Datasheet
3A 52KHz 40V Buck DC to DC Converter
Features
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
LM2576
General Description
The LM2576 is a 52 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. An internal compensation
block is built in to minimize external
component count.
Fixed 52KHz Switching Frequency
3A Constant Output Current Capability
Internal Optimize Power Transistor
High e
fficiency
Excellent line and load regulation
TTL shutdown capability
ON/OFF pin with hysteresis function
Built in thermal shutdown function
Built in current limit function
Available in TO-220,TO-263 packages
Applications
LCD Monitor and LCD TV
Digital Photo Frame
Set-up Box
ADSL Modem
Telecom / Networking Equipment
Figure1. Package Type of LM2576
REV1.1
SHENZHEN CYT OPTO-ELECTRONIC TECHNOLOGY CO.,LTD
1
www.szcyt.com
Datasheet
3A 52KHz 40V Buck DC to DC Converter
Pin Configurations
LM2576
Figure2. Pin Configuration of LM2576 (Top View)
Table 1 Pin Description
Pin Number
1
2
3
Description
Supply Voltage Input Pin. LM2576 operates from a 4.5V to
VIN
40V DC voltage. Bypass Vin to GND with a suitably large
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 LM2576.
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
REV1.1
SHENZHEN CYT OPTO-ELECTRONIC TECHNOLOGY CO.,LTD
2
www.szcyt.com
Datasheet
3A 52KHz 40V Buck DC to DC Converter
Function Block
LM2576
Figure3. Function Block Diagram of LM2576
Typical Application Circuit
LM
Figure4. LM2576 Typical Application Circuit 12V-5V/3A
REV1.1
SHENZHEN CYT OPTO-ELECTRONIC TECHNOLOGY CO.,LTD
3
www.szcyt.com
Datasheet
3A 52KHz 40V Buck DC to DC Converter
Ordering Information
LM2576
E1
E1: Lead Free
Circuit Type
Packing
Blank: Tube
TR:
Type and Reel
Package
S: TO263-5L
T: TO220-5L
TB: TO220B-5L
Version
ADJ: Adjust
3.3:
3.3V
5.0:
5V
12:
12V
LM2576
Package
Temperature
Range
-40
o
C ~ 85
o
C
TO220-5L
TO220B-5L
-40
o
C ~ 85
o
C
TO263-5L
-40
o
C ~ 85
o
C
Part Number
Lead Free
LM2576T-ADJE1
LM2576T-3.3E1
LM2576T-5.0E1
LM2576T-12E1
LM2576TB-ADJE1
LM2576TB-3.3E1
LM2576TB-5.0E1
LM2576TB-12E1
LM2576S-ADJE1
LM2576S-3.3E1
LM2576S-5.0E1
LM2576S-12E1
LM2576S-ADJTRE1
LM2576S-3.3TRE1
LM2576S-5.0TRE1
LM2576S-12TRE1
Marking ID
Lead Free
LM2576T-ADJE1
LM2576T-3.3E1
LM2576T-5.0E1
LM2576T-12E1
LM2576TB-ADJE1
LM2576TB-3.3E1
LM2576TB-5.0E1
LM2576TB-12E1
LM2576S-ADJE1
LM2576S-3.3E1
LM2576S-5.0E1
LM2576S-12E1
LM2576S-ADJE1
LM2576S-3.3E1
LM2576S-5.0E1
LM2576S-12E1
Packing Type
Tube
Tube
Tube
Tube
Tube
Tube
Tube
Tube
Tube
Tube
Tube
Tube
Tape & Reel
Tape & Reel
Tape & Reel
Tape & Reel
Pb-free products, as designated with “E1” suffix in the par number, are RoHS compliant.
REV1.1
SHENZHEN CYT OPTO-ELECTRONIC TECHNOLOGY CO.,LTD
4
www.szcyt.com
Datasheet
3A 52KHz 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
50
-40 to 125
-65 to 150
260
2000
Unit
V
V
V
V
mW
ºC/W
ºC
ºC
ºC
V
LM2576
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.
REV1.1
SHENZHEN CYT OPTO-ELECTRONIC TECHNOLOGY CO.,LTD
5
www.szcyt.com
京公网安备 11010802033920号
EEWORLD
