LP2951D Equivalent & Substitute Parts

Part Overview

The LP2951D 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 is classified as Last Time Buy, indicating limited future availability. Finding equivalent and substitute parts ensures design continuity and supply chain reliability for applications requiring positive linear regulation with adjustable or fixed output configurations.

Key Parameters

Parameter	Value
Output Configuration	Positive
Output Type	Adjustable (Fixed)
Number of Regulators	1
Voltage - Input (Max)	30V
Voltage - Output (Min/Fixed)	1.235V (5V)
Voltage - Output (Max)	30V
Voltage Dropout (Max)	0.6V @ 100mA
Current - Output	100mA
Current - Quiescent (Iq)	120 µA
Operating Temperature	-40°C ~ 125°C (TJ)
Package / Case	8-SOIC (0.154", 3.90mm Width)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the LP2951D is determined by the following critical parameters:

Primary Substitution Criteria:

Output configuration (Positive)
Output type (Adjustable or Fixed)
Number of regulators (1)
Current output capability (100mA minimum)
Package type (8-SOIC surface mount)
Input voltage rating (30V or higher)
Operating temperature range (-40°C to 125°C or compatible)
RoHS3 compliance

Substitute Categories:

MFR Recommended Substitute (Packaging Variant): LP2951DR maintains identical electrical specifications and base product lineage with alternative packaging (Cut Tape & Digi-Reel) and Active product status.

Parametric Equivalent (Same Series): LP2951-50D provides identical electrical performance within the LP2951 series with Tube packaging and Last Time Buy status.

Cross-Manufacturer Alternative: RT2560Q-33GSP offers fixed 3.3V output with compatible package and automotive qualification, suitable for applications where fixed 3.3V output meets system requirements.

Parameter Comparison

Parameter	LP2951D	LP2951DR	LP2951-50D	RT2560Q-33GSP
Manufacturer	Texas Instruments	Texas Instruments	Texas Instruments	Richtek USA Inc.
Output Configuration	Positive	Positive	Positive	Positive
Output Type	Adjustable (Fixed)	Adjustable (Fixed)	Adjustable (Fixed)	Fixed
Number of Regulators	1	1	1	1
Voltage - Input (Max)	30V	30V	30V	36V
Voltage - Output (Min/Fixed)	1.235V (5V)	1.235V (5V)	1.235V (5V)	3.3V
Voltage - Output (Max)	30V	30V	30V	-
Voltage Dropout (Max)	0.6V @ 100mA	0.6V @ 100mA	0.6V @ 100mA	0.55V @ 10mA
Current - Output	100mA	100mA	100mA	100mA
Current - Quiescent (Iq)	120 µA	120 µA	120 µA	5 µA
Operating Temperature	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 85°C
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC Exposed Pad
Product Status	Last Time Buy	Active	Last Time Buy	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Recommended): LP2951DR is the primary substitute, offering identical electrical specifications and Active product status, ensuring long-term availability. This part is suitable for immediate design transitions from LP2951D.

For Series Continuity: LP2951-50D maintains full parametric equivalence within the LP2951 product family. While classified as Last Time Buy, this part provides identical performance for applications requiring adjustable output voltage configuration.

For Fixed Output Applications: RT2560Q-33GSP serves as an alternative for designs requiring fixed 3.3V output. This part features Active status, automotive qualification (AEC-Q100), and lower quiescent current (5 µA). Selection requires confirmation that 3.3V fixed output meets system voltage requirements and that the reduced operating temperature maximum (-40°C to 85°C) is acceptable.

Compliance Considerations: All substitute parts maintain ROHS3 compliance and EAR99 export classification, ensuring regulatory consistency with the original LP2951D.

Frequently Asked Questions (FAQ)

Q: Can LP2951DR replace LP2951D in existing designs without modification?

A: Yes. LP2951DR is electrically and functionally identical to LP2951D. The primary difference is packaging format (Cut Tape & Digi-Reel versus Tube). Both use the same 8-SOIC package footprint and pinout. No circuit modifications are required.

Q: What is the key difference between LP2951-50D and LP2951D?

A: Both parts are parametrically equivalent with identical electrical specifications. The difference is packaging (Tube) and product status (Last Time Buy). LP2951-50D is suitable for designs where adjustable output voltage is required and inventory availability is confirmed.

Q: When should RT2560Q-33GSP be selected instead of LP2951D?

A: RT2560Q-33GSP is appropriate when: (1) the application requires fixed 3.3V output, (2) lower quiescent current (5 µA versus 120 µA) provides design advantage, (3) automotive qualification is required, and (4) the operating temperature range of -40°C to 85°C meets system requirements. This part is not suitable for applications requiring adjustable output voltage.

Q: Are there package compatibility concerns between these substitutes?

A: All parts use 8-SOIC surface mount packages with identical 0.154" (3.90mm) width. PCB footprints are compatible. RT2560Q-33GSP includes an exposed pad variant, which may provide thermal benefits in high-current applications but does not prevent use in standard 8-SOIC footprints.

Q: Which substitute offers the best long-term availability?

A: LP2951DR and RT2560Q-33GSP both carry Active product status, indicating ongoing manufacturer support and availability. LP2951D and LP2951-50D are both Last Time Buy, indicating limited future production.

Q: Do all substitutes meet the same compliance standards?

A: Yes. All four parts are ROHS3 compliant, REACH unaffected, and classified as EAR99 for export purposes. Moisture sensitivity level (MSL) varies: LP2951D, LP2951DR, and LP2951-50D are MSL 1 (Unlimited); RT2560Q-33GSP is MSL 3 (168 Hours).

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