MMBTA28-7 NPN Darlington Transistor Equivalent & Substitute Parts

Part Overview

The MMBTA28-7 is an NPN Darlington bipolar junction transistor manufactured by Diodes Incorporated, designed for surface mount applications in the SOT-23-3 package. This device is rated for 80 V collector-emitter breakdown voltage and 500 mA maximum collector current, with a maximum power dissipation of 300 mW. The part carries automotive-grade qualification (AEC-Q101) and operates across a temperature range of -55°C to 150°C.

The MMBTA28-7 is currently discontinued at DiGi Electronics, necessitating identification of equivalent and substitute components that maintain functional compatibility within system designs. Substitute parts are selected based on matching or exceeding critical electrical parameters including collector current rating, breakdown voltage, saturation characteristics, and DC current gain specifications.

Substiute Parts

MMBTA28-7

Diodes IncorporatedIn Stock: 12166MMBTA28-7 Datasheet

Current PartRFQ

MMBTA28-7-F

Diodes IncorporatedIn Stock: 275499MMBTA28-7-F Datasheet

DirectRFQ

2SD1383KT146B

Rohm SemiconductorIn Stock: 575062SD1383KT146B Datasheet

MFR RecommendedRFQ

2SD2142KT146

Rohm SemiconductorIn Stock: 191142SD2142KT146 Datasheet

MFR RecommendedRFQ

MMBTA28

onsemiIn Stock: 4129MMBTA28 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MMBTA28-7 are classified into two categories based on electrical parameter compatibility:

Direct Equivalents (Identical Electrical Specifications): Parts that maintain all critical electrical parameters including collector current rating (500 mA), breakdown voltage (80 V), saturation voltage, DC current gain, and power dissipation (300 mW). These parts are interchangeable without circuit redesign.

Functional Substitutes (Reduced Electrical Ratings): Parts that operate within the same application space but with reduced maximum ratings. These substitutes are suitable when circuit design margins accommodate lower collector current (300 mA), reduced breakdown voltage (30-32 V), or lower power dissipation (200 mW). Selection of functional substitutes requires verification that the application does not demand the full electrical capability of the original part.

The substitution logic is determined by the following key parameters:

• Collector current rating (Ic Max)
• Collector-emitter breakdown voltage (VCEO Max)
• DC current gain (hFE Min)
• Power dissipation (P Max)
• Package compatibility (SOT-23-3)
• Transistor topology (NPN Darlington)

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: MMBTA28-7-F (Diodes Incorporated)

The MMBTA28-7-F is the direct equivalent replacement for the discontinued MMBTA28-7. This part maintains identical electrical specifications across all critical parameters: 500 mA collector current, 80 V breakdown voltage, 300 mW power dissipation, and 10000 minimum DC current gain. The MMBTA28-7-F is currently in active production status with high inventory availability (275,400 units). This part carries ROHS3 compliance and AEC-Q101 automotive qualification, matching the original part's certifications. The packaging is identical (SOT-23-3). This substitute requires no circuit modifications and provides direct pin-for-pin compatibility.

Secondary Substitute: MMBTA28 (onsemi)

The MMBTA28 from onsemi provides equivalent electrical performance with enhanced current capability (800 mA maximum collector current versus 500 mA). This part maintains the same 80 V breakdown voltage, 125 MHz transition frequency, and 10000 minimum DC current gain. Power dissipation is rated at 350 mW, exceeding the original specification. The MMBTA28 carries AEC-Q101 qualification and ROHS3 compliance. This part is suitable for applications where increased current headroom is beneficial. Inventory availability is lower (4,036 units) compared to the MMBTA28-7-F.

Functional Substitutes: 2SD2142KT146 and 2SD1383KT146B (Rohm Semiconductor)

The 2SD2142KT146 and 2SD1383KT146B are functional substitutes with reduced electrical ratings. Both parts are rated for 300 mA maximum collector current (versus 500 mA) and reduced breakdown voltages (30 V and 32 V respectively, versus 80 V). These parts are suitable only for applications where the circuit design does not require the full electrical capability of the original MMBTA28-7. The 2SD2142KT146 maintains the 10000 minimum DC current gain specification, while the 2SD1383KT146B is rated at 5000 minimum. Both parts carry ROHS3 compliance and are in active production. These substitutes are not recommended for direct replacement in existing designs without circuit analysis.

Frequently Asked Questions (FAQ)

Q: Can the MMBTA28-7-F be used as a direct replacement for the MMBTA28-7?

A: Yes. The MMBTA28-7-F is a direct equivalent with identical electrical specifications. All critical parameters including collector current (500 mA), breakdown voltage (80 V), saturation voltage, DC current gain (10000), and power dissipation (300 mW) are matched. The part is pin-for-pin compatible in the SOT-23-3 package and requires no circuit modifications.

Q: What is the difference between the MMBTA28-7 and MMBTA28?

A: The MMBTA28 from onsemi has a higher maximum collector current rating (800 mA versus 500 mA) and slightly higher power dissipation (350 mW versus 300 mW). Both parts maintain the same 80 V breakdown voltage and 10000 minimum DC current gain. The MMBTA28 is suitable for applications requiring increased current capacity.

Q: Are the Rohm 2SD2142KT146 and 2SD1383KT146B suitable replacements for the MMBTA28-7?

A: These parts are functional substitutes only, not direct replacements. Both are rated for 300 mA maximum collector current (versus 500 mA) and reduced breakdown voltages (30 V and 32 V versus 80 V). These substitutes are appropriate only when circuit design margins accommodate the reduced electrical ratings. Direct replacement without circuit analysis is not recommended.

Q: What packaging options are available for MMBTA28-7 substitutes?

A: The primary substitutes (MMBTA28-7-F and MMBTA28) are available in SOT-23-3 packaging, matching the original part. The Rohm substitutes (2SD2142KT146 and 2SD1383KT146B) are supplied in SMT3 packaging, which is mechanically compatible with SOT-23-3 footprints but may require verification for specific assembly equipment.

Q: Does the MMBTA28-7-F meet automotive qualification requirements?

A: Yes. The MMBTA28-7-F carries AEC-Q101 automotive qualification and ROHS3 compliance, matching the original MMBTA28-7 certifications. This part is suitable for automotive applications.

Q: What is the inventory status of available substitutes?

A: The MMBTA28-7-F has the highest inventory availability (275,400 units). The MMBTA28 from onsemi has lower availability (4,036 units). The Rohm substitutes have moderate availability (2SD2142KT146: 19,091 units; 2SD1383KT146B: 57,400 units).

Q: Can the MMBTA28-7-F be used in applications originally designed for the MMBTA28-7 without any modifications?

A: Yes. The MMBTA28-7-F is electrically and mechanically identical to the MMBTA28-7. No circuit modifications, layout changes, or design alterations are required. The part is a direct replacement.