FDN371N N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The FDN371N is an N-Channel MOSFET manufactured by onsemi, rated for 20V drain-to-source voltage with 2.5A continuous drain current at 25°C. The device is housed in a SOT-23-3 surface mount package and features a maximum power dissipation of 500mW. The FDN371N is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility within the specified parameter ranges while offering improved availability and product status.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	20	V
Continuous Drain Current (Id) @ 25°C	2.5	A
On-State Resistance (Rds On) @ 4.5V	50	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	1.5	V
Power Dissipation (Max)	500	mW
Operating Temperature Range	-55 to 150	°C
Package Type	SOT-23-3	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution eligibility for the FDN371N is determined by the following critical parameters:

Primary Compatibility Criteria:

Drain-to-Source Voltage (Vdss): Must equal or exceed 20V
Package Type: Must be SOT-23-3 (TO-236-3, SC-59)
Mounting Type: Must be Surface Mount
Operating Temperature Range: Must span -55°C to 150°C
FET Type: Must be N-Channel MOSFET

Secondary Performance Criteria:

Continuous Drain Current (Id): Must meet or exceed 2.5A at 25°C
On-State Resistance (Rds On): Lower values indicate improved performance
Gate Threshold Voltage (Vgs(th)): Must be compatible with drive circuitry
Power Dissipation: Must support thermal requirements

Substitute parts are grouped into two categories:

Category A - Direct Electrical Equivalents: Parts with Vdss = 20V, Id ≥ 2.5A, and identical SOT-23-3 packaging. These parts maintain the same voltage rating and current capability.

Category B - Enhanced Performance Substitutes: Parts with Vdss ≥ 20V, Id ≥ 2.5A, and improved electrical characteristics such as lower Rds On or higher power dissipation ratings. These parts provide superior performance in the same package footprint.

Parameter Comparison

Parameter	FDN371N	FDN339AN	NTR4501NT1G	AO3414	DMN3053L-7
Manufacturer	onsemi	onsemi	onsemi	Alpha & Omega	Diodes Inc.
Vdss (V)	20	20	20	20	30
Id @ 25°C (A)	2.5	3	3.2	3	4
Rds On @ 4.5V (mOhm)	50	35	80	50	45
Vgs(th) @ 250µA (V)	1.5	1.5	1.2	1	1.4
Gate Charge @ 4.5V (nC)	10.7	10	6	6.2	17.2
Power Dissipation (mW)	500	500	1250	1400	760
Ciss @ 10V (pF)	815	700	200	436	676
Package	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3	SOT-23-3
Product Status	Obsolete	Active	Active	Not For New Designs	Active
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Recommended Primary Substitute: FDN339AN

The FDN339AN is the optimal substitute for the FDN371N. Both devices are manufactured by onsemi within the PowerTrench® series and share identical Vdss (20V) and package specifications (SOT-23-3). The FDN339AN provides enhanced performance with 3A continuous drain current versus 2.5A, improved on-state resistance of 35mOhm compared to 50mOhm, and maintains the same 500mW power dissipation rating. The FDN339AN holds Active product status with ROHS3 compliance and unlimited moisture sensitivity level (MSL 1), ensuring long-term availability and regulatory compliance for new designs.

Secondary Substitute: NTR4501NT1G

The NTR4501NT1G is an onsemi alternative rated for 20V with 3.2A continuous drain current. This device offers superior power dissipation (1.25W) and lower gate charge (6nC), making it suitable for applications requiring reduced switching losses. The lower input capacitance (200pF) provides faster switching characteristics. The NTR4501NT1G is Active with ROHS3 compliance. Selection of this part is appropriate when thermal performance or switching speed is a design priority.

Alternative Substitute: DMN3053L-7

The DMN3053L-7 manufactured by Diodes Incorporated provides enhanced voltage rating (30V Vdss) with 4A continuous drain current and improved power dissipation (760mW). This part is suitable for applications requiring higher voltage margin or increased current capacity. The DMN3053L-7 is Active with ROHS3 compliance. The higher Vdss rating provides additional design margin in voltage-sensitive applications.

Not Recommended: AO3414

The AO3414 is classified as Not For New Designs and should not be selected for new product development despite its electrical compatibility. This status indicates the manufacturer has discontinued active support for this component.

Frequently Asked Questions (FAQ)

Q: Can the FDN339AN directly replace the FDN371N without circuit modifications?

A: Yes. The FDN339AN is a direct replacement. Both devices share identical Vdss (20V), SOT-23-3 package, and operating temperature range (-55°C to 150°C). The FDN339AN provides equal or superior electrical performance with 3A versus 2.5A current rating and improved on-state resistance (35mOhm versus 50mOhm). No circuit modifications are required.

Q: What is the primary difference between the FDN339AN and NTR4501NT1G?

A: Both devices meet the 20V/2.5A minimum requirements. The FDN339AN maintains the original 500mW power dissipation specification, while the NTR4501NT1G offers significantly higher power dissipation (1.25W) and lower gate charge (6nC versus 10nC). The NTR4501NT1G is preferred in high-frequency switching applications where reduced switching losses are beneficial.

Q: Why is the DMN3053L-7 listed as a substitute if it has 30V Vdss instead of 20V?

A: The DMN3053L-7 is a valid substitute because it exceeds the minimum Vdss requirement of 20V. The higher 30V rating provides additional voltage margin and is electrically compatible with 20V applications. The device also offers improved current capacity (4A) and power dissipation (760mW). Higher voltage ratings do not create incompatibility in lower-voltage applications.

Q: Are all substitute parts available in the same SOT-23-3 package?

A: Yes. All listed substitute parts (FDN339AN, NTR4501NT1G, AO3414, and DMN3053L-7) are packaged in SOT-23-3 (TO-236-3, SC-59) surface mount configuration, ensuring identical PCB footprint and assembly compatibility.

Q: What is the significance of the "Obsolete" status for the FDN371N?

A: Obsolete status indicates that onsemi has discontinued manufacturing and active support for the FDN371N. Long-term availability cannot be guaranteed. Substitution with an Active-status part (FDN339AN, NTR4501NT1G, or DMN3053L-7) is necessary for new designs and ongoing production to ensure component supply continuity.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. The FDN339AN, NTR4501NT1G, AO3414, and DMN3053L-7 are all ROHS3 compliant. The original FDN371N does not specify RoHS status. All substitute parts meet current environmental and regulatory requirements for commercial and industrial applications.

Q: Can the FDN371N be used in new product designs?

A: No. The FDN371N is classified as Obsolete. New product designs must utilize an Active-status substitute such as FDN339AN, NTR4501NT1G, or DMN3053L-7 to ensure long-term component availability and manufacturer support.

Q: What is the difference between Vgs(th) values across the substitute parts?

A: Gate threshold voltage (Vgs(th)) varies from 1V (AO3414) to 1.5V (FDN371N and FDN339AN). Lower threshold voltages enable operation with lower gate drive voltages. All listed values fall within the standard range for logic-level gate drive circuits. Verify that your gate drive voltage accommodates the selected part's Vgs(th) specification.

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