KA78M05TU Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The KA78M05TU is a linear voltage regulator IC manufactured by onsemi, delivering a fixed positive 5V output at 500mA in a TO-220-3 package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The KA78M05TU provides thermal and short-circuit protection with a maximum input voltage of 35V and operates across the industrial temperature range of -40°C to 125°C.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	5V
Output Current	500mA
Input Voltage (Max)	35V
Voltage Dropout (Max)	2V @ 500mA (Typ)
Quiescent Current	6 mA
PSRR	80dB (120Hz)
Protection Features	Over Temperature, Short Circuit
Operating Temperature	-40°C to 125°C
Package	TO-220-3
Mounting Type	Through Hole

Substitute Part Grouping Explanation

Substitution for the KA78M05TU is determined by the following critical parameters:

Output Voltage: Must be fixed at 5V
Output Current Capability: Minimum 500mA required
Package Type: TO-220-3 form factor for mechanical and thermal compatibility
Input Voltage Rating: Maximum 35V or higher
Protection Features: Over temperature and short circuit protection required
Operating Temperature Range: Must support -40°C to 125°C or equivalent industrial range

Substitute parts are grouped into two categories:

Parametric Equivalents maintain identical electrical specifications and are direct pin-compatible replacements. These include MC78M05BTG and NCV78M05BTG, both rated for 500mA output current.

Similar Substitutes provide higher output current capability (1A or 1.5A) while maintaining the same 5V output, package type, and protection features. These include MC7805 series parts and L7805ABV, suitable when higher current capacity is acceptable or beneficial.

Direct Equivalents from alternative manufacturers include LM78M05CT/NOPB from Texas Instruments, which matches the KA78M05TU specification exactly.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Dropout Voltage	Quiescent Current	PSRR (120Hz)	Operating Temp	Package	Product Status
KA78M05TU	onsemi	500mA	35V	2V @ 500mA	6 mA	80dB	-40°C to 125°C	TO-220-3	Obsolete
MC78M05BTG	onsemi	500mA	35V	—	—	80dB	-40°C to 125°C	TO-220-3	Active
NCV78M05BTG	onsemi	500mA	35V	—	—	80dB	-40°C to 125°C	TO-220-3	Obsolete
LM78M05CT/NOPB	Texas Instruments	500mA	35V	—	3 mA	78dB	-40°C to 125°C	TO-220-3	Active
MC7805BTG	onsemi	1A	35V	2V @ 1A	8 mA	68dB	-40°C to 125°C	TO-220-3	Active
MC7805CTG	onsemi	1A	35V	2V @ 1A	6.5 mA	83dB	0°C to 125°C	TO-220-3	Active
NCV7805BTG	onsemi	1A	35V	2V @ 1A	8 mA	83dB	-40°C to 125°C	TO-220-3	Obsolete
L7805ABV	STMicroelectronics	1.5A	35V	2V @ 1A	6 mA	68dB	-40°C to 125°C	TO-220-3	Active

Engineering Selection Recommendations

For Direct Replacement (Parametric Equivalent):

MC78M05BTG is the recommended primary substitute. It is an active product from onsemi with identical 500mA output current, 5V fixed output, and full -40°C to 125°C operating range. Pin compatibility and package type are identical to KA78M05TU.

LM78M05CT/NOPB from Texas Instruments provides an alternative parametric equivalent with active product status and ROHS3 compliance. Lower quiescent current (3mA vs 6mA) may provide marginal power efficiency benefits in low-load applications.

For Higher Current Capability:

MC7805BTG and MC7805CTG deliver 1A output current while maintaining 5V output and TO-220-3 packaging. Both are active products with ROHS3 compliance. MC7805CTG offers superior PSRR (83dB) but operates only to 0°C minimum temperature. MC7805BTG maintains the full -40°C to 125°C range.

L7805ABV from STMicroelectronics provides 1.5A output current with active product status and ROHS3 compliance, suitable for applications requiring additional current margin.

Automotive-Grade Alternative:

NCV7805BTG is an automotive-qualified part (AEC-Q100) rated for 1A output, though classified as obsolete. This part is appropriate only if automotive qualification is a design requirement and inventory is available.

Frequently Asked Questions (FAQ)

Q: Can MC78M05BTG directly replace KA78M05TU without circuit modification?

A: Yes. MC78M05BTG is a parametric equivalent with identical output current (500mA), output voltage (5V), input voltage rating (35V), and TO-220-3 package. Pin configuration is identical. No circuit changes are required.

Q: What is the difference between MC78M05BTG and MC7805BTG?

A: The primary difference is output current rating. MC78M05BTG is rated for 500mA, while MC7805BTG is rated for 1A. Both deliver 5V output and use the same TO-220-3 package. MC7805BTG can be used as a substitute if higher current capacity is acceptable or beneficial to the application.

Q: Why is LM78M05CT/NOPB from Texas Instruments listed as a direct equivalent?

A: LM78M05CT/NOPB matches the KA78M05TU specification exactly: 500mA output current, 5V fixed output, 35V maximum input voltage, TO-220-3 package, and -40°C to 125°C operating range. It is an active product with ROHS3 compliance and serves as a cross-manufacturer equivalent.

Q: Can I use L7805ABV (1.5A) in place of KA78M05TU (500mA)?

A: Yes. L7805ABV is a higher-current variant of the same 5V regulator family in the same TO-220-3 package. It is pin-compatible and can deliver up to 1.5A. This substitution is appropriate when additional current capacity is needed or when the original part is unavailable. No circuit modification is required.

Q: What is the significance of the "Obsolete" product status?

A: Obsolete status indicates the manufacturer has discontinued production. KA78M05TU, NCV78M05BTG, and NCV7805BTG are all obsolete. Active alternatives such as MC78M05BTG, LM78M05CT/NOPB, and L7805ABV should be prioritized for new designs and ongoing production to ensure long-term supply availability.

Q: Are all listed substitutes ROHS3 compliant?

A: LM78M05CT/NOPB, MC7805 series, NCV7805BTG, MC78M05BTG, NCV78M05BTG, and L7805ABV are all ROHS3 compliant. KA78M05TU ROHS status is not specified in the provided data.

Q: Does package type affect substitution?

A: All listed substitutes use the TO-220-3 package, which is mechanically and thermally compatible with KA78M05TU. Package type is not a limiting factor for substitution among these parts.

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