MC78T05ACT Linear Voltage Regulator - Equivalent & Substitute Parts

Part Overview

The MC78T05ACT is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed positive 5V output at 3A current capacity in a TO-220-3 package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

The MC78T05ACT operates with a maximum input voltage of 35V, dropout voltage of 2.5V at 3A, and includes over-current and over-temperature protection. It is suitable for through-hole mounting applications requiring regulated 5V power distribution.

Key Parameters

Parameter	MC78T05ACT
Manufacturer	onsemi
Output Voltage (Fixed)	5V
Output Current	3A
Input Voltage (Max)	35V
Dropout Voltage (Max)	2.5V @ 3A
Package / Case	TO-220-3
Mounting Type	Through Hole
Operating Temperature	0°C ~ 125°C
Product Status	Obsolete
Protection Features	Over Current, Over Temperature

Substitute Part Grouping Explanation

Substitution for the MC78T05ACT is determined by the following critical parameters:

Fixed output voltage of 5V
TO-220-3 package configuration for through-hole mounting
Positive output configuration
Maximum input voltage of 35V
Over-temperature protection

Substitute parts are grouped into two categories based on output current capacity:

Group 1: High Current Substitutes (1.2A - 1.5A Output) Parts L7805ABV, L7805ACV, L7805CV, and L7805CV-DG provide reduced output current compared to the original 3A specification. These are suitable for applications where the full 3A capacity is not required.

Group 2: Low Current Substitutes (100mA Output) Parts LM2931T-5.0/NOPB and LM2931AT-5.0/NOPB are low-dropout regulators with significantly reduced output current. These are applicable only to low-power 5V regulation circuits.

Parameter Comparison

Parameter	MC78T05ACT	L7805ABV	L7805ACV	L7805CV	L7805CV-DG	LM2931T-5.0/NOPB	LM2931AT-5.0/NOPB
Manufacturer	onsemi	STMicroelectronics	STMicroelectronics	UMW	STMicroelectronics	Texas Instruments	National Semiconductor
Output Voltage	5V	5V	5V	5V	5V	5V	5V
Output Current	3A	1.5A	1.5A	1.2A	1.5A	100mA	100mA
Input Voltage (Max)	35V	35V	35V	35V	35V	26V	26V
Dropout Voltage (Max)	2.5V @ 3A	2V @ 1A (Typ)	2V @ 1A (Typ)	—	2V @ 1A (Typ)	0.3V @ 100mA	0.3V @ 100mA
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Operating Temperature	0°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C	-40°C ~ 105°C	0°C ~ 125°C	-40°C ~ 85°C	-40°C ~ 85°C
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
Protection Features	Over Current, Over Temperature	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Reverse Polarity, Short Circuit	Over Temperature, Reverse Polarity, Short Circuit
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

For applications requiring 1.2A to 1.5A output current:

L7805ACV and L7805CV-DG are preferred substitutes. Both are manufactured by STMicroelectronics, are ROHS3 compliant, and maintain active product status. L7805ACV operates across 0°C to 125°C, matching the original temperature range. L7805CV-DG extends operation to the same range with slightly lower quiescent current (8mA vs. 5mA in the original).

L7805ABV is also suitable, with extended operating temperature range (-40°C to 125°C) and ROHS3 compliance.

L7805CV (UMW) provides 1.2A output with ROHS3 compliance and active status, though operating temperature is limited to -40°C to 105°C.

For applications requiring 100mA output current:

LM2931T-5.0/NOPB (Texas Instruments) and LM2931AT-5.0/NOPB (National Semiconductor) are low-dropout alternatives. Both are ROHS3 compliant with active product status. These parts feature superior dropout voltage (0.3V @ 100mA) and include reverse polarity protection. Operating temperature is limited to -40°C to 85°C.

Compliance considerations:

All substitute parts are ROHS3 compliant or unaffected by REACH regulations, addressing environmental compliance requirements absent in the obsolete MC78T05ACT.

Frequently Asked Questions (FAQ)

Q: Can L7805ACV directly replace MC78T05ACT in all applications?

A: L7805ACV is a direct pin-compatible substitute in TO-220-3 package. However, output current is reduced from 3A to 1.5A. Substitution is valid only if your circuit draws 1.5A or less at 5V output.

Q: What is the key difference between L7805 series and LM2931 series substitutes?

A: L7805 series (L7805ABV, L7805ACV, L7805CV, L7805CV-DG) provide 1.2A to 1.5A output current with standard dropout characteristics. LM2931 series (LM2931T-5.0/NOPB, LM2931AT-5.0/NOPB) are low-dropout regulators limited to 100mA output but with superior dropout voltage performance (0.3V vs. 2V). Select based on your circuit's current requirements.

Q: Are all substitute parts RoHS compliant?

A: Yes. All active substitute parts listed are ROHS3 compliant. The original MC78T05ACT is RoHS non-compliant, making these substitutes necessary for new designs subject to environmental regulations.

Q: Can I use LM2931T-5.0/NOPB in a circuit designed for 3A output?

A: No. LM2931T-5.0/NOPB is rated for 100mA maximum output current. Using it in a 3A circuit will cause thermal shutdown and circuit failure. Select L7805 series parts for higher current applications.

Q: What is the operating temperature limitation when substituting with LM2931 series?

A: LM2931 series parts operate from -40°C to 85°C, compared to the original 0°C to 125°C range. If your application requires operation above 85°C, use L7805 series substitutes instead.

Q: Are the TO-220-3 packages identical across all substitutes?

A: Yes. All substitute parts use TO-220-3 through-hole package configuration, ensuring mechanical and thermal compatibility with the original MC78T05ACT footprint.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message