LM2596S-ADJ Buck Converter Specifications and Applications

ElecSuppliers Part Number GuideSep 25, 2026

LM2596S-ADJ is an adjustable-output version of the LM2596 SIMPLE SWITCHER power converter from Texas Instruments. It is a monolithic step-down switching regulator designed to convert a higher DC input voltage into a lower regulated output voltage.

The device supports an input voltage range of up to 40 V and can deliver up to 3 A of output current. The adjustable version provides an output voltage range from 1.2 V to 37 V under the specified operating conditions. The LM2596 operates at a fixed 150 kHz switching frequency and is designed to achieve regulation with a relatively small number of external components.

LM2596S-ADJ Key Specifications

The LM2596S-ADJ is designed for applications where a simple non-synchronous buck converter is required. Its main electrical characteristics include a wide input voltage range, adjustable output voltage and 3 A load capability.

The device supports input voltages from 4.5 V to 40 V. For the adjustable version, the regulated output can be set from 1.2 V to 37 V, with a maximum output voltage tolerance of ±4% under the specified line and load conditions.

The LM2596 family operates at a fixed 150 kHz switching frequency. This allows the use of standard inductors and external filter components suitable for a wide range of step-down power supply designs.

Other important characteristics include TTL shutdown capability, low standby current, thermal shutdown and current-limit protection.

LM2596S-ADJ Adjustable Output Voltage

One of the main differences between LM2596S-ADJ and the fixed-output versions of the LM2596 is the adjustable feedback configuration.

The output voltage is determined by an external resistor divider connected to the feedback pin. According to the TI datasheet, the output voltage can be calculated using the following relationship:

VOUT = VREF × (1 + R2/R1)

For the LM2596 adjustable version, the reference voltage is approximately 1.23 V. The resistor values can therefore be selected according to the required output voltage. TI recommends using an approximately 1 kΩ value for R1 and a 1% resistor for improved stability in the typical application circuit.

This adjustable configuration allows one regulator design to support different output voltages without changing the main regulator IC.

LM2596S-ADJ Switching Regulator Operation

The LM2596S-ADJ operates as a step-down switching regulator. During operation, the internal power switch transfers energy from the input supply into the inductor. The inductor, diode and output capacitor then work together to provide a regulated DC output.

Because the regulator switches the input rather than continuously dissipating excess voltage as heat, a buck converter can provide higher efficiency than a linear regulator when there is a significant difference between the input and output voltages.

The fixed 150 kHz switching frequency simplifies the design of the power stage and allows designers to select from commonly available inductors and capacitors.

LM2596S-ADJ External Components

A typical LM2596S-ADJ circuit requires several external power components, including an input capacitor, output capacitor, inductor, catch diode and feedback resistors.

The selection of these components affects output ripple, efficiency, transient response and thermal performance. TI's typical adjustable-output circuit uses a Schottky rectifier, an inductor and capacitor network together with the feedback resistor divider.

The feedback network should be laid out carefully because noise around the switching node and inductor can affect regulation. TI recommends placing the programming resistors close to the feedback pin and keeping feedback wiring away from the magnetic field around the inductor.

LM2596S-ADJ Package Options

Texas Instruments offers the LM2596 in both through-hole and surface-mount package configurations. The LM2596S-ADJ/NOPB ordering information identifies the TO-263 surface-mount package with five pins, while the LM2596 family is also available in TO-220 configurations.

Package selection depends on PCB layout, thermal requirements and manufacturing preferences. For compact power supply designs, the TO-263 version can provide a surface-mount solution, while TO-220 versions can be convenient for through-hole assembly and applications requiring a different mechanical arrangement.

When replacing an LM2596S-ADJ device, the package and pin configuration should be checked in addition to the electrical specifications.

LM2596S-ADJ Protection Features

The LM2596 incorporates several protection functions intended to protect the regulator under abnormal operating conditions.

Current limiting helps restrict excessive current through the internal power switch. The device also includes thermal shutdown to reduce the risk of damage when the junction temperature becomes excessive. TI specifies a two-stage current-limit mechanism and overtemperature shutdown as part of the device's self-protection features.

The shutdown function can also place the device into a low-power standby state. TI specifies typical standby current of approximately 80 µA for the LM2596.

LM2596S-ADJ Applications

The LM2596S-ADJ can be used in a wide range of DC power conversion applications where an adjustable step-down output is required.

Industrial Power Supplies

The device can be used to generate lower DC supply rails from higher-voltage industrial power sources. For example, a suitable input supply can be converted to a regulated voltage required by control electronics or interface circuits.

Embedded Electronics

Microcontroller systems, control boards and embedded devices often require regulated low-voltage power from a higher DC input. The adjustable output of LM2596S-ADJ allows designers to configure the required voltage without changing the main regulator.

Automotive Electronics

The wide input capability makes the LM2596 family relevant to certain automotive and vehicle-related power conversion applications. However, designers should evaluate transient conditions and the complete electrical environment before using the device in automotive systems.

Communications Equipment

The regulator can be used to generate intermediate or auxiliary power rails in communications equipment and other electronic systems that require a regulated DC output.

Battery-Powered Systems

LM2596S-ADJ can also be considered for battery-powered systems where the input voltage is higher than the required regulated output. The actual suitability depends on battery voltage, output current, efficiency requirements and operating conditions.

LM2596S-ADJ Design Considerations

Although the LM2596S-ADJ is rated for up to 3 A output current, the actual output current available in a finished design depends on thermal conditions, input voltage, output voltage, switching losses, PCB layout and component selection.

Thermal performance becomes particularly important when the input voltage is substantially higher than the output voltage. The difference in voltage and load current affects the overall power conversion losses and therefore the temperature of the regulator and surrounding components.

The inductor should also be selected according to the required load current and switching conditions. The catch diode must have appropriate voltage and current ratings, while the input and output capacitors should be selected according to the required ripple current and operating temperature.

LM2596S-ADJ Sourcing Considerations

When sourcing LM2596S-ADJ, buyers should confirm the complete manufacturer part number and package before requesting quotations.

The current Texas Instruments product information lists LM2596S-ADJ/NOPB as an active product with a TO-263 package and a five-pin configuration. The LM2596 family also includes fixed-output versions and other package configurations, so the suffix should be checked carefully when comparing products.

For production purchasing, buyers should also confirm packaging requirements, quantity, product condition, manufacturer information and delivery requirements. Different package versions or fixed-output versions should not be treated as direct replacements simply because they belong to the same LM2596 family.

LM2596S-ADJ for Electronic Component Procurement

LM2596S-ADJ remains a relevant part number for adjustable step-down power supply designs requiring up to 3 A of output current and an input voltage of up to 40 V.

Its adjustable 1.2 V to 37 V output range, 150 kHz switching frequency, relatively simple external circuit and integrated protection functions make it suitable for many industrial, embedded and general-purpose DC power applications.

For engineers, the main selection factors are input voltage, required output voltage, load current, efficiency, thermal performance and external component selection. For procurement teams, verifying the complete LM2596S-ADJ ordering code and package is important when comparing available electronic component suppliers.