MMBF170LT1 N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The MMBF170LT1 is an N-Channel MOSFET manufactured by onsemi, rated for 60V drain-to-source voltage with 500mA continuous drain current in a surface mount SOT-23-3 package. This device is classified as obsolete product status. Due to its obsolete designation, identifying equivalent and substitute parts with active product status is necessary to ensure design continuity and supply chain reliability for new applications and production runs.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Technology	MOSFET (Metal Oxide)	—
Drain to Source Voltage (Vdss)	60	V
Continuous Drain Current (Id) @ 25°C	500	mA
Drive Voltage (Max Rds On)	10	V
Rds On (Max) @ Id, Vgs	5	Ohm @ 200mA, 10V
Vgs(th) (Max) @ Id	3	V @ 1mA
Vgs (Max)	±20	V
Input Capacitance (Ciss) (Max) @ Vds	60	pF @ 10V
Power Dissipation (Max)	225	mW
Operating Temperature Range	-55 to 150	°C (TJ)
Package Type	SOT-23-3 (TO-236)	—
Mounting Type	Surface Mount	—
RoHS Status	RoHS non-compliant	—

Substitute Part Grouping Explanation

Substitution of the MMBF170LT1 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Drain-to-source voltage rating (Vdss) must equal or exceed 60V
Package type must be SOT-23-3 (TO-236) for mechanical compatibility
FET type must be N-Channel MOSFET
Operating temperature range must encompass -55°C to 150°C

Secondary Compatibility Factors:

Continuous drain current (Id) at 25°C: minimum 500mA required for direct replacement
Gate threshold voltage (Vgs(th)): maximum 3V @ 1mA for gate drive compatibility
Maximum gate voltage (Vgs): ±20V or greater
On-resistance (Rds On) at specified conditions: 5 Ohm or lower preferred for thermal performance

Substitute parts are grouped into two categories:

Direct Equivalents: Parts with identical or superior electrical specifications and active product status, suitable for direct board-level replacement without circuit modification.

Functional Alternatives: Parts with reduced drain current capability or modified electrical characteristics that require application-level verification but maintain core voltage and package compatibility.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (mA)	Rds On (Ohm)	Vgs(th) Max (V)	Ciss (pF)	Package	Product Status	RoHS Status
MMBF170LT1	onsemi	60	500	5 @ 200mA, 10V	3 @ 1mA	60 @ 10V	SOT-23-3	Obsolete	Non-compliant
MMBF170LT1G	onsemi	60	500	5 @ 200mA, 10V	3 @ 1mA	60 @ 10V	SOT-23-3	Active	ROHS3 Compliant
MMBF170	onsemi	60	500	5 @ 200mA, 10V	3 @ 1mA	40 @ 10V	SOT-23-3	Active	ROHS3 Compliant
FDN5630	onsemi	60	1700	0.1 @ 1.7A, 10V	3 @ 250µA	400 @ 15V	SOT-23-3	Active	ROHS3 Compliant
2N7002,215	Nexperia USA Inc.	60	300	5 @ 500mA, 10V	2.5 @ 250µA	50 @ 10V	TO-236AB	Active	ROHS3 Compliant
2N7002-7-F	Diodes Incorporated	60	115	7.5 @ 50mA, 5V	2.5 @ 250µA	50 @ 25V	SOT-23-3	Active	ROHS3 Compliant
2N7002A-7	Diodes Incorporated	60	180	6 @ 115mA, 5V	2 @ 250µA	23 @ 25V	SOT-23-3	Active	ROHS3 Compliant
2N7002AQ-7	Diodes Incorporated	60	180	5 @ 115mA, 10V	2 @ 250µA	23 @ 25V	SOT-23-3	Active	ROHS3 Compliant
2N7002AQ-13	Diodes Incorporated	60	180	5 @ 115mA, 10V	2 @ 250µA	23 @ 25V	SOT-23-3	Active	ROHS3 Compliant
BS170FTA	Diodes Incorporated	60	150	5 @ 200mA, 10V	3 @ 1mA	60 @ 10V	SOT-23-3	Active	ROHS3 Compliant
BS870-7-F	Diodes Incorporated	60	250	5 @ 200mA, 10V	3 @ 250µA	50 @ 10V	SOT-23-3	Active	ROHS3 Compliant

Engineering Selection Recommendations

Tier 1 Direct Replacement (Recommended):

MMBF170LT1G is the primary recommended substitute. This part maintains identical electrical specifications to the MMBF170LT1 across all critical parameters including Vdss, Id, Rds On, and Vgs(th). The MMBF170LT1G carries active product status and ROHS3 compliance, eliminating supply chain risk associated with the obsolete MMBF170LT1. Packaging and mounting type are identical, enabling direct board-level substitution without design modification.

Tier 2 Compatible Alternatives (Application-Dependent):

MMBF170 (onsemi) provides equivalent electrical performance with active product status and ROHS3 compliance. Input capacitance differs slightly (40 pF versus 60 pF), which may affect switching characteristics in high-frequency applications but remains compatible for general-purpose switching applications.

FDN5630 (onsemi) offers superior current handling (1.7A versus 500mA) and lower on-resistance (100 mOhm versus 5 Ohm) within the same SOT-23-3 package. This part is suitable for applications requiring higher current capacity or lower power dissipation. Increased input capacitance (400 pF) may require gate drive circuit adjustment.

Tier 3 Reduced-Current Alternatives (Limited Compatibility):

2N7002,215 (Nexperia) provides 300mA continuous drain current with active status and ROHS3 compliance. This part is suitable only for applications where 300mA drain current is sufficient. Package designation differs (TO-236AB versus SOT-23-3) but maintains mechanical compatibility.

2N7002AQ-7 and 2N7002AQ-13 (Diodes Incorporated) are automotive-grade parts (AEC-Q101 qualified) rated for 180mA continuous drain current. These parts are suitable for automotive applications requiring reduced current capacity. Automotive qualification adds design assurance for automotive end-use.

BS870-7-F (Diodes Incorporated) provides 250mA continuous drain current, intermediate between reduced-current and full-current alternatives. This part is suitable for applications where 250mA drain current is acceptable.

Not Recommended for Direct Replacement:

2N7002-7-F (Diodes Incorporated) is rated for only 115mA continuous drain current, significantly below the 500mA specification of the MMBF170LT1. This part is unsuitable for applications requiring the full 500mA current capacity.

BS170FTA (Diodes Incorporated) is rated for only 150µA continuous drain current and is unsuitable for applications requiring 500mA drain current.

Frequently Asked Questions (FAQ)

Q: Can MMBF170LT1G be used as a direct replacement for MMBF170LT1 without circuit modification?

A: Yes. MMBF170LT1G maintains identical electrical specifications across all critical parameters (Vdss, Id, Rds On, Vgs(th), and operating temperature range) and uses the same SOT-23-3 package. Direct board-level substitution is supported without circuit modification. The primary difference is product status (active versus obsolete) and RoHS compliance (ROHS3 compliant versus non-compliant).

Q: What is the difference between MMBF170LT1G and MMBF170?

A: Both parts are manufactured by onsemi with identical drain-to-source voltage (60V), continuous drain current (500mA), on-resistance (5 Ohm @ 200mA, 10V), and gate threshold voltage (3V @ 1mA). The primary difference is input capacitance: MMBF170LT1G specifies 60 pF @ 10V while MMBF170 specifies 40 pF @ 10V. This difference may affect switching speed in high-frequency applications. Both parts carry active product status and ROHS3 compliance.

Q: Can FDN5630 replace MMBF170LT1 in all applications?

A: FDN5630 is electrically compatible for voltage and package considerations but offers significantly higher current capacity (1.7A versus 500mA) and lower on-resistance (100 mOhm versus 5 Ohm). FDN5630 is suitable for applications where the MMBF170LT1 operates below its maximum current rating. However, the substantially higher input capacitance (400 pF versus 60 pF) may require gate drive circuit adjustment for high-frequency switching applications. Thermal characteristics differ due to higher power dissipation capability (500mW versus 225mW).

Q: Are automotive-qualified alternatives available?

A: Yes. 2N7002AQ-7 and 2N7002AQ-13 (Diodes Incorporated) are automotive-grade MOSFETs with AEC-Q101 qualification. Both parts are rated for 180mA continuous drain current and maintain 60V Vdss with SOT-23-3 packaging. These parts are suitable for automotive applications where reduced current capacity (180mA versus 500mA) is acceptable and automotive qualification is required.

Q: What is the significance of the package designation difference between SOT-23-3 and TO-236AB?

A: SOT-23-3 and TO-236AB are equivalent package designations for the same physical form factor. Both refer to a three-terminal surface mount package with identical pin spacing and dimensions. Parts specified as either SOT-23-3 or TO-236AB are mechanically interchangeable on the same PCB footprint.

Q: Why does MMBF170LT1 have non-compliant RoHS status?

A: MMBF170LT1 is classified as obsolete product status, which typically indicates manufacturing has ceased. RoHS compliance status reflects the manufacturing date and process used. Active alternatives such as MMBF170LT1G and MMBF170 incorporate current manufacturing processes and carry ROHS3 compliance certification, meeting current regulatory requirements for new designs and production.

Q: Can reduced-current alternatives such as 2N7002-7-F be used in applications designed for 500mA drain current?

A: No. 2N7002-7-F is rated for only 115mA continuous drain current, which is insufficient for applications requiring 500mA. Using an undersized device in a 500mA application will result in device thermal stress, reduced reliability, and potential failure. Application-specific current requirements must be verified before selecting a substitute part.

Q: What factors should be considered when selecting between multiple compatible alternatives?

A: Selection should prioritize: (1) product status (active preferred over obsolete), (2) RoHS compliance (ROHS3 compliant preferred for regulatory alignment), (3) current capacity (must meet or exceed application requirements), (4) on-resistance (lower values reduce power dissipation and thermal stress), (5) input capacitance (affects switching speed and gate drive requirements), and (6) supply availability (inventory levels and lead times). Application-specific requirements such as automotive qualification or temperature extremes should also be evaluated.

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