FMMT489TC Equivalent & Substitute Parts

Part Overview

The FMMT489TC is an NPN bipolar junction transistor manufactured by Diodes Incorporated, designed for general-purpose switching and amplification applications. This device features a 30 V collector-emitter breakdown voltage, 1 A maximum collector current, and 500 mW power dissipation in a surface mount SOT-23-3 package. The FMMT489TC is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and production continuity.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Collector Current (Max)	1	A
Collector-Emitter Breakdown Voltage (Max)	30	V
Power Dissipation (Max)	500	mW
Transition Frequency	150	MHz
Operating Temperature Range	−55 to 150	°C
Package Type	SOT-23-3	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the FMMT489TC is determined by the following critical parameters:

Primary Substitution Criteria:

Transistor type (NPN)
Collector-emitter breakdown voltage (30 V minimum)
Collector current rating (1 A or greater)
Power dissipation (500 mW or greater)
Package compatibility (SOT-23-3 or equivalent surface mount)
Operating temperature range (−55°C to 150°C or subset thereof)

Substitution Categories:

Parametric Equivalents maintain identical electrical specifications and are direct replacements. The FMMT489TA from Diodes Incorporated is a parametric equivalent available in active product status with tape and reel packaging.

Functional Equivalents meet or exceed the primary electrical requirements but may differ in secondary parameters such as saturation voltage, DC current gain, or transition frequency. These include the FMMT449TA (Diodes Incorporated), 2SD2657KT146 (Rohm Semiconductor), and BC848-series devices (onsemi, Nexperia, Infineon).

Current-Limited Substitutes provide reduced collector current capability (100 mA) and are suitable only for applications not requiring the full 1 A rating. These include BC848ALT1G, BC848BLT1G, BC848CLT1G, BC849B,215, and related variants.

Parameter Comparison

Part Number	Manufacturer	Status	Ic (Max) [A]	Vce(br) [V]	Power [mW]	fT [MHz]	Temp Range [°C]	Package
FMMT489TC	Diodes Inc.	Obsolete	1	30	500	150	−55 to 150	SOT-23-3
FMMT489TA	Diodes Inc.	Active	1	30	500	150	−55 to 150	SOT-23-3
FMMT449TA	Diodes Inc.	Active	1	30	500	150	−55 to 150	SOT-23-3
2SD2657KT146	Rohm Semi.	Active	1.5	30	200	330	−55 to 150	SOT-23-3
BC848ALT1G	onsemi	Active	0.1	30	300	100	−55 to 150	SOT-23-3
BC848B,215	Nexperia	Active	0.1	30	250	100	−55 to 150	SOT-23-3
BC848B,235	Nexperia	Active	0.1	30	250	100	−55 to 150	SOT-23-3
BC848BE6327HTSA1	Infineon	Last Time Buy	0.1	30	330	250	−55 to 150	SOT-23-3
BC848BLT1G	onsemi	Active	0.1	30	300	100	−55 to 150	SOT-23-3
BC848CLT1G	onsemi	Active	0.1	30	300	100	−55 to 150	SOT-23-3
BC849B,215	Nexperia	Active	0.1	30	250	100	−55 to 150	SOT-23-3

Engineering Selection Recommendations

Direct Replacement (Parametric Equivalent):

FMMT489TA is the recommended direct replacement for FMMT489TC. Both devices are manufactured by Diodes Incorporated and share identical electrical specifications. FMMT489TA is in active product status with 46,960 units in stock, ensuring supply continuity. This part is ROHS3 compliant and carries MSL-1 moisture sensitivity rating.

Primary Functional Equivalent:

FMMT449TA (Diodes Incorporated, Active) provides full electrical compatibility with the FMMT489TC for applications requiring 1 A collector current and 30 V breakdown voltage. The primary difference is saturation voltage specification (1 V at 200 mA, 2 A versus 600 mV at 200 mA, 2 A). This part is suitable for switching applications where saturation voltage tolerance is not critical.

Alternative Functional Equivalent:

2SD2657KT146 (Rohm Semiconductor, Active) exceeds the FMMT489TC specifications with 1.5 A collector current and 330 MHz transition frequency. However, power dissipation is reduced to 200 mW. This device is suitable for applications requiring higher current capability or frequency performance but operating within reduced power envelope.

Current-Limited Alternatives:

BC848-series devices (onsemi, Nexperia, Infineon) are suitable only for applications where collector current does not exceed 100 mA. These parts share the 30 V breakdown voltage and SOT-23-3 package but are not direct replacements for 1 A applications. BC848ALT1G and BC848BLT1G (onsemi, Active) provide extended temperature range (−55°C to 150°C). BC848B,215 and BC848B,235 (Nexperia, Active) include AEC-Q101 automotive qualification.

Compliance Status:

All recommended substitutes are ROHS3 compliant, REACH unaffected, and carry MSL-1 moisture sensitivity rating. No additional qualification or testing is required for compliance purposes.

Frequently Asked Questions (FAQ)

Q: Can FMMT489TA directly replace FMMT489TC in all applications?

A: Yes. FMMT489TA is a parametric equivalent with identical electrical specifications. The only difference is product status (active versus obsolete) and packaging format (tape and reel versus tube). Electrical performance and pin configuration are identical.

Q: What is the difference between FMMT489TA and FMMT449TA?

A: Both devices meet the 1 A, 30 V specification. The primary difference is saturation voltage: FMMT489TA specifies 600 mV at 200 mA, 2 A, while FMMT449TA specifies 1 V at the same conditions. FMMT489TA is preferred for applications sensitive to saturation voltage. Both are in active status.

Q: Can BC848-series transistors replace FMMT489TC?

A: BC848-series devices are not suitable as direct replacements because they are rated for 100 mA maximum collector current, not 1 A. They are suitable only for applications requiring 100 mA or less. If your application requires the full 1 A capability, use FMMT489TA or FMMT449TA instead.

Q: Is 2SD2657KT146 a suitable replacement?

A: 2SD2657KT146 is a functional equivalent for applications requiring 1 A or greater collector current at 30 V. However, power dissipation is reduced to 200 mW compared to 500 mW for FMMT489TC. Verify that your application operates within the 200 mW power budget before selecting this device.

Q: Are all substitute parts available in SOT-23-3 packaging?

A: Yes. All recommended substitutes use SOT-23-3 (TO-236-3, SC-59) surface mount packaging, ensuring mechanical and electrical compatibility with existing PCB layouts.

Q: What is the difference between cut tape and tape and reel packaging?

A: Cut tape (CT) and tape and reel (TR) are different supply formats for the same component. Tape and reel is used for automated assembly lines, while cut tape is used for manual assembly or smaller quantities. Electrical specifications are identical; packaging format affects only handling and assembly process.

Q: Do I need to re-qualify my design if I switch from FMMT489TC to FMMT489TA?

A: No re-qualification is required. FMMT489TA is a parametric equivalent with identical electrical specifications. Both parts are ROHS3 compliant and carry the same MSL-1 rating. Design re-qualification is necessary only if switching to a functionally different device such as FMMT449TA or 2SD2657KT146.

Q: Which substitute offers the best long-term availability?

A: FMMT489TA (Diodes Incorporated, 46,960 units in stock) and FMMT449TA (Diodes Incorporated, 17,557 units in stock) are both in active product status from the same manufacturer. Both offer superior long-term availability compared to BC848-series alternatives or the last-time-buy BC848BE6327HTSA1.

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