Document
XLSEMI
3A 180KHz 45V Buck DC/DC Converter With Constant Current Loop
Datasheet XL4301
Features
Operation Voltage from 8V to 40V Adjust VOUT from 1.25V to VIN-2V Minimum Drop Out 0.3V Fixed 180KHz Switching Frequency Maximum 3A Switching Current Internal Optimize Power MOSFET Excellent line and load regulation With output constant current loop Built in thermal shutdown function Built in current limit function Built in output cable compensation Recommend output power less than 13W SOP8-EP (Exposed PAD) package
Applications
Car Charger Battery Charger LCD Monitor and LCD TV Portable instrument power supply Telecom / Networking Equipment Buck constant current driver
General Description
The XL4301 is a 180KHz fixed frequency PWM buck (step-down) DC/DC converter, capable of driving a 2.5A load with high efficiency, low ripple and excellent line and load regulation. Requiring a minimum number of external components, the regulator is simple to use and include internal frequency compensation and a fixed-frequency oscillator.
The PWM control circuit is able to adjust the duty ratio linearly from 0 to 100%. An enable function, an over current protection function is built inside. An internal compensation block is built in to minimize external component count.
The XL4301 built in a simple, user-programmable output cable voltage drop compensation function. Use the curve in Table 2 to choose the proper compensation resistance values for cable compensation.
Rev1.0
Figure1. Package Type of XL4301
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XLSEMI
Datasheet
3A 180KHz 45V Buck DC/DC Converter With Constant Current Loop
XL4301
Pin Configurations
The back exposed PAD is SW.
Figure2. Pin Configuration of XL4301 (Top View)
Table 1. Pin Description
Pin Number 1
2
3
4
5 6 7
8
Pin Name NC
SW
GND
FB
CS LC VC
VIN
Description
Not connected. Power Switch Output Pin (SW). Output is the switch node that supplies power to the output. (Note: Connected the back exposed PAD to SW.) Ground Pin. Feedback Pin (FB). Through an external resistor divider network, Feedback senses the output voltage and regulates it. The feedback threshold voltage is 1.25V. Output Current Sense Pin (Iload=0.11V/Rcs). Output cable compensation. Internal Voltage Regulator Bypass Capacity. In typical system application, The VC pin connect a 1uF capacity to VIN. Supply Voltage Input Pin. XL4301 operates from a 8V to 40V DC voltage. Bypass Vin to GND with a suitably large capacitor to eliminate noise on the input.
Rev1.0
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XLSEMI
3A 180KHz 45V Buck DC/DC Converter With Constant Current Loop Function Block
Datasheet XL4301
Figure3. Function Block Diagram of XL4301
Typical Application Circuit (Car Charger)
Figure4. XL4301 Typical Application Circuit
Rev1.0
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XLSEMI
Datasheet
3A 180KHz 45V Buck DC/DC Converter With Constant Current Loop
XL4301
Ordering Information
Order Information
Marking ID
Package Type Packing Type Supplied As
XL4301
XL4301E1
SOP8-EP
2500 Units on Tape & Reel
XLSEMI Pb-free products, as designated with “E1” suffix in the par number, are RoHS compliant.
Absolute Maximum Ratings Note1
Parameter
Symbol
Value
Unit
Input Voltage
Vin -0.3 to 45 V
FB Pin Voltage SW Pin Voltage Power Dissipation Thermal Resistance (Junction to Ambient, No Heatsink, Free Air)
VFB VSW PD
RJA
-0.3 to Vin -0.3 to Vin Internally limited
60
V V mW
ºC/W
Maximum Junction Temperature Operating Junction Temperature Storage Temperature Lead Temperature (Soldering, 10 sec) ESD (HBM)
TJ TJ TSTG TLEAD
-40 to 150 -40 to 125 -65 to 150
260 >2000
ºC ºC ºC ºC V
Note1: Stresses greater than those listed under Maximum Ratings may cause permanent damage
to the device. This is a stress rating only and functional operation of the device at these or any
other conditions above those indicated in the operation is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect reliability.
Rev1.0
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XLSEMI
Datasheet
3A 180KHz 45V Buck DC/DC Converter With Constant Current Loop
XL4301
XL4301 Electrical Characteristics
Ta = 25 ;unless otherwise specified.
Symbol Parameter
Test Condition
System parameters test circuit figure4
VFB Efficiency
Feedback Voltage
ŋ
Vin = 8V to 40V, Vout=5V Iload=0.2A to 2A Vin=12V ,Vout=5V Iout=2.5A
Min. Typ. Max. Unit
1.231 1.25 1.269 V - 88 - %
Electrical Characteristics (DC Parameters)
Vin = 12V, GND=0V, Vin & GND parallel connect a 100uF/50V capacitor; Iout=500mA, Ta = 25 ; the others floating unless otherwise specified.
Parameters
Symbol Test Condition Min. Typ. Max. Unit
VIN operation voltage
Vin
8 40 V
VIN UVLO
Vuvlo
5V
Quiescent Supply Current
Iq
VFB =Vin
2 5 mA
Oscillator Frequency
Fosc
153 180 225 KHz
Switch Current Limit
IL
Output Power PMOS
Rdson
Constant current sense Voltage Thermal Shutdown temperature Thermal Shutdown Hysteresis
VCS OTP
VFB =0
VFB=0V, Vin=12V, ISW=3A
104.5
3.5 A 75 100 mohm .