KA78M08RTM Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The KA78M08RTM is a linear voltage regulator IC manufactured by onsemi, delivering a fixed positive 8V output at 500mA in a DPAK surface mount package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. The KA78M08RTM serves as a positive fixed output regulator suitable for power management applications requiring stable 8V regulation from input sources up to 35V.

Substiute Parts

KA78M08RTM

onsemiIn Stock: 8949KA78M08RTM Datasheet

Current PartRFQ

MC78M08BDTRKG

onsemiIn Stock: 2208MC78M08BDTRKG Datasheet

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MC78M08ACDTRKG

onsemiIn Stock: 3368MC78M08ACDTRKG Datasheet

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MC78M08CDTRKG

onsemiIn Stock: 28716MC78M08CDTRKG Datasheet

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UA78M08CKVURG3

Texas InstrumentsIn Stock: 2223UA78M08CKVURG3 Datasheet

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L78M08ABDT-TR

STMicroelectronicsIn Stock: 106104L78M08ABDT-TR Datasheet

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L78M08CDT-TR

STMicroelectronicsIn Stock: 140249L78M08CDT-TR Datasheet

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MC78M08BDTG

onsemiIn Stock: 2407MC78M08BDTG Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the KA78M08RTM are qualified based on the following critical parameters that determine functional equivalence:

Core Electrical Parameters:

• Output voltage: 8V fixed
• Output current capability: 500mA
• Maximum input voltage: 35V
• Output configuration: Positive
• Output type: Fixed
• Number of regulators: 1
• Protection features: Over Temperature and Short Circuit minimum

Physical Parameters:

• Package / Case: TO-252-3, DPAK (2 Leads + Tab), SC-63
• Mounting type: Surface Mount
• Supplier device package: DPAK or TO-252-3

Compliance Parameters:

• Moisture Sensitivity Level (MSL): 1 (Unlimited)
• REACH Status: REACH Unaffected
• ECCN: EAR99
• HTSUS: 8542.39.0001

Substitute parts may vary in product status (Active, Obsolete, Last Time Buy), operating temperature range, quiescent current specifications, and PSRR values, provided the core electrical and physical parameters remain within specification for the intended application.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation for New Designs: MC78M08CDTRKG (onsemi) is the preferred substitute. This part maintains full electrical and physical compatibility with the KA78M08RTM while offering Active product status, ensuring long-term availability and supply chain stability. It carries ROHS3 compliance and MSL-1 rating, matching the original part's reliability profile.

Alternative Selections Based on Application Requirements:

For applications requiring extended low-temperature operation (-40°C), MC78M08BDTRKG or L78M08ABDT-TR provide expanded operating temperature ranges while maintaining all core electrical specifications and DPAK packaging.

For applications with stricter input voltage constraints (maximum 25V), UA78M08CKVURG3 from Texas Instruments is suitable, though this part carries Last Time Buy status and MSL-3 rating, requiring careful inventory planning.

L78M08ABDT-TR and L78M08CDT-TR from STMicroelectronics are Active products with robust supply availability. L78M08ABDT-TR supports -40°C to 125°C operation, while L78M08CDT-TR operates from 0°C to 125°C. Both include Over Current protection in addition to Over Temperature and Short Circuit protection.

Obsolete Part Considerations: MC78M08ACDTRKG and MC78M08BDTG carry Obsolete status. These parts should only be selected for legacy system maintenance where supply is confirmed available.

Frequently Asked Questions (FAQ)

Q: Can I directly substitute the KA78M08RTM with any of these parts? A: Yes, all listed parts are electrically and mechanically compatible for the core 8V, 500mA regulation function. However, verify your specific application requirements regarding operating temperature range, input voltage limits, and protection feature needs before selection.

Q: What is the difference between the onsemi MC78M08 variants? A: The MC78M08BDTRKG (Active) and MC78M08CDTRKG (Active) are the current production options. MC78M08ACDTRKG and MC78M08BDTG are Obsolete variants. The primary differences are product status and operating temperature ranges. MC78M08BDTRKG supports -40°C to 125°C, while MC78M08CDTRKG operates 0°C to 125°C.

Q: Why does UA78M08CKVURG3 have a lower maximum input voltage (25V vs 35V)? A: This is a specified electrical characteristic of the Texas Instruments part. Applications requiring input voltages above 25V must use alternative parts with 35V maximum input voltage ratings.

Q: What does MSL-3 rating mean for UA78M08CKVURG3? A: MSL-3 indicates 168-hour moisture sensitivity. This part requires controlled storage conditions and has a shorter shelf life compared to MSL-1 parts. Verify storage and handling procedures align with your supply chain capabilities.

Q: Are all these parts RoHS compliant? A: All substitute parts listed carry ROHS3 compliance. The original KA78M08RTM does not specify RoHS status in the provided data.

Q: Which part has the best PSRR performance? A: onsemi parts (KA78M08RTM, MC78M08BDTRKG, MC78M08ACDTRKG, MC78M08CDTRKG, MC78M08BDTG) and UA78M08CKVURG3 all specify 80dB PSRR at 120Hz. STMicroelectronics parts (L78M08ABDT-TR, L78M08CDT-TR) specify 56dB PSRR at 120Hz.

Q: Can I use these parts interchangeably in existing PCB designs? A: Yes. All parts use identical TO-252-3 DPAK packaging with the same pinout and footprint. No PCB modifications are required for mechanical compatibility.

Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging? A: Both are surface mount delivery formats. Tape & Reel (TR) is suitable for high-volume automated assembly. Cut Tape (CT) is appropriate for lower-volume or manual assembly processes. Electrical performance is identical.