LP2951CN Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LP2951CN is a linear voltage regulator IC from Texas Instruments designed for positive adjustable (fixed) output applications with 100mA current capability in an 8-PDIP through-hole package. This device is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The LP2951CN provides regulated output voltage from 1.235V to 29V with integrated protection features including over-current, over-temperature, and short-circuit protection.

Substiute Parts

LP2951CN

Texas InstrumentsIn Stock: 11656LP2951CN Datasheet

Current PartRFQ

LP2951D

Texas InstrumentsIn Stock: 2152LP2951D Datasheet

MFR RecommendedRFQ

LP2951ACN/NOPB

Texas InstrumentsIn Stock: 949LP2951ACN/NOPB Datasheet

Parametric EquivalentRFQ

LP2951CN/NOPB

Texas InstrumentsIn Stock: 5458LP2951CN/NOPB Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the LP2951CN is determined by the following critical parameters:

Electrical Equivalence Requirements:

• Output configuration (Positive)
• Output type (Adjustable/Fixed)
• Number of regulators (1)
• Voltage specifications: Input Max (30V), Output Min/Fixed (1.235V/5V), Output Max (29V)
• Voltage dropout (0.6V @ 100mA)
• Current output (100mA)
• Quiescent current (120 µA)
• Control features (Enable)
• Protection features (Over Current, Over Temperature, Short Circuit)
• Operating temperature range (-40°C ~ 125°C)

Mechanical Compatibility:

• Package type determines board layout compatibility
• Mounting type (through-hole vs. surface mount) affects PCB design

Substitute parts are grouped into two categories:

1. Parametric Equivalents (Same Package): LP2951ACN/NOPB and LP2951CN/NOPB maintain identical electrical specifications and 8-PDIP through-hole packaging, enabling direct board-level replacement.

2. Manufacturer Recommended Alternative (Different Package): LP2951D provides electrical equivalence with a package change from 8-PDIP to 8-SOIC surface mount, requiring PCB redesign but offering improved RoHS3 compliance status.

Parameter Comparison

Engineering Selection Recommendations

For Direct Board Replacement (No PCB Redesign): Select LP2951CN/NOPB or LP2951ACN/NOPB. Both maintain identical electrical specifications and 8-PDIP through-hole packaging as the obsolete LP2951CN. LP2951CN/NOPB is preferred due to active product status and higher inventory availability (5400 pcs). Both alternatives provide ROHS3 compliance, addressing environmental regulatory requirements that the original obsolete part does not meet.

For New Designs or PCB Redesign Scenarios: LP2951D is the manufacturer-recommended alternative, offering ROHS3 compliance and active product support. The transition from 8-PDIP through-hole to 8-SOIC surface mount requires PCB layout modification but enables smaller form factor and improved manufacturing efficiency. This option is suitable when design flexibility permits package change. Note that LP2951D has Last Time Buy status, indicating limited future availability.

Compliance Considerations: All substitute parts (LP2951D, LP2951ACN/NOPB, LP2951CN/NOPB) are ROHS3 compliant, whereas the original LP2951CN is RoHS non-compliant. This compliance improvement is significant for applications subject to environmental regulations. All parts maintain REACH Unaffected and EAR99 ECCN classifications.

Frequently Asked Questions (FAQ)

Q: Can LP2951CN/NOPB directly replace LP2951CN without PCB modification? A: Yes. LP2951CN/NOPB is a parametric equivalent with identical electrical specifications and 8-PDIP through-hole packaging. No PCB redesign is required for direct substitution.

Q: What is the difference between LP2951CN and LP2951CN/NOPB? A: Both parts are electrically and mechanically identical. The "/NOPB" suffix indicates lead-free (no-lead) and RoHS3 compliance. LP2951CN/NOPB is the active production version with improved environmental compliance.

Q: Why is LP2951D listed as a manufacturer-recommended alternative if it uses a different package? A: LP2951D provides electrical equivalence with improved compliance status (ROHS3, active product status vs. Last Time Buy). The 8-SOIC surface mount package requires PCB redesign but is recommended for new designs where layout flexibility exists.

Q: What are the key electrical parameters that determine substitutability? A: Substitutes must match: output configuration (positive), output type (adjustable/fixed), voltage specifications (30V input max, 1.235V/5V output min, 29V output max), 100mA output current, 0.6V dropout at 100mA, 120 µA quiescent current, enable control feature, and over-current/over-temperature/short-circuit protection.

Q: Is LP2951ACN/NOPB equivalent to LP2951CN/NOPB? A: Yes. Both are parametric equivalents with identical electrical specifications and 8-PDIP through-hole packaging. LP2951CN/NOPB has higher inventory availability (5400 pcs vs. 885 pcs) and is the preferred choice for equivalent substitution.

Q: What mounting considerations apply when selecting a substitute? A: LP2951CN, LP2951ACN/NOPB, and LP2951CN/NOPB use through-hole mounting (8-DIP package) and are interchangeable at the board level. LP2951D uses surface mount (8-SOIC package) and requires PCB redesign with different footprint and soldering process.

Q: Are all substitute parts RoHS compliant? A: Yes. LP2951D, LP2951ACN/NOPB, and LP2951CN/NOPB are all ROHS3 compliant. The original LP2951CN is RoHS non-compliant. For applications requiring RoHS compliance, any of the three substitutes are suitable.