V, 2.5V or 3.3V |
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Figure 2. Fixed Voltage Regulator |
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Functional Pin Description
Pin No. |
Pin Name |
Pin Function |
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1 |
VIN2 |
Power Input of Channel 2. |
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2 |
LX2 |
Pin for Switching of Channel 2. |
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3, 9, |
GND |
Ground. The exposed pad must be soldered to a large PCB and connected to |
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Exposed Pad (13) |
GND for maximum power dissipation. |
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4 |
FB1 |
Feedback of Channel 1. |
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5, 11 |
NC1, NC2 |
No Connection or Connect to VIN. |
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6 |
EN1 |
Chip Enable of Channel 1 (Active High). VEN1 |
VIN1. |
7 |
VIN1 |
Power Input of Channel 1. |
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8 |
LX1 |
Pin for Switching of Channel 1. |
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10 |
FB2 |
Feedback of Channel 2. |
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12 |
EN2 |
Chip Enable of Channel 2 (Active High). VEN2 |
VIN2. |
Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
DS8020-06 March 2012 |
www.richtek.com |
|
3 |
RT8020
Function Block Diagram
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ENx |
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VINx |
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OSC and |
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RS1 |
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Current Limit |
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Shutdown |
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Detector |
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Control |
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Slope |
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Compensation |
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Current |
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Sense |
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PWM |
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Comparator |
Control |
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Driver |
LXx |
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Logic |
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Error |
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Amplifier |
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FBx |
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RC |
UVLO and |
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Power Good |
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COMP |
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Detector |
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RS2 |
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VREF |
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GND |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
www.richtek.com |
DS8020-06 March 2012 |
4
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RT8020 |
Absolute Maximum Ratings (Note 1) |
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Supply Input Voltage, VIN1, VIN2 ---------------------------------------------------------------------------------- |
−0.3V to 6.5V |
EN1, FB1, LX1, EN2, FB2 and LX2 Pin Voltage -------------------------------------------------------------- |
−0.3V to (VIN + 0.3V) |
Power Dissipation, PD @ TA = 25°C |
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WDFN-12L 3x3 -------------------------------------------------------------------------------------------------------- |
1.667W |
Package Thermal Resistance (Note 2) |
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WDFN-12L 3x3, θJA -------------------------------------------------------------------------------------------------- |
60°C/W |
WDFN-12L 3x3, θJC -------------------------------------------------------------------------------------------------- |
8.2°C/W |
Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------- |
260°C |
Junction Temperature ------------------------------------------------------------------------------------------------ |
150°C |
Storage Temperature Range --------------------------------------------------------------------------------------- |
−65°C to 150°C |
ESD Susceptibility (Note 3) |
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HBM (Human Body Mode) ----------------------------------------------------------------------------------------- |
2kV |
MM (Machine Mode) ------------------------------------------------------------------------------------------------- |
200V |
Recommended Operating Conditions |
(Note 4) |
Supply Input Voltage ------------------------------------------------------------------------------------------------- |
2.5V to 5.5V |
Junction Temperature Range --------------------------------------------------------------------------------------- |
−40°C to 125°C |
Ambient Temperature Range --------------------------------------------------------------------------------------- |
−40°C to 85°C |
Electrical Characteristics
(VIN = 3.6V, VOUT = 2.5V, VREF = 0.6V, L = 2.2uH, CIN = 4.7μF, COUT = 10μF, TA = 25°C, IMAX= 1A unless otherwise specified)
Parameter |
Symbol |
Test Conditions |
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Min |
Typ |
Max |
Unit |
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Channel 1 and Channel 2 |
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Input Voltage Range |
VIN |
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2.5 |
-- |
5.5 |
V |
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Under Voltage Lock Out |
UVLO |
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-- |
1.8 |
-- |
V |
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threshold |
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Hysteresis |
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-- |
0.1 |
-- |
V |
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Quiescent Current |
IQ |
IOUT = 0mA, VFB = VREF + 5% |
-- |
50 |
70 |
μA |
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Shutdown Current |
ISHDN |
EN = GND |
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-- |
0.1 |
1 |
μA |
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Reference Voltage |
VREF |
For Adjustable Output Voltage |
0.588 |
0.6 |
0.612 |
V |
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Adjustable Output Voltage |
VOUT |
(Note 6) |
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VREF |
-- |
VIN − V |
V |
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Range |
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VOUT |
VIN = 2.5V to 5.5V, VOUT = 1.2V |
−3 |
-- |
3 |
% |
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0A < IOUT < 1A |
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VOUT |
VIN = 2.5V to 5.5V, VOUT = 1.3V |
−3 |
-- |
3 |
% |
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0A < IOUT < 1A |
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Output Voltage |
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Fix |
VOUT |
VIN = 2.5 to 5.5V, VOUT = 1.8V |
−3 |
-- |
3 |
% |
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Accuracy |
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0A < IOUT < 1A |
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VOUT |
VIN = VOUT + |
V to 5.5V |
(Note 5) |
− |
-- |
3 |
% |
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VOUT = 2.5V, 0A < IOUT < 1A |
3 |
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VOUT |
VIN = VOUT + |
V to 5.5V |
(Note 5) |
−3 |
-- |
3 |
% |
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VOUT = 3.3V, 0A < IOUT < 1A |
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Copyright ©2012 Richtek Technology Corporation. All rights reserved. |
is a registered trademark of Richtek Technology Corporation. |
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DS8020-06 March |
2012 |
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www.richtek.com |
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5 |
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