Datasheet
3A 150KHz 40V Buck DC to DC Converter
Features
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Wide 4.5V to 40V Input Voltage Range
3.3V,5V,12V, and adjustable versions
Output Adjustable from 1.23V to 37V
Maximum Duty Cycle 100%
Minimum Drop Out 1.5V
Fixed 150KHz Switching Frequency
3A Constant Output Current Capability
Internal Optimize Power Transistor
High efficiency
Excellent line and load regulation
TTL shutdown capability
ON/OFF pin with hysteresis function
Built in thermal shutdown function
Built in current limit function
Built in second current limit function
Available in TO-220,TO-263 packages
XL2596
General Description
The XL2596 is a 150 KHz fixed frequency
PWM buck (step-down) DC/DC converter,
capable of driving a 3A 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. When second current limit
function happens, the operation frequency
will be reduced from 150KHz to 50KHz. An
internal compensation block is built in to
minimize external component count.
Applications
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LCD Monitor and LCD TV
Digital Photo Frame
Set-up Box
ADSL Modem
Telecom / Networking Equipment
Figure1. Package Type of XL2596
Rev 2.4
1
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Datasheet
3A 150KHz 40V Buck DC to DC Converter
Pin Configurations
XL2596
Figure2. Pin Configuration of XL2596 (Top View)
Table 1 Pin Description
Pin Number
1
2
3
Description
Supply Voltage Input Pin. XL2596 operates from a 4.5V to
40V DC voltage. Bypass Vin to GND with a suitably large
VIN
capacitor to eliminate noise on the input.
Power Switch Output Pin (SW). Output is the switch node that
OUTPUT
supplies power to the output.
Ground Pin. Care must be taken in layout. This pin should be
placed outside of the Schottky Diode to output capacitor
GND
ground path to prevent switching current spikes from inducing
voltage noise into XL2596.
Feedback Pin (FB). Through an external resistor divider
FEEDBACK network, Feedback senses the output voltage and regulates it.
The feedback threshold voltage is 1.23V.
Enable Pin. Drive ON/OFF pin low to turn on the device, drive
ON/OFF
it high to turn it off. Floating is default low.
Pin Name
4
5
Rev 2.4
2
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Datasheet
3A 150KHz 40V Buck DC to DC Converter
Function Block
XL2596
Figure3. Function Block Diagram of XL2596
Typical Application Circuit
Figure4. XL2596 Typical Application Circuit 12V-5V/3A
Rev 2.4
3
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Datasheet
3A 150KHz 40V Buck DC to DC Converter
Ordering Information
XL2596
E1
E1: Lead Free
Circuit Type
Package
S: TO263-5L
T: TO220-5L
XL2596
Version
ADJ: Adjust
3.3: 3.3V
5.0: 5V
12: 12V
Package
Temperature
Range
-40
o
C ~ 85
o
C
TO220-5L
TO263-5L
-40
o
C ~ 85
o
C
Marking ID
Lead Free
XL2596T-ADJE1
XL2596T-3.3E1
XL2596T-5.0E1
XL2596T-12E1
XL2596S-ADJE1
XL2596S-3.3E1
XL2596S-5.0E1
XL2596S-12E1
Packing Type Supplied As
Tube
Tube
Tube
Tube
800 Units on Tape & Reel
800 Units on Tape & Reel
800 Units on Tape & Reel
800 Units on Tape & Reel
XLSEMI Pb-free products, as designated with
“E1”
suffix in the par number, are RoHS compliant.
Rev 2.4
4
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Datasheet
3A 150KHz 40V Buck DC to DC Converter
Absolute Maximum Ratings（Note1）
Parameter
Input Voltage
Feedback Pin Voltage
ON/OFF Pin Voltage
Output Switch Pin Voltage
Power Dissipation
Thermal Resistance (TO220 & TO263)
(Junction to Ambient, No Heatsink, Free Air)
Operating Junction Temperature
Storage Temperature
Lead Temperature (Soldering, 10 sec)
ESD (HBM)
Symbol
Vin
V
FB
V
ON/OFF
V
Output
P
D
R
JA
T
J
T
STG
T
LEAD
Value
-0.3 to 45
-0.3 to Vin
-0.3 to Vin
-0.3 to Vin
Internally limited
30
-40 to 125
-65 to 150
260
2000
Unit
V
V
V
V
mW
ºC/W
ºC
ºC
ºC
V
XL2596
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.
Rev 2.4
5
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