Document
AT2003
Wide Input sensorless CC/CV 2A Buck Converter
General Description
AT2003 is a wide input voltage, high efficiency stepdown DC/DC converter that operates in either CV (Constant Output Voltage) mode or CC (Constant Output Current) mode. AT2003 provides up to 3A output current at 120kHz switching frequency ,and the CC level can be adjusted by changing external sensing resister.
The AT2003 provides full protection functions, thermal shutdown is to prevent over temperature operating from damage; cycle by cycle current limit is against over current operating of the switch; and over voltage protection (OVP) that can avoid high Vout voltage to damage circuit and capacitor.
The devices is available in PSOP8-8L package and
require very few external devices for operation.
Features
Wide Input Voltage with 9V ~ 40V Operation Up to 3A Output Current Fixed Frequency 120 kHz with Easy EMI Control Constant voltage and constant voltage control Precision Feedback Voltage 1.2V+-1% Precision CC Limit with +-5% Accuracy Integrated 140mohm High Side NMOS Internal MOS 4.5A Current Peak Protected in Cycle
by Cycle Current Limit PSOP8-8 Package
Applications
Car Charger/Adaptor General-Purposed DC/DC Converters with
Ordering and Marking Information
Constant Current Limit
Order Number Package
Top Marking
Rechargeable Portable Devices
AT2003SSP8 PSOP-8L
AT2003S
Pin Configuration
Note: Aplustek products are compatible with the current IPC/JEDEC J-STD-020 requirement. They are halogen-free, RoHS compliant and 100% matte tin (Sn) plating that are suitable for use in SnPb or Pb-free soldering processes.
VCC GND FB COMP
GND
LX BST SENN SENP
Aplustek Integrated Circuits Corp., Rev. C00, File Name: AT2001-DSC001
www.sntoweb.com 13667868567 ,
1
Typical Application Circuit
AT2003
VCC=9~40V C IN
AT2003
C BST
LOUT
R SENSE
VOUT
C OUT
Aplustek Integrated Circuits Corp., Rev. C00, File Name: AT2001-DSC001
www.sntoweb.com 13667868567 ,
2
Function Blocks
VCC
AT2003
FB
COMP SENP
Regulator
5V
0.4V 1.45V 1.2V
UVP OVP
CV loop
OTP POR
OCP
Fault Logics
Ramp 120KHz CC loop
LX 5V
Duty Logics
Driver
BST LX GND
SENN
Function Pin Description
No. Pin Name Pin Function
1
VCC
Power Supply Input. Bypass this pin with a 0.1uF ceramic capacitor to GND, placed as close to the IC as possible.
2 GND Ground.
3
FB
Feedback Input. The voltage at this pin is regulated to 1.2V.Connect to resistor divider between output and GND to set the output voltage.
4 COMP Error Amplifier output Pin.The pin is used to compensate the converter.
5 SENP Current sense positive input pin.
6 SENN Current sense negative input pin.
7
BST
Bootstrap Bias Pin. It provides power to the internal high-side MOSFET gate driver. Connect a 0.1uF capacitor from BST to LX pin.
8 LX Power Switching Output to external Inductor.
Aplustek Integrated Circuits Corp., Rev. C00, File Name: AT2001-DSC001
www.sntoweb.com 13667868567 ,
3
AT2003
Absolute Maximum Ratings
(Note1) Supply Input Voltage, VCC ------------------------------------------------------------------------------------------- -0.3V to +44V BST to LX ----------------------------------------------------------------------------------------------------------- - 0.3V to +7V LX to GND DC ----------------------------------------------------------------------------------------------------- -0.3V to +44V FB,COMP to GND DC ---------------------------------------------------------------------------------------------- -0.3V to +7V Storage Temperature Range ------------------------------------------------------------------------------------------- -65OC to +150OC Junction Temperature ----------------------------------------------------------------------------------------------------------- -40OC to +150OC
Lead Temperature Range(Soldering 10sec) ------------------------------------------------------------------------------------------ 260OC
ESD Rating (Note2)
HBM(Human Body Mode)-------------------------------------------------------------------------------------------------------------2KV
MM(Mechine Mode)-----------------------------------------------------------------------------------------------------------------------------200V
Thermal Characteristics
Package Thermal Resistance (Note3) PSOP-8L θJA ------------------------------------------------------------------------------------------------------------------------ 50OC/W PSOP-8L θJC ------------------------------------------------------------------------------------------------------------------------- 5OC/W
Power Dissipation, PD @ TA = 25°C
PSOP-8L ------------------------------------------------------------------------------------------------------------------------ 2.0W
Electrical Characteristics
( VCC = 12V, TA = +25OC unless otherwise specified.)
Parameter
Symbol
Test Conditions
Min Typ Max Units
Supply Input Section
VCC operation range VCC UVLO threshold
VCC operation current Oscillation Sectio.