LM79M05CT Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LM79M05CT is a linear voltage regulator IC manufactured by onsemi, designed to provide a fixed negative 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 LM79M05CT serves applications requiring negative voltage regulation with thermal and short-circuit protection in through-hole mounting configurations.

Substiute Parts

LM79M05CT

onsemiIn Stock: 10182LM79M05CT Datasheet

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MC7905BTG

onsemiIn Stock: 2072MC7905BTG Datasheet

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MC7905CTG

onsemiIn Stock: 4068MC7905CTG Datasheet

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L7905ACV

STMicroelectronicsIn Stock: 11263L7905ACV Datasheet

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L7905ACV-DG

STMicroelectronicsIn Stock: 13993L7905ACV-DG Datasheet

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L7905CV

STMicroelectronicsIn Stock: 88829L7905CV Datasheet

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L7905CV-DG

STMicroelectronicsIn Stock: 2119L7905CV-DG Datasheet

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UA79M05CKCS

Texas InstrumentsIn Stock: 1856UA79M05CKCS Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the LM79M05CT is determined by the following critical parameters:

• Output Voltage: Must be fixed at -5V
• Output Configuration: Must be negative polarity
• Package / Case: Must be TO-220-3 for mechanical and thermal compatibility
• Mounting Type: Must be through-hole
• Current - Output: Minimum 500mA required; higher ratings are acceptable
• Voltage - Input (Max): Minimum -25V; -35V preferred for full compatibility
• Operating Temperature Range: Must encompass 0°C ~ 125°C minimum
• Protection Features: Over temperature and short circuit protection required

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

Category A (500mA Output): Direct replacements with identical current ratings

• UA79M05CKCS (Texas Instruments)

Category B (1A or Higher Output): Enhanced current capability substitutes

• MC7905BTG (onsemi)
• MC7905CTG (onsemi)
• L7905ACV (STMicroelectronics)
• L7905ACV-DG (STMicroelectronics)
• L7905CV (STMicroelectronics)
• L7905CV-DG (STMicroelectronics)

Parameter Comparison

Engineering Selection Recommendations

For Direct Current Replacement (500mA Applications):

UA79M05CKCS is the only substitute maintaining the exact 500mA output current specification. However, this part carries Last Time Buy status, indicating limited future availability. The input voltage maximum is -25V, which is lower than the LM79M05CT's -35V specification. This part is suitable only for applications where input voltage does not exceed -25V.

For Enhanced Current Capability (1A Output):

MC7905CTG and MC7905BTG are active onsemi products providing 1A output current. MC7905CTG matches the LM79M05CT operating temperature range (0°C ~ 125°C) and maintains -35V input voltage rating. MC7905BTG extends the operating temperature to -40°C ~ 125°C, offering broader thermal coverage. Both are ROHS3 compliant and actively produced.

For Maximum Current Capability (1.5A Output):

L7905CV and L7905CV-DG are STMicroelectronics active products with 1.5A output current and full -35V input voltage compatibility. L7905CV has the highest inventory availability (88,791 pcs). L7905ACV is also active with identical electrical specifications. L7905ACV-DG is obsolete and should be avoided for new designs despite adequate technical specifications.

Compliance and Availability Considerations:

All active substitute parts are ROHS3 compliant. For new designs, prioritize MC7905CTG, L7905CV, or L7905CV-DG based on current requirements and inventory availability. Avoid parts with Last Time Buy or Obsolete status for long-term production commitments.

Frequently Asked Questions (FAQ)

Q: Can I use a 1A rated regulator in place of the 500mA LM79M05CT?

A: Yes. Higher current-rated regulators are functionally compatible substitutes. The 1A and 1.5A variants will operate correctly in 500mA applications. The circuit will draw only the current it requires; the higher rating provides design margin and thermal headroom.

Q: What is the difference between MC7905BTG and MC7905CTG?

A: Both are onsemi 1A negative 5V regulators in TO-220-3 packages with identical electrical specifications. The primary difference is operating temperature range: MC7905BTG operates from -40°C to 125°C, while MC7905CTG operates from 0°C to 125°C. Select based on your application's minimum operating temperature requirement.

Q: Why does UA79M05CKCS have a lower input voltage maximum (-25V vs -35V)?

A: This is a design specification difference between manufacturers. UA79M05CKCS is suitable only for applications where the input voltage magnitude does not exceed 25V. If your circuit requires -35V input capability, use MC7905 series or L7905 series regulators.

Q: Are all substitute parts pin-compatible with the LM79M05CT?

A: Yes. All listed substitutes use the TO-220-3 package with identical pin configuration: Input, Ground, and Output. Direct PCB replacement is possible without layout modifications.

Q: Which substitute has the best long-term availability?

A: L7905CV (STMicroelectronics) is the recommended choice for new designs, with 88,791 pcs in stock and active product status. MC7905CTG (onsemi) is also actively produced with 4,000 pcs available.

Q: What does ROHS3 compliance mean for my application?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead and other hazardous materials. All active substitute parts are ROHS3 compliant, suitable for commercial and industrial applications subject to environmental regulations.

Q: Can I substitute L7905ACV-DG even though it is obsolete?

A: L7905ACV-DG meets all electrical and mechanical requirements for substitution. However, its obsolete status means limited future availability. Use only if existing inventory is available and long-term supply is not a concern. For new designs, select active alternatives.