LM340T-5.0 Equivalent & Substitute Parts

Part Overview

The LM340T-5.0 is a linear voltage regulator IC from Texas Instruments designed for positive fixed 5V output at 1.5A in a TO-220-3 package. This device is classified as Last Time Buy, indicating limited availability from the original manufacturer. Finding equivalent and substitute parts is necessary to ensure design continuity and maintain supply chain reliability for applications requiring 5V regulated power output.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	5V
Output Current	1.5A
Input Voltage (Max)	35V
Voltage Dropout (Max)	2V @ 1A
Package / Case	TO-220-3
Mounting Type	Through Hole
Operating Temperature	0°C ~ 125°C
Protection Features	Over Temperature, Short Circuit
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the LM340T-5.0 is determined by the following critical parameters:

Output Voltage: Must be fixed at 5V
Output Current Capability: Minimum 1.5A required for direct substitution
Package: TO-220-3 form factor for mechanical compatibility
Input Voltage Rating: 25V or higher to accommodate 35V maximum input
Protection Features: Over temperature and short circuit protection required
RoHS Compliance: ROHS3 Compliant status for regulatory alignment

Parts are grouped into three categories:

Category 1 - Direct Equivalents (1.5A Output): Parts with identical 1.5A output current rating and full parameter compatibility.

Category 2 - Reduced Current Alternatives (500mA - 1A Output): Parts with lower output current ratings suitable only for applications with reduced current requirements.

Category 3 - Enhanced Current Alternative (2A Output): Parts with higher output current rating providing additional design margin.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Voltage Dropout	Quiescent Current	PSRR (120Hz)	Protection Features	Operating Temp	Product Status
LM340T-5.0	Texas Instruments	1.5A	35V	2V @ 1A	8 mA	80dB	Over Temperature, Short Circuit	0°C ~ 125°C	Last Time Buy
LM340AT-5.0/NOPB	Texas Instruments	1.5A	35V	2V @ 1A	6 mA	70dB	Over Current, Short Circuit	0°C ~ 125°C	Active
LM340T-5.0/NOPB	Texas Instruments	1.5A	35V	2V @ 1A	8 mA	80dB	Over Temperature, Short Circuit	0°C ~ 125°C	Active
UA7805CKCS	Texas Instruments	1.5A	25V	2V @ 1A	—	78dB ~ 68dB	Over Temperature, Reverse Polarity	0°C ~ 125°C	Last Time Buy
L7805ABV	STMicroelectronics	1.5A	35V	2V @ 1A (Typ)	6 mA	68dB	Over Temperature, Short Circuit	-40°C ~ 125°C	Active
L78M05ABV	STMicroelectronics	500mA	35V	—	6 mA	62dB	Over Current, Over Temperature, Short Circuit	-40°C ~ 125°C	Active
L78M05CV	STMicroelectronics	500mA	35V	—	6 mA	62dB	Over Current, Over Temperature, Short Circuit	0°C ~ 150°C	Active
L78S05CV	STMicroelectronics	2A	35V	—	8 mA	54dB	Over Current, Over Temperature, Short Circuit	0°C ~ 150°C	Obsolete
LM2931AT-5.0G	onsemi	100mA	26V	0.6V @ 100mA	1 mA	90dB	Over Current, Over Temperature	-40°C ~ 125°C	Active
LM2931T-5.0G	onsemi	100mA	26V	0.6V @ 100mA	1 mA	90dB	Over Current, Over Temperature	-40°C ~ 125°C	Active
MC7805ABTG	onsemi	1A	35V	2V @ 1A (Typ)	6 mA	83dB	Over Temperature, Short Circuit	-40°C ~ 125°C	Active

Engineering Selection Recommendations

Primary Substitutes (Full Compatibility)

LM340T-5.0/NOPB from Texas Instruments is the direct equivalent with Active product status and identical electrical specifications. This part maintains the same 1.5A output current, 80dB PSRR, and protection feature set as the original LM340T-5.0.

L7805ABV from STMicroelectronics provides full electrical compatibility with 1.5A output current and 35V maximum input voltage. This part is Active and ROHS3 Compliant, with extended operating temperature range (-40°C to 125°C) compared to the original specification.

Secondary Substitutes (Conditional Compatibility)

LM340AT-5.0/NOPB from Texas Instruments maintains 1.5A output current and Active status. This variant includes over current protection instead of over temperature protection and exhibits slightly lower PSRR (70dB vs 80dB).

UA7805CKCS from Texas Instruments is functionally compatible but operates with a reduced maximum input voltage of 25V compared to the original 35V specification. This part is Last Time Buy status.

MC7805ABTG from onsemi delivers 1A output current with Active status and extended temperature range (-40°C to 125°C). This part is suitable for applications with reduced current requirements.

Not Recommended for Direct Substitution

L78M05ABV and L78M05CV are rated for 500mA output current, insufficient for applications requiring the full 1.5A capability of the original part.

L78S05CV is Obsolete status and should not be selected for new designs despite its 2A output rating.

LM2931AT-5.0G and LM2931T-5.0G are rated for only 100mA output current and operate with a maximum input voltage of 26V, making them unsuitable for this application.

Frequently Asked Questions (FAQ)

Q: Can I use LM340AT-5.0/NOPB as a direct replacement for LM340T-5.0?

A: Yes. Both parts are from Texas Instruments, deliver 1.5A output current, and operate within the same temperature range. The LM340AT-5.0/NOPB is Active status, providing better long-term availability. Minor differences exist in quiescent current (6mA vs 8mA) and PSRR (70dB vs 80dB), which are not significant for most applications.

Q: What is the difference between L7805ABV and L78M05ABV?

A: L7805ABV is rated for 1.5A output current and is a direct equivalent to the LM340T-5.0. L78M05ABV is rated for only 500mA output current and is suitable only for low-current applications. Do not substitute L78M05ABV if your circuit requires 1.5A.

Q: Why is UA7805CKCS listed if it has a lower maximum input voltage?

A: UA7805CKCS maintains 1.5A output current and is electrically compatible for applications where the input voltage does not exceed 25V. For designs requiring the full 35V input capability, select L7805ABV or LM340T-5.0/NOPB instead.

Q: Is the TO-220-3 package the same across all substitute parts?

A: Yes. All listed substitute parts use the TO-220-3 package, ensuring mechanical and thermal compatibility with the original LM340T-5.0 without PCB redesign.

Q: Can I use MC7805ABTG if my application only requires 1A instead of 1.5A?

A: Yes. MC7805ABTG is rated for 1A output current and is suitable for applications with reduced current requirements. It maintains the same 5V output voltage, TO-220-3 package, and includes over temperature and short circuit protection.

Q: Are all substitute parts ROHS3 Compliant?

A: Yes. All listed substitute parts carry ROHS3 Compliant status, meeting regulatory requirements for hazardous substance restrictions.

Q: What is the advantage of L7805ABV over LM340T-5.0/NOPB?

A: L7805ABV from STMicroelectronics offers an extended operating temperature range (-40°C to 125°C vs 0°C to 125°C) and is currently in Active production status with higher inventory availability. Both parts deliver identical 1.5A output current and 35V maximum input voltage.

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