Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Features
General Description



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 52KHz Switching Frequency
3A Constant Output Current Capability
Internal Optimize Power Transistor
High efficiency
The XL2576 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.







Excellent line and load regulation
TTL shutdown capability
ON/OFF pin with hysteresis function
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.
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 XL2576
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Pin Configurations
Figure2. Pin Configuration of XL2576 (Top View)
Table 1 Pin Description
Pin Number
1
2
3
4
5
Pin Name
Description
Supply Voltage Input Pin. XL2576 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 XL2576.
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.
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Function Block
Figure3. Function Block Diagram of XL2576
Typical Application Circuit
FEEDBACK
4
VIN
OUTPUT
1 XL2576-5.0 2
3
5
GND
ON/OFF
+12V
CIN
470uf 35V
C1
105
L1 100uh/3A
5V/3A
COUT
D1
330uf 35V
1N5820
OFF
ON
LOAD
Figure4. XL2576 Typical Application Circuit 12V-5V/3A
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Ordering Information
E1
XL2576
E1: Lead Free
Circuit Type
Package
Version
ADJ: Adjust
3.3: 3.3V
5.0: 5V
12: 12V
S: TO263-5L
T: TO220-5L
Package
Temperature
Range
TO220-5L
-40oC ~ 85oC
TO263-5L
-40oC ~ 85oC
Marking ID
Lead Free
XL2576T-ADJE1
XL2576T-3.3E1
XL2576T-5.0E1
XL2576T-12E1
XL2576S-ADJE1
XL2576S-3.3E1
XL2576S-5.0E1
XL2576S-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 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
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
VFB
VON/OFF
VOutput
PD
Value
-0.3 to 45
-0.3 to Vin
-0.3 to Vin
-0.3 to Vin
Internally limited
Unit
V
V
V
V
mW
RJA
30
ºC/W
TJ
TSTG
TLEAD
-40 to 125
-65 to 150
260
>2000
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.
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
XL2576-3.3 Electrical Characteristics
Ta = 25℃;unless otherwise specified.
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
3.168
3.3
3.432
V
-
75
-
%
Min.
Typ.
Max.
Unit
4.8
5
5.2
V
-
78
-
%
Min.
Typ.
Max.
Unit
11.52
12
12.48
V
-
92
-
%
Min.
Typ.
Max.
Unit
1.193
1.23
1.267
V
-
73
-
%
System parameters test circuit figure6
VOUT
Efficiency
Output
Voltage
ŋ
Vin = 4.75V to 40V
Iload=0.2A to 3A
Vin=12V ,Vout=3.3V
Iout=3A
XL2576-5.0 Electrical Characteristics
Ta = 25℃;unless otherwise specified.
Symbol
Test Condition
Parameter
System parameters test circuit figure7
VOUT
Efficiency
Output
Voltage
ŋ
Vin = 7V to 40V
Iload=0.2A to 3A
Vin=12V ,Vout=5V
Iout=3A
XL2576-12 Electrical Characteristics
Ta = 25℃;unless otherwise specified.
Symbol
Parameter
Test Condition
System parameters test circuit figure5
VOUT
Efficiency
Output
Voltage
ŋ
Vin = 15V to 40V
Iload=0.2A to 2A
Vin=24V ,Vout=12V
Iout=2A
XL2576-ADJ Electrical Characteristics
Ta = 25℃;unless otherwise specified.
Symbol
Parameter
Test Condition
System parameters test circuit figure8
VOUT
Efficiency
Output
Voltage
ŋ
Vin = 4.5V to 40V
Iload=0.2A to 3A
Vin=12V ,Vout=3V
Iout=3A
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Electrical Characteristics (DC Parameters)
Vin = 12V for the 3.3V,5V,and Adjustable versions and Vin=24V for the 12V version, GND=0V,
Vin & GND parallel connect a 220uf/50V capacitor; Iout=500mA, Ta = 25℃; the others floating
unless otherwise specified.
Parameters
Symbol
Input operation voltage
Test Condition
Vin
Min.
Typ.
4.5
Max.
Unit
40
V
Shutdown Supply Current
ISTBY
VON/OFF=5V
80
200
uA
Quiescent Supply Current
Iq
VON/OFF =0V,
VFB =Vin
2
10
mA
40
52
64
Khz
3.6
4.8
6.9
A
Oscillator Frequency
Fosc
Switch Current Limit
IL
VFB =0
VON/OFF
High (Regulator OFF)
Low (Regulator ON)
1.4
0.8
IH
VON/OFF =2.5V (OFF)
5
15
uA
IL
VON/OFF =0.5V (ON)
0.2
5
uA
VCE
VFB=0V
Iout=3A
1.3
1.5
V
DMAX
VFB=0V
100
ON/OFF Pin Threshold
ON/OFF
Pin
Leakage Current
Input
Output Saturation Voltage
Max. Duty Cycle
Rev 2.5
V
%
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Test Circuit and Layout guidelines
Figure5. Standard Test Circuits and Layout Guides
Select R1 to be approximately 1K, use a 1% resistor for best stability.
C1 and CFF are optional; in order to increase stability and reduce the input power line noise, CIN
and C1 must be placed near to PIN1 and PIN3;
For output voltages greater than approximately 10V, an additional capacitor CFF is required. The
compensation capacitor is typically between 100 pf and 33 nf, and is wired in parallel with the
output voltage setting resistor, R2. It provides additional stability for high output voltage, low
input-output voltages, and/or very low ESR output capacitors, such as solid tantalum capacitors.
CFF=1/(31*1000*R2); This capacitor type can be ceramic, plastic, silver mica, etc. (Because of
the unstable characteristics of ceramic capacitors made with Z5U material, they are not
recommended.)
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
XL2576 Series Buck Regulator Design Procedure (Fixed Output)
Conditions
Output
Voltage
(V)
3.3
Load
Current
(A)
3
5
3
Max Input
Voltage (V)
Inductor
(L1)
Inductance
(uh)
5
10
20
40
7
9
15
40
47
68
100
150
47
68
100
150
Output Capacitor (COUT)
Through Hole Electrolytic
Panasonic
Nichicon
HFQ Series
PL Series
(uf/V)
(uf/V)
470/25
560/16
560/35
560/35
680/35
680/35
560/35
470/35
470/25
560/16
560/25
560/25
330/35
330/35
330/35
270/35
Rev 2.5
Surface Mount Tantalum
AVX TPS
Sprague
Series
595D Series
(uf/V)
(uf/V)
330/6.3
390/6.3
330/6.3
390/6.3
330/6.3
390/6.3
330/6.3
390/6.3
220/10
330/10
220/10
330/10
220/10
330/10
220/10
330/10
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
XL2576 Series Buck Regulator Design Procedure (Adjustable Output)
Output
Voltage
(V)
2
4
6
9
12
15
24
28
Through Hole Output Electrolytic
Panasonic
Nichicon
Feedforward
HFQ Series
PL Series
Capacitor
(uf/V)
(uf/V)
820/35
820/35
33nf
560/35
470/35
10nf
470/25
470/35
3.3nf
330/25
330/25
1.5nf
330/25
330/25
1nf
220/25
220/35
680pf
220/35
150/35
560pf
100/50
100/50
390pf
Surface Mount Output Capacitor
AVX TPS
Sprague
Feedforward
Series
595D Series
Capacitor
(uf/V)
(uf/V)
330/6.3
470/4
33nf
330/6.3
390/6.3
10nf
220/10
330/10
3.3nf
100/16
180/16
1.5nf
100/16
180/16
1nf
68/20
120/20
680pf
33/25
33/25
220pf
10/35
15/50
220pf
Schottky Diode Selection Table
Current
1A
3A
Surface Through VR (The same as system maximum input voltage)
Mount Hole
20V
30V
40V
50V
1N5817
1N5818
1N5819
√
√
1N5820
1N5821
1N5822
√
MBR320
MBR330
MBR340 MBR350
MBR360
SK32
SK33
SK34
SK36
30WQ03
30WQ04 30WQ05
31DQ03
31DQ04
31DQ05
SR305
SR306
√
√
√
5A
√
60V
SK35
√
SR302
SR303
SR304
√
1N5823
1N5824
1N5825
√
SR502
SR503
SR504
SR505
SR506
√
SB520
SB530
SB540
SB550
SB560
50WQ03
50WQ04 50WQ05
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Typical System Application for 3.3V Version
FEEDBACK
4
VIN
OUTPUT
1 XL2576-3.3 2
3
5
GND
ON/OFF
+12V
CIN
470uf 35V
C1
105
L1 100uh/3A
3.3V/3A
COUT
D1
470uf 35V
1N5820
OFF
ON
LOAD
Figure6. XL2576-3.3 System Parameters Test Circuit
Typical System Application for 5V Version
FEEDBACK
4
VIN
OUTPUT
1 XL2576-5.0 2
3
5
GND
ON/OFF
+12V
CIN
470uf 35V
C1
105
L1 100uh/3A
5V/3A
COUT
D1
330uf 35V
1N5820
OFF
ON
LOAD
Figure7. XL2576-5.0 System Parameters Test Circuit
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Typical System Application for ADJ Version
CFF 10n
R1 1K
R2 3.1K
FEEDBACK
4
VIN
OUTPUT
1 XL2576-ADJ 2
3
5
GND
ON/OFF
+24V
CIN
470uf 50V
C1
105
L1 150uh/3A
5V/3A
COUT
D1
470uf 35V
1N5821
OFF
ON
LOAD
VOUT=1.23*(1+R2/R1)
Figure8. XL2576-ADJ System Parameters Test Circuit
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Package Information
(1) TO220-5L
Rev 2.5
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Datasheet
3A 52KHz 40V Buck DC to DC Converter
XL2576
Package Information
(2) TO263-5L
Rev 2.5
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