LP2951-50D Equivalent & Substitute Parts

Part Overview

The LP2951-50D is a linear voltage regulator IC from Texas Instruments designed for positive adjustable (fixed) output applications with 100mA current capability in an 8-SOIC surface mount package. This device operates across a wide input voltage range (up to 30V) and supports output voltages from 1.235V to 30V with integrated protection features including over-current, over-temperature, and short-circuit protection.

The LP2951-50D is currently in Last Time Buy status, indicating discontinued production. Identifying equivalent and substitute parts is necessary to ensure design continuity and maintain supply chain reliability for new production runs or design revisions.

Substiute Parts

LP2951-50D

Texas InstrumentsIn Stock: 4007LP2951-50D Datasheet

Current PartRFQ

LP2951-50DR

Texas InstrumentsIn Stock: 44355LP2951-50DR Datasheet

MFR RecommendedRFQ

LP2951D

Texas InstrumentsIn Stock: 2152LP2951D Datasheet

Parametric EquivalentRFQ

LP2951CS-L-3-3/TR

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

MFR RecommendedRFQ

LP2951CS-L-5-0/TR

MaxLinear, Inc.In Stock: 2720LP2951CS-L-5-0/TR Datasheet

MFR RecommendedRFQ

RT2560Q-33GSP

Richtek USA Inc.In Stock: 1762RT2560Q-33GSP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LP2951-50D is determined by the following critical parameters:

Primary Substitution Criteria:

• Output configuration (Positive)
• Output type (Adjustable or Fixed)
• Package type (8-SOIC surface mount)
• Current rating (100mA minimum)
• Input voltage range (30V maximum or higher)
• Output voltage range compatibility (1.235V to 30V for adjustable; fixed outputs must match application requirements)
• Operating temperature range (-40°C to 125°C minimum)
• Protection features (Over-current and over-temperature required)

Substitute Categories:

1. Direct Functional Equivalents (Same Manufacturer): LP2951-50DR and LP2951D maintain identical electrical specifications and packaging, differing only in packaging format (Cut Tape/Digi-Reel vs. Tube).

2. Parametric Equivalents with Output Variants (MaxLinear): LP2951CS-L-3-3/TR and LP2951CS-L-5-0/TR provide equivalent functionality with fixed or adjustable outputs. These parts feature improved dropout voltage (0.45V vs. 0.6V) and higher quiescent current (170 µA vs. 120 µA).

3. Cross-Manufacturer Alternative (Richtek): RT2560Q-33GSP offers fixed 3.3V output with superior quiescent current (5 µA) and automotive qualification (AEC-Q100), though with narrower operating temperature range (-40°C to 85°C) and higher moisture sensitivity level (MSL 3).

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Active Product Status): LP2951-50DR is the primary recommended substitute. It maintains identical electrical specifications and package type as the LP2951-50D while offering Active product status and significantly higher inventory availability (44,250 pcs vs. 3,978 pcs). The only difference is packaging format (Cut Tape/Digi-Reel vs. Tube), which does not affect electrical performance or PCB assembly compatibility.

For Adjustable Output Applications with Improved Performance: LP2951CS-L-5-0/TR from MaxLinear provides equivalent adjustable output functionality with improved dropout voltage (0.45V vs. 0.6V) and Active product status. This part is suitable for designs where lower dropout voltage reduces thermal dissipation requirements. Tape & Reel packaging is standard for high-volume production.

For Fixed 3.3V Output Applications: LP2951CS-L-3-3/TR (MaxLinear) or RT2560Q-33GSP (Richtek) are suitable for applications requiring fixed 3.3V output. The MaxLinear part maintains full temperature range (-40°C to 125°C) and MSL 1 rating. The Richtek part offers superior quiescent current (5 µA) and automotive qualification (AEC-Q100) but operates only to 85°C and carries MSL 3 moisture sensitivity, requiring controlled storage conditions.

Compliance Considerations: All substitute parts maintain RoHS3 compliance and REACH unaffected status, consistent with the original LP2951-50D. The RT2560Q-33GSP includes AEC-Q100 automotive qualification for applications requiring automotive-grade components.

Frequently Asked Questions (FAQ)

Q: Can LP2951-50DR be used as a direct replacement for LP2951-50D? A: Yes. LP2951-50DR is electrically and functionally identical to LP2951-50D. The difference is packaging format: LP2951-50DR is supplied in Cut Tape/Digi-Reel format while LP2951-50D is supplied in Tube format. Both are 8-SOIC surface mount packages with identical pinout and electrical characteristics. LP2951-50DR has Active product status with higher inventory availability.

Q: What is the difference between adjustable and fixed output variants? A: Adjustable output variants (LP2951-50D, LP2951-50DR, LP2951D, LP2951CS-L-5-0/TR) allow output voltage configuration from 1.235V to 30V through external resistor networks. Fixed output variants (LP2951CS-L-3-3/TR, RT2560Q-33GSP) provide a preset 3.3V output without external configuration. Select adjustable variants for multi-voltage designs; select fixed variants for single-voltage applications.

Q: Are there package differences between substitute parts? A: Most substitutes use standard 8-SOIC packaging. RT2560Q-33GSP uses 8-SOIC-EP (exposed pad) variant, which includes a thermal pad for improved heat dissipation. All are surface mount compatible with standard PCB assembly processes. Verify PCB footprint compatibility before design implementation.

Q: What is the impact of quiescent current differences? A: Quiescent current (Iq) represents standby power consumption. LP2951-50D and direct equivalents draw 120 µA. MaxLinear variants draw 170 µA. RT2560Q-33GSP draws only 5 µA. For battery-powered or low-power standby applications, RT2560Q-33GSP offers significant power savings. For standard applications, the difference is negligible.

Q: Can RT2560Q-33GSP replace LP2951-50D in all applications? A: RT2560Q-33GSP is suitable only for applications requiring fixed 3.3V output. It cannot replace adjustable output designs. Additionally, RT2560Q-33GSP operates only to 85°C (vs. 125°C for LP2951-50D) and carries MSL 3 moisture sensitivity requiring controlled storage. Verify temperature range and storage requirements before substitution.

Q: What does "Last Time Buy" status mean? A: Last Time Buy indicates the manufacturer has discontinued production and will not accept new orders after a specified date. Existing inventory may be available but will eventually deplete. Active status parts (LP2951-50DR, LP2951CS-L-3-3/TR, LP2951CS-L-5-0/TR, RT2560Q-33GSP) are recommended for new designs to ensure long-term supply availability.

Q: Are all substitutes RoHS compliant? A: Yes. All listed substitute parts maintain RoHS3 compliance, consistent with the original LP2951-50D. REACH status is unaffected for all parts, indicating no restricted substances of concern.