LP2951ACM Linear Voltage Regulator IC Equivalent & Substitute Parts

Part Overview

The LP2951ACM 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 provides output voltage adjustment from 1.235V to 29V with integrated protection features including over-current, over-temperature, and short-circuit protection.

The LP2951ACM carries a Last Time Buy product status, indicating end-of-life designation. Equivalent and substitute parts are necessary to ensure design continuity and long-term supply chain reliability for applications currently utilizing this regulator.

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)	29V
Voltage Dropout (Max)	0.6V @ 100mA
Current - Output	100mA
Current - Quiescent (Iq)	120 µA
Current - Supply (Max)	14 mA
Control Features	Enable
Protection Features	Over Current, Over Temperature, Short Circuit
Operating Temperature	-40°C ~ 125°C (TJ)
Mounting Type	Surface Mount
Package / Case	8-SOIC (0.154", 3.90mm Width)
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the LP2951ACM is determined by strict alignment across the following critical parameters:

Output Configuration & Type: Must be Positive, Adjustable (Fixed)
Voltage Specifications: Input (Max) 30V, Output range 1.235V–29V, Dropout 0.6V @ 100mA
Current Ratings: Output 100mA, Quiescent current ≤ 150 µA, Supply current ≤ 14 mA
Package: 8-SOIC surface mount form factor
Operating Temperature: -40°C ~ 125°C
Control & Protection: Enable feature, protection against over-current, over-temperature, and short-circuit conditions

Substitute parts are categorized as follows:

Direct Manufacturer Equivalent: LP2951ACM/NOPB (Texas Instruments) — identical electrical specifications with NOPB (No Plumbum/Lead-Free) designation and active product status.

Parametric Equivalents: LP2951CM (onsemi) and LP2951CM/NOPB (Texas Instruments) — functionally compatible with minor parameter variations within acceptable tolerances.

Manufacturer Recommended Alternatives: LP2951-02YM, LP2951-02YM-TR, LP2951-03YM, and LP2951-03YM-TR (Microchip Technology) — cross-compatible designs with enhanced control features (Error Flag) and active product status.

Parameter Comparison

Part Number	Manufacturer	Product Status	Voltage - Output (Min/Fixed)	Current - Quiescent (Iq)	Current - Supply (Max)	Protection Features	Control Features	RoHS Status	Packaging
LP2951ACM	Texas Instruments	Last Time Buy	1.235V (5V)	120 µA	14 mA	Over Current, Over Temperature, Short Circuit	Enable	RoHS non-compliant	Not specified
LP2951ACM/NOPB	Texas Instruments	Active	1.235V (5V)	120 µA	14 mA	Over Current, Over Temperature, Short Circuit	Enable	ROHS3 Compliant	Tube
LP2951CM	onsemi	Obsolete	1.26V (5V)	140 µA	7 mA	Over Temperature, Short Circuit	Enable	Not specified	Not specified
LP2951CM/NOPB	Texas Instruments	Active	1.235V (5V)	120 µA	14 mA	Over Current, Over Temperature, Short Circuit	Enable	ROHS3 Compliant	Tube
LP2951-02YM	Microchip Technology	Active	1.24V (5V)	150 µA	14 mA	Not specified	Enable, Error Flag	ROHS3 Compliant	Tube
LP2951-02YM-TR	Microchip Technology	Active	1.24V (5V)	150 µA	14 mA	Not specified	Enable, Error Flag	ROHS3 Compliant	Cut Tape (CT) & Digi-Reel®
LP2951-03YM	Microchip Technology	Active	1.24V (5V)	150 µA	14 mA	Not specified	Enable, Error Flag	ROHS3 Compliant	Tube
LP2951-03YM-TR	Microchip Technology	Active	1.24V (5V)	150 µA	14 mA	Not specified	Enable, Error Flag	ROHS3 Compliant	Cut Tape (CT) & Digi-Reel®

Engineering Selection Recommendations

For Direct Replacement (Recommended Primary Choice)

LP2951ACM/NOPB is the optimal substitute. It maintains identical electrical specifications to the LP2951ACM while offering active product status and ROHS3 compliance. The NOPB designation indicates lead-free construction, meeting modern environmental and regulatory requirements. Available in Tube packaging with 2555 units in stock.

For Active Supply Chain Continuity

Microchip Technology's LP2951-02YM, LP2951-02YM-TR, LP2951-03YM, and LP2951-03YM-TR variants provide long-term availability with active product status and ROHS3 compliance. These parts feature enhanced control functionality (Error Flag output) and maintain electrical compatibility within specified tolerances. The -02YM and -03YM variants differ in output voltage adjustment range but both support the standard 5V fixed output configuration. Tape and reel packaging options (LP2951-02YM-TR, LP2951-03YM-TR) are available for high-volume applications.

For Compliance-Critical Applications

LP2951CM/NOPB (Texas Instruments) offers ROHS3 compliance and active status with identical electrical performance to the original LP2951ACM. This variant is suitable when regulatory compliance is a primary selection criterion.

Avoid

LP2951CM (onsemi) carries obsolete product status and should not be selected for new designs or long-term supply commitments despite adequate parametric compatibility.

Frequently Asked Questions (FAQ)

Q: Can LP2951ACM/NOPB be used as a direct drop-in replacement for LP2951ACM?

A: Yes. LP2951ACM/NOPB maintains identical electrical specifications, package form factor (8-SOIC), and pinout. The primary difference is the NOPB (lead-free) designation and active product status. No circuit modifications are required.

Q: What is the difference between LP2951-02YM and LP2951-03YM from Microchip?

A: Both variants are electrically compatible with the LP2951ACM across all critical parameters (voltage, current, temperature range, package). The numerical suffix (-02 vs -03) indicates different internal trim settings for output voltage adjustment, but both support standard 5V fixed output operation. Selection between these variants depends on specific application requirements and Microchip's availability.

Q: Are the Microchip LP2951-02YM-TR and LP2951-03YM-TR suitable replacements?

A: Yes. These parts are parametrically equivalent to their Tube-packaged counterparts (LP2951-02YM and LP2951-03YM). The -TR suffix indicates Cut Tape and Digi-Reel packaging, suitable for automated assembly processes. Electrical performance and compatibility are identical.

Q: Why is LP2951CM (onsemi) listed but not recommended?

A: While LP2951CM meets the core electrical and package requirements, it carries obsolete product status, limiting long-term supply availability. Additionally, it lacks over-current protection compared to the original LP2951ACM. For new designs or sustained production, active-status alternatives are preferred.

Q: What packaging options are available for substitutes?

A: Tube packaging is available for LP2951ACM/NOPB, LP2951CM/NOPB, LP2951-02YM, and LP2951-03YM. Cut Tape and Digi-Reel packaging is available for LP2951-02YM-TR and LP2951-03YM-TR. Selection depends on assembly process requirements and volume.

Q: Are all substitutes ROHS3 compliant?

A: All recommended active-status substitutes (LP2951ACM/NOPB, LP2951CM/NOPB, and all Microchip variants) are ROHS3 compliant. The original LP2951ACM is RoHS non-compliant. For applications requiring regulatory compliance, select ROHS3-compliant alternatives.

Q: What is the significance of the Error Flag feature in Microchip variants?

A: The Error Flag output (present in LP2951-02YM, LP2951-02YM-TR, LP2951-03YM, and LP2951-03YM-TR) provides an additional control signal not present in the original LP2951ACM. This feature enables enhanced system monitoring but is not required for basic regulator operation. Existing designs using LP2951ACM can omit this signal without functional impact.

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