LP2951CD-3.3G Equivalent & Substitute Parts

Part Overview

The LP2951CD-3.3G 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 ongoing design support and production continuity. 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

LP2951CD-3.3G

onsemiIn Stock: 12678LP2951CD-3.3G Datasheet

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LP2951ACD-3.3R2G

onsemiIn Stock: 2633LP2951ACD-3.3R2G 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

Substitution for the LP2951CD-3.3G is determined by the following critical parameters:

• Output voltage fixed at 3.3V
• 100mA output current capability
• 8-SOIC package form factor
• Maximum 30V input voltage rating
• Operating temperature range -40°C to 125°C
• Surface mount mounting type
• RoHS3 compliance and MSL Level 1

Substitute parts are grouped into two categories:

Direct Substitutes (Functionally Identical): LP2951ACD-3.3R2G and LP2951CS-L-3-3/TR maintain identical electrical specifications and package requirements, with the primary difference being product status (active vs. obsolete) and packaging format (Cut Tape/Digi-Reel vs. Tape & Reel).

Similar Substitutes (Compatible with Design Considerations): LP2951ACM-3.3/NOPB, LP2951ACMX-3.3/NOPB, LP2951CM-3.3/NOPB, and LP2951CMX-3.3/NOPB are Texas Instruments variants with adjustable output type capability (fixed at 3.3V). These parts share identical electrical performance at the 3.3V fixed setting but include additional control features (Enable function) and enhanced protection (Short Circuit protection).

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Preferred): LP2951ACD-3.3R2G from onsemi is the primary substitute, maintaining identical electrical specifications and protection features while offering active product status and Cut Tape/Digi-Reel packaging. This part ensures seamless integration without design modification.

For Alternative Sourcing: LP2951CS-L-3-3/TR from MaxLinear, Inc. provides equivalent functionality with active product status. Note the slightly elevated quiescent current (170 µA vs. 120 µA) and the addition of an Enable control feature. This part is suitable when onsemi sourcing is constrained.

For Enhanced Capability: Texas Instruments variants (LP2951ACM-3.3/NOPB, LP2951ACMX-3.3/NOPB, LP2951CM-3.3/NOPB, LP2951CMX-3.3/NOPB) offer identical performance at 3.3V fixed output with additional short-circuit protection and Enable control functionality. These parts are suitable for designs requiring enhanced protection or control features. Maximum supply current increases to 14 mA and dropout voltage to 0.6V @ 100mA.

All substitute parts maintain ROHS3 compliance and MSL Level 1 rating, ensuring compatibility with standard manufacturing and storage requirements.

Frequently Asked Questions (FAQ)

Q: Can LP2951ACD-3.3R2G directly replace LP2951CD-3.3G without PCB modification?

A: Yes. LP2951ACD-3.3R2G maintains identical pin configuration, package dimensions (8-SOIC), electrical specifications, and output voltage. No PCB layout changes are required.

Q: What is the difference between "Fixed" and "Adjustable (Fixed)" output types?

A: Fixed output types have the voltage set internally by the manufacturer. Adjustable (Fixed) types have internal voltage dividers that can be configured for different outputs but are preset to 3.3V in these variants. At the 3.3V setting, electrical performance is equivalent.

Q: Why do Texas Instruments parts show higher dropout voltage (0.6V vs. 0.45V)?

A: This reflects different internal circuit design. Both values remain within acceptable limits for 3.3V regulation from typical 5V or higher input sources. Verify dropout performance against your specific input voltage requirements.

Q: Does the Enable control feature on substitute parts require PCB changes?

A: The Enable pin is optional. If unused, it can be tied to VCC (always enabled) or left floating depending on the specific part datasheet. Consult the manufacturer datasheet for proper handling of unused control pins.

Q: Are all substitute parts available in the same packaging formats?

A: No. LP2951ACD-3.3R2G is available in Cut Tape/Digi-Reel format. LP2951CS-L-3-3/TR is available in Tape & Reel. Texas Instruments variants are available in both Tube and Cut Tape/Digi-Reel formats. Verify packaging availability with your supplier.

Q: What is the significance of the quiescent current difference (120 µA vs. 170 µA)?

A: Quiescent current represents standby power consumption. The 50 µA difference is negligible in most applications but becomes relevant in ultra-low-power battery-operated designs. For standard applications, both values are acceptable.

Q: Are all parts RoHS compliant?

A: Yes. LP2951CD-3.3G, LP2951ACD-3.3R2G, and all Texas Instruments variants are ROHS3 compliant. LP2951CS-L-3-3/TR is RoHS compliant. All meet environmental regulatory requirements.