MMBF170LT3 N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The MMBF170LT3 is an N-Channel 60V 500mA surface mount MOSFET manufactured by onsemi in SOT-23-3 packaging. This device is classified as obsolete, which necessitates identification of functionally equivalent alternatives for new designs and ongoing production requirements. The MMBF170LT3 operates across a temperature range of -55°C to 150°C and dissipates a maximum of 225mW, making it suitable for general-purpose switching applications in low-power circuits.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	60	V
Continuous Drain Current (Id) @ 25°C	500	mA
Rds On (Max) @ 200mA, 10V	5	Ohm
Vgs(th) (Max) @ 1mA	3	V
Vgs (Max)	±20	V
Input Capacitance (Ciss) @ 10V	60	pF
Power Dissipation (Max)	225	mW
Operating Temperature Range	-55 to 150	°C
Package Type	SOT-23-3	—
Mounting Type	Surface Mount	—
RoHS Status	Non-compliant	—

Substitute Part Grouping Explanation

Substitution of the MMBF170LT3 is determined by strict adherence to the following electrical and mechanical parameters:

Critical Matching Parameters:

Drain to Source Voltage (Vdss): Must equal or exceed 60V
Package Type: Must be SOT-23-3 (TO-236-3, SC-59)
Mounting Type: Surface Mount
FET Type: N-Channel MOSFET technology
Operating Temperature Range: Must encompass -55°C to 150°C

Functional Compatibility Parameters:

Continuous Drain Current (Id): Substitute must support minimum 500mA or be suitable for lower-current applications where the original 500mA rating is not required
Rds On: Lower or equal values indicate improved performance
Vgs(th): Threshold voltage compatibility within ±20V gate supply range
Power Dissipation: Substitute must handle thermal requirements of the application

Substitutes are grouped into two categories: Direct Replacements (matching or exceeding all primary electrical specifications) and Functional Alternatives (meeting voltage and package requirements with different current or power ratings suitable for specific application constraints).

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (mA)	Rds On (Ohm)	Vgs(th) (V)	Ciss (pF)	Power Diss. (mW)	Package	Status	RoHS
MMBF170LT3	onsemi	60	500	5 @ 200mA, 10V	3 @ 1mA	60 @ 10V	225	SOT-23-3	Obsolete	Non-compliant
MMBF170	onsemi	60	500	5 @ 200mA, 10V	3 @ 1mA	40 @ 10V	300	SOT-23-3	Active	ROHS3 Compliant
FDN5630	onsemi	60	1700	0.1 @ 1.7A, 10V	3 @ 250µA	400 @ 15V	500	SOT-23-3	Active	ROHS3 Compliant
2N7002,215	Nexperia USA Inc.	60	300	5 @ 500mA, 10V	2.5 @ 250µA	50 @ 10V	830	SOT-23-3	Active	ROHS3 Compliant
2N7002-7-F	Diodes Incorporated	60	115	7.5 @ 50mA, 5V	2.5 @ 250µA	50 @ 25V	370	SOT-23-3	Active	ROHS3 Compliant
2N7002A-7	Diodes Incorporated	60	180	6 @ 115mA, 5V	2 @ 250µA	23 @ 25V	370	SOT-23-3	Active	ROHS3 Compliant
2N7002AQ-7	Diodes Incorporated	60	180	5 @ 115mA, 10V	2 @ 250µA	23 @ 25V	370	SOT-23-3	Active	ROHS3 Compliant
2N7002AQ-13	Diodes Incorporated	60	180	5 @ 115mA, 10V	2 @ 250µA	23 @ 25V	370	SOT-23-3	Active	ROHS3 Compliant
BS170FTA	Diodes Incorporated	60	150	5 @ 200mA, 10V	3 @ 1mA	60 @ 10V	330	SOT-23-3	Active	ROHS3 Compliant
BS870-7-F	Diodes Incorporated	60	250	5 @ 200mA, 10V	3 @ 250µA	50 @ 10V	300	SOT-23-3	Active	ROHS3 Compliant
BSS7728NH6327XTSA2	Infineon Technologies	60	200	5 @ 500mA, 10V	2.3 @ 26µA	56 @ 25V	360	SOT-23-3	Obsolete	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: MMBF170 (onsemi)

The MMBF170 is the direct active equivalent of the MMBF170LT3. It maintains identical electrical specifications (60V Vdss, 500mA Id, 5Ohm Rds On) and package configuration (SOT-23-3). The MMBF170 is currently in active production status with ROHS3 compliance, eliminating obsolescence risk. This part is the preferred choice for direct replacement in new designs and production continuity.

Secondary Recommendation: FDN5630 (onsemi)

The FDN5630 offers superior performance characteristics with 1.7A continuous drain current and significantly lower Rds On (0.1Ohm @ 1.7A, 10V). It maintains the same 60V Vdss rating and SOT-23-3 package. The FDN5630 is suitable for applications requiring higher current capacity or lower on-resistance. Active production status and ROHS3 compliance are confirmed.

Functional Alternatives for Current-Limited Applications:

BS870-7-F (Diodes Incorporated): 250mA Id, 5Ohm Rds On, active status, ROHS3 compliant. Suitable for applications requiring 250mA or less.
2N7002AQ-7 or 2N7002AQ-13 (Diodes Incorporated): 180mA Id, 5Ohm Rds On @ 115mA, 10V, active status, ROHS3 compliant, AEC-Q101 automotive qualification. Suitable for lower-current switching applications.
2N7002,215 (Nexperia USA Inc.): 300mA Id, 5Ohm Rds On @ 500mA, 10V, active status, ROHS3 compliant. Suitable for moderate-current applications.

Obsolete Alternative (Not Recommended for New Designs):

BSS7728NH6327XTSA2 (Infineon Technologies) is obsolete despite ROHS3 compliance. This part should not be selected for new designs due to production discontinuation risk.

All recommended active substitutes maintain the critical 60V Vdss rating, SOT-23-3 package form factor, and -55°C to 150°C operating temperature range. Selection among alternatives depends on specific application current requirements and thermal constraints.

Frequently Asked Questions (FAQ)

Q: Can MMBF170 directly replace MMBF170LT3 in existing designs?

A: Yes. The MMBF170 is electrically and mechanically identical to the MMBF170LT3, with matching Vdss (60V), Id (500mA), Rds On (5Ohm @ 200mA, 10V), and SOT-23-3 package. The primary difference is product status: MMBF170 is active and ROHS3 compliant, while MMBF170LT3 is obsolete and non-compliant. Direct substitution is valid.

Q: What is the difference between MMBF170 and FDN5630?

A: Both are onsemi N-Channel MOSFETs with 60V Vdss in SOT-23-3 packaging. The FDN5630 provides higher current capacity (1.7A vs. 500mA) and significantly lower on-resistance (0.1Ohm vs. 5Ohm @ 10V). FDN5630 is suitable for higher-power applications; MMBF170 is appropriate for standard 500mA switching. Both are active and ROHS3 compliant.

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

A: Yes. All listed substitutes use SOT-23-3 (also designated TO-236-3 or SC-59) surface mount packaging. This ensures mechanical and electrical compatibility with existing PCB layouts designed for MMBF170LT3.

Q: Which substitutes are suitable for automotive applications?

A: 2N7002AQ-7 and 2N7002AQ-13 (Diodes Incorporated) carry AEC-Q101 automotive qualification. BSS7728NH6327XTSA2 (Infineon) also has AEC-Q101 qualification but is obsolete. For automotive designs, 2N7002AQ-7 or 2N7002AQ-13 are recommended.

Q: What is the significance of RoHS compliance in selecting a substitute?

A: ROHS3 compliance indicates the part meets current environmental and hazardous substance restrictions. The original MMBF170LT3 is non-compliant. All active substitutes listed are ROHS3 compliant, making them suitable for modern manufacturing and regulatory requirements. Obsolete parts may have compliance status but should not be selected due to production discontinuation.

Q: Can I use a lower-current part like 2N7002AQ-7 (180mA) instead of MMBF170LT3 (500mA)?

A: Substitution depends on application requirements. If the circuit operates at or below 180mA drain current, 2N7002AQ-7 is functionally suitable. If the application requires the full 500mA capability, a lower-current substitute will not function correctly. Verify actual circuit current requirements before selecting a lower-rated alternative.

Q: What does Rds On specification mean for substitution?

A: Rds On (on-resistance) determines voltage drop and power dissipation when the MOSFET conducts. Lower Rds On values reduce heat generation. MMBF170LT3 specifies 5Ohm @ 200mA, 10V. Substitutes with equal or lower Rds On values provide equivalent or improved performance. Higher Rds On values increase power dissipation and may require thermal management review.

Q: Are there any pin-compatible alternatives outside the listed substitutes?

A: All listed substitutes are pin-compatible within SOT-23-3 packaging (Gate, Drain, Source in standard configuration). No additional alternatives meeting the specified electrical parameters and package requirements are included in this reference. Consult component datasheets to confirm pin assignment before substitution.

Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging formats?

A: Cut Tape and Digi-Reel are supplied on continuous tape in smaller quantities suitable for manual assembly or small production runs. Tape & Reel format is supplied on full reels for automated assembly lines. Both formats contain identical components; the difference is in supply and handling method. Select based on production volume and assembly process requirements.

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