LM2931CD Equivalent & Substitute Parts

Part Overview

The LM2931CD is a linear voltage regulator IC from onsemi, designed for positive adjustable output applications with 100mA current capability in an 8-SOIC surface mount package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The LM2931CD provides adjustable output voltage regulation with integrated over-current and over-temperature protection features.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM2931CD
Manufacturer	onsemi
Category	Power Management (PMIC)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Output Configuration	Positive
Output Type	Adjustable
Voltage - Input (Max)	26V
Voltage - Output (Min/Fixed)	2.7V
Voltage - Output (Max)	29.5V
Current - Output	100mA
Operating Temperature	-40°C ~ 125°C
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the LM2931CD are qualified based on the following critical parameters that determine functional compatibility:

Package compatibility: 8-SOIC surface mount package with identical 0.154" (3.90mm) width
Output configuration: Positive adjustable voltage regulator topology
Current rating: 100mA output current capability
Input voltage range: Maximum 26V input voltage support
Mounting type: Surface mount technology
Base product series: LM2931 family

The substitute parts LM2931CM/NOPB and LM2931CMX/NOPB meet these core electrical and mechanical requirements. Both are from the same LM2931 base product family and maintain identical package specifications and current ratings. Differences in output voltage range, dropout voltage, and operating temperature limits are noted in the parameter comparison but do not prevent functional substitution in applications within the overlapping specifications.

Parameter Comparison

Parameter	LM2931CD (onsemi)	LM2931CM/NOPB (TI)	LM2931CMX/NOPB (TI)
Manufacturer	onsemi	Texas Instruments	Texas Instruments
Product Status	Obsolete	Active	Active
Package / Case	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)
Output Configuration	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable
Voltage - Input (Max)	26V	26V	26V
Voltage - Output (Min/Fixed)	2.7V	3V	3V
Voltage - Output (Max)	29.5V	24V	24V
Voltage Dropout (Max)	0.6V @ 100mA	0.3V @ 100mA	0.3V @ 100mA
Current - Output	100mA	100mA	100mA
Current - Quiescent (Iq)	1 mA	1 mA	1 mA
Operating Temperature	-40°C ~ 125°C	-40°C ~ 85°C	-40°C ~ 85°C
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging	-	Bulk	Cut Tape (CT) & Digi-Reel®

Engineering Selection Recommendations

Both LM2931CM/NOPB and LM2931CMX/NOPB from Texas Instruments are active product alternatives to the obsolete LM2931CD. The Texas Instruments variants offer ROHS3 compliance, addressing regulatory requirements that the original onsemi part does not meet. Both substitute parts maintain identical package specifications and current ratings, enabling direct functional replacement in 8-SOIC surface mount applications.

The LM2931CMX/NOPB is supplied in Cut Tape and Digi-Reel packaging, while the LM2931CM/NOPB is supplied in bulk packaging. Selection between these two should be based on procurement and assembly requirements rather than electrical performance, as both are electrically equivalent.

Applications requiring output voltage adjustment below 3V or operating temperatures above 85°C should verify compatibility with the substitute parts' specifications before implementation.

Frequently Asked Questions (FAQ)

Q: Can LM2931CM/NOPB or LM2931CMX/NOPB directly replace LM2931CD without circuit modifications?

A: Both Texas Instruments parts are pin-compatible and functionally equivalent for applications within the overlapping electrical specifications. The 8-SOIC package dimensions are identical, and output current, input voltage range, and quiescent current match the original part. No circuit modifications are required for standard applications.

Q: What is the difference between LM2931CM/NOPB and LM2931CMX/NOPB?

A: Both parts are electrically identical. The primary difference is packaging: LM2931CM/NOPB is supplied in bulk, while LM2931CMX/NOPB is supplied in Cut Tape and Digi-Reel format. Selection depends on assembly and procurement workflow requirements.

Q: Are there output voltage range limitations when substituting?

A: The Texas Instruments substitutes support a minimum output voltage of 3V compared to the LM2931CD's 2.7V minimum, and a maximum of 24V compared to 29.5V. Applications requiring output voltages outside the 3V to 24V range are not compatible with these substitutes.

Q: What is the operating temperature difference, and does it affect substitution?

A: The LM2931CD operates to 125°C, while the Texas Instruments substitutes operate to 85°C maximum. Applications requiring operation above 85°C require verification of alternative solutions. Standard industrial and commercial temperature range applications (-40°C to 85°C) are fully compatible.

Q: Do the substitute parts meet current regulatory compliance?

A: Yes. Both LM2931CM/NOPB and LM2931CMX/NOPB are ROHS3 compliant, addressing modern regulatory requirements. The original LM2931CD is RoHS non-compliant, making the substitutes preferable for new designs and production requiring regulatory compliance.

Q: Is the improved dropout voltage of the substitutes a concern?

A: The Texas Instruments parts feature 0.3V dropout at 100mA compared to 0.6V for the LM2931CD. This represents an improvement, reducing power dissipation and improving regulator efficiency. This difference does not prevent substitution and may provide performance benefits.

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