2SA812-M4-AP Equivalent & Substitute Parts

Part Overview

The 2SA812-M4-AP is a PNP bipolar junction transistor manufactured by Micro Commercial Co, designed for surface mount applications in the SOT-23 package. This component operates at a maximum collector voltage of 50 V with a collector current rating of 100 mA and a maximum power dissipation of 200 mW. The device is classified as obsolete, necessitating identification of active substitute components that maintain electrical and mechanical compatibility for ongoing production and repair applications.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) Max	100	mA
Voltage - Collector Emitter Breakdown (Max)	50	V
Power - Max	200	mW
Frequency - Transition	180	MHz
Operating Temperature Range	−55 to 150	°C
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the 2SA812-M4-AP is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

Transistor polarity must remain PNP
Collector current rating must be equal to or greater than 100 mA
Collector-emitter breakdown voltage must be equal to or greater than 50 V
Power dissipation must be equal to or greater than 200 mW
Operating temperature range must encompass the application requirements

Mechanical Compatibility Criteria:

Package type must be TO-236-3, SC-59, or SOT-23-3 (all equivalent surface mount packages)
Mounting type must be surface mount
Pin configuration must be compatible with SOT-23 footprint

Compliance Requirements:

RoHS3 compliance is mandatory
Moisture sensitivity level of 1 (unlimited) is required

Substitute parts are grouped into two categories: Direct Substitutes (meeting or exceeding all parameters with active product status) and Conditional Substitutes (meeting electrical parameters but with specific operational or status considerations).

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce Breakdown (Max) V	Power (Max) mW	Frequency MHz	Temp Range °C	Product Status	Grade
2SA812-M4-AP	Micro Commercial Co	100	50	200	180	−55 to 150	Obsolete	—
MSA1162GT1G	onsemi	100	50	200	80	−55 to 150	Active	—
2PB709ARL,215	Nexperia USA Inc.	100	45	250	70	−55 to 150	Active	Automotive
BC857BLT1G	onsemi	100	45	300	100	−55 to 150	Active	—
BC857C,215	Nexperia USA Inc.	100	45	250	100	−55 to 150	Active	Automotive
BC857C-HF	Comchip Technology	100	45	250	100	−65 to 150	Active	—
BC860B,235	Nexperia USA Inc.	100	45	250	100	−55 to 150	Active	Automotive
BCX71GE6327HTSA1	Infineon Technologies	100	45	330	250	−55 to 150	Last Time Buy	—
BCX71H,215	Nexperia USA Inc.	100	45	250	100	−55 to 150	Active	Automotive
SBC857ALT1G	onsemi	100	45	300	100	−55 to 150	Active	Automotive
TMBT3906,LM	Toshiba Semiconductor and Storage	150	50	320	250	−55 to 150	Active	—

Engineering Selection Recommendations

Primary Substitute: MSA1162GT1G (onsemi)

The MSA1162GT1G is the optimal direct substitute for the 2SA812-M4-AP. This component matches the original part's collector voltage specification (50 V), collector current rating (100 mA), and power dissipation (200 mW). The operating temperature range (−55 to 150°C) is identical to the original device. The part is in active production status with high inventory availability (155,100 units), ensuring long-term supply continuity. RoHS3 compliance and MSL 1 rating are maintained.

Secondary Substitutes: BC857BLT1G and SBC857ALT1G (onsemi)

Both BC857BLT1G and SBC857ALT1G provide enhanced performance characteristics with higher power dissipation (300 mW) and improved frequency response (100 MHz). These components operate at 45 V collector-emitter breakdown voltage, which is acceptable for applications designed for the 50 V specification. Both are in active production with substantial inventory. SBC857ALT1G carries automotive grade qualification (AEC-Q101), suitable for automotive applications.

Automotive-Grade Alternatives: BC857C,215, BC860B,235, BCX71H,215 (Nexperia USA Inc.)

These Nexperia components are qualified to AEC-Q101 automotive standards and are suitable for applications requiring automotive-grade reliability. All three maintain the 45 V collector-emitter breakdown voltage and 100 mA collector current rating. BC857C,215 and BC860B,235 provide 250 mW power dissipation, while BCX71H,215 offers the same specifications with enhanced current gain characteristics. All are in active production status.

Extended Performance Option: TMBT3906,LM (Toshiba)

The TMBT3906,LM exceeds the original specification with 150 mA collector current, 50 V breakdown voltage matching the original, and 320 mW power dissipation. The 250 MHz transition frequency provides enhanced high-frequency performance. This component is suitable for applications requiring higher current capacity or improved frequency response while maintaining the original voltage specification.

Conditional Substitute: BCX71GE6327HTSA1 (Infineon Technologies)

The BCX71GE6327HTSA1 offers superior frequency performance (250 MHz) and power dissipation (330 mW) but carries a Last Time Buy status. This component is suitable only for applications where extended performance is critical and supply continuity is not a primary concern.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with a lower collector-emitter breakdown voltage than the original 2SA812-M4-AP?

A: No. The substitute part must have a collector-emitter breakdown voltage equal to or greater than 50 V. Parts rated at 45 V are acceptable only if the circuit design ensures that the maximum operating voltage does not exceed 45 V. Verify circuit requirements before selecting a 45 V rated substitute.

Q: What is the difference between the SOT-23 and TO-236-3 packages?

A: SOT-23 and TO-236-3 are equivalent designations for the same surface mount package. SC-59 is an alternative designation for the same physical package. All three terms refer to the identical 3-pin surface mount package with compatible footprints and pin configurations.

Q: Is the MSA1162GT1G a direct replacement for the 2SA812-M4-AP?

A: Yes. The MSA1162GT1G matches all critical electrical parameters: 100 mA collector current, 50 V breakdown voltage, 200 mW power dissipation, and −55 to 150°C operating temperature range. The package is compatible (SC-59/SOT-23-3), and RoHS3 compliance is maintained. This is the recommended primary substitute.

Q: Why do some substitute parts have lower transition frequencies than the original?

A: Transition frequency is not a limiting parameter for substitution. A lower frequency rating (such as 70 MHz in the 2PB709ARL,215) is acceptable for applications that do not require the original 180 MHz performance. If high-frequency operation is required, select substitutes with equal or higher frequency ratings.

Q: Can I use TMBT3906,LM as a substitute if my circuit only requires 100 mA?

A: Yes. The TMBT3906,LM is rated for 150 mA maximum collector current, which exceeds the 100 mA requirement. The higher current rating does not create compatibility issues in circuits designed for 100 mA operation. The 50 V breakdown voltage matches the original specification exactly.

Q: What does AEC-Q101 qualification mean?

A: AEC-Q101 is an automotive industry standard qualification that certifies the component meets stringent reliability, quality, and performance requirements for automotive applications. Components carrying this qualification (such as BC857C,215, BC860B,235, BCX71H,215, and SBC857ALT1G) are suitable for automotive-grade designs requiring enhanced reliability assurance.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed in this reference maintain RoHS3 compliance, matching the original 2SA812-M4-AP specification. This compliance is mandatory for modern electronic component selection.

Q: What is the significance of product status (Active, Obsolete, Last Time Buy)?

A: Product status indicates supply availability and long-term viability. Active status ensures ongoing production and supply continuity. Obsolete status (original part) indicates no further production. Last Time Buy status (BCX71GE6327HTSA1) indicates limited remaining inventory before discontinuation. For new designs, select components with Active status to ensure long-term availability.

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