FMMT551TC Equivalent & Substitute Parts

Part Overview

The FMMT551TC is a PNP bipolar junction transistor manufactured by Diodes Incorporated, rated for 60V collector-emitter breakdown voltage and 1A maximum collector current. This surface mount device in SOT-23-3 packaging is designed for general-purpose switching and amplification applications requiring 500mW power dissipation capability.

The FMMT551TC is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications currently utilizing this component.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Collector Current (Max)	1	A
Collector-Emitter Breakdown Voltage (Max)	60	V
Power Dissipation (Max)	500	mW
Transition Frequency	150	MHz
Operating Temperature Range	−55 to 200	°C
Package Type	SOT-23-3	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the FMMT551TC is determined by the following critical parameters:

Primary Substitution Criteria:

Transistor type must be PNP
Collector-emitter breakdown voltage must be 60V or greater
Maximum collector current must be 1A or greater
Package must be surface mount SOT-23-3 or compatible footprint
Power dissipation must be 500mW or greater
Operating temperature range must support −55°C to 200°C or the application's required subset

Substitute Categories:

Direct Parametric Equivalents: Parts matching all primary criteria with identical or superior electrical specifications and the same SOT-23-3 package.

Functional Equivalents with Package Variation: Parts meeting all electrical criteria but utilizing alternative surface mount packages (UMT3/SC-70, TO-236AB) that require footprint verification before implementation.

Enhanced Performance Substitutes: Parts exceeding the FMMT551TC specifications in current capacity, power dissipation, or frequency response while maintaining voltage and package compatibility.

Parameter Comparison

Part Number	Manufacturer	Ic (Max)	Vce(br)	Power (Max)	fT	Package	Status
FMMT551TC	Diodes Incorporated	1 A	60 V	500 mW	150 MHz	SOT-23-3	Obsolete
FMMT551TA	Diodes Incorporated	1 A	60 V	500 mW	150 MHz	SOT-23-3	Active
2STR2160	STMicroelectronics	1 A	60 V	500 mW	—	SOT-23-3	Active
PBSS5160T,215	Nexperia USA Inc.	1 A	60 V	400 mW	220 MHz	TO-236AB	Active
PBSS4041PT,215	Nexperia USA Inc.	2.7 A	60 V	1.1 W	150 MHz	TO-236AB	Active
2SA2088T106Q	Rohm Semiconductor	500 mA	60 V	200 mW	400 MHz	UMT3	Not For New Designs
UMT2907AT106	Rohm Semiconductor	600 mA	60 V	200 mW	200 MHz	UMT3	Active

Engineering Selection Recommendations

Recommended Primary Substitute: FMMT551TA

The FMMT551TA is the direct parametric equivalent to the FMMT551TC. Manufactured by Diodes Incorporated, it maintains identical electrical specifications across all critical parameters: 1A collector current, 60V breakdown voltage, 500mW power dissipation, and 150MHz transition frequency. The FMMT551TA is packaged in SOT-23-3 and carries Active product status, ensuring long-term availability and supply chain continuity. This part requires no design modification and provides the most direct replacement path.

Secondary Substitute: 2STR2160

The 2STR2160 from STMicroelectronics meets all primary substitution criteria with 1A collector current, 60V breakdown voltage, and 500mW power dissipation in SOT-23-3 packaging. This part is Active and widely available. The transition frequency specification is not provided in the datasheet, but the part is suitable for applications where the 150MHz specification of the FMMT551TC is not a critical design constraint.

Alternative Substitute with Enhanced Specifications: PBSS5160T,215

The PBSS5160T,215 from Nexperia USA Inc. provides 1A collector current and 60V breakdown voltage with enhanced transition frequency of 220MHz. The power dissipation is rated at 400mW, which is lower than the FMMT551TC. This part uses TO-236AB packaging, which is footprint-compatible with SOT-23-3 but requires PCB layout verification. The part is Active and suitable for applications where higher frequency performance is beneficial.

Higher Current Capacity Alternative: PBSS4041PT,215

The PBSS4041PT,215 from Nexperia USA Inc. exceeds the FMMT551TC specifications with 2.7A collector current and 1.1W power dissipation while maintaining 60V breakdown voltage and 150MHz transition frequency. This part is qualified to AEC-Q100 automotive standards and carries Active status. It is suitable for applications requiring higher current handling or where design margin is necessary. The TO-236AB package requires footprint compatibility verification.

Lower Current Alternatives: 2SA2088T106Q and UMT2907AT106

The 2SA2088T106Q and UMT2907AT106 from Rohm Semiconductor provide 60V breakdown voltage but with reduced maximum collector current (500mA and 600mA respectively) and lower power dissipation (200mW). These parts are suitable only for applications where the FMMT551TC is operated below 600mA. The 2SA2088T106Q carries Not For New Designs status. Both parts use UMT3/SC-70 packaging, requiring footprint redesign.

Frequently Asked Questions (FAQ)

Q: Can FMMT551TA directly replace FMMT551TC without any design changes?

A: Yes. The FMMT551TA is a direct parametric equivalent with identical electrical specifications and SOT-23-3 packaging. No circuit modifications or PCB layout changes are required.

Q: What is the difference between FMMT551TC and FMMT551TA?

A: The primary difference is product status. FMMT551TC is obsolete, while FMMT551TA is active. Both parts share identical electrical specifications and packaging. FMMT551TA is supplied in Tape & Reel packaging format.

Q: Can I use 2STR2160 as a substitute if the application requires 150MHz transition frequency?

A: The 2STR2160 datasheet does not specify transition frequency. If 150MHz minimum transition frequency is a critical design requirement, use FMMT551TA or PBSS5160T,215 instead.

Q: Is PBSS5160T,215 compatible with the FMMT551TC footprint?

A: PBSS5160T,215 uses TO-236AB packaging, which is physically compatible with SOT-23-3 footprints. However, PCB layout verification is required to confirm pad alignment and spacing compatibility with your specific design.

Q: Can I use PBSS4041PT,215 in place of FMMT551TC?

A: Yes, for applications where the FMMT551TC is not operating at its maximum 1A current rating. PBSS4041PT,215 provides superior current capacity (2.7A) and power dissipation (1.1W) with the same 60V breakdown voltage. Verify that the TO-236AB package is compatible with your PCB footprint.

Q: Why are 2SA2088T106Q and UMT2907AT106 listed as substitutes if they have lower current ratings?

A: These parts are listed as substitutes for applications where the FMMT551TC operates below 600mA. They are not suitable for designs requiring the full 1A capability. Both parts require footprint redesign due to UMT3/SC-70 packaging.

Q: What does "Not For New Designs" status mean for 2SA2088T106Q?

A: This status indicates that Rohm Semiconductor does not recommend this part for new circuit designs. While it may be used in legacy applications, FMMT551TA or other active-status alternatives are preferred for new development.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts carry RoHS3 compliance certification, matching the FMMT551TC compliance status.

Q: What is the operating temperature range difference between FMMT551TC and the substitutes?

A: FMMT551TC operates from −55°C to 200°C. Most substitutes operate to 150°C maximum junction temperature. Verify that your application's temperature requirements fall within the substitute part's operating range.

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