LM2940CT-5.0/NOPB Equivalent & Substitute Parts

Part Overview

The LM2940CT-5.0/NOPB is a linear voltage regulator IC manufactured by Texas Instruments, designed to provide a fixed 5V output at 1A current capacity in a TO-220-3 package. This device is classified as a positive fixed output regulator with integrated protection features including over-temperature, reverse polarity, and short-circuit protection. The part is currently in active production status with 20,850 units in stock inventory.

Substitute parts are necessary when the primary part becomes unavailable, when design requirements demand enhanced performance characteristics such as lower dropout voltage or higher output current, or when alternative manufacturers' components offer superior specifications within the same functional category and package type.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM2940CT-5.0/NOPB
Manufacturer	Texas Instruments
Output Voltage (Fixed)	5V
Output Current	1A
Input Voltage (Max)	26V
Dropout Voltage (Max)	1V @ 1A
Package / Case	TO-220-3
Operating Temperature Range	0°C ~ 125°C
Protection Features	Over Temperature, Reverse Polarity, Short Circuit
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the LM2940CT-5.0/NOPB is determined by the following critical parameters:

Primary Substitution Criteria:

Fixed output voltage of 5V
TO-220-3 package configuration
Positive output configuration
Through-hole mounting type
ROHS3 compliance

Secondary Compatibility Parameters:

Output current capacity (minimum 1A required for direct substitution; higher ratings acceptable)
Input voltage maximum rating (minimum 26V required)
Dropout voltage performance (lower values preferred but not mandatory)
Operating temperature range (0°C to 125°C minimum required)
Protection features (over-temperature and reverse polarity protection required)

Substitute parts are grouped into two categories: direct equivalents with identical electrical specifications, and parametric equivalents with enhanced performance characteristics that maintain full backward compatibility.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Dropout Voltage (Max)	Operating Temp Range	Product Status	Inventory
LM2940CT-5.0/NOPB	Texas Instruments	1A	26V	1V @ 1A	0°C ~ 125°C	Active	20,850 Pcs
LM2940T-5.0/NOPB	Texas Instruments	1A	26V	1V @ 1A	-40°C ~ 125°C	Active	25,400 Pcs
LM2940CT-5.0	Texas Instruments	1A	26V	1V @ 1A	0°C ~ 125°C	Last Time Buy	1,539 Pcs
UA7805CKCS	Texas Instruments	1.5A	25V	2V @ 1A	0°C ~ 125°C	Last Time Buy	18,999 Pcs
L4940V5	STMicroelectronics	1.5A	17V	0.9V @ 1.5A	-40°C ~ 150°C	Active	10,100 Pcs
L4941BV	STMicroelectronics	1A	16V	0.7V @ 1A	-40°C ~ 150°C	Active	16,099 Pcs
MIC29150-5.0WT	Microchip Technology	1.5A	26V	0.6V @ 1.5A	-40°C ~ 125°C	Active	5,100 Pcs
MIC2940A-5.0WT	Microchip Technology	1.25A	26V	0.6V @ 1.25A	-40°C ~ 125°C	Active	9,400 Pcs
MIC2937A-5.0WT	Microchip Technology	750mA	26V	Not Specified	-40°C ~ 125°C	Active	11,632 Pcs
MIC29300-5.0WT	Microchip Technology	3A	26V	0.6V @ 3A	-40°C ~ 125°C	Active	3,288 Pcs
MIC2920A-5.0WT	Microchip Technology	400mA	26V	0.75V @ 400mA	-40°C ~ 125°C	Active	2,300 Pcs

Engineering Selection Recommendations

Tier 1 - Direct Substitutes (Recommended Priority):

LM2940T-5.0/NOPB is the primary recommended substitute. This Texas Instruments part maintains identical electrical specifications to the LM2940CT-5.0/NOPB while offering an extended operating temperature range of -40°C to 125°C. Both parts share the same base product number (LM2940), identical output current (1A), input voltage rating (26V), and dropout voltage characteristics (1V @ 1A). The part is in active production status with higher inventory availability (25,400 units). All protection features and compliance certifications are equivalent.

MIC2940A-5.0WT from Microchip Technology provides a direct functional equivalent with enhanced performance. This part delivers 1.25A output current within the same 26V input rating and TO-220-3 package. The dropout voltage is reduced to 0.6V @ 1.25A compared to 1V @ 1A on the original part. Operating temperature range extends to -40°C to 125°C. The part is in active production with 9,400 units in stock.

Tier 2 - Higher Current Capacity Substitutes:

MIC29150-5.0WT and MIC29300-5.0WT from Microchip Technology are suitable when higher output current capacity is required. MIC29150-5.0WT provides 1.5A output with 0.6V dropout voltage. MIC29300-5.0WT delivers 3A output with 0.6V dropout voltage. Both maintain 26V input rating and TO-220-3 package compatibility. These parts are in active production status.

Tier 3 - Alternative Manufacturers:

L4941BV from STMicroelectronics matches the 1A output current specification with improved dropout voltage (0.7V @ 1A) and extended temperature range (-40°C to 150°C). However, the input voltage maximum is limited to 16V compared to 26V on the original part. This part is suitable only for applications with input voltages not exceeding 16V.

L4940V5 from STMicroelectronics provides 1.5A output current with 0.9V dropout voltage and extended temperature range. Input voltage maximum is 17V, limiting applicability to lower input voltage designs.

Not Recommended:

MIC2937A-5.0WT provides only 750mA output current, below the 1A requirement of the original part. MIC2920A-5.0WT provides only 400mA output current and is unsuitable for direct substitution. UA7805CKCS is in Last Time Buy status and exhibits higher dropout voltage (2V @ 1A), making it a less favorable choice despite higher current capacity.

Frequently Asked Questions (FAQ)

Q: Can LM2940T-5.0/NOPB be used as a direct replacement for LM2940CT-5.0/NOPB?

A: Yes. Both parts are Texas Instruments LM2940 series regulators with identical electrical specifications: 5V fixed output, 1A output current, 26V maximum input voltage, and 1V dropout voltage at 1A. The primary difference is the operating temperature range: LM2940T-5.0/NOPB extends to -40°C while LM2940CT-5.0/NOPB operates from 0°C. For applications within the 0°C to 125°C range, both parts are fully interchangeable. The TO-220-3 package and pin configuration are identical.

Q: What is the significance of dropout voltage when selecting a substitute?

A: Dropout voltage determines the minimum difference between input and output voltage required for proper regulation. The LM2940CT-5.0/NOPB has a maximum dropout voltage of 1V @ 1A. Substitute parts with lower dropout voltage (such as MIC2940A-5.0WT at 0.6V @ 1.25A) provide improved efficiency and allow operation with lower input voltages. Higher dropout voltage substitutes may require higher input voltages to maintain stable 5V output.

Q: Can I use MIC29150-5.0WT (1.5A) instead of the original 1A part?

A: Yes. Higher output current capacity is a valid substitution parameter. MIC29150-5.0WT provides 1.5A output current, exceeding the 1A requirement. The part maintains 5V fixed output, 26V input rating, TO-220-3 package, and ROHS3 compliance. The lower dropout voltage (0.6V @ 1.5A) provides additional performance benefit. This substitution is suitable for all applications designed for the original 1A part.

Q: Why is the input voltage maximum rating important?

A: The input voltage maximum rating (26V for the original part) defines the maximum voltage the regulator can safely handle. Substitute parts with lower input voltage ratings (such as L4941BV at 16V) cannot be used in applications where input voltage may exceed their rating. Conversely, substitute parts with equal or higher input voltage ratings maintain full compatibility.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed in this document are ROHS3 compliant, matching the compliance status of the LM2940CT-5.0/NOPB. All parts are also REACH unaffected and classified as EAR99 for export control purposes.

Q: What is the difference between "Active" and "Last Time Buy" product status?

A: Active status indicates the part is in current production and will remain available for the foreseeable future. Last Time Buy status indicates the manufacturer has announced end-of-life for the part; existing inventory is available but no new production is planned. For long-term design reliability, Active status parts are preferred. LM2940T-5.0/NOPB and MIC2940A-5.0WT are both in Active status with strong inventory levels.

Q: Can I substitute a part with a lower output current rating?

A: No. Parts with lower output current ratings (such as MIC2920A-5.0WT at 400mA or MIC2937A-5.0WT at 750mA) cannot reliably supply the full 1A required by the original design. Using an undersized regulator may result in voltage regulation failure, thermal stress, or activation of current-limiting protection circuits.

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