FMMT6520TC PNP Bipolar Transistor Equivalent & Substitute Parts

Part Overview

The FMMT6520TC is a PNP bipolar junction transistor manufactured by Diodes Incorporated, designed for surface mount applications in the SOT-23-3 package. This device operates at 350 V collector-emitter breakdown voltage with a maximum collector current of 500 mA and is rated for 330 mW power dissipation. The FMMT6520TC is classified as obsolete, necessitating identification of active equivalent and substitute parts for new designs and ongoing production requirements. Equivalent parts maintain identical or superior electrical performance within the same package footprint, while substitute parts provide functional alternatives with acceptable parameter variations for specific application requirements.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Collector-Emitter Breakdown Voltage (Max)	350	V
Collector Current (Max)	500	mA
Power Dissipation (Max)	330	mW
Transition Frequency	50	MHz
DC Current Gain (hFE Min)	20	@ 50mA, 10V
Vce Saturation (Max)	1	V @ 5mA, 50mA
Operating Temperature Range	-55 to 150	°C
Package	SOT-23-3	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the FMMT6520TC is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor Type: PNP configuration required
Collector-Emitter Breakdown Voltage: Minimum 350 V
Collector Current: Minimum 500 mA
Package: SOT-23-3 (TO-236-3, SC-59) surface mount
Operating Temperature Range: -55°C to 150°C minimum

Secondary Compatibility Parameters:

Power Dissipation: 300 mW or greater
Transition Frequency: 50 MHz or greater
DC Current Gain (hFE): 20 or greater at specified conditions
Vce Saturation: 1 V or less at specified bias conditions

Parts are classified into two categories:

Direct Equivalents: Parts meeting all primary and secondary criteria with identical or superior specifications. These include FMMT6520TA (Diodes Incorporated), DP350T05-7 (Diodes Incorporated), MMBT6520LT1G (onsemi), and NSVMMBT6520LT1G (onsemi).

Functional Substitutes: Parts with reduced electrical performance in specific parameters but maintaining core functionality for applications with relaxed requirements. These include MMBTA92LT1G (onsemi), MMBTA92,215 (Nexperia), PMBTA92,215 (Nexperia), BF821,215 (Nexperia), and 2SA1721RTE85LF (Toshiba).

Parameter Comparison

Part Number	Manufacturer	Status	Vce(BR) Max (V)	Ic Max (mA)	Power Max (mW)	Freq (MHz)	hFE Min	Package	Temp Range (°C)
FMMT6520TC	Diodes Inc.	Obsolete	350	500	330	50	20	SOT-23-3	-55 to 150
FMMT6520TA	Diodes Inc.	Active	350	500	330	50	20	SOT-23-3	-55 to 150
DP350T05-7	Diodes Inc.	Active	350	500	300	50	20	SOT-23-3	-55 to 150
MMBT6520LT1G	onsemi	Active	350	500	225	200	20	SOT-23-3	-55 to 150
NSVMMBT6520LT1G	onsemi	Active	350	500	225	200	20	SOT-23-3	-55 to 150
MMBTA92LT1G	onsemi	Active	300	500	300	50	25	SOT-23-3	-55 to 150
MMBTA92,215	Nexperia	Active	300	100	250	50	25	SOT-23-3	-55 to 150
PMBTA92,215	Nexperia	Active	300	100	250	50	25	SOT-23-3	-55 to 150
BF821,215	Nexperia	Active	300	50	250	60	50	SOT-23-3	-55 to 150
2SA1721RTE85LF	Toshiba	Active	300	100	150	50	30	SOT-23-3	-55 to 150

Engineering Selection Recommendations

Direct Equivalent Selection:

FMMT6520TA (Diodes Incorporated) is the primary recommended replacement for the obsolete FMMT6520TC. This part maintains identical electrical specifications and packaging, with active product status and full RoHS3 compliance. Tape & Reel packaging is available with 101,100 units in stock.

DP350T05-7 (Diodes Incorporated) provides an alternative direct equivalent with marginally reduced power dissipation (300 mW versus 330 mW). This part is suitable for applications where the 30 mW reduction does not impact thermal design. Active status with 29,300 units available in Tape & Reel packaging.

MMBT6520LT1G (onsemi) and NSVMMBT6520LT1G (onsemi) maintain the 350 V breakdown voltage and 500 mA collector current specifications. Both parts feature enhanced transition frequency (200 MHz versus 50 MHz), providing superior high-frequency performance. NSVMMBT6520LT1G includes AEC-Q101 automotive qualification. Power dissipation is reduced to 225 mW, requiring thermal evaluation for high-power applications. onsemi parts are available in high quantities (311,400 and 27,400 units respectively).

Functional Substitute Selection:

MMBTA92LT1G (onsemi) operates at reduced breakdown voltage (300 V versus 350 V) but maintains 500 mA collector current and 300 mW power dissipation. This part is suitable for applications with maximum operating voltages below 300 V. Active status with 155,300 units in stock.

MMBTA92,215 (Nexperia) and PMBTA92,215 (Nexperia) reduce both breakdown voltage (300 V) and collector current (100 mA). These parts are applicable only to low-current applications. Both include AEC-Q101 automotive qualification. Nexperia parts are available with 4,100 and 6,400 units respectively.

BF821,215 (Nexperia) further reduces collector current to 50 mA with 300 V breakdown voltage. This part includes AEC-Q101 automotive qualification and is suitable for signal-level switching applications only. 3,331 units available.

2SA1721RTE85LF (Toshiba) reduces collector current to 100 mA and power dissipation to 150 mW with 300 V breakdown voltage. This part is limited to low-current applications and is available with 1,005 units in stock.

Compliance and Certification:

All recommended parts maintain RoHS3 compliance and REACH unaffected status. Parts designated with AEC-Q101 qualification (NSVMMBT6520LT1G, MMBTA92,215, PMBTA92,215, BF821,215) are suitable for automotive applications. Standard industrial applications may utilize any listed part based on electrical requirements.

Frequently Asked Questions (FAQ)

Q: Can FMMT6520TA directly replace FMMT6520TC without circuit modification?

A: Yes. FMMT6520TA is a parametric equivalent with identical electrical specifications and SOT-23-3 packaging. No circuit modifications are required. The primary difference is product status change from obsolete to active.

Q: What is the key difference between MMBT6520LT1G and FMMT6520TC?

A: MMBT6520LT1G maintains the 350 V breakdown voltage and 500 mA collector current but features 200 MHz transition frequency (versus 50 MHz) and reduced power dissipation (225 mW versus 330 mW). The enhanced frequency response is beneficial for high-speed switching applications. Thermal design must account for the 105 mW power reduction.

Q: Why do MMBTA92 series parts have lower collector current ratings?

A: MMBTA92 series parts are designed for different application classes with maximum collector current of 100 mA (MMBTA92,215, PMBTA92,215) or 500 mA (MMBTA92LT1G). The 100 mA variants are optimized for signal-level switching, while MMBTA92LT1G maintains 500 mA capability at reduced breakdown voltage (300 V).

Q: Is NSVMMBT6520LT1G suitable for automotive applications?

A: Yes. NSVMMBT6520LT1G includes AEC-Q101 qualification, meeting automotive industry standards. This part is recommended for automotive designs requiring 350 V breakdown voltage and 500 mA collector current with enhanced frequency response.

Q: What is the minimum breakdown voltage required for direct substitution?

A: Direct substitution requires minimum 350 V collector-emitter breakdown voltage to maintain design margin. Parts with 300 V breakdown voltage (MMBTA92 series, BF821, 2SA1721) are functional substitutes only and require application voltage verification.

Q: Can BF821,215 replace FMMT6520TC in a 500 mA application?

A: No. BF821,215 is rated for maximum 50 mA collector current, making it unsuitable for applications requiring 500 mA. This part is limited to signal-level switching applications with currents below 50 mA.

Q: What packaging options are available for equivalent parts?

A: All equivalent and substitute parts utilize SOT-23-3 (TO-236-3, SC-59) surface mount packaging. Packaging variants include Cut Tape (CT) & Digi-Reel, Tape & Reel (TR), and standard reels. Consult supplier documentation for specific packaging availability.

Q: Are there temperature range limitations for substitute parts?

A: All listed parts maintain -55°C to 150°C operating temperature range, matching the FMMT6520TC specification. No temperature-related limitations apply to substitution decisions.

Q: Which part offers the best high-frequency performance?

A: MMBT6520LT1G and NSVMMBT6520LT1G both feature 200 MHz transition frequency, providing four times the frequency response of the original FMMT6520TC (50 MHz). These parts are recommended for high-speed switching applications.

Q: What is the inventory status for each equivalent part?

A: FMMT6520TA (101,100 units), DP350T05-7 (29,300 units), MMBT6520LT1G (311,400 units), and NSVMMBT6520LT1G (27,400 units) are available in substantial quantities. Functional substitutes have lower availability: MMBTA92LT1G (155,300 units), MMBTA92,215 (4,100 units), PMBTA92,215 (6,400 units), BF821,215 (3,331 units), and 2SA1721RTE85LF (1,005 units).

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