LM2598S-ADJ Buck Switching Regulator IC

Part Overview

The LM2598S-ADJ is a buck switching regulator IC from Texas Instruments' SIMPLE SWITCHER® series, designed for step-down voltage conversion with positive adjustable output. This device delivers 1A output current with an input voltage range of 4.5V to 40V and adjustable output voltage from 1.2V to 37V, operating at a fixed switching frequency of 150kHz.

The LM2598S-ADJ is classified as obsolete. Finding equivalent substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support long-term product availability for applications currently using this regulator.

Substiute Parts

LM2598S-ADJ

Texas InstrumentsIn Stock: 2151LM2598S-ADJ Datasheet

Current PartRFQ

LM2598S-ADJ/NOPB

Texas InstrumentsIn Stock: 1307LM2598S-ADJ/NOPB Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LM2598S-ADJ is determined by strict equivalence across the following critical parameters:

• Topology and Function: Buck (step-down) converter with positive adjustable output configuration
• Electrical Specifications: Input voltage range (4.5V to 40V), output voltage range (1.2V to 37V), and output current rating (1A)
• Switching Frequency: Fixed at 150kHz
• Package and Pinout: TO-263-8 (D2PAK with 7 leads plus tab) for direct PCB compatibility
• Operating Temperature Range: -40°C to 125°C (TJ)
• Synchronous Rectifier: Not present in this topology

The substitute part LM2598S-ADJ/NOPB maintains identical electrical and mechanical specifications, ensuring functional and physical interchangeability.

Parameter Comparison

Engineering Selection Recommendations

The LM2598S-ADJ/NOPB is the direct substitute for the obsolete LM2598S-ADJ. Both parts share identical electrical and mechanical specifications, ensuring drop-in compatibility in existing designs.

The primary distinction between the two parts is product status and compliance:

• LM2598S-ADJ: Obsolete status with RoHS non-compliant classification
• LM2598S-ADJ/NOPB: Active product status with ROHS3 compliance

For new designs or applications requiring regulatory compliance with modern environmental standards, the LM2598S-ADJ/NOPB is the appropriate selection. The "/NOPB" suffix indicates lead-free (Pb-free) packaging, aligning with RoHS3 requirements.

Both parts carry identical REACH Unaffected and EAR99 ECCN classifications, with Moisture Sensitivity Level (MSL) 3 (168 Hours).

Frequently Asked Questions (FAQ)

Q: Can LM2598S-ADJ/NOPB directly replace LM2598S-ADJ in existing designs?

A: Yes. The LM2598S-ADJ/NOPB is electrically and mechanically identical to the LM2598S-ADJ. All electrical parameters, switching frequency, output voltage range, current rating, and package pinout are equivalent. Direct PCB substitution is possible without circuit modification.

Q: What does the "/NOPB" suffix indicate?

A: The "/NOPB" suffix denotes a lead-free (Pb-free) package variant that complies with RoHS3 environmental regulations. This is the modern manufacturing standard for this device.

Q: Why is the original LM2598S-ADJ marked as obsolete?

A: Obsolescence typically reflects manufacturer discontinuation of older product variants in favor of updated versions with improved compliance certifications. The LM2598S-ADJ/NOPB represents the current active equivalent.

Q: Are there any differences in thermal performance between the two parts?

A: No. Both parts operate within the same temperature range (-40°C to 125°C TJ) and use the identical TO-263-8 (D2PAK) package, which provides equivalent thermal characteristics.

Q: What is the Moisture Sensitivity Level (MSL) for these parts?

A: Both the LM2598S-ADJ and LM2598S-ADJ/NOPB carry MSL 3 (168 Hours), indicating standard moisture sensitivity handling requirements during storage and assembly.

Q: Can these parts be used interchangeably in high-reliability applications?

A: Yes, provided compliance requirements are met. For applications requiring RoHS3 compliance, the LM2598S-ADJ/NOPB is the appropriate choice. Both parts maintain identical electrical performance and reliability characteristics within their specified operating ranges.