FMMT734TC PNP Darlington Transistor Equivalent & Substitute Parts

Part Overview

The FMMT734TC is a PNP Darlington bipolar junction transistor manufactured by Diodes Incorporated, designed for surface mount applications in the SOT-23-3 package. This component is rated for 100 V collector-emitter breakdown voltage and 800 mA maximum collector current, with a maximum power dissipation of 625 mW. The FMMT734TC is classified as obsolete product status, necessitating identification of active equivalent and substitute components for new designs and ongoing production requirements. Equivalent parts maintain identical electrical and mechanical specifications, while substitute parts provide functional alternatives with modified electrical parameters suitable for specific application requirements.

Substiute Parts

FMMT734TC

Diodes IncorporatedIn Stock: 988FMMT734TC Datasheet

Current PartRFQ

FMMT734TA

Diodes IncorporatedIn Stock: 15576FMMT734TA Datasheet

Parametric EquivalentRFQ

2SB852KT146B

Rohm SemiconductorIn Stock: 241382SB852KT146B Datasheet

MFR RecommendedRFQ

MMBTA63LT1G

onsemiIn Stock: 152698MMBTA63LT1G Datasheet

MFR RecommendedRFQ

MMBTA64LT1G

onsemiIn Stock: 23209MMBTA64LT1G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FMMT734TC is determined by the following critical electrical and mechanical parameters:

Parametric Equivalents maintain all key electrical specifications: 100 V collector-emitter breakdown voltage, 800 mA maximum collector current, 625 mW power dissipation, 140 MHz transition frequency, and identical DC current gain characteristics. These parts are functionally interchangeable with the FMMT734TC in all circuit applications. Parametric equivalents differ only in packaging format (Tape & Reel versus bulk) and product status (Active versus Obsolete).

Functional Substitutes operate within reduced electrical ratings while maintaining the PNP Darlington transistor topology and SOT-23-3 package form factor. Substitutes are selected based on compatibility with application voltage and current requirements. Reduced voltage ratings (30 V or 32 V) and current ratings (300 mA to 500 mA) require circuit analysis to confirm suitability. Power dissipation, transition frequency, and DC current gain may differ from the original specification.

The following parameters determine substitution validity:

• Transistor Type: PNP - Darlington (mandatory)
• Package / Case: SOT-23-3 (mandatory for mechanical compatibility)
• Mounting Type: Surface Mount (mandatory)
• Voltage - Collector Emitter Breakdown (Max): Equal to or greater than application requirement
• Current - Collector (Ic) (Max): Equal to or greater than application requirement
• Power - Max: Equal to or greater than application requirement
• Operating Temperature Range: Must encompass application operating conditions
• RoHS Status: ROHS3 Compliant (mandatory for regulatory compliance)

Parameter Comparison

Engineering Selection Recommendations

FMMT734TA is the primary equivalent replacement for the obsolete FMMT734TC. This part maintains identical electrical specifications across all parameters: 100 V breakdown voltage, 800 mA collector current, 625 mW power dissipation, and 20000 minimum DC current gain. The FMMT734TA is manufactured by Diodes Incorporated and carries Active product status with full ROHS3 compliance and unlimited moisture sensitivity rating. The only distinction is packaging format (Tape & Reel versus bulk). This part is suitable for direct substitution in all applications without circuit modification.

MMBTA64LT1G is recommended as a secondary equivalent for applications where the full 100 V and 800 mA specifications are not required. This onsemi component maintains the 20000 minimum DC current gain specification matching the FMMT734TC, operates across the identical temperature range (-55 to 150°C), and carries Active product status with ROHS3 compliance. The MMBTA64LT1G is rated for 30 V and 500 mA, suitable for lower-voltage applications. Power dissipation is reduced to 225 mW, requiring verification that application power requirements do not exceed this limit.

MMBTA63LT1G provides an alternative substitute with reduced DC current gain (5000 minimum) and identical voltage/current ratings to the MMBTA64LT1G. This part is suitable only for applications where lower current gain is acceptable. Active product status and ROHS3 compliance are maintained.

2SB852KT146B is a functional substitute manufactured by Rohm Semiconductor with the most restrictive electrical ratings: 32 V breakdown voltage, 300 mA collector current, and 200 mW power dissipation. This part is suitable only for low-voltage, low-current applications. The reduced DC current gain (5000 minimum) and higher collector cutoff current (1 µA) represent significant departures from the original specification. Active product status and ROHS3 compliance are confirmed.

All recommended substitutes maintain SOT-23-3 package compatibility, surface mount mounting type, and regulatory compliance certifications required for production environments.

Frequently Asked Questions (FAQ)

Q: Can FMMT734TA be used as a direct replacement for FMMT734TC?

A: Yes. The FMMT734TA is a parametric equivalent with identical electrical specifications. The only difference is packaging format (Tape & Reel). Both parts are PNP Darlington transistors rated for 100 V, 800 mA, and 625 mW in the SOT-23-3 package. The FMMT734TA is Active status, making it the recommended replacement for the obsolete FMMT734TC.

Q: What are the key differences between the FMMT734TC and MMBTA64LT1G?

A: The MMBTA64LT1G has reduced voltage and current ratings: 30 V versus 100 V breakdown voltage, and 500 mA versus 800 mA collector current. Power dissipation is reduced from 625 mW to 225 mW. The DC current gain is maintained at 20000 minimum. The MMBTA64LT1G is suitable for applications operating below 30 V with collector currents not exceeding 500 mA.

Q: Can MMBTA63LT1G replace MMBTA64LT1G?

A: Both parts have identical voltage (30 V), current (500 mA), and power (225 mW) ratings in the SOT-23-3 package. The primary difference is DC current gain: MMBTA63LT1G has 5000 minimum versus 20000 minimum for MMBTA64LT1G. Substitution is valid only if the application circuit does not require the higher current gain specification.

Q: Is 2SB852KT146B suitable for all FMMT734TC applications?

A: No. The 2SB852KT146B has significantly reduced electrical ratings: 32 V versus 100 V, 300 mA versus 800 mA, and 200 mW versus 625 mW. This part is suitable only for low-voltage, low-current applications. Circuit analysis is required to confirm compatibility with specific application requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts (FMMT734TA, MMBTA64LT1G, MMBTA63LT1G, and 2SB852KT146B) carry ROHS3 Compliant status and are suitable for regulated production environments.

Q: What is the significance of the SOT-23-3 package specification?

A: The SOT-23-3 package (also designated TO-236-3 or SC-59) is a three-lead surface mount package. All equivalent and substitute parts maintain this package form factor, ensuring mechanical compatibility with existing printed circuit board layouts and assembly processes. Package compatibility is mandatory for substitution.

Q: Can I use FMMT734TC in new product designs?

A: No. The FMMT734TC is classified as Obsolete product status. New designs must use active alternatives such as FMMT734TA or MMBTA64LT1G to ensure long-term component availability and supply chain continuity.

Q: What does "Moisture Sensitivity Level 1 (Unlimited)" mean?

A: MSL 1 indicates the component has unlimited shelf life and does not require special moisture control during storage or handling. All listed parts carry MSL 1 rating, eliminating moisture-related handling constraints.