FMMT549TC Equivalent & Substitute Parts

Part Overview

The FMMT549TC is a PNP bipolar junction transistor manufactured by Diodes Incorporated, designed for general-purpose switching and amplification applications. This device features a 30V collector-emitter breakdown voltage, 1A maximum collector current, and 500mW power dissipation in a surface mount SOT-23-3 package. The FMMT549TC is classified as obsolete, necessitating identification of active equivalent and substitute parts for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across critical parameters including voltage ratings, current capacity, and thermal characteristics while accommodating packaging and availability constraints.

Key Parameters

Parameter	FMMT549TC Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) Max	1	A
Voltage - Collector Emitter Breakdown (Max)	30	V
Vce Saturation (Max) @ Ib, Ic	750mV @ 200mA, 2A	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) Min @ Ic, Vce	100 @ 500mA, 2V	—
Power - Max	500	mW
Frequency - Transition	100	MHz
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOT-23-3 (TO-236-3, SC-59)	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the FMMT549TC are classified into two categories based on electrical and mechanical compatibility:

Direct Electrical Equivalents (Same Base Specifications): Parts that maintain identical or superior performance across all critical parameters including collector current (1A), collector-emitter breakdown voltage (30V), power dissipation (500mW or higher), transition frequency (100MHz or higher), and DC current gain (hFE ≥100 @ 500mA, 2V). These parts are interchangeable in applications where the FMMT549TC was originally specified.

Parametric Equivalents with Enhanced Ratings: Parts that exceed the FMMT549TC specifications in one or more parameters (higher current capacity, higher power rating, higher transition frequency, or higher DC current gain) while maintaining compatibility with the 30V voltage rating and SOT-23-3 package form factor. These parts are suitable for applications requiring improved performance margins or higher reliability.

Key Substitution Criteria:

Transistor Type: PNP (mandatory)
Collector-Emitter Breakdown Voltage: ≥30V
Maximum Collector Current: ≥1A
Maximum Power Dissipation: ≥500mW
DC Current Gain (hFE): ≥100 @ 500mA, 2V
Transition Frequency: ≥100MHz
Operating Temperature Range: -55°C to 150°C minimum
Package: SOT-23-3 compatible
RoHS3 Compliance: Required
Moisture Sensitivity Level: 1 (Unlimited)

Parameter Comparison

Part Number	Manufacturer	Product Status	Ic Max (A)	Vce Breakdown (V)	Vce Sat (mV)	hFE Min @ Ic, Vce	Power Max (mW)	Freq Trans (MHz)	Package	Inventory (Pcs)
FMMT549TC	Diodes Inc.	Obsolete	1	30	750 @ 200mA, 2A	100 @ 500mA, 2V	500	100	SOT-23-3	6,300
FMMT589TA	Diodes Inc.	Active	1	30	650 @ 200mA, 2A	100 @ 500mA, 2V	500	100	SOT-23-3	68,400
FMMT549TA	Diodes Inc.	Active	1	30	750 @ 200mA, 2A	100 @ 500mA, 2V	500	100	SOT-23-3	5,163
MMBT589LT1G	onsemi	Active	1	30	650 @ 200mA, 2A	100 @ 500mA, 2V	310	100	SOT-23-3	59,300
NSS30100LT1G	onsemi	Active	1	30	650 @ 200mA, 2A	100 @ 500mA, 2V	310	100	SOT-23-3	32,000
NSVMMBT589LT1G	onsemi	Active	1	30	650 @ 200mA, 2A	100 @ 500mA, 2V	310	100	SOT-23-3	4,300
2SB1695KT146	Rohm Semi.	Active	1.5	30	370 @ 50mA, 1A	270 @ 100mA, 2V	200	280	SOT-23-3	267,100
2SB1695TL	Rohm Semi.	Active	1.5	30	370 @ 50mA, 1A	270 @ 100mA, 2V	500	280	SC-96	99,300
2SB1706TL	Rohm Semi.	Active	2	30	370 @ 75mA, 1.5A	270 @ 200mA, 2V	500	280	SC-96	1,852
2SB1708TL	Rohm Semi.	Active	3	30	250 @ 30mA, 1.5A	270 @ 200mA, 2V	500	200	SC-96	6,400
2SB1710TL	Rohm Semi.	Active	1	30	350 @ 25mA, 500mA	270 @ 100mA, 2V	500	320	SC-96	15,500

Engineering Selection Recommendations

Primary Recommendation - Direct Replacement (SOT-23-3 Package):

FMMT589TA (Diodes Incorporated) is the preferred direct substitute for FMMT549TC. Both parts are manufactured by Diodes Incorporated, share identical electrical specifications for collector current (1A), collector-emitter breakdown voltage (30V), DC current gain (100 @ 500mA, 2V), and transition frequency (100MHz). FMMT589TA is active in production with substantial inventory (68,400 pcs), ensuring long-term availability. The primary difference is improved Vce saturation (650mV vs. 750mV), which provides superior switching performance. Both parts are ROHS3 compliant with MSL 1 rating.

FMMT549TA (Diodes Incorporated) provides an alternative direct replacement maintaining identical Vce saturation characteristics (750mV) to the original FMMT549TC. This part is active with 5,163 pcs in inventory and is suitable for applications requiring exact saturation voltage matching.

Secondary Recommendations - Cross-Manufacturer Equivalents (SOT-23-3 Package):

MMBT589LT1G and NSS30100LT1G (onsemi) are functionally equivalent to FMMT549TC across all critical parameters. Both maintain 1A collector current, 30V breakdown voltage, 100MHz transition frequency, and 100 hFE minimum. These parts feature improved Vce saturation (650mV) and are available in high quantities (59,300 and 32,000 pcs respectively). The primary consideration is reduced power dissipation rating (310mW vs. 500mW), which is acceptable for applications not requiring maximum thermal headroom. Both are ROHS3 compliant with MSL 1 rating.

NSVMMBT589LT1G (onsemi) is an alternative onsemi source with identical electrical specifications to MMBT589LT1G but lower inventory (4,300 pcs).

Enhanced Performance Options - Alternative Package Formats:

2SB1710TL (Rohm Semiconductor) provides superior performance in a SC-96 package with 1A collector current, 30V breakdown voltage, and enhanced transition frequency (320MHz). This part is suitable for applications requiring higher switching speeds and is available in high quantity (15,500 pcs). The SC-96 package requires PCB layout modification compared to SOT-23-3.

2SB1695TL (Rohm Semiconductor) offers 1.5A collector current capacity with 500mW power dissipation in SC-96 package, providing performance margin for applications approaching current or thermal limits. Inventory is substantial (99,300 pcs).

2SB1706TL (Rohm Semiconductor) and 2SB1708TL (Rohm Semiconductor) provide further current capacity increases (2A and 3A respectively) for applications requiring higher collector current handling.

Compliance and Certification:

All recommended substitute parts maintain ROHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating, ensuring compatibility with standard manufacturing and storage processes. All parts are rated for -55°C to 150°C operating temperature range, matching the original FMMT549TC specification.

Frequently Asked Questions (FAQ)

Q: Can FMMT589TA be used as a direct replacement for FMMT549TC without circuit modification?

A: Yes. FMMT589TA is a direct electrical equivalent with identical collector current (1A), collector-emitter breakdown voltage (30V), DC current gain (100 @ 500mA, 2V), and transition frequency (100MHz). The improved Vce saturation (650mV vs. 750mV) provides better switching performance. Both parts use SOT-23-3 packaging with identical pinout. No circuit modification is required.

Q: What is the difference between FMMT589TA and FMMT549TA?

A: Both are Diodes Incorporated PNP transistors with identical electrical ratings for the FMMT549TC application. The primary difference is Vce saturation: FMMT589TA saturates at 650mV while FMMT549TA saturates at 750mV (matching the original FMMT549TC). Selection depends on whether improved saturation performance (FMMT589TA) or exact saturation matching (FMMT549TA) is required for the application.

Q: Are onsemi MMBT589LT1G and NSS30100LT1G suitable replacements despite lower power rating (310mW vs. 500mW)?

A: Yes, for applications where continuous power dissipation does not exceed 310mW. Both parts maintain all critical electrical parameters: 1A collector current, 30V breakdown voltage, 100MHz transition frequency, and 100 hFE minimum. The reduced power rating reflects thermal design differences, not reduced electrical capability. Applications operating below 310mW dissipation experience no functional difference.

Q: Can Rohm 2SB1710TL be used in place of FMMT549TC?

A: Electrically yes, but with package considerations. 2SB1710TL provides superior performance (320MHz transition frequency vs. 100MHz, 270 hFE vs. 100 hFE) while maintaining 1A collector current and 30V breakdown voltage. However, 2SB1710TL uses SC-96 package instead of SOT-23-3, requiring PCB layout modification. This substitution is suitable for new designs or redesigns where package change is acceptable.

Q: What is the significance of the Vce saturation difference between FMMT549TC (750mV) and FMMT589TA (650mV)?

A: Vce saturation determines the voltage drop across the transistor when fully saturated (conducting maximum current). Lower saturation voltage (650mV) reduces power dissipation and heat generation, improving efficiency. For switching applications, this difference is typically negligible. For linear amplification or precision applications, the lower saturation voltage of FMMT589TA may provide performance benefits.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All recommended substitute parts (FMMT589TA, FMMT549TA, MMBT589LT1G, NSS30100LT1G, NSVMMBT589LT1G, 2SB1695KT146, 2SB1695TL, 2SB1706TL, 2SB1708TL, 2SB1710TL) are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, matching the original FMMT549TC compliance status.

Q: Which substitute offers the best inventory availability?

A: 2SB1695KT146 (Rohm Semiconductor) offers the highest inventory with 267,100 pcs in stock. Among SOT-23-3 package options, FMMT589TA (Diodes Incorporated) provides the best availability with 68,400 pcs. For onsemi options, MMBT589LT1G offers 59,300 pcs.

Q: What is the operating temperature range for substitute parts?

A: All substitute parts are rated for -55°C to 150°C operating temperature range (TJ), matching the original FMMT549TC specification. This range is suitable for industrial and commercial applications.

Q: Can multiple substitute parts be used interchangeably within a single design?

A: Yes, provided the application tolerates the electrical differences. For critical applications, standardizing on a single substitute part (such as FMMT589TA) is recommended to simplify procurement, inventory management, and quality control. For non-critical applications, any substitute meeting the minimum electrical requirements can be used.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message