LM2940CS-15 Linear Voltage Regulator - Equivalent & Substitute Parts

Part Overview

The LM2940CS-15 is a positive fixed linear voltage regulator IC designed for low-dropout applications, delivering 1A output current at a fixed 15V output. Manufactured by Texas Instruments, this Surface Mount device in TO-263 (DDPAK-3) packaging is classified as Last Time Buy, indicating end-of-life status. Identifying equivalent substitute parts is essential for design continuity, long-term supply chain planning, and production sustainability when original inventory becomes unavailable.

Substiute Parts

LM2940CS-15

Texas InstrumentsIn Stock: 4578LM2940CS-15 Datasheet

Current PartRFQ

LM2940CS-15/NOPB

National SemiconductorIn Stock: 5315LM2940CS-15/NOPB Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM2940CS-15 is determined by strict equivalence across the following critical parameters:

• Output voltage: 15V fixed
• Output current capability: 1A minimum
• Maximum input voltage: 26V or greater
• Voltage dropout: 0.8V @ 1A or lower
• Package type: TO-263 (DDPAK-3) Surface Mount
• Protection features: Over Current, Over Temperature, Reverse Polarity, Short Circuit
• Operating temperature range: 0°C ~ 125°C minimum
• Output configuration: Positive fixed regulator

The substitute part LM2940CS-15/NOPB meets all these criteria and is therefore classified as a direct equivalent.

Parameter Comparison

Engineering Selection Recommendations

The LM2940CS-15/NOPB is a direct functional equivalent to the LM2940CS-15. The primary distinction is product status: the original part is Last Time Buy, while the substitute is Active. This status difference indicates continued availability and manufacturing support for the LM2940CS-15/NOPB.

Both parts share identical electrical specifications, including output voltage, current capacity, dropout voltage, quiescent current, and protection features. Both are housed in the same TO-263 (DDPAK-3) Surface Mount package, ensuring mechanical and thermal compatibility in existing PCB designs without layout modifications.

The LM2940CS-15/NOPB is suitable for new designs and production continuity when LM2940CS-15 inventory is exhausted. No design changes or re-qualification are required for this substitution.

Frequently Asked Questions (FAQ)

Q: Can LM2940CS-15/NOPB be used as a direct replacement for LM2940CS-15 in existing designs?

A: Yes. Both parts are electrically and mechanically identical. The LM2940CS-15/NOPB operates at the same output voltage (15V), current (1A), dropout voltage (0.8V @ 1A), and protection specifications. Both use the TO-263 (DDPAK-3) package, requiring no PCB modifications.

Q: What is the significance of the "/NOPB" suffix in LM2940CS-15/NOPB?

A: The "/NOPB" designation indicates the part is supplied without lead (Pb) plating on the leads, consistent with RoHS compliance requirements. This is a packaging and supply specification that does not affect electrical performance or functionality.

Q: Why is the original LM2940CS-15 marked as Last Time Buy?

A: Last Time Buy status indicates the manufacturer has discontinued production. Existing inventory may still be available, but no new manufacturing runs are planned. Transitioning to the active LM2940CS-15/NOPB ensures long-term supply chain stability.

Q: Are there any thermal or performance differences between these parts?

A: No. Both parts have identical thermal characteristics, quiescent current (10 mA), PSRR (64dB at 120Hz), and operating temperature range (0°C ~ 125°C). Thermal performance in the TO-263 package is equivalent.

Q: Can these parts be used interchangeably on the same PCB assembly line?

A: Yes. Identical package geometry, pin configuration, and electrical specifications allow seamless substitution in manufacturing. No assembly process changes are required.