Document
3.0 A, Step-Down Switching Regulator
LM2596
The LM2596 regulator is monolithic integrated circuit ideally suited for easy and convenient design of a step−down switching regulator (buck converter). It is capable of driving a 3.0 A load with excellent line and load regulation. This device is available in adjustable output version and it is internally compensated to minimize the number of external components to simplify the power supply design.
Since LM2596 converter is a switch−mode power supply, its efficiency is significantly higher in comparison with popular three−terminal linear regulators, especially with higher input voltages.
The LM2596 operates at a switching frequency of 150 kHz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Available in a standard 5−lead TO−220 package with several different lead bend options, and D2PAK surface mount package.
The other features include a guaranteed $4% tolerance on output voltage within specified input voltages and output load conditions, and $15% on the oscillator frequency. External shutdown is included, featuring 80 mA (typical) standby current. Self protection features include switch cycle−by−cycle current limit for the output switch, as well as thermal shutdown for complete protection under fault conditions.
Features
• Adjustable Output Voltage Range 1.23 V − 37 V • Guaranteed 3.0 A Output Load Current • Wide Input Voltage Range up to 40 V • 150 kHz Fixed Frequency Internal Oscillator • TTL Shutdown Capability • Low Power Standby Mode, typ 80 mA • Thermal Shutdown and Current Limit Protection • Internal Loop Compensation • Moisture Sensitivity Level (MSL) Equals 1 • These Devices are Pb−Free
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
DATA SHEET www.onsemi.com
1 5
TO−220 TV SUFFIX CASE 314B
Heatsink surface connected to Pin 3
1 5
TO−220 T SUFFIX CASE 314D
Pin 1. Vin 2. Output 3. Ground 4. Feedback 5. ON/OFF
1 5
D2PAK D2T SUFFIX CASE 936A
Heatsink surface (shown as terminal 6 in case outline drawing) is connected to Pin 3
MARKING DIAGRAMS
LM 2596T−ADJ AWLYWWG
LM 2596−ADJ AWLYWWG
1
5
LM 2596T−ADJ AWLYWWG
1
5
1
5
A = Assembly Location WL = Wafer Lot Y = Year WW = Work Week G = Pb−Free Package
ORDERING INFORMATION
See detailed ordering and shipping information in the package dimensions section on page 23 of this data sheet.
© Semiconductor Components Industries, LLC, 2008
1
Dcember, 2022 − Rev. 1
Publication Order Number: LM2596/D
LM2596
Typical Application (Adjustable Output Voltage Version)
12 V
+Vin
Unregulated
DC Input
1
Cin
100 mF
Feedback
R1
LM2596
4
L1 R2
Output 33 mH 3.1k
1.0k CFF 5.0 V Regulated
2 3 GND 5 ON/OFF
D1 1N5822
Cout 220 mF
Output 3.0 A Load
Block Diagram
Unregulated DC Input
Cin
+Vin 1
Feedback
R2
CFF
4
R1
3.1 V Internal Regulator
ON/OFF
ON/OFF 5
Fixed Gain Error Amplifier Comparator
Freq Shift 30 kHz
1.235 V Band-Gap Reference
150 kHz Oscillator
Current Limit
Latch Reset
Driver
3.0 Amp Switch Thermal Shutdown
Output
2 GND
3
L1 D1
Regulated Output Vout
Cout Load
Figure 1. Typical Application and Internal Block Diagram
MAXIMUM RATINGS
Rating
Symbol
Value
Unit
Maximum Supply Voltage ON/OFF Pin Input Voltage Output Voltage to Ground (Steady−State)
Vin
45
V
−
−0.3 V ≤ V ≤ +Vin
V
−
−1.0
V
Power Dissipation
Case 314B and 314D (TO−220, 5−Lead) Thermal Resistance, Junction−to−Ambient Thermal Resistance, Junction−to−Case
Case 936A (D2PAK) Thermal Resistance, Junction−to−Ambient Thermal Resistance, Junction−to−Case
Storage Temperature Range Minimum ESD Rating (Human Body Model: C = 100 pF, R = 1.5 kW)
PD RqJA RqJC PD RqJA RqJC Tstg
−
Internally Limited 65 5.0
Internally Limited 70 5.0
−65 to +150 2.0
W °C/W °C/W
W °C/W °C/W
°C kV
Lead Temperature (Soldering, 10 seconds)
−
260
°C
Maximum Junction Temperature
TJ
150
°C
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected.
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LM2596
PIN FUNCTION DESCRIPTION
Pin Symbol
Description (Refer to Figure 1)
1
Vin
This pin is the positive input supply for the LM2596 step−down switching regulator. In order to minimize voltage transi-
ents and to supply the switching currents needed by the regulator, a suitable input bypass capacitor must be present
(Cin in Figure 1).
2
Output This is the emitter of the internal switch. The saturation voltage Vsat of this output switch is typically 1.5 V. It should be
kept in mind that the PCB area connected t.