LP2951CD-3.3 Equivalent & Substitute Parts

Part Overview

The LP2951CD-3.3 is a linear voltage regulator IC from onsemi, classified as a Power Management (PMIC) component. This fixed 3.3V output regulator delivers 100mA with a maximum dropout voltage of 0.45V and operates across the industrial temperature range of -40°C to 125°C. The device is mounted in an 8-SOIC package and includes over-current and over-temperature protection features.

The LP2951CD-3.3 is currently listed as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this regulator topology.

Substiute Parts

LP2951CD-3.3

onsemiIn Stock: 3612LP2951CD-3.3 Datasheet

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LP2951CS-L-3-3/TR

MaxLinear, Inc.In Stock: 7183LP2951CS-L-3-3/TR Datasheet

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LP2951ACM-3.3/NOPB

Texas InstrumentsIn Stock: 3307LP2951ACM-3.3/NOPB Datasheet

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LP2951ACMX-3.3/NOPB

Texas InstrumentsIn Stock: 163442LP2951ACMX-3.3/NOPB Datasheet

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LP2951CM-3.3/NOPB

Texas InstrumentsIn Stock: 26178LP2951CM-3.3/NOPB Datasheet

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LP2951CMX-3.3/NOPB

Texas InstrumentsIn Stock: 30192LP2951CMX-3.3/NOPB Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LP2951CD-3.3 are qualified based on the following critical parameters:

• Fixed 3.3V output voltage
• 100mA output current capability
• 30V maximum input voltage rating
• 8-SOIC package compatibility
• Operating temperature range of -40°C to 125°C
• Positive output configuration
• Over-current and over-temperature protection

The substitute parts identified maintain electrical and mechanical compatibility with the original LP2951CD-3.3 specification. All candidates share the same base product number (LP2951) and package footprint, ensuring direct replacement capability in existing PCB designs.

Parameter Comparison

Engineering Selection Recommendations

All identified substitute parts are active products with current manufacturing status, addressing the obsolescence of the LP2951CD-3.3. The following selection criteria apply:

LP2951CS-L-3-3/TR (MaxLinear, Inc.) provides the closest electrical match to the original part, with identical dropout voltage specification (0.45V @ 100mA) and quiescent current performance. This part is RoHS compliant and available in Tape & Reel packaging.

LP2951ACM-3.3/NOPB, LP2951ACMX-3.3/NOPB, LP2951CM-3.3/NOPB, and LP2951CMX-3.3/NOPB (all Texas Instruments) are functionally equivalent alternatives. These parts feature adjustable output capability with fixed 3.3V configuration, enhanced short-circuit protection, and ROHS3 compliance. The dropout voltage is 0.6V @ 100mA, which is acceptable for most applications requiring the original 0.45V specification. Variants with "X" suffix (ACMX, CMX) are supplied in Cut Tape & Digi-Reel packaging, while non-X variants are supplied in Tube packaging.

All substitute parts maintain the same 8-SOIC package footprint, operating temperature range, and 100mA output current rating, ensuring direct PCB compatibility.

Frequently Asked Questions (FAQ)

Q: Can LP2951CS-L-3-3/TR be used as a direct replacement for LP2951CD-3.3?

A: Yes. Both parts share identical electrical specifications for output voltage (3.3V fixed), output current (100mA), maximum input voltage (30V), dropout voltage (0.45V @ 100mA), and package type (8-SOIC). The primary difference is manufacturer (MaxLinear vs. onsemi) and packaging format (Tape & Reel vs. standard).

Q: What is the difference between the Texas Instruments variants (ACM, ACMX, CM, CMX)?

A: The functional electrical specifications are identical across all four Texas Instruments variants. The differences are in packaging format: ACM and CM are supplied in Tube packaging, while ACMX and CMX are supplied in Cut Tape & Digi-Reel packaging. Selection depends on your procurement and assembly requirements.

Q: Why do the Texas Instruments parts show adjustable output voltage when the original is fixed?

A: The Texas Instruments LP2951 family uses an adjustable topology that can be configured for fixed 3.3V output through external resistor networks. When configured for 3.3V fixed output, these parts are functionally equivalent to the fixed-output LP2951CD-3.3.

Q: Is the 0.6V dropout voltage of Texas Instruments parts acceptable as a replacement for the 0.45V specification?

A: The 0.6V dropout voltage is within acceptable tolerance for most linear regulator applications. Applications with tight input voltage margins should verify that the higher dropout voltage does not impact system performance.

Q: Are all substitute parts RoHS compliant?

A: Yes. LP2951CS-L-3-3/TR is RoHS compliant. All Texas Instruments variants (ACM, ACMX, CM, CMX) are ROHS3 compliant. The original LP2951CD-3.3 is RoHS non-compliant.

Q: Do the substitute parts offer additional protection features?

A: The MaxLinear LP2951CS-L-3-3/TR maintains the same protection features as the original (over-current and over-temperature). The Texas Instruments variants add short-circuit protection in addition to over-current and over-temperature protection.

Q: Which substitute part has the highest inventory availability?

A: LP2951ACMX-3.3/NOPB has the highest reported inventory at 163,395 pieces, followed by LP2951CMX-3.3/NOPB at 30,100 pieces.