FDS6900AS Equivalent & Substitute Parts

Part Overview

The FDS6900AS is a dual N-channel MOSFET array manufactured by onsemi, designed for surface mount applications in 8-SOIC packaging. This device features logic level gate operation with a 30V drain-to-source voltage rating and continuous drain current capabilities of 6.9A and 8.2A. The part is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing design support and procurement.

Substiute Parts

FDS6900AS

onsemiIn Stock: 50308FDS6900AS Datasheet

Current PartRFQ

FDS6986AS

Fairchild SemiconductorIn Stock: 50378FDS6986AS Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FDS6900AS is determined by strict equivalence across the following critical parameters:

Voltage Rating: Both the main part and substitute must maintain a Vdss of 30V to ensure compatibility with circuit design specifications.

Package Configuration: The 8-SOIC surface mount package with 0.154" (3.90mm) width is mandatory for PCB layout compatibility.

Dual N-Channel Configuration: The device must contain two N-channel MOSFETs in a single package to match the functional architecture.

Logic Level Gate Operation: The substitute must support logic level gate drive characteristics for direct interface with standard digital control circuits.

Continuous Drain Current: The substitute must support drain current ratings within the operational range of the original design. The FDS6900AS specifies 6.9A and 8.2A; substitutes with 6.5A and 7.9A remain functionally compatible within this category.

Thermal and Electrical Characteristics: Operating temperature range, on-resistance, gate charge, and input capacitance must fall within acceptable tolerances for the intended application.

Parameter Comparison

Engineering Selection Recommendations

The FDS6900AS is classified as obsolete, making the FDS6986AS the primary substitute for ongoing procurement and design continuity.

Compliance and Certification: The FDS6986AS maintains RoHS3 compliance and REACH unaffected status, consistent with modern regulatory requirements. The FDS6900AS, while RoHS3 compliant, carries obsolete status that limits long-term availability.

Product Status: The FDS6986AS is active in production, ensuring reliable supply chain access and manufacturer support. The obsolete status of the FDS6900AS creates procurement risk and potential discontinuation of technical documentation.

Electrical Performance: The FDS6986AS exhibits slightly higher on-resistance (29mOhm versus 27mOhm) and gate charge (17nC versus 15nC), representing marginal increases within acceptable engineering tolerances. The continuous drain current rating is lower (6.5A/7.9A versus 6.9A/8.2A), requiring verification that circuit current demands do not exceed the substitute's specifications.

Package and Configuration: Both devices share identical 8-SOIC packaging and dual N-channel configuration, enabling direct PCB layout compatibility without redesign.

Thermal Characteristics: Operating temperature ranges are identical, supporting equivalent thermal management strategies.

Frequently Asked Questions (FAQ)

Q: Can the FDS6986AS directly replace the FDS6900AS in existing designs?

A: Direct replacement is possible when circuit current requirements do not exceed 6.5A or 7.9A continuous drain current. The FDS6986AS maintains identical voltage rating, package configuration, and operating temperature range. Verification of actual circuit current draw against the substitute's specifications is required before implementation.

Q: What is the significance of the slightly higher on-resistance in the FDS6986AS?

A: The FDS6986AS exhibits 29mOhm on-resistance compared to 27mOhm in the FDS6900AS. This 2mOhm difference results in marginally increased power dissipation during conduction. For applications operating near thermal limits, thermal analysis of the substitute device is necessary to confirm adequate heat dissipation.

Q: Are there differences in gate drive requirements between these devices?

A: Both devices specify identical gate threshold voltage (Vgs(th)) of 3V at 250µA, supporting equivalent gate drive circuits. The FDS6986AS exhibits slightly higher gate charge (17nC versus 15nC), requiring marginally increased gate drive energy but remaining compatible with standard logic level gate drivers.

Q: Does the higher input capacitance of the FDS6986AS affect circuit performance?

A: The FDS6986AS specifies 720pF input capacitance at 10V compared to 600pF at 15V in the FDS6900AS. Higher input capacitance increases gate drive current requirements and may slightly increase switching losses in high-frequency applications. Circuit-level analysis is necessary for applications operating above 1MHz switching frequency.

Q: What packaging considerations apply to this substitution?

A: Both devices utilize 8-SOIC surface mount packaging with identical 0.154" (3.90mm) width. PCB footprints, solder reflow profiles, and pick-and-place equipment settings remain unchanged. No mechanical redesign is required.

Q: Why is the FDS6900AS classified as obsolete?

A: Obsolete status indicates the manufacturer has discontinued production and support. The FDS6986AS, maintained in active production status, provides equivalent functionality with assured long-term availability and manufacturer technical support.

Q: Are there compliance differences between the two devices?

A: Both devices are RoHS3 compliant. The FDS6900AS carries REACH unaffected status, as does the FDS6986AS. No regulatory compliance barriers exist for substitution in applications subject to RoHS or REACH requirements.