BA78M15FP-E2 Linear Voltage Regulator — Equivalent & Substitute Parts

Part Overview

The BA78M15FP-E2 is a linear voltage regulator IC manufactured by Rohm Semiconductor, designed to provide a fixed positive 15V output at 500mA. This device operates as a single-output positive regulator in a TO-252-3 (DPAK) surface mount package. The part is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across output voltage, current capacity, input voltage tolerance, and thermal performance specifications while meeting modern compliance standards.

Key Parameters

Parameter	BA78M15FP-E2
Manufacturer	Rohm Semiconductor
Output Voltage (Fixed)	15V
Output Current	500mA
Input Voltage (Max)	30V
Voltage Dropout (Max)	2V @ 500mA (Typ)
Quiescent Current	6 mA
PSRR	60dB (120Hz)
Protection Features	Over Current, Over Temperature
Operating Temperature	-40°C ~ 85°C
Package	TO-252-3 (DPAK)
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the BA78M15FP-E2 are qualified based on the following electrical and mechanical parameters:

Fixed output voltage of 15V
Output current rating of 500mA minimum
Input voltage tolerance of 30V or greater
Surface mount DPAK (TO-252-3) package compatibility
Positive output configuration with single regulator
Over temperature protection as minimum requirement
ROHS3 compliance and unlimited moisture sensitivity level (MSL 1)

All substitute parts listed maintain these core specifications. Variations in quiescent current, PSRR, dropout voltage, and operating temperature range are noted where they differ from the main part but do not disqualify substitution when the primary electrical and mechanical requirements are met.

Parameter Comparison

Parameter	BA78M15FP-E2	L78M15ABDT-TR	MC78M15ABDTRKG	MC78M15ACDTRKG	MC78M15BDTRKG	MC78M15CDTG	MC78M15CDTRKG
Manufacturer	Rohm Semiconductor	STMicroelectronics	onsemi	onsemi	onsemi	onsemi	onsemi
Output Voltage	15V	15V	15V	15V	15V	15V	15V
Output Current	500mA	500mA	500mA	500mA	500mA	500mA	500mA
Input Voltage (Max)	30V	35V	35V	35V	35V	35V	35V
Quiescent Current	6 mA	6 mA	—	—	—	—	—
PSRR (120Hz)	60dB	54dB	70dB	70dB	70dB	70dB	70dB
Protection Features	Over Current, Over Temperature	Over Current, Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Short Circuit	Over Temperature, Short Circuit
Operating Temperature	-40°C ~ 85°C	-40°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C
Package	TO-252-3 (DPAK)	TO-252-3 (DPAK)	TO-252-3 (DPAK)	TO-252-3 (DPAK)	TO-252-3 (DPAK)	TO-252-3 (DPAK)	TO-252-3 (DPAK)
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

All listed substitute parts are active products with ROHS3 compliance and unlimited moisture sensitivity level (MSL 1), making them suitable for new designs and production transitions from the obsolete BA78M15FP-E2.

For applications requiring full temperature range operation (-40°C to 125°C): L78M15ABDT-TR, MC78M15ABDTRKG, and MC78M15BDTRKG are preferred selections. These parts extend the upper operating temperature limit from 85°C to 125°C, providing enhanced thermal margin for demanding environments.

For applications with restricted lower temperature requirements (0°C minimum): MC78M15ACDTRKG, MC78M15CDTG, and MC78M15CDTRKG are suitable alternatives. These parts maintain the 125°C upper limit while accepting a 0°C lower bound.

For input voltage margin: All substitute parts accept 35V maximum input, exceeding the BA78M15FP-E2 specification of 30V. This provides additional design headroom for input supply variations.

For PSRR performance: onsemi variants (MC78M15 series) deliver 70dB PSRR at 120Hz, compared to 60dB for the original part and 54dB for the STMicroelectronics L78M15ABDT-TR. Higher PSRR values indicate superior noise rejection.

For protection features: All substitute parts include short circuit protection in addition to over temperature protection. The BA78M15FP-E2 includes over current protection; substitute parts implement short circuit protection as the primary current-limiting mechanism.

Frequently Asked Questions (FAQ)

Q: Can I directly replace BA78M15FP-E2 with any of these substitute parts?

A: Yes, all listed parts are direct substitutes from an electrical and mechanical standpoint. They share the same 15V fixed output, 500mA current rating, TO-252-3 package, and positive output configuration. Pin-to-pin compatibility is maintained across all variants.

Q: What is the difference between the onsemi MC78M15 variants (A, B, C)?

A: The variants differ in operating temperature range and packaging format. MC78M15A variants operate from -40°C to 125°C. MC78M15C variants operate from 0°C to 125°C. Packaging options include Cut Tape (CT), Tape & Reel (TR), and Tube formats. Electrical performance (PSRR, protection features) is identical across all variants.

Q: Why does the STMicroelectronics L78M15ABDT-TR have lower PSRR than onsemi parts?

A: PSRR (Power Supply Rejection Ratio) is a design characteristic that varies by manufacturer. The L78M15ABDT-TR delivers 54dB at 120Hz compared to 70dB for onsemi variants. Both values meet the functional requirement for 15V regulation; the difference reflects manufacturing design choices and does not disqualify substitution.

Q: Is the higher input voltage rating (35V vs 30V) on substitute parts a concern?

A: No. The 35V maximum input rating on substitute parts provides additional margin compared to the BA78M15FP-E2 specification of 30V. This is a beneficial characteristic that does not create compatibility issues in existing designs.

Q: Which substitute part has the best availability?

A: MC78M15CDTRKG shows the highest inventory level at 212,036 pieces. L78M15ABDT-TR and MC78M15BDTRKG also maintain substantial stock levels (17,508 and 22,600 pieces respectively), ensuring supply continuity for production requirements.

Q: Do all substitute parts meet the same compliance standards?

A: Yes. All substitute parts are ROHS3 compliant, REACH unaffected, and carry MSL 1 (unlimited) moisture sensitivity rating. Compliance certifications are identical across all variants.

Q: What is the practical difference between -40°C to 85°C and -40°C to 125°C operating ranges?

A: The extended upper temperature limit on substitute parts (125°C vs 85°C) provides additional thermal margin in high-temperature environments. For applications operating within -40°C to 85°C, both specifications are functionally equivalent. For applications approaching or exceeding 85°C ambient or junction temperature, the extended range of substitute parts is advantageous.

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