LP2951ACD-3.3 Equivalent & Substitute Parts

Part Overview

The LP2951ACD-3.3 is a linear voltage regulator IC from onsemi, delivering a fixed 3.3V output at 100mA 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 LP2951 series provides positive fixed output regulation with integrated over-current and over-temperature protection across the -40°C to 125°C operating range.

Substiute Parts

LP2951ACD-3.3

onsemiIn Stock: 7990LP2951ACD-3.3 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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LP2951CS-L-3-3/TR

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

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the LP2951ACD-3.3 is determined by the following critical parameters:

• Output voltage: 3.3V fixed
• Output current capability: 100mA minimum
• Package: 8-SOIC form factor
• Input voltage rating: 30V maximum
• Operating temperature range: -40°C to 125°C
• Protection features: Over-current and over-temperature

Substitute parts are grouped into two categories based on output type:

Category 1: Fixed Output (Direct Equivalents) Parts with fixed 3.3V output matching the original specification exactly. These include LP2951CS-L-3-3/TR from MaxLinear, Inc.

Category 2: Adjustable Output (Functional Equivalents) Parts with adjustable output configured to 3.3V, offering additional design flexibility. These include LP2951ACM-3.3/NOPB, LP2951ACMX-3.3/NOPB, LP2951CM-3.3/NOPB, and LP2951CMX-3.3/NOPB from Texas Instruments.

All substitute parts maintain the same 8-SOIC package, 100mA output current, 30V maximum input voltage, and -40°C to 125°C operating temperature range.

Parameter Comparison

Engineering Selection Recommendations

For New Designs: Texas Instruments LP2951 variants (LP2951ACM-3.3/NOPB, LP2951ACMX-3.3/NOPB, LP2951CM-3.3/NOPB, LP2951CMX-3.3/NOPB) are recommended. All are active products with ROHS3 compliance and include short-circuit protection. The adjustable output configuration provides design flexibility while maintaining fixed 3.3V operation. Packaging options include Tube (ACM, CM) and Cut Tape & Digi-Reel (ACMX, CMX) for different procurement workflows.

For Direct Replacement (Fixed Output Preference): LP2951CS-L-3-3/TR from MaxLinear, Inc. provides a fixed 3.3V output matching the original specification exactly. This part is active and RoHS compliant, with identical dropout voltage (0.45V @ 100mA) and quiescent current (170 µA) characteristics. Tape & Reel packaging supports high-volume production.

Compliance Considerations: All substitute parts are RoHS compliant, addressing the non-compliance status of the obsolete LP2951ACD-3.3. Texas Instruments parts carry ROHS3 certification. All parts maintain REACH unaffected status and EAR99 export classification.

Inventory Availability: Texas Instruments LP2951ACMX-3.3/NOPB offers the highest inventory (163,395 pcs), followed by LP2951CMX-3.3/NOPB (30,100 pcs). MaxLinear LP2951CS-L-3-3/TR maintains 7,163 pcs in stock.

Frequently Asked Questions (FAQ)

Q: Can I use an adjustable output LP2951 variant as a direct replacement for the fixed output LP2951ACD-3.3?

A: Yes. The adjustable variants (LP2951ACM-3.3/NOPB, LP2951ACMX-3.3/NOPB, LP2951CM-3.3/NOPB, LP2951CMX-3.3/NOPB) are configured to deliver 3.3V fixed output and are electrically equivalent. The adjustable topology provides identical performance when configured for fixed output operation.

Q: What is the difference between LP2951ACM-3.3/NOPB and LP2951ACMX-3.3/NOPB?

A: Both parts are identical electrically. The difference is packaging: ACM is supplied in Tube, while ACMX is supplied in Cut Tape & Digi-Reel format. Select based on your procurement and assembly requirements.

Q: Does the MaxLinear LP2951CS-L-3-3/TR have higher quiescent current than the Texas Instruments variants?

A: Yes. The MaxLinear part specifies 170 µA quiescent current compared to 120 µA for Texas Instruments parts. This 50 µA difference is negligible in most applications but should be considered in ultra-low-power designs.

Q: Are all substitute parts RoHS compliant?

A: Yes. All substitute parts are RoHS compliant. The original LP2951ACD-3.3 is RoHS non-compliant. Texas Instruments parts carry ROHS3 certification, and MaxLinear part is RoHS compliant.

Q: What is the voltage dropout difference between the original and substitutes?

A: The original LP2951ACD-3.3 and MaxLinear LP2951CS-L-3-3/TR specify 0.45V dropout at 100mA. Texas Instruments variants specify 0.6V dropout at 100mA. This 0.15V difference is acceptable for most 3.3V supply applications but should be verified if operating near minimum input voltage limits.

Q: Do the substitute parts include short-circuit protection?

A: Texas Instruments variants include short-circuit protection in addition to over-current and over-temperature protection. The original LP2951ACD-3.3 and MaxLinear LP2951CS-L-3-3/TR include over-current and over-temperature protection only.

Q: Can I mix packaging formats in production?

A: Yes. All substitute parts maintain identical electrical specifications and 8-SOIC package dimensions. Tube and Cut Tape & Digi-Reel formats are interchangeable from an assembly perspective; select based on your procurement and pick-and-place equipment capabilities.