LM2596

Part: LM2596 — Texas Instruments

Type: Step-Down (Buck) Switching Regulator

Description: 4.5–40 V input, 3 A step-down switching regulator with integrated switch, 150 kHz fixed-frequency oscillator, and 3.3 V, 5 V, 12 V, and adjustable (1.2–37 V) output versions.

Operating Conditions:

• Supply voltage: 4.5–40 V
• Operating temperature: -40 to 125 °C
• Adjustable output voltage range: 1.2–37 V (±4% max over line and load)
• Switching frequency: 150 kHz fixed (±15%)

Absolute Maximum Ratings:

• Max supply voltage (VIN): 45 V
• Feedback pin voltage: -0.3 to 25 V
• Flag pin voltage: -0.3 to 45 V
• Max junction temperature: 150 °C
• Storage temperature: -65 to 150 °C

Key Specs:

• Output load current: 3 A
• Input voltage range: 4.5–40 V (operating)
• Switching frequency: 150 kHz, ±15%
• Output voltage accuracy: ±4% max over line and load
• Standby quiescent current: typically 80 μA (ON/OFF pin high)
• ON/OFF threshold: approx. 1.3 V (max 25 V on pin)
• RθJC(top): 2 °C/W
• ESD HBM: ±2000 V

Features:

• 3.3 V, 5 V, 12 V, and adjustable output versions
• Requires only four external components
• Internal frequency compensation and fixed-frequency oscillator
• TTL shutdown capability
• Two-stage frequency-reducing current limit
• Thermal shutdown protection
• Uses readily available standard inductors
• WEBENCH Power Designer support

Applications:

• Appliances
• Grid infrastructure
• EPOS
• Home theater

Package:

• NDH (TO-220, 5 pin), 14.986 mm × 10.16 mm
• KTT (TO-263, 5 pin), 10.10 mm × 8.89 mm

• New product available:
• -LMR51430 4.5 to 36-V, 3-A, 500-kHz and 1.1MHz synchronous converter
• For faster time to market:
• -TLVM13630 3 to 36-V, 3-A, 200-kHz to 2.2-MHz power module
• 3.3-V, 5-V, 12-V, and adjustable output versions
• Adjustable version output voltage range: 1.2-V to 37-V ±4% maximum over line and load conditions
• Available in TO-220 and TO-263 packages
• 3-A output load current
• Input voltage range up to 40 V
• Requires only four external components
• Excellent line and load regulation specifications
• 150-kHz fixed-frequency internal oscillator
• TTL shutdown capability
• Low power standby mode, IQ, typically 80 μA
• High efficiency
• Uses readily available standard inductors
• Thermal shutdown and current-limit protection
• Create a custom design using the LM2596 with the WEBENCH ® Power Designer

• Appliances
• Grid infrastructure
• EPOS
• Home theater

(Fixed Output Voltage Versions)

Figure 6-1. 5-Pin TO-220 NDH Package Top View

Table 6-1. Pin Functions

Figure 6-2. 5-Pin TO-263 KTT Package Top View

Specifications are for TJ = 25°C (unless otherwise noted)

• (3) 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 Figure 9-13, system performance is shown in the test conditions column.

over operating free-air temperature range (unless otherwise noted) (1) (2)

• (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions . Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
• (2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications.
• (3) Voltage internally clamped. If clamp voltage is exceeded, limit current to a maximum of 1 mA.

• (1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

• (2) The package thermal impedance is calculated in accordance to JESD 51-7.

• (3) Thermal Resistances were simulated on a 4-layer, JEDEC board.

• (4) Junction to ambient thermal resistance (no external heat sink) for the package mounted TO-220 package mounted vertically, with the leads soldered to a printed circuit board with (1 oz.) copper area of approximately 1 in 2 .

• (5) Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 0.5 in 2 of 1-oz copper area.

• (6) Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 2.5 in 2 of 1-oz copper area.

• (7) Junction to ambient thermal resistance with the TO-263 package tab soldered to a double sided printed circuit board with 3 in 2 of 1-oz copper area on the LM2596S side of the board, and approximately 16 in 2 of copper on the other side of the PCB.

• (1) For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application