FMMT493TC Equivalent & Substitute Parts

Part Overview

The FMMT493TC is an NPN bipolar junction transistor manufactured by Diodes Incorporated, designed for general-purpose switching and amplification applications. This surface mount device operates at 100 V collector-emitter breakdown voltage with a maximum collector current of 1 A and 500 mW power dissipation. The part is currently in active production status with 1310 units in stock. Equivalent and substitute parts are identified to address inventory availability, packaging format requirements, or specific application performance needs while maintaining functional compatibility within defined electrical and mechanical parameters.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Collector Current (Max)	1	A
Collector-Emitter Breakdown Voltage (Max)	100	V
Vce Saturation (Max)	600 mV @ 100 mA, 1 A	—
DC Current Gain (hFE Min)	100 @ 250 mA, 10 V	—
Power Dissipation (Max)	500	mW
Transition Frequency	150	MHz
Operating Temperature Range	−55 to 150	°C
Package	SOT-23-3	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the FMMT493TC is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor type (NPN)
Collector-emitter breakdown voltage (100 V minimum)
Collector current rating (1 A minimum)
Power dissipation capability (500 mW minimum)
Surface mount package compatibility (SOT-23-3)
Operating temperature range (−55 to 150 °C)

Substitution Categories:

Category 1: Parametric Equivalents (Identical Specifications) Parts FMMT493QTA and FMMT493TA are parametric equivalents manufactured by Diodes Incorporated under the same base product number FMMT493. These parts maintain identical electrical specifications and differ only in packaging format (Tape & Reel versus Cut Tape & Digi-Reel).

Category 2: Functional Equivalents (Relaxed Parameters) Parts NSS1C201LT1G and CPH3240-TL-E meet or exceed the primary electrical requirements with variations in secondary parameters. NSS1C201LT1G provides higher collector current (2 A) and lower saturation voltage. CPH3240-TL-E offers higher power dissipation (900 mW) but operates at reduced transition frequency (120 MHz) and is marked obsolete.

Category 3: Partial Equivalents (Limited Substitution) Parts MMBT6429LT1G, MMBT2484LT1G, MMBT2484LT3G, and FJV1845FMTF do not meet all primary criteria. These parts are listed as substitutes in the original part documentation but exhibit reduced collector current, reduced breakdown voltage, or reduced power dissipation relative to FMMT493TC specifications.

Parameter Comparison

Part Number	Manufacturer	Ic (Max)	Vce(BR) (Max)	Power (Max)	fT	hFE (Min)	Package	Status
FMMT493TC	Diodes Inc.	1 A	100 V	500 mW	150 MHz	100 @ 250 mA, 10 V	SOT-23-3	Active
FMMT493QTA	Diodes Inc.	1 A	100 V	500 mW	150 MHz	100 @ 250 mA, 10 V	SOT-23-3	Active
FMMT493TA	Diodes Inc.	1 A	100 V	500 mW	150 MHz	100 @ 250 mA, 10 V	SOT-23-3	Active
NSS1C201LT1G	onsemi	2 A	100 V	490 mW	110 MHz	120 @ 500 mA, 2 V	SOT-23-3	Active
CPH3240-TL-E	onsemi	1 A	100 V	900 mW	120 MHz	140 @ 100 mA, 5 V	3-CPH	Obsolete
MMBT6429LT1G	onsemi	200 mA	45 V	225 mW	700 MHz	500 @ 100 µA, 5 V	SOT-23-3	Active
MMBT2484LT1G	onsemi	100 mA	60 V	225 mW	—	SOT-23-3	Active
MMBT2484LT3G	onsemi	100 mA	60 V	225 mW	—	SOT-23-3	Active
FJV1845FMTF	onsemi	50 mA	120 V	300 mW	110 MHz	300 @ 1 mA, 6 V	SOT-23-3	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): FMMT493QTA and FMMT493TA are direct parametric equivalents to FMMT493TC. Selection between these three parts depends solely on packaging format availability. FMMT493TA offers the highest inventory (60,020 units) in Cut Tape & Digi-Reel format. FMMT493QTA provides 6,880 units in Tape & Reel format. All three parts maintain identical electrical performance and are ROHS3 compliant with MSL 1 rating.

For Higher Current Applications: NSS1C201LT1G supports 2 A collector current while maintaining 100 V breakdown voltage and SOT-23-3 package compatibility. This part is suitable for applications requiring higher current handling than the 1 A FMMT493TC specification. Saturation voltage is lower (150 mV @ 200 mA, 2 A), indicating improved switching efficiency at elevated currents. Transition frequency is reduced to 110 MHz. This part is active in production with 65,400 units available.

For Higher Power Dissipation: CPH3240-TL-E provides 900 mW power dissipation versus 500 mW for FMMT493TC, supporting applications with higher thermal requirements. However, this part is marked obsolete and uses a different package format (3-CPH instead of SOT-23-3), requiring circuit board redesign. Transition frequency is reduced to 120 MHz.

Not Recommended for Direct Substitution: MMBT6429LT1G, MMBT2484LT1G, MMBT2484LT3G, and FJV1845FMTF do not meet the full electrical specification of FMMT493TC. These parts exhibit reduced collector current (50–200 mA), reduced breakdown voltage (45–60 V), or reduced power dissipation (225–300 mW). Use of these parts requires circuit redesign and performance verification.

Frequently Asked Questions (FAQ)

Q: Can FMMT493QTA or FMMT493TA be used as direct replacements for FMMT493TC?

A: Yes. FMMT493QTA and FMMT493TA are parametric equivalents with identical electrical specifications. The only difference is packaging format: FMMT493TC and FMMT493TA use Cut Tape & Digi-Reel format, while FMMT493QTA uses Tape & Reel format. All three parts are manufactured by Diodes Incorporated under the same base product number FMMT493 and are pin-compatible in SOT-23-3 packages.

Q: What is the difference between Cut Tape & Digi-Reel and Tape & Reel packaging?

A: Cut Tape & Digi-Reel format provides individual component strips suitable for manual handling and small-volume assembly. Tape & Reel format provides components on continuous tape wound on reels, optimized for automated pick-and-place assembly equipment. Electrical performance is identical; packaging selection depends on assembly process requirements.

Q: Can NSS1C201LT1G replace FMMT493TC in all applications?

A: NSS1C201LT1G is suitable for applications where higher collector current (2 A versus 1 A) is beneficial or where lower saturation voltage (150 mV versus 600 mV) improves efficiency. However, transition frequency is reduced from 150 MHz to 110 MHz. Applications requiring the full 150 MHz bandwidth should retain FMMT493TC or equivalent parts. NSS1C201LT1G maintains 100 V breakdown voltage and SOT-23-3 package compatibility.

Q: Why are MMBT6429LT1G and MMBT2484LT1G listed as substitutes if they have lower ratings?

A: These parts are listed in the original FMMT493TC substitute documentation but do not meet all primary electrical specifications. MMBT6429LT1G is limited to 200 mA collector current and 45 V breakdown voltage. MMBT2484LT1G is limited to 100 mA collector current and 60 V breakdown voltage. These parts are suitable only for applications with reduced current and voltage requirements. Use requires circuit redesign and performance verification.

Q: Is CPH3240-TL-E a viable substitute despite being marked obsolete?

A: CPH3240-TL-E is not recommended for new designs. Although it provides higher power dissipation (900 mW) and meets the 100 V breakdown voltage requirement, it uses a different package format (3-CPH instead of SOT-23-3), requiring circuit board redesign. Obsolete status indicates discontinued production, creating long-term supply risk. FMMT493TA or NSS1C201LT1G are preferred alternatives.

Q: What compliance certifications apply to all substitute parts?

A: All listed parts are ROHS3 compliant, REACH unaffected, and classified as EAR99 for export control purposes. All parts carry MSL 1 (Unlimited) moisture sensitivity rating, indicating no special moisture protection requirements during storage or handling. These certifications are consistent across all substitute options.

Q: Can I mix different substitute parts in the same circuit board design?

A: Yes, provided the circuit design accommodates the electrical parameter variations of each part. However, using identical parts throughout a design simplifies inventory management, reduces assembly errors, and ensures consistent performance. If multiple part numbers are necessary, clearly document part-specific requirements in assembly documentation and bill of materials.

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

A: FMMT493TA offers the highest availability with 60,020 units in stock. NSS1C201LT1G provides 65,400 units. FMMT493QTA offers 6,880 units. MMBT6429LT1G provides 155,200 units. MMBT2484LT3G offers 30,428 units. CPH3240-TL-E provides 50,300 units despite obsolete status. Inventory levels should be verified at time of procurement.

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