LM2931CD2T Linear Voltage Regulator - Equivalent & Substitute Parts

Part Overview

The LM2931CD2T is a linear voltage regulator IC with positive adjustable output, rated for 100mA maximum output current in a D2PAK-5 surface mount package. This device is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and procurement planning. The LM2931CD2T operates across an input voltage range of up to 26V with adjustable output from 2.7V to 29.5V, featuring integrated over-current and over-temperature protection.

Key Parameters

Parameter	Value
Manufacturer	onsemi
Part Number	LM2931CD2T
Product Status	Obsolete
Output Configuration	Positive
Output Type	Adjustable
Voltage - Input (Max)	26V
Voltage - Output (Min/Fixed)	2.7V
Voltage - Output (Max)	29.5V
Current - Output	100mA
Voltage Dropout (Max)	0.6V @ 100mA
Operating Temperature	-40°C ~ 125°C
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)
Mounting Type	Surface Mount
Protection Features	Over Current, Over Temperature

Substitute Part Grouping Explanation

Equivalent and substitute parts for the LM2931CD2T are identified based on the following critical parameters that determine functional interchangeability:

Output configuration (Positive)
Output type (Adjustable)
Maximum output current (100mA)
Package type (D2PAK-5 / TO-263-6)
Surface mount compatibility
Input voltage rating (26V maximum)
Adjustable output voltage range capability

Parts are grouped into two categories: parametric equivalents (identical electrical specifications) and functional substitutes (compatible within application constraints).

Parameter Comparison

Parameter	LM2931CD2T	LM2931CD2TG	LM2931CS/NOPB
Manufacturer	onsemi	onsemi	National Semiconductor
Product Status	Obsolete	Obsolete	Active
Output Configuration	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable
Voltage - Input (Max)	26V	26V	26V
Voltage - Output (Min/Fixed)	2.7V	2.7V	3V
Voltage - Output (Max)	29.5V	29.5V	24V
Current - Output	100mA	100mA	100mA
Voltage Dropout (Max)	0.6V @ 100mA	0.6V @ 100mA	0.3V @ 100mA
Operating Temperature	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 85°C
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)	TO-263-6, D2PAK (5 Leads + Tab)	TO-263-6, D2PAK (5 Leads + Tab)
Protection Features	Over Current, Over Temperature	Over Current, Over Temperature	Over Temperature, Reverse Polarity, Short Circuit
RoHS Status	RoHS non-compliant	ROHS3 Compliant	Not specified

Engineering Selection Recommendations

LM2931CD2TG is a parametric equivalent to the LM2931CD2T with identical electrical specifications and package configuration. The primary distinction is RoHS3 compliance status, making LM2931CD2TG suitable for applications requiring environmental compliance certification. Both devices share obsolete product status.

LM2931CS/NOPB is a functional substitute with active product status from National Semiconductor. This part maintains compatibility across core parameters: positive adjustable output, 100mA current rating, and D2PAK-5 packaging. Differences include a lower minimum output voltage (3V versus 2.7V), reduced maximum output voltage (24V versus 29.5V), superior dropout voltage performance (0.3V versus 0.6V), and a narrower operating temperature range (-40°C to 85°C versus -40°C to 125°C). The LM2931CS/NOPB includes additional protection features (reverse polarity and short circuit protection) and maintains active availability status.

Selection between these alternatives depends on specific application requirements regarding output voltage range, temperature operating envelope, and compliance certifications.

Frequently Asked Questions (FAQ)

Q: Can LM2931CD2TG be used as a direct replacement for LM2931CD2T?

A: Yes. LM2931CD2TG is a parametric equivalent with identical electrical specifications, output voltage range (2.7V to 29.5V), dropout voltage (0.6V @ 100mA), and D2PAK-5 package configuration. The primary difference is RoHS3 compliance status.

Q: What are the limitations of using LM2931CS/NOPB as a substitute?

A: LM2931CS/NOPB has three application constraints: minimum output voltage is 3V (not 2.7V), maximum output voltage is 24V (not 29.5V), and maximum operating temperature is 85°C (not 125°C). Verify your application does not require output voltages below 3V or above 24V, and confirm thermal operating conditions remain within -40°C to 85°C.

Q: Are all three parts pin-compatible?

A: Yes. All three parts use the D2PAK-5 (TO-263-6) surface mount package with identical pinout configuration, enabling direct PCB layout compatibility.

Q: Which substitute offers the best dropout voltage performance?

A: LM2931CS/NOPB provides superior dropout voltage at 0.3V @ 100mA, compared to 0.6V @ 100mA for both LM2931CD2T and LM2931CD2TG. This advantage is relevant for applications with tight input-to-output voltage margins.

Q: What is the significance of active versus obsolete product status?

A: LM2931CS/NOPB maintains active product status with ongoing manufacturer support and procurement availability. LM2931CD2T and LM2931CD2TG are obsolete, indicating discontinued production and limited future availability. For new designs, LM2931CS/NOPB is preferred where application parameters permit its use.

Q: Do all parts include the same protection features?

A: No. LM2931CD2T and LM2931CD2TG include over-current and over-temperature protection. LM2931CS/NOPB adds reverse polarity and short circuit protection, providing enhanced circuit protection capabilities.

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