Richtek RT8020AGQW, RT8020APQW, RT8020BGQW, RT8020BPQW, RT8020CGQW Schematic [ru]
...
®
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 hand-
held devices.
Two operational modes are available : PWM/Low-Dropout
auto-switch and shutdown modes. Internal synchronous
rectifier with low R
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 0.1μA when EN pin is pulled
low.
dramatically reduces conduction
DS(ON)
Features
2.5V to 5.5V Input Range
Adjustable Output From 0.6V to V
1.2V, 1.3V, 1.8V, 2.5V and 3.3V Fixed/ Adjustable
IN
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
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)
GND
12
EN2
11
NC2
10
FB2
9
GND
8
LX1
13
VIN1
1
VIN2
2
LX2
3
GND
4
FB1
5
NC1
67
EN1
WDFN-12L 3x3
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 require-
ments 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
1
RT8020
(
)
Marking Information
RT8020APQW
C2- : Product Code
C2-YM
DNN
YMDNN : Date Code
RT8020CPQW
C4-YM
DNN
C4- : Product Code
YMDNN : Date Code
RT8020AGQW
C2=YM
DNN
RT8020BPQW
C3-YM
DNN
RT8020BGQW
C3=YM
DNN
C2= : Product Code
YMDNN : Date Code
C3- : Product Code
YMDNN : Date Code
C3= : Product Code
YMDNN : Date Code
RT8020CGQW
C4=YM
DNN
RT8020DPQW
C5-YM
DNN
RT8020DGQW
C5=YM
DNN
C4= : Product Code
YMDNN : Date Code
C5- : Product Code
YMDNN : Date Code
C5=: Product Code
YMDNN : Date Code
Typical Application Circuit
C
L2
2.2µH
V
IN2
C
IN2
4.7µF
3, Exposed Pad (13)
R12
C11
22pF
V
OUT1
Rx1
1 VV
REFOUTx
+×=
Rx2
R11
850k
C
OUT1
4.7µF
1
2
4
5
6
VIN2
LX2
GND
FB1
NC1
EN1
RT8020
L1
2.2µH
EN2
NC2
FB2
GND
LX1
VIN1
12
11
10
9
8
7
Figure 1. Adjustable Voltage Regulator
Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
2
©
OUT2
4.7µF
R21
850k
C
IN1
4.7µF
V
OUT2
C21
22pF
R22
V
IN1
DS8020-06 March 2012www.richtek.com
V
= 1.2V, 1.3V, 1.8V, 2.5V or 3.3V
OUTx
V
IN2
C
IN2
4.7µF
3, Exposed Pad (13)
V
OUT1
C
4.7µF
L2
2.2µH
RT8020
OUT1
1
2
4
5
6
VIN2
LX2
GND
FB1
NC1
EN1
L1
2.2µH
EN2
NC2
FB2
GND
LX1
VIN1
12
11
10
9
8
7
Figure 2. Fixed Voltage Regulator
C
IN1
4.7µF
C
V
IN1
OUT2
4.7µF
V
RT8020
OUT2
Functional Pin Description
Pin No. Pin Name Pin Function
1 VIN2 Power Input of Channel 2.
2 LX2 Pin for Switching of Channel 2.
3, 9,
Exposed Pad (13)
4 FB1 Feedback of Channel 1.
5, 11 NC1, NC2 No Connection or Connect to VIN.
6 EN1 Chip Enable of Channel 1 (Active High). V
7 VIN1 Power Input of Channel 1.
8 LX1 Pin for Switching of Channel 1.
10 FB2 Feedback of Channel 2.
12 EN2 Chip Enable of Channel 2 (Active High). V
GND
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
EN1
EN2
≦ V
≦ V
IN1.
IN2.
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
ENx VINx
FBx
Slope
Compensation
Error
Amplifier
COMP
OSC and
Shutdown
Control
Current
Sense
PWM
Comparator
RC
UVLO and
Power Good
Detector
Current Limit
Detector
Control
Logic
V
REF
Driver
RS1
LXx
RS2
GND
Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
©
DS8020-06 March 2012www.richtek.com
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Absolute Maximum Ratings (Note 1)
RT8020
Supply Input Voltage, V
EN1, FB1, LX1, EN2, FB2 and LX2 Pin Voltage -------------------------------------------------------------- −0.3V to (V
Power Dissipation, P
, V
IN1
IN2
@ TA = 25°C
D
---------------------------------------------------------------------------------- −0.3V to 6.5V
IN
+ 0.3V)
WDFN-12L 3x3 -------------------------------------------------------------------------------------------------------- 1.667W
Package Thermal Resistance (Note 2)
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)
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 ---------------------------------------------------------------------------------------
Ambient Temperature Range ---------------------------------------------------------------------------------------
−40°C to 125°C
−40°C to 85°C
Electrical Characteristics
(VIN = 3.6V, V
= 2.5V, V
OUT
= 0.6V, L = 2.2uH, CIN = 4.7μF, C
REF
= 10μF, T
OUT
= 25°C, I
A
= 1A unless otherwise specified)
MAX
Parameter Symbol Test Conditions Min Typ Max Unit
Channel 1 and Channel 2
Input Voltage Range
Under Voltage Lock Out
threshold
V
IN
UVLO -- 1.8 -- V
2.5 -- 5.5 V
Hysteresis -- 0.1 -- V
Quiescent Current
Shutdown Current
Reference Voltage
Adjustable Output Voltage
Range
Output Voltage
Accuracy
Fix
I
I
Q
I
SHDN
V
REF
V
OUT
ΔV
ΔV
ΔV
ΔV
ΔV
OUT
OUT
OUT
OUT
OUT
OU T
EN = GND -- 0.1 1
For Adjustable Output Voltage 0.588 0.6 0.612 V
(Note 6)
V
IN
0A < I
V
IN
0A < I
V
IN
0A < I
V
IN
V
OUT
V
IN
V
OUT
= 0mA, VFB = V
= 2.5V to 5.5V, V
< 1A
OUT
= 2.5V to 5.5V, V
< 1A
OUT
= 2.5 to 5.5V, V
< 1A
OUT
= V
+ ΔV to 5.5V (Note 5)
OUT
= 2.5V, 0A < I
= V
+ ΔV to 5.5V (Note 5)
OUT
= 3.3V, 0A < I
REF
OUT
OUT
OUT
OU T
OU T
+ 5%
= 1.2V
= 1.3V
= 1.8V
< 1A
< 1A
-- 50 70 μA
μA
V
REF
−3
--
V
−ΔV
IN
-- 3 %
V
−3 -- 3 %
−3 -- 3 %
−3
−3
-- 3 %
-- 3 %
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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