BA78M18CP-E2 Equivalent & Substitute Parts

Part Overview

The BA78M18CP-E2 is a linear voltage regulator IC manufactured by Rohm Semiconductor, designed to provide a fixed positive 18V output at 500mA. This device is classified as a Power Management (PMIC) component and is packaged in TO-220CP-3 (cropped leads) configuration for through-hole mounting applications.

The BA78M18CP-E2 is currently listed as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support legacy system maintenance and repairs.

Substiute Parts

BA78M18CP-E2

Rohm SemiconductorIn Stock: 1674BA78M18CP-E2 Datasheet

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MC78M18CTG

onsemiIn Stock: 3179MC78M18CTG Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the BA78M18CP-E2 is determined by the following critical parameters:

• Fixed output voltage of 18V
• Output current capability of 500mA
• Maximum input voltage rating of 33V or higher
• Through-hole mounting in TO-220 package family
• Positive fixed output configuration
• Over temperature protection as minimum protection requirement

The MC78M18CTG from onsemi meets these substitution criteria. Both devices share identical output voltage (18V) and current rating (500mA), compatible through-hole TO-220 packaging, and equivalent protection features. The MC78M18CTG provides a higher maximum input voltage rating (35V vs. 33V) and improved PSRR performance (70dB vs. 58dB at 120Hz), making it a direct functional equivalent.

Parameter Comparison

Engineering Selection Recommendations

The MC78M18CTG is a direct substitute for the BA78M18CP-E2 based on electrical and mechanical compatibility. Both devices are obsolete products with ROHS3 compliance and REACH unaffected status.

Selection between these parts should consider the following factors:

• Operating temperature requirements: The BA78M18CP-E2 operates from -40°C to 85°C, while the MC78M18CTG operates from 0°C to 125°C. Applications requiring sub-zero operation must use the BA78M18CP-E2.
• Input voltage margin: The MC78M18CTG provides 2V additional input voltage headroom (35V vs. 33V maximum), beneficial for applications with variable input supplies.
• Protection features: The MC78M18CTG includes short circuit protection in addition to over temperature protection, whereas the BA78M18CP-E2 includes over current protection. Both provide thermal protection.
• Signal integrity: The MC78M18CTG offers superior power supply rejection ratio (70dB vs. 58dB at 120Hz), advantageous for noise-sensitive applications.

Both parts are ROHS3 compliant and REACH unaffected, meeting modern regulatory requirements for electronic component procurement.

Frequently Asked Questions (FAQ)

Q: Can the MC78M18CTG directly replace the BA78M18CP-E2 in existing designs?

A: Yes, the MC78M18CTG is electrically and mechanically compatible as a direct substitute. Both devices provide 18V fixed output at 500mA in TO-220 through-hole packages. Verify that your application's operating temperature range does not require sub-zero operation, as the MC78M18CTG minimum operating temperature is 0°C.

Q: What is the difference between TO-220CP-3 (cropped leads) and TO-220-3 packaging?

A: Both are TO-220 three-pin through-hole packages suitable for identical PCB footprints. The "CP" designation indicates cropped leads on the BA78M18CP-E2, while the MC78M18CTG uses standard TO-220 leads. This difference does not affect electrical performance or board-level compatibility.

Q: Are there any compliance or certification differences between these parts?

A: Both the BA78M18CP-E2 and MC78M18CTG are ROHS3 compliant and REACH unaffected. No compliance barriers exist for substitution in regulated applications.

Q: Which part should I select for applications requiring operation below 0°C?

A: The BA78M18CP-E2 is rated for operation from -40°C to 85°C and must be used for sub-zero temperature applications. The MC78M18CTG minimum operating temperature is 0°C.

Q: How do the protection features differ between these regulators?

A: The BA78M18CP-E2 includes over current and over temperature protection. The MC78M18CTG includes over temperature and short circuit protection. Both provide thermal shutdown capability. Select based on your circuit's specific protection requirements.

Q: What is the significance of the higher PSRR rating on the MC78M18CTG?

A: Power Supply Rejection Ratio (PSRR) of 70dB on the MC78M18CTG versus 58dB on the BA78M18CP-E2 indicates superior rejection of input voltage ripple and noise. Applications requiring lower output noise should prioritize the MC78M18CTG.