LP4951CM Equivalent & Substitute Parts

Part Overview

The LP4951CM is a linear voltage regulator IC from Texas Instruments designed for positive adjustable output applications with 100mA current capacity in an 8-SOIC surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The LP4951CM provides adjustable output voltage regulation from 1.235V to 30V with integrated over-current and over-temperature protection features.

Substiute Parts

LP4951CM

Texas InstrumentsIn Stock: 10387LP4951CM Datasheet

Current PartRFQ

LP4951CM/NOPB

Texas InstrumentsIn Stock: 1314LP4951CM/NOPB Datasheet

DirectRFQ

LP2951ACDR2G

onsemiIn Stock: 45411LP2951ACDR2G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LP4951CM are identified based on strict electrical and mechanical parameter matching within the linear voltage regulator category. The substitution logic is based on the following critical parameters:

Electrical Compatibility Criteria:

• Output Configuration: Positive
• Number of Regulators: 1
• Voltage - Input (Max): 30V
• Voltage - Output Range: 1.235V to 30V
• Current - Output: 100mA
• Protection Features: Over Current, Over Temperature
• Operating Temperature: -40°C ~ 125°C

Mechanical Compatibility Criteria:

• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)

Two substitute parts meet these criteria: LP4951CM/NOPB (direct equivalent from Texas Instruments) and LP2951ACDR2G (manufacturer-recommended alternative from onsemi).

Parameter Comparison

Engineering Selection Recommendations

LP4951CM/NOPB is the direct equivalent substitute for the obsolete LP4951CM. Both parts are manufactured by Texas Instruments with identical electrical specifications and package configuration. The primary distinction is product status: LP4951CM/NOPB is active and available in production quantities, while the original LP4951CM is obsolete. LP4951CM/NOPB achieves ROHS3 compliance, addressing regulatory requirements for new designs. This part is the preferred choice for direct replacement in existing applications.

LP2951ACDR2G is a manufacturer-recommended alternative from onsemi that meets all critical electrical and mechanical substitution parameters. This part demonstrates improved performance characteristics: lower voltage dropout (0.45V vs 0.6V @ 100mA), reduced quiescent current (120 µA vs 170 µA), and lower maximum supply current (12 mA vs 19 mA). LP2951ACDR2G is ROHS3 compliant and actively produced. The absence of an Enable control feature in LP2951ACDR2G requires circuit design verification for applications dependent on this functionality.

Both substitute parts maintain compatibility with the 8-SOIC package footprint and support the full -40°C to 125°C operating temperature range. Selection between LP4951CM/NOPB and LP2951ACDR2G depends on design requirements regarding control features and performance optimization priorities.

Frequently Asked Questions (FAQ)

Q: Can LP4951CM/NOPB be used as a direct replacement for LP4951CM?

A: Yes. LP4951CM/NOPB is the active production equivalent of the obsolete LP4951CM. Both parts share identical electrical specifications, output configuration, current ratings, voltage ranges, and 8-SOIC package dimensions. The primary difference is product status and RoHS compliance level.

Q: What are the key differences between LP4951CM/NOPB and LP2951ACDR2G?

A: Both parts meet the core substitution criteria for output configuration, current capacity, voltage ranges, and package type. LP2951ACDR2G offers improved performance with lower dropout voltage (0.45V vs 0.6V), reduced quiescent current (120 µA vs 170 µA), and lower supply current (12 mA vs 19 mA). However, LP2951ACDR2G lacks the Enable control feature present in LP4951CM/NOPB. Circuit design verification is required if the Enable function is critical to the application.

Q: Are the substitute parts pin-compatible with LP4951CM?

A: Both LP4951CM/NOPB and LP2951ACDR2G use the 8-SOIC package with identical 0.154" width and 3.90mm dimensions. Physical footprint compatibility is confirmed. Functional pin compatibility requires verification of control feature requirements, specifically the Enable pin functionality in LP2951ACDR2G.

Q: Do the substitute parts support the same voltage range as LP4951CM?

A: Yes. Both substitute parts support input voltage up to 30V and adjustable output voltage from 1.235V to 30V, matching the original LP4951CM specifications.

Q: What is the impact of RoHS compliance on part selection?

A: LP4951CM is RoHS non-compliant, while both LP4951CM/NOPB and LP2951ACDR2G are ROHS3 compliant. For new designs and applications subject to RoHS regulations, either substitute part satisfies compliance requirements. Existing designs using LP4951CM may require material declaration updates when transitioning to compliant alternatives.

Q: Which substitute part should be selected for new designs?

A: LP4951CM/NOPB is recommended for new designs requiring direct functional equivalence to the original LP4951CM, including the Enable control feature. LP2951ACDR2G is suitable for applications where improved performance characteristics (lower dropout voltage and quiescent current) are beneficial and where the absence of Enable control does not impact circuit operation.