3.0A, 150kHz, Step-Down Switching Regulator
FEATURES
3.3V, 5.0V, 12V, and Adjustable Output Versions
Adjustable Version Output Voltage Range, 1.2 to 37V
+/- 4%. Maximum Over Line and Load Conditions
Guaranteed 3.0A Output Current
Wide Input Voltage Range
Requires Only 4 External Components
150kHz Fixed Frequency Internal Oscillator
TTL Shutdown Capability, Low Power Standby Mode
High Efficiency
Uses Readily Available Standard Inductors
Thermal Shutdown and Current Limit Protection
Moisture Sensitivity Level 3
LM2596
TO-220 PKG
1
5
TO-220V PKG
1
5
TO-263 PKG
Applications
Simple High-Efficiency Step-Down(Buck) Regulator
Efficient Pre-Regulator for Linear Regulators
On-Card Switching Regulators
Positive to Negative Converter(Buck-Boost)
Negative Step-Up Converters
Power Supply for Battery Chargers
1
5
1. Vin 2. Output 3. Ground
4. Feedback 5. On/Off
DESCRIPTION
The LM2596 series of regulators are monolithic integrated
circuits ideally suited for easy and convenient design of a
step-down switching regulator(buck converter).
All circuits of this series are capable of driving a 3.0A load
with excellent line and load regulation. These devices are
available in fixed output voltages of 3.3V, 5.0V,12V,
and an adjustable output version.
ORDERING INFORMATION
Device
LM2596T-X.X
LM2596TV-X.X
LM2596R
Marking
LM2596-X.X
LM2596-X.X
LM2596-X.X
Package
TO-220
TO-220V
TO-263
These regulators were designed to minimize the number of external components to simplify the
power supply design. Standard series of inductors optimized for use with the LM2596 are offered
by several different inductor manufacturers.
Since the LM2596 converter is a switch-mode power supply, its efficiency is significantly higher in
comparison with popular three-terminal limear regulators, especially with higher input voltages.
In many cases, the power dissipated is so low that no heatsink is required or its size could
be reduced dramatically. A standard series of inductors optimized for use with the TJ2596 are
available from several different manufacturers. This feature greatly simplifies the design of
switch-mode power supplies. The LM2596 features include a guaranteed +/- 4% tolerance
on output voltage within specified input voltages and output load conditions, and +/-15% on the
oscillator frequency (+/- 2% over 0℃ to 125℃).
External shutdown is included, featuring 80㎂ (typical) standby current. Self protection features include
a two stage frequency reducing current limit for output switch and an over temperature shutdown for complete
protection under fault conditions.
Dec. 2009 - Rev.1.3.1
HTC
−
1
−
3.0A, 150kHz, Step-Down Switching Regulator
Typical Application (Fixed Output Voltage Versions)
LM2596
LM2596-5.0
33 uH
680 uF
1N5824
220 uF
Figure 1. Block Diagram and Typical Application
ABSOLUTE MAXIMUM RATINGS
(Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.)
Rating
Symbol
Value
Unit
Maximum Supply Voltage
V
Vin
45
-0.3V ≤ V ≤ +Vin
On/Off Pin Input Voltage
V
-
- 1.0
Output Voltage to Ground (Steady-State)
V
-
Power Dissipation
P
D
Internally Limited
TO-220 5Lead
W
P
θJA
Thermal Resistance, Juntion to Ambient
65
℃/W
P
θJC
Thermal Resistance, Juntion to Case
5.0
℃/W
P
D
TO-263 5Lead
Internally Limited
W
P
θJA
70
Thermal Resistance, Juntion to Ambient
℃/W
P
θJC
5.0
Thermal Resistance, Juntion to Case
℃/W
T
stg
-60 to +150
Storage Temperature Range
℃
Minimum ESD Rating(Human Body Model :
2.0
-
kV
C=100 pF, R=1.5㏀)
260
Lead Temperature (Soldering,10seconds)
-
℃
T
J
℃
Maximum Junction Temperature
150
HTC
−
2
−
3.0A, 150kHz, Step-Down Switching Regulator
LM2596
OPERATING RATINGS
(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.)
Rating
Operating Junction Temperature Range
Supply Voltage
Symbol
T
J
Vin
Value
-40 to +125
40
Unit
℃
V
ELECTRICAL CHARACTERISTICS
/
SYSTEM PARAMETERS ([Note 1] Test Circuit Figure 2)
(Unless otherwise specified, Vin = 12V for the 3.3V, 5.0V, and Adjustable version, Vin = 25V for the 12V versio
ILoad = 500 mA. For typical values TJ = 25°C, for min/max values TJ is the operating junction temperature
range that applies [Note 2], unless otherwise noted.)
Characteristics
LM2596-3.3V ([Note 1] Test Circuit Figure 2)
Output Voltage (Vin = 12V, I
LOAD
=0.5A, T
J
=25℃)
Output Voltage (6.0V≤Vin≤40V, 0.5A≤I
LOAD
≤3.0A
T
J
=25℃
T
J
= -40℃ ~ +125℃
Efficiency (Vin=12V, I
LOAD
=3.0A)
LM2596-5.0V ([Note 1] Test Circuit Figure 2)
Output Voltage (Vin = 12V, I
LOAD
=0.5A, T
J
=25℃)
Output Voltage (8.0V≤Vin≤40V, 0.5A≤I
LOAD
≤3.0A
T
J
=25℃
T
J
= -40℃ ~ +125℃
Efficiency (Vin=12V, I
LOAD
=3.0A)
LM2596-12V ([Note 1] Test Circuit Figure 2)
Output Voltage (Vin = 25V, I
LOAD
=0.5A, T
J
=25℃)
Output Voltage (15V≤Vin≤40V, 0.5A≤I
LOAD
≤3.0A
T
J
=25℃
T
J
= -40℃ ~ +125℃
Efficiency (Vin=12V, I
LOAD
=3.0A)
LM2596-ADJ ([Note 1] Test Circuit Figure 2)
Feedback Voltage (Vin=12V, I
LOAD
=0.5A, T
J
=25℃)
Feedback Voltage(8.0V≤Vin≤40V, 0.5A≤I
LOAD
≤3.0A, Vout=5.0V)
Symbol
Min
TYP
Max
Unit
Vout
Vout
3.234
3.168
3.135
-
3.3
3.3
-
73
3.366
3.432
3.465
-
V
V
%
η
Vout
Vout
4.9
4.8
4.75
-
5.0
5.0
-
80
5.1
5.2
5.25
-
V
V
%
η
Vout
Vout
11.76
11.52
11.4
-
12
12
-
90
12.24
12.48
12.6
-
V
V
%
η
Vout
Vout
1.217
1.193
1.18
-
1.23
1.23
-
73
1.243
1.267
1.28
-
V
V
%
T
J
=25℃
T
J
= -40℃ ~ +125℃
Efficiency (Vin=12V, I
LOAD
=3.0A, Vout=5.0V)
η
HTC
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3
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3.0A, 150kHz, Step-Down Switching Regulator
ELECTRICAL CHARACTERISTICS
/ Device Parameters
LM2596
(Unless otherwise specified, Vin = 12V for the 3.3V, 5.0V, and Adjustable version, Vin = 25V for the 12V versio
ILoad = 500 mA. For typical values Tj = 25°C, for min/max values TJ is the operating junction temperature ran
that applies [Note 2], unless otherwise noted.)
Characteristics
All Output Voltage Versions
Feedback Bias Current (Vout=5.0V [Adjustable Version Only])
Symbol
Min
TYP
Max
Unit
I
b
T
J
=25℃
11.52
12
12.48 nA
T
J
= 0 ~ +125℃
11.4
-
12.6
Oscillator Frequency [Note 3]
Fosc
T
J
=25℃
kHz
127
150
173
T
J
= 0 ~ +125℃
173
110
-
Saturation Voltage (Iout=3.0A [note 4])
Vsat
T
J
=25℃
V
1.4
-
1.16
T
J
= 0 ~ +125℃
-
-
1.5
%
Max Duty Cycle ("0") [Note 5]
DC
-
100
-
I
CL
Current Limit (Peak Current [Note 3 and 4])
T
J
=25℃
A
3.6
4.5
6.9
T
J
= 0 ~ +125℃
3.4
-
7.5
I
L
Output Leakage Current [Note 6 and 7], T
J
=25℃
mA
50
Output = 0V
-
-
Output = -1.0V
-
2
30
I
Q
Quiescent Current [Note 6]
T
J
=25℃
mA
-
-
5
T
J
= 0 ~ +125℃
-
-
10
I
STBY
Standby Quiescent Current (ON/OFF Pin = 5.0V ("off"))
T
J
=25℃
㎂
200
-
80
T
J
= 0 ~ +125℃
-
-
250
ON/OFF Pin Logic Input Level (Test circuit Figure 2)
V
IH
Vout=0V
T
J
=25℃
2.0
1.3
-
T
J
= 0 ~ +125℃
V
2.0
-
-
V
IL
Vout=Nominal Ouput Voltage
T
J
=25℃
-
1.3
0.6
T
J
= 0 ~ +125℃
-
-
0.6
ON/OFF Pin Input Current (Test Circuit Figure 2)
I
IH
V
LOGIC
= 2.5V (Regulator OFF)
㎂
-
5
15
I
IL
V
LOGIC
= 0.5V (Regulator ON)
-
0.02
5.0
1. External components such as the catch diode, inductor, input and output capacitors can affect
switching regulator system performance. When the LM2596 is used as shown in the Figure 1 test
circuit, system performance will be as shown in system parameters section .
2. Tested junction temperature range for the TJ2596 : T
LOW
= –40°C T
HIGH
= +125°C
3. The oscillator frequency reduces to approximately 18kHz 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 dissipation of the IC by lowering the
minimum duty cycle from 5% down to approximately 2%.
4. Output (Pin 2) sourcing current. No diode, inductor or capacitor connected to output pin.
5. Feedback (Pin 4) removed from output and connected to 0 V.
6. Feedback (Pin 4) removed from output and connected to +12V for the Adjustable, 3.3V, and 5.0V
versions, and '+25 V for the 12V versions, to force the output transistor “off”.C195
7. Vin = 40 V.
HTC
−
4
−
3.0A, 150kHz, Step-Down Switching Regulator
TYPICAL PERFORMANCE CHARACTERISTICS
(Circuit of Figure 2)
LM2596
HTC
−
5
−
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