BA178M18FP Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The BA178M18FP is a linear voltage regulator IC manufactured by Rohm Semiconductor, designed to deliver a fixed positive 18V output at 500mA in a surface-mount TO-252-3 (DPAK) package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The regulator operates across an input voltage range up to 33V with a maximum dropout voltage of 2V at full load, suitable for applications requiring stable 18V power delivery in compact form factors.

Substiute Parts

BA178M18FP

Rohm SemiconductorIn Stock: 1075BA178M18FP Datasheet

Current PartRFQ

BA78M18FP-E2

Rohm SemiconductorIn Stock: 1306BA78M18FP-E2 Datasheet

DirectRFQ

MC78M18CDTRKG

onsemiIn Stock: 1548MC78M18CDTRKG Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the BA178M18FP are identified based on the following critical parameters that determine functional equivalence:

• Fixed output voltage of 18V
• Output current capability of 500mA
• Maximum input voltage rating of 33V or higher
• Surface-mount TO-252-3 (DPAK) package compatibility
• Operating temperature range encompassing -40°C to 85°C
• Positive output configuration with fixed regulation type

Two substitute parts meet these criteria: the BA78M18FP-E2 (direct manufacturer equivalent from Rohm Semiconductor) and the MC78M18CDTRKG (cross-manufacturer equivalent from onsemi). Both maintain the same output voltage, current rating, and package footprint while offering active product status and enhanced protection features.

Parameter Comparison

Engineering Selection Recommendations

The BA78M18FP-E2 is the primary substitute for the BA178M18FP. Both parts are manufactured by Rohm Semiconductor and share identical electrical specifications, including output voltage, current rating, dropout voltage, and PSRR performance. The BA78M18FP-E2 maintains active product status and adds over-current and over-temperature protection features. This part is available in Tape & Reel packaging and is recommended for new designs and production continuity.

The MC78M18CDTRKG from onsemi is a cross-manufacturer equivalent suitable for applications where supply chain diversification is required. It maintains the same 18V output and 500mA current capability in the identical TO-252-3 package. The MC78M18CDTRKG offers a higher input voltage rating (35V versus 33V) and superior PSRR performance (70dB versus 58dB), with an extended operating temperature range (0°C to 125°C). Both substitute parts carry ROHS3 compliance and are actively manufactured.

Frequently Asked Questions (FAQ)

Q: Can the BA78M18FP-E2 be used as a direct replacement for the BA178M18FP?

A: Yes. The BA78M18FP-E2 is a direct equivalent with identical electrical specifications, including 18V fixed output, 500mA current capability, 33V maximum input voltage, and 2V typical dropout voltage at full load. Both parts use the TO-252-3 DPAK package with identical pinout and footprint. The primary difference is product status: BA78M18FP-E2 is active while BA178M18FP is obsolete.

Q: What are the key differences between the BA78M18FP-E2 and MC78M18CDTRKG?

A: Both parts deliver 18V at 500mA in the same TO-252-3 package. The MC78M18CDTRKG offers a higher input voltage rating (35V versus 33V), better PSRR performance (70dB versus 58dB), and an extended operating temperature range (0°C to 125°C versus -40°C to 85°C). The MC78M18CDTRKG is manufactured by onsemi rather than Rohm Semiconductor. Both are actively produced and ROHS3 compliant.

Q: Are the package footprints identical between all three parts?

A: Yes. The BA178M18FP, BA78M18FP-E2, and MC78M18CDTRKG all use the TO-252-3 DPAK package (2 Leads + Tab, SC-63 designation). PCB layouts and thermal management designs are directly compatible across all three parts.

Q: Which substitute part should be selected for new designs?

A: The BA78M18FP-E2 is recommended for new designs requiring Rohm Semiconductor sourcing. The MC78M18CDTRKG is recommended when cross-manufacturer qualification is acceptable or when the extended input voltage rating (35V) and superior PSRR (70dB) provide design advantages.

Q: Do the substitute parts include protection features?

A: Yes. The BA78M18FP-E2 includes over-current and over-temperature protection. The MC78M18CDTRKG includes over-temperature and short-circuit protection. The original BA178M18FP does not specify protection features.