LM2576-XXE5/F5

CYStech Electronics Corp.
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 1/12
Simple Switcher
3A Step- Down Voltage Regulator
LM2576-XXE5/F5
Features
● 3.3V, 5V, 12V, 15V, and adjustable output versions.
● Adjustable version output voltage range, 1.23V to 37V±4% max over line
and load conditions.
● Guaranteed 3A output current.
● Wide input voltage range.
● Requires only 4 external components
● 52 kHz fixed frequency oscillator
● TTL shutdown capability, low power standby mode.
● High efficiency
● Uses readily available standard inductors.
● Thermal shutdown and current limit protection.
Description
The LM2576-XXE5/F5 series of regulators are monolithic integrated circuits that provide all the active functions
for a step-down (buck) switching regulator, capable of driving 3A load with excellent line and load regulation.
These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, and an adjustable output version.
Requiring a minimum number of external components, these regulators are simple to use and include internal
frequency compensation and a fixed-frequency oscillator.
The LM2576-XXE5/F5 series offers a high-efficiency replacement for popular three-terminal linear regulators.
It substantially reduces the size of the heat sink, and in some cases no heat sink is required.
A standard series if inductors optimized for use with the LM2576 are available from several different
manufacturers. This feature greatly simplifies the design of switch-mode power supplies.
Other features include a guaranteed ±4% tolerance on output voltage within specified input voltages and output
load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring 50μA (typical)
standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full
protection under fault conditions.
Applications
● Simple high-efficiency step-down (buck) regulator.
● Efficient pre-regulator for linear regulators.
● On-card switching regulators.
● Positive to negative converter (Buck-Boost).
LM2576-XXE5/F5
CYStek Product Specification
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 2/12
CYStech Electronics Corp.
Typical Application (Fixed Output Voltage Version)
7V-40V unregulated
DC input
+VIN
LM2576-50
PL2576-5.0
1
+
Cin
100μF
Feedback
4
Output
2
3 GND 5 ON/OFF
+5V regulated output
3A load
L1
100μH
D1
1N5822
+
Cout
1000μF
Figure. 1
Block Diagram
Vin
Unregulated
DC Input
Internal
Regulator
1
ON / OFF
5
ON/OFF
Feedback
Cin
+
4
R2
Fixed Gain
Error Amp
Comparator
Driver
1.0k
3 Amp
Switch
R1
2
1.23V
band-gap
reference
52kHz
Oscillator
Reset
Thermal Current
Shutdown Limit
Output
L1
Cout
GND
3
Vout
D1
+
L
O
A
D
3.3V, R2=1.7k
5V, R2=3.1k
12V, R2=8.84k
15V, R2=11.3k
For Adjustable version, R1=open, R2=0
Ordering Information
LM2576-XXE5/F5
CYStek Product Specification
CYStech Electronics Corp.
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 3/12
Absolute Maximum Ratings (Note 1)
Parameter
Supply Voltage
On/Off Pin Input Voltage
Output Voltage to Ground
Power Dissipation
Operating Temperature
Storage Temperature
ESD Susceptibility (Note 2)
Lead Temperature (soldering, 10 seconds)
Symbol
VCC
VSD
VOUT
PD
Topr
Tstg
Value
45
-0.3 ~ +VIN
-1
Internally Limited
-40 ~ +125
-65 ~ +150
2000
260
TL
Unit
V
V
V
W
℃
℃
V
℃
LM2576-33 Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range
Symbol
Parameter
Conditions
Typ
Min
Max
Units
3.3
3.234
3.336
V
3.3
3.168/3.135
3.432/3.465
V
System Parameters (Note 3) Test Circuit Figure 2
VOUT
VOUT
η
Output Voltage VIN=12V, ILOAD=0.5A
Circuit of Figure 2
6V≤VIN≤40V, 0.5A≤ILOAD≤3A
Output Voltage Circuit of Figure 2
Efficiency
VIN=12V, ILOAD=3A
75
%
LM2576-50 Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range
Symbol
Parameter
Conditions
Typ
Min
Max
Units
5.0
4.9
5.1
V
5.0
4.800/4.750
5.200/5.250
V
System Parameters (Note 3) Test Circuit Figure 2
VOUT
VOUT
η
LM2576-XXE5/F5
Output Voltage VIN=12V, ILOAD=0.5A
Circuit of Figure 2
8V≤VIN≤40V, 0.5A≤ILOAD≤3A
Output Voltage Circuit of Figure 2
Efficiency
VIN=12V, ILOAD=3A
77
%
CYStek Product Specification
CYStech Electronics Corp.
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 4/12
LM2576-12 Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range
Symbol
Parameter
Conditions
Typ
Min
Max
Units
Output Voltage VIN=25V, ILOAD=0.5A
Circuit of Figure 2
15V≤VIN≤40V, 0.5A≤ILOAD≤3A
Output Voltage Circuit of Figure 2
12
11.76
12.24
V
12
11.52/11.40
12.48/12.60
V
Efficiency
88
System Parameters (Note 3) Test Circuit Figure 2
VOUT
VOUT
η
VIN=15V, ILOAD=3A
%
LM2576-15 Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range
Symbol
Parameter
Conditions
Typ
Min
Max
Units
Output Voltage VIN=25V, ILOAD=0.5A
Circuit of Figure 2
18V≤VIN≤40V, 0.5A≤ILOAD≤3A
Output Voltage Circuit of Figure 2
15
14.7
15.3
V
15
14.40/14.25
15.60/15.75
V
Efficiency
88
System Parameters (Note 3) Test Circuit Figure 2
VOUT
VOUT
η
VIN=18V, ILOAD=3A
%
LM2576-ADJ Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range
Symbol
Parameter
Conditions
Typ
Min
Max
Units
1.230
1.217
1.243
V
1.230
1.193/1.180
1.267/1.280
V
System Parameters (Note 3) Test Circuit Figure 2
VOUT
VOUT
η
LM2576-XXE5/F5
Feedback
Voltage
Feedback
Voltage
VIN=12V, ILOAD=0.5A,
VOUT=5V, Circuit of Figure 2
8V≤VIN≤40V, 0.5A≤ILOAD≤3A
VOUT=5V, Circuit of Figure 2
Efficiency
VIN=12V, ILOAD=3A,
VOUT=5V
77
%
CYStek Product Specification
CYStech Electronics Corp.
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 5/12
All Output Voltage Versions Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with boldface type apply over full
operating temperature range. Unless otherwise specified, VIN=12V for the 3.3V, 5.0V, and adjustable versions,
VIN=25V for the 12V version, and VIN=30V for the 15V version. ILOAD=500mA.
Symbol
Ib
fO
VSAT
DC
ICL
IL
IQ
ISTBY
Parameter
Conditions
Typ
Feedback bias current VOUT=5V (adjustable version only) 50
Oscillator frequency (Note 8)
52
Saturation voltage
IOUT=3A (Note 4)
1.4
Maximum duty cycle (Note 5)
98
(ON)
(Notes 4, 8)
Current limit
5.8
(Notes 6, 7) Output = 0V
Output leakage current
Output = -1V
7.5
(Note 6)
Quiescent current
5
Standby quiescent
50
ON/OFF pin=5V (OFF)
current
Min
Max
Units
-
100/500
nA
47/42
-
58/63
1.8/2.0
kHz
V
93
-
%
4.2/3.5
-
6.9/7.5
2
30
10
A
mA
-
200
μA
mA
ON/OFF Control
VIH
VIL
IIH
IIL
ON/OFF pin logic
input level
ON/OFF pin input
current
VOUT=0V
1.4
2.2/2.4
-
V
VOUT=Nominal output voltage
1.2
-
1.0/0.8
V
12
-
30
μA
0
-
10
μA
ON/OFF pin=5V (OFF)
ON/OFF pin=0V (ON)
Note 1 : Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate
conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For
guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2 : All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face).
Note 3 : External components such as the catch diode, inductor, input and output capacitors can affect switching regulator
system performance. When the LM2576 is used as shown in the figure 2 test circuit, system performance will be as
shown in system parameters section of Electrical Characteristics.
Note 4 : Output pin sourcing current. No diode, inductor or capacitor connected to output.
Note 5 : Feedback pin removed from output and connected to 0V.
Note 6 : Feedback pin removed from output and connected to +12V for the Adjustable, 3.3V, and 5V versions, and +25V for
the 12V and 15V versions, to force the output transistor OFF.
Note 7 : VIN=40V.
Note 8 : The oscillator frequency reduces to approximately 11 kHz in the event of an output short or an overload which causes
the regulated output voltage to drop approximately 40% from the nominal output voltage. This self protection feature
lowers the average power dissipation of the IC by lowering the minimum duty cycle from 5% down to approximately
2%.
LM2576-XXE5/F5
CYStek Product Specification
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 6/12
CYStech Electronics Corp.
Typical Performance Characteristics (circuit of Figure 2)
Norm alized Output Voltage
Line Regulation
1
1.4
0.8
1.2
VIN = 20V,ILOAD = 500mA
Normalized at TJ = 25℃
0.6
0.4
ILOAD = 500mA,
TJ = 25℃
1
0.8
0.2
0
0.6
-0.2
0.2
-0.4
0
-0.6
-0.2
-0.8
-0.4
0.4
-1
3.3V, 5V & ADJ
12V & 15V
-0.6
-50
-25
0
25
50
75
100
0
125
10
20
30
40
50
Input Voltage(V)
Junction Temperature(℃)
Dropout Voltage
Standby Quiescent Current
200
1.75
1.5
175
ILOAD=3A
150
1.25
ILOAD=1A
VIN=40V
125
1
VON/OFF = 5V
100
0.75
75
0.5
ILOAD=0.2A
L1 = 150μH
Rind = 0.1Ω
0.25
50
VIN=12V
25
0
0
-75 -50 -25
0
25
50
75
-50
100 125 150
-25
0
25
50
75
100
125
Junction Temperature(℃)
Junction Temperature(℃)
Current Lim it
Quiescent Current
20
6.5
18
VIN =25V
VOUT = 5V, measured
at ground pin, TJ = 25℃
16
6
14
5.5
12
10
5
ILOAD=3A
8
4.5
6
ILOAD=0.2A
4
4
0
LM2576-XXE5/F5
10
20
30
Input Voltage (V)
40
50
-75 -50 -25
0
25
50
75
100 125 150
Junction Temperature (℃)
CYStek Product Specification
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 7/12
CYStech Electronics Corp.
Switch Saturation Voltage
Efficiency
1.6
95
1.4
-55℃
ILOAD = 3A
90
15V OUT
1.2
85
1
ILOAD = 0.2A
80
0.8
25℃
5V
75
ILOAD = 3A
0.6
150℃
0.4
70
ILOAD = 0.2A
65
0.2
TJ = 25℃
60
0
0
0.5
1
1.5
2
Switch Current (A)
2.5
0
3
10
20
30
40
50
Input Voltage (V)
Oscillator Frequency
Minim um Operating Voltage
5
8
6
Adjustable version only
4.5
Normalized at 25℃
4
4
3.5
2
3
0
2.5
-2
2
VIN = 40V
1.5
-4
VOUT ≒1.23V
ILOAD = 0.5A
1
VIN = 12V
-6
0.5
-8
0
-75 -50 -25
0
25
50
75
100 125 150
-50
-25
0
25
50
75
100
125
Junction Temperature (℃)
Junction Temperature (℃)
Feedback Voltage vs Duty Cycle
Quiescent Current vs Duty Cycle
20
20
17.5
15
Adjustable version only
15
Adjustable version only
ILOAD = 0.5A
10
ILOAD = 0.5A
12.5
5
VIN=7V
VIN=40V
0
10
7.5
-5
VIN=40V
5
-10
2.5
-15
0
VIN=7V
-20
0
20
40
60
Duty Cycle (%)
LM2576-XXE5/F5
80
10 0
0
20
40
60
80
100
Duty Cycle (%)
CYStek Product Specification
CYStech Electronics Corp.
Minim um Power Dissipation
Feedback Pin Current
100
5
4.5
Adjustable version only
75
θJA = 32℃/W
4
50
3.5
θJA = 37℃/W
25
3
θJA = 50℃/W
2.5
2
0
-25
1.5
-50
1
0.5
-75
θJA = 73℃/W
0
-100
0
10
20
30
40
50
60
70
80
90 100
-75 -50 -25
Ambient Temperature (℃)
25
50
75
100 125 150
Load Transient Response
50V
0
100mV
Output
0
Voltage
Change -100mV
4A
B
0
Junction Temperature (℃)
Switching Waveforms
A
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 8/12
2A
0
3A
4A
C
D
Load
Current
2A
0
2A
1A
0
5μs/ div
100 μs / div
VOUT=15V
A : Output Pin Voltage, 50 V / div
B : Output Pin Current, 2A / div
C : Inductor Current, 2A / div
D : Output Ripple Voltage, 50mV / div
AC Coupled
Horizontal Time Base : 5μs / div
LM2576-XXE5/F5
CYStek Product Specification
CYStech Electronics Corp.
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 9/12
Test Circuit and Layout Guidelines
As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring
inductance generate voltage transients which can cause problems. For minimal inductance and ground
loops, the length of the leads indicated by heavy lines should be kept as short as possible. Single-point
grounding (as indicated) or ground plane construction should be used for best results. When using the
Adjustable version, physically locate the programming resistors near the regulator, to keep the sensitive
feedback wiring short.
Fixed Output Voltage Versions
Feedback
4
PL2576
LM2576
+Vin
Fixed Output
1
Output
2
Vin
Unregulated
DC Input
+
Cin
100μF
GND
3
ON / OFF
5
Vout
L1
100μH
D1
MBR360
+
Cout
1000μF
L
O
A
D
Cin--100μF, 75V, Aluminum Electrolytic
Cout--1000μF, 25V, Aluminum Electrolytic
D1--Schottky, MBR360
L1--100μH, Pulse Eng, PE92108
R1--2k, 0.1%
R2--6.12k, 0.1%
Adjustable Output Voltage Version
+Vin
1
LM2576-ADJ
PL2576-ADJ
Feedback
4
Output
2
7V-40V
Unregulated
DC Input
+
Cin
100μF
GND 3
ON / OFF 5
Vout
5.00V
L1
100μH
+
D1
MBR360
Cout
1000μF
R2
R1
Vout=VREF(1+
R2=R1(
Vout
VREF
L
O
A
D
R2
)
R1
-1)
where VREF=1.23V, R1 between 1k and 5k
Figure 2
LM2576-XXE5/F5
CYStek Product Specification
CYStech Electronics Corp.
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 10/12
TO-263-5L Dimension
Marking:
Date Code
LM2576□□□
□□□□
Vout:
3.3V→-33
5.0V→-50
12V→-12
15V→-15
ADJ→
blank
5-Lead TO-220-5L Plastic Package
CYStek Package Code: E5
Style: Pin 1.Vin 2.Vout 3.GND
4.Feedback 5.ON/OFF
Inches
Min.
Max.
0.173
0.189
0.030
0.039
0.014
0.020
0.339
0.354
0.386
0.409
0.579
0.602
DIM
A
b
c
D
E
L4
Millimeters
Min.
Max.
4.40
4.80
0.76
1.00
0.36
0.50
8.60
9.00
9.80
10.4
14.7
15.3
DIM
L5
c1
L
e
L1
φ
Inches
Min.
Max.
0.244
0.260
0.049
0.057
0.522
0.561
0.067 REF
0.102
0.114
0.146
0.156
Millimeters
Min.
Max.
6.20
6.60
1.25
1.45
13.25
14.25
1.70 REF
2.60
2.89
3.71
3.96
Notes: 1.Controlling dimension: millimeter
2.Maximum lead thickness includes lead finish thickness, and minimum lead thickness is the minimum thickness of base material.
3.If there is any question with packing specification or packing method, please contact your local CYStek sales office.
Material:
• Mold Compound: Epoxy resin family, flammability solid burning class: UL94V-0
LM2576-XXE5/F5
CYStek Product Specification
CYStech Electronics Corp.
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 11/12
TO-263-5L Dimension
Marking:
LM2576□□□
Date Code
□□□□
Vout:
3.3V→-33
5.0V→-50
12V→-12
15V→-15
ADJ→
blank
Style: Pin
1.Vin 2.Vout 3.GND
4.Feedback 5.ON/OFF
5-Lead TO-263-5L Plastic Package
CYStek Package Code: F5
Inches
Min.
Max.
0.173
0.189
0.026
0.036
0.000
0.012
0.014
0.020
0.090
0.110
0.386
0.409
DIM
A
b
L4
c
L1
E
Millimeters
Min.
Max.
4.40
4.80
0.66
0.91
0.00
0.30
0.36
0.50
2.29
2.79
9.80
10.4
DIM
c2
L2
D
e
L
θ
Inches
Min.
Max.
0.049
0.057
0.050 REF
0.339
0.354
0.067 REF
0.575
0.622
0°
8°
Millimeters
Min.
Max.
1.25
1.45
1.27 REF
8.60
9.00
1.70 REF
14.6
15.8
0°
8°
Notes: 1.Controlling dimension :millimeter
2.Maximum lead thickness includes lead finish thickness, and minimum lead thickness is the minimum thickness of base material.
3.If there is any question with packing specification or packing method, please contact your local CYStek sales office.
Material:
• Mold Compound: Epoxy resin family, flammability solid burning class: UL94V-0
Recommended wave soldering condition
Product
Pb-free devices
LM2576-XXE5/F5
Peak Temperature
260 +0/-5 °C
Soldering Time
5 +1/-1 seconds
CYStek Product Specification
CYStech Electronics Corp.
Spec. No. : C543E5/F5
Issued Date : 2004.02.27
Revised Date :2007.12.13
Page No. : 12/12
Recommended temperature profile for IR reflow
Profile feature
Average ramp-up rate
(Tsmax to Tp)
Preheat
−Temperature Min(TS min)
−Temperature Max(TS max)
−Time(ts min to ts max)
Time maintained above:
−Temperature (TL)
− Time (tL)
Peak Temperature(TP)
Time within 5°C of actual peak
temperature(tp)
Ramp down rate
Time 25 °C to peak temperature
Sn-Pb eutectic Assembly
Pb-free Assembly
3°C/second max.
3°C/second max.
100°C
150°C
60-120 seconds
150°C
200°C
60-180 seconds
183°C
60-150 seconds
240 +0/-5 °C
217°C
60-150 seconds
260 +0/-5 °C
10-30 seconds
20-40 seconds
6°C/second max.
6 minutes max.
6°C/second max.
8 minutes max.
Note : All temperatures refer to topside of the package, measured on the package body surface.
Important Notice:
• All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of CYStek.
• CYStek reserves the right to make changes to its products without notice.
• CYStek semiconductor products are not warranted to be suitable for use in Life-Support Applications, or systems.
• CYStek assumes no liability for any consequence of customer product design, infringement of patents, or application assistance.
LM2576-XXE5/F5
CYStek Product Specification