LM2931CS Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LM2931CS is a linear voltage regulator IC from Texas Instruments designed for positive adjustable output applications. It delivers 100mA output current in a surface-mount TO-263 (DDPAK-5) package. The device is classified as Last Time Buy, indicating end-of-life status from the original manufacturer. Identifying equivalent and substitute parts is necessary to ensure continued design support, maintain supply chain flexibility, and enable procurement from active inventory sources.

Key Parameters

Parameter	Value
Output Configuration	Positive
Output Type	Adjustable
Number of Regulators	1
Voltage - Input (Max)	26V
Voltage - Output (Min/Fixed)	3V
Voltage - Output (Max)	24V
Voltage Dropout (Max)	0.3V @ 100mA
Current - Output	100mA
Current - Quiescent (Iq)	1 mA
PSRR	55dB (120Hz)
Protection Features	Over Temperature, Reverse Polarity, Short Circuit
Operating Temperature	-40°C ~ 85°C
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the LM2931CS are identified based on strict electrical and mechanical parameter alignment. The following criteria determine substitution eligibility:

Critical Parameters for Substitution:

Output configuration (Positive)
Output type (Adjustable)
Number of regulators (1)
Maximum input voltage (26V minimum)
Output voltage range (minimum 3V, maximum 24V)
Output current (100mA)
Package type (TO-263 / D2PAK-5)
Surface-mount capability

Substitutes identified:

LM2931CS/NOPB (National Semiconductor) – Direct equivalent with identical electrical specifications and packaging
LM2931ACD2TR4G (onsemi) – Manufacturer-recommended substitute with compatible core functionality and enhanced operating temperature range

Parameter Comparison

Parameter	LM2931CS (Main)	LM2931CS/NOPB (Substitute)	LM2931ACD2TR4G (Substitute)
Manufacturer	Texas Instruments	National Semiconductor	onsemi
Product Status	Last Time Buy	Active	Active
Output Configuration	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable
Voltage - Input (Max)	26V	26V	26V
Voltage - Output (Min)	3V	3V	2.7V
Voltage - Output (Max)	24V	24V	29.5V
Voltage Dropout (Max)	0.3V @ 100mA	0.3V @ 100mA	0.6V @ 100mA
Current - Output	100mA	100mA	100mA
Current - Quiescent (Iq)	1 mA	1 mA	1 mA
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 125°C
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)	TO-263-6, D2PAK (5 Leads + Tab)	TO-263-6, D2PAK (5 Leads + Tab)
Mounting Type	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	Not specified	ROHS3 Compliant
Packaging Format	Tube	Bulk	Cut Tape (CT)

Engineering Selection Recommendations

LM2931CS/NOPB (National Semiconductor) is the direct electrical equivalent. It maintains identical voltage dropout, quiescent current, and output specifications. Product status is Active, ensuring continued availability. This substitute is suitable for applications where the original LM2931CS specifications are required without modification.

LM2931ACD2TR4G (onsemi) is the manufacturer-recommended substitute. It provides extended operating temperature range (-40°C to 125°C versus -40°C to 85°C), wider output voltage range (2.7V to 29.5V), and ROHS3 compliance. The increased voltage dropout (0.6V @ 100mA versus 0.3V) must be evaluated against application thermal and efficiency requirements. This substitute is suitable for designs requiring enhanced temperature performance or extended output voltage flexibility.

Both substitutes are available in active production status with confirmed inventory. Package compatibility (TO-263 / D2PAK-5) is maintained across all three parts.

Frequently Asked Questions (FAQ)

Q: Can LM2931CS/NOPB be used as a direct replacement for LM2931CS? A: Yes. Electrical specifications, output current, voltage dropout, and package type are identical. The primary difference is packaging format (Bulk versus Tube) and product status (Active versus Last Time Buy).

Q: What are the key differences between LM2931CS and LM2931ACD2TR4G? A: The LM2931ACD2TR4G offers extended operating temperature range (to 125°C), wider output voltage range (2.7V to 29.5V), and lower quiescent supply current (6mA versus 15mA). Voltage dropout is higher at 0.6V @ 100mA. These differences must be evaluated for specific application requirements.

Q: Are all three parts pin-compatible? A: Yes. All three parts use the TO-263 (D2PAK-5) package with 5 leads plus tab, ensuring mechanical and electrical pin compatibility.

Q: Which substitute should be selected for new designs? A: Selection depends on application requirements. For designs requiring the original LM2931CS specifications without modification, use LM2931CS/NOPB. For designs benefiting from extended temperature range or wider output voltage range, use LM2931ACD2TR4G.

Q: Are there compliance or certification differences? A: LM2931CS and LM2931ACD2TR4G are both ROHS3 compliant. All three parts are REACH Unaffected and classified as EAR99 for export control purposes.

Q: What is the impact of higher voltage dropout in LM2931ACD2TR4G? A: The 0.6V dropout (versus 0.3V in the original) results in increased power dissipation and reduced efficiency in low-input-voltage applications. Thermal design must account for this difference.

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