FDMS3686S Equivalent & Substitute Parts

Part Overview

The FDMS3686S is a dual N-channel MOSFET array manufactured by onsemi, rated for 30V drain-to-source voltage with continuous drain current ratings of 13A and 23A. This device features logic level gate operation and is housed in an 8-PowerTDFN (Power56) surface mount package. The FDMS3686S is classified as obsolete product status, making identification of equivalent and substitute components necessary for ongoing design support, production continuity, and system maintenance applications.

Substiute Parts

FDMS3686S

onsemiIn Stock: 2135FDMS3686S Datasheet

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FDMC007N30D

onsemiIn Stock: 2227FDMC007N30D Datasheet

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STL66DN3LLH5

STMicroelectronicsIn Stock: 22720STL66DN3LLH5 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the FDMS3686S is determined by the following critical parameters that must be maintained or exceeded:

Mandatory Matching Parameters:

• Drain to Source Voltage (Vdss): 30V minimum
• Configuration: Dual N-Channel MOSFET
• Mounting Type: Surface Mount
• Operating Temperature Range: -55°C to 150°C minimum
• RoHS3 Compliance and MSL Level 1 rating

Performance Parameters for Functional Equivalence:

• Continuous Drain Current (Id): Substitute must support 13A minimum at 25°C
• On-State Resistance (Rds On): Lower or equal values indicate improved performance
• Gate Threshold Voltage (Vgs(th)): Logic level operation (typically ≤ 3V @ 250µA)
• Gate Charge (Qg): Lower values reduce switching losses
• Input Capacitance (Ciss): Lower values improve switching speed

The substitute parts FDMC007N30D and STL66DN3LLH5 meet these criteria with enhanced current handling and thermal performance characteristics while maintaining voltage and temperature specifications.

Parameter Comparison

Engineering Selection Recommendations

FDMC007N30D (onsemi): This substitute maintains onsemi manufacturing continuity and active product status. The FDMC007N30D provides 46A continuous drain current, exceeding the FDMS3686S 23A maximum rating. On-state resistance of 11.6 mOhm at 10A is comparable to the original device. The 8-PowerWDFN package (8-Power33 3x3) differs from the original Power56 package, requiring PCB layout modification. This device is suitable for applications requiring higher current capacity within the same voltage class. ROHS3 compliance and MSL Level 1 rating match the original specification.

STL66DN3LLH5 (STMicroelectronics): This substitute offers the highest performance metrics with 78.5A continuous drain current and 6.5 mOhm on-state resistance at 10A, providing superior thermal and switching characteristics. The STL66DN3LLH5 features AEC-Q101 automotive qualification and extended operating temperature range to 175°C, exceeding the original -55°C to 150°C specification. The 8-PowerVDFN package (PowerFlat 5x6) requires PCB layout redesign. Gate charge of 12 nC at 4.5V is significantly lower than the original 29 nC, reducing switching losses. This device is appropriate for high-reliability and automotive applications. ROHS3 compliance and MSL Level 1 rating are maintained.

Selection Basis: Both substitute parts satisfy the mandatory electrical parameters (30V Vdss, dual N-channel configuration, logic level gate operation, surface mount mounting). Selection between substitutes depends on application current requirements, thermal management capability, package space constraints, and automotive qualification requirements. All three devices maintain RoHS3 compliance and unlimited moisture sensitivity rating.

Frequently Asked Questions (FAQ)

Q: Can the FDMC007N30D directly replace the FDMS3686S without PCB modification?

A: No. While both devices are onsemi dual N-channel MOSFETs rated for 30V operation, the package types differ. The FDMS3686S uses 8-PowerTDFN (Power56) while the FDMC007N30D uses 8-PowerWDFN (8-Power33 3x3). PCB footprint and layout modifications are required.

Q: What are the key electrical differences between the FDMS3686S and STL66DN3LLH5?

A: The STL66DN3LLH5 provides significantly higher continuous drain current (78.5A versus 23A), lower on-state resistance (6.5 mOhm versus 8 mOhm), and lower gate charge (12 nC versus 29 nC). Operating temperature range extends to 175°C compared to 150°C. Package type and footprint differ, requiring PCB redesign.

Q: Is the STL66DN3LLH5 suitable for automotive applications?

A: Yes. The STL66DN3LLH5 carries AEC-Q101 automotive qualification, making it appropriate for automotive-grade applications. The FDMS3686S and FDMC007N30D do not carry automotive qualification.

Q: Do all three devices maintain RoHS3 compliance?

A: Yes. The FDMS3686S, FDMC007N30D, and STL66DN3LLH5 are all ROHS3 compliant with MSL Level 1 (unlimited) moisture sensitivity rating.

Q: What is the primary reason for substituting the FDMS3686S?

A: The FDMS3686S is classified as obsolete product status. Substitute parts with active product status ensure long-term availability, supply chain continuity, and access to current manufacturing processes and quality standards.

Q: How do gate charge differences affect circuit performance?

A: Gate charge (Qg) determines the energy required to switch the MOSFET. The STL66DN3LLH5 with 12 nC gate charge requires less switching energy than the FDMS3686S with 29 nC, resulting in reduced power dissipation and improved switching speed in gate driver circuits.

Q: Are package footprints interchangeable between the three devices?

A: No. The three devices use different package types: FDMS3686S (8-PowerTDFN Power56), FDMC007N30D (8-PowerWDFN 8-Power33), and STL66DN3LLH5 (8-PowerVDFN PowerFlat 5x6). Each requires a distinct PCB footprint and layout design.

Q: What thermal performance improvement does the STL66DN3LLH5 provide?

A: The STL66DN3LLH5 supports maximum power dissipation of 72W compared to 1W for the FDMS3686S, indicating substantially improved thermal handling capability. Lower on-state resistance (6.5 mOhm) also reduces resistive heating during operation.