AT2003

Wide Input sensorless CC/CV 2A Buck Converter

General Description Features
AT2003 is a wide input voltage, high efficiency step-  Wide Input Voltage with 9V ~ 40V Operation
down DC/DC converter that operates in either CV (Con-  Up to 3A Output Current
stant Output Voltage) mode or CC (Constant Output
Current) mode. AT2003 provides up to 3A output current  Fixed Frequency 120 kHz with Easy EMI Control
at 120kHz switching frequency ,and the CC level can be  Constant voltage and constant voltage control
adjusted by changing external sensing resister.
 Precision Feedback Voltage 1.2V+-1%
The AT2003 provides full protection functions, thermal
shutdown is to prevent over temperature operating from  Precision CC Limit with +-5% Accuracy
damage; cycle by cycle current limit is against over  Integrated 140mohm High Side NMOS
current operating of the switch; and over voltage protec-
tion (OVP) that can avoid high Vout voltage to damage  Internal MOS 4.5A Current Peak Protected in Cycle
circuit and capacitor. by Cycle Current Limit
The devices is available in PSOP8-8L package and  PSOP8-8 Package
require very few external devices for operation.

Applications
 Car Charger/Adaptor
Ordering and Marking Information
 General-Purposed DC/DC Converters with
Constant Current Limit Order Number Package Top Marking
 Rechargeable Portable Devices AT2003ZSP8 PSOP-8L AT2003Z
Note: Aplustek products are compatible with the current
IPC/JEDEC J-STD-020 requirement. They are halogen-free,
Pin Configuration RoHS compliant and 100% matte tin (Sn) plating that are
suitable for use in SnPb or Pb-free soldering processes.

VCC LX

GND BST
GND

FB SENN

COMP SENP

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Rev. C00, File Name: AT2003-DSF001
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Typical Application Circuit

VC C =9~40V

LOUT
R SENSE V OUT

C IN C BST

AT2003 C OUT

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Rev. C00, File Name: AT2003-DSF001
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Function Blocks

VCC

Regulator

OCP
OTP POR LX
5V

5V
UVP BST

0.4V
Fault
OVP Logics

Driver
1.45V Duty
Logics
CV loop
FB
1.2V LX

COMP Ramp 120KHz

SENP CC loop

GND

SENN

Function Pin Description

N o. Pin Name Pin Function
Pow er Supply Input. Bypass this pin with a 0.1uF ceramic capacitor to GND, placed as close
1 VC C
to the IC as possible.
2 GND Ground.
Feedback Input. The voltage at this pin is regulated to 1.2V.Connect to resistor divider between
3 FB
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.
Bootstrap Bias Pin. It provides power to the internal high-side MOSFET gate driver.
7 BST
Connect a 0.1uF capacitor from BST to LX pin.
8 LX Power Switching Output to external Inductor.

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Rev. C00, File Name: AT2003-DSF001
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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 C onditions Min Typ Max U nits
Supply Input Section
VC C operati on range VCC,R 9 -- 40 V
VCC,R VC C Ri si ng -- 8.2 -- V
VC C UVLO threshold
VCC,F VC C Falli ng -- 6.3 -- V
VC C operati on current ICC VC C =9V to 40V, C OMP short to FB -- 1 1.5 mA
Oscillation Section
-- 120 -- kHz
PWM Frequency FSW
-15% -- +15 %
Max D uty D MAX -- 90 -- %
PWM loop Section
Feedback reference voltage VREF -- 1.2 -- V
Feedback reference accuracy -1% -- +1% %
C OMP source current FB<1.2V -- 85 -- uA
C OMP si nk current FB>1.2V -- 85 -- uA
C OMP Hi gh voltae FB<1.2V -- 4.3 -- V
C OMP Low voltae FB>1.2V -- 0.8 -- V
Fault protection Section
FB under voltage level VUVP -- 0.4 -- V
FB over voltage level VOVP -- 1.45 -- V
FB short Impedance level VSHORT -- 0.2 -- V
O
TOTP -- 150 -- C
Over Tempperature level
O
THYS -- 40 -- C

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Rev. C00, File Name: AT2003-DSF001
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Parameter Symbol Test C onditions Min Typ Max U nits
Fault protection Section
C C C ontrol accuracy -5 -- +5 %
Internal Soft Start ti me TSS -- 4.5 -- mS
Fault recycle wai tti ng ti me Trecycle -- 0.5 -- S
H igh side MOS Section
Hi gh si de MOS ON resi stance RDSON -- 0.14 -- ohm
Hi gh Si de MOS peak current Li mi t -- 4.5 -- A

Note 1. Exceeding these limits may impaire the life of the device. Exposure to absolute maximum rating conditions
for long periods may affect device reliability.
Note 2. θJA is measured with the component mounted on a high effective thermal conductivity test board in free
air.The exposed pad of the package is soldered directly on the PCB.

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Rev. C00, File Name: AT2003-DSF001
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Typical Operation Characteristics
VFB vs. VCC Frequency vs. VCC
1.30 140

1.25 130

Frequency (KHz)
VFB (V)

1.20 120

1.15
110

1.10
10 15 20 25 30 35 40 100
10 15 20 25 30 35 40

VCC (V) VCC (V)

Power On from VCC Power Off from VCC

VCC (10V/Div) VCC (10V/Div)

LX (10V/Div) LX (10V/Div)

VOUT (5V/Div) VOUT (5V/Div)

IOUT (2A/Div) IOUT (2A/Div)

20ms/Div 200ms/Div

Short Circuit Enter Short Circuit Recovery

VCC (10V/Div) VCC (10V/Div)

LX (10V/Div) LX (10V/Div)

VOUT (5V/Div) VOUT (5V/Div)

IL (2A/Div) IL (2A/Div)

20ms/Div 20ms/Div

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Rev. C00, File Name: AT2003-DSF001
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Package Information

PSOP-8L

0.70 ± 0. 10 4.80 - 5.00

1.27 ± 0. 10
2.60 - 3.40

1.50 ± 0.10
3.20 ± 0. 10

2.30 ± 0. 10
4.00 ± 0. 10
7.00 ± 0. 10
5.50 ± 0. 10

5.79 - 6.20
3.80 - 4.00

1.90 - 2.55
1

1.27 BSC 0.31 - 0.51

Recommended Solder Pad Layout

0.10 - 0.25 1.70 MAX

0.00 - 0.15

0.40 - 1.27

Note
1.Package Outline Unit Description:
BSC: Basic. Represents theoretical exact dimension .
MAX: Maximum dimension specified.
MIN: Minimum dimension specified.
REF: Represents dimension for reference use only. The value is not the device specification.
TYP: Represents as a typical value. The value is not the device specification.
2.All linear dimensions are in Millimeters.

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Rev. C00, File Name: AT2003-DSF001