FDS8672S N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The FDS8672S is an N-Channel 30V 18A surface mount MOSFET manufactured by onsemi in the 8-SOIC package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and design requirements. The FDS8672S features the PowerTrench® and SyncFET™ series technology with a maximum drain-source voltage of 30V and continuous drain current of 18A at 25°C. Identifying suitable alternatives ensures design continuity and supply chain reliability for applications requiring N-Channel MOSFET functionality in this voltage and current class.

Key Parameters

Parameter	FDS8672S	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	30	V
Current - Continuous Drain (Id) @ 25°C	18	A
Rds On (Max) @ Id, Vgs	4.8	mOhm @ 18A, 10V
Vgs(th) (Max) @ Id	3	V @ 1mA
Gate Charge (Qg) (Max) @ Vgs	41	nC @ 10V
Input Capacitance (Ciss) (Max) @ Vds	2670	pF @ 15V
Power Dissipation (Max)	2.5	W
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Surface Mount	—
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the FDS8672S is determined by strict alignment of electrical and mechanical parameters. The critical parameters that define substitutability are:

Electrical Parameters:

Drain to Source Voltage (Vdss): Must be equal to or greater than 30V
Continuous Drain Current (Id): Must be equal to or greater than 18A at 25°C
On-State Resistance (Rds On): Must be within acceptable operating limits for the application
Gate Charge (Qg): Lower values indicate faster switching performance
Input Capacitance (Ciss): Affects gate drive requirements

Mechanical Parameters:

Mounting Type: Surface Mount (required)
Package / Case: 8-SOIC or compatible 8-pin surface mount packages
Operating Temperature Range: Must support -55°C to 150°C minimum

Compliance Parameters:

RoHS Status: ROHS3 Compliant (required)
Moisture Sensitivity Level: MSL 1 or MSL 3 acceptable for standard applications
FET Technology: N-Channel MOSFET (Metal Oxide)

Substitute parts are grouped into two categories: direct equivalents (matching all primary electrical specifications) and functional alternatives (meeting or exceeding electrical requirements with potential trade-offs in secondary parameters such as gate charge or input capacitance).

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Qg (nC)	Ciss (pF)	Package	Status
FDS8672S	onsemi	30	18	4.8 @ 18A, 10V	41 @ 10V	2670 @ 15V	8-SOIC	Obsolete
FDS8638	onsemi	40	18	4.3 @ 18A, 10V	86 @ 10V	5680 @ 15V	8-SOIC	Active
IRF8736TRPBF	Infineon	30	18	4.8 @ 18A, 10V	26 @ 4.5V	2315 @ 15V	8-SOIC	Active
IRF7832TRPBF	Infineon	30	20	4 @ 20A, 10V	51 @ 4.5V	4310 @ 15V	8-SOIC	Active
AO4430	Alpha & Omega Semiconductor Inc.	30	18	5.5 @ 18A, 10V	124 @ 10V	7270 @ 15V	8-SOIC	Not For New Designs
NTMS4802NR2G	onsemi	30	11.1	4 @ 18A, 10V	36 @ 4.5V	5300 @ 25V	8-SOIC	Obsolete
BSO040N03MSGXUMA1	Infineon	30	16	4 @ 20A, 10V	73 @ 10V	5700 @ 15V	8-SOIC	Not For New Designs
SQ4182EY-T1_GE3	Vishay Siliconix	30	32	3.8 @ 14A, 10V	110 @ 10V	5400 @ 15V	8-SOIC	Active

Engineering Selection Recommendations

Primary Recommendation: IRF8736TRPBF

The IRF8736TRPBF is the preferred direct substitute for the FDS8672S. This part matches the critical electrical specifications exactly: 30V Vdss, 18A continuous drain current, and 4.8mOhm on-state resistance at 18A and 10V gate-source voltage. The IRF8736TRPBF is manufactured by Infineon, carries Active product status, and is ROHS3 compliant with MSL 1 rating. The 8-SOIC package is mechanically compatible. Gate charge is lower (26nC versus 41nC), providing improved switching performance. Input capacitance is also lower (2315pF versus 2670pF), reducing gate drive requirements. This part is suitable for direct replacement in existing designs.

Secondary Recommendation: FDS8638

The FDS8638 is an onsemi alternative with Active product status. It provides higher voltage rating (40V Vdss) while maintaining 18A continuous drain current and 8-SOIC package compatibility. On-state resistance is improved (4.3mOhm versus 4.8mOhm). However, gate charge is significantly higher (86nC versus 41nC) and input capacitance is doubled (5680pF versus 2670pF), requiring higher gate drive capability. This part is suitable when higher voltage margin is required.

Alternative Recommendation: IRF7832TRPBF

The IRF7832TRPBF offers higher continuous drain current (20A versus 18A) at the same 30V rating. On-state resistance is lower (4mOhm versus 4.8mOhm). Gate charge is moderate (51nC versus 41nC). This part is suitable for applications requiring higher current capability with improved efficiency.

Not Recommended for New Designs:

AO4430 carries "Not For New Designs" status and exhibits higher on-state resistance (5.5mOhm) and significantly higher gate charge (124nC), making it unsuitable for new applications.

NTMS4802NR2G is obsolete and provides only 11.1A continuous drain current, insufficient for 18A applications.

BSO040N03MSGXUMA1 carries "Not For New Designs" status and provides only 16A continuous drain current, below the 18A requirement.

Compliance Verification:

All recommended parts are ROHS3 compliant and operate within the -55°C to 150°C temperature range. MSL ratings are acceptable for standard manufacturing environments. All parts are rated for ±20V gate-source voltage, matching the FDS8672S specification.

Frequently Asked Questions (FAQ)

Q: Can the IRF8736TRPBF be used as a direct drop-in replacement for the FDS8672S?

A: Yes. The IRF8736TRPBF matches the FDS8672S in Vdss (30V), continuous drain current (18A), on-state resistance (4.8mOhm @ 18A, 10V), and 8-SOIC package. The part is pin-compatible and electrically equivalent. Gate charge and input capacitance are lower, which improves switching performance without requiring circuit modifications.

Q: What is the difference between the FDS8638 and FDS8672S?

A: The FDS8638 has a higher drain-source voltage rating (40V versus 30V) and lower on-state resistance (4.3mOhm versus 4.8mOhm). However, it has significantly higher gate charge (86nC versus 41nC) and input capacitance (5680pF versus 2670pF). The FDS8638 is suitable when higher voltage margin is needed, but gate drive circuits must accommodate the higher capacitive load.

Q: Why is NTMS4802NR2G not suitable as a substitute?

A: The NTMS4802NR2G provides only 11.1A continuous drain current, which is below the 18A requirement of the FDS8672S. Additionally, it is classified as obsolete. This part cannot support applications requiring 18A operation.

Q: Are there package compatibility concerns with these substitutes?

A: All recommended substitutes use the 8-SOIC package with 0.154" (3.90mm) width, matching the FDS8672S. Pin assignments are compatible for standard N-Channel MOSFET applications. Physical footprints are identical, allowing direct PCB replacement without layout modifications.

Q: What is the significance of the "Not For New Designs" status?

A: Parts marked "Not For New Designs" are in mature or declining production phases. While they may function in existing applications, manufacturers do not recommend their use in new product development due to potential supply discontinuation or lack of ongoing technical support. For new designs, Active status parts such as IRF8736TRPBF or FDS8638 are preferred.

Q: How do gate charge differences affect circuit performance?

A: Gate charge (Qg) determines the amount of charge required to switch the MOSFET on or off. Lower gate charge (IRF8736TRPBF at 26nC) requires less gate drive current and energy, enabling faster switching and reduced power dissipation in the gate driver circuit. Higher gate charge (FDS8638 at 86nC) requires proportionally more gate drive capability. Circuit design must account for these differences to ensure proper switching speed and reliability.

Q: Is the SQ4182EY-T1_GE3 suitable for this application?

A: The SQ4182EY-T1_GE3 exceeds the electrical requirements with 32A continuous drain current and lower on-state resistance (3.8mOhm). However, it carries higher gate charge (110nC) and input capacitance (5400pF), requiring enhanced gate drive capability. This part is suitable only if the application can accommodate the higher capacitive load and the gate driver is designed for higher charge transfer. The part is Active and ROHS3 compliant, with automotive qualification (AEC-Q101).

Q: What compliance certifications should be verified before substitution?

A: All recommended substitutes are ROHS3 compliant and REACH unaffected, matching the FDS8672S compliance profile. Moisture sensitivity levels are acceptable (MSL 1 or MSL 3). For automotive applications, the SQ4182EY-T1_GE3 carries AEC-Q101 qualification. Verify that the selected substitute meets any application-specific compliance requirements before implementation.

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