FDS9933 MOSFET Equivalent & Substitute Parts

Part Overview

The FDS9933 is a dual P-channel MOSFET array manufactured by onsemi, designed for surface mount applications in the 8-SOIC package. This device features logic level gate operation with a maximum drain-source voltage rating of 20V and continuous drain current capability of 5A at 25°C. The FDS9933 is classified as obsolete, which necessitates identification of functionally equivalent substitute components for ongoing design support and procurement requirements. The part belongs to the PowerTrench® series and is suitable for applications requiring low on-resistance switching performance in compact form factors.

Substiute Parts

FDS9933

onsemiIn Stock: 80336FDS9933 Datasheet

Current PartRFQ

FDS9933A

onsemiIn Stock: 7900FDS9933A Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the FDS9933 is determined by strict adherence to the following electrical and mechanical parameters:

Critical Matching Parameters:

• Drain to Source Voltage (Vdss): Must equal or exceed 20V
• Package Type: Must be 8-SOIC surface mount configuration
• Configuration: Must be dual P-channel MOSFET array
• Technology: Must be MOSFET (Metal Oxide) with logic level gate operation
• Maximum Power Dissipation: Must support 900mW rating

Allowable Variation Parameters:

• Continuous Drain Current (Id): Substitute may be lower than 5A if application requirements permit
• On-Resistance (Rds On): Substitute may be higher than 55mOhm if thermal and power dissipation constraints are satisfied
• Gate Charge (Qg): Substitute may differ from 20nC based on switching speed requirements
• Input Capacitance (Ciss): Substitute may differ from 825pF based on gate drive circuit design
• Operating Temperature Range: Substitute may have a narrower range than -55°C to 175°C if application operates within the substitute's specified limits

The FDS9933A meets all critical matching parameters and is identified as a direct substitute.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: FDS9933A

The FDS9933A is the direct substitute for the obsolete FDS9933. Both devices share identical voltage ratings, package configuration, and maximum power dissipation specifications. The FDS9933A is manufactured by onsemi and maintains active product status with current manufacturing support.

Substitution Feasibility:

The FDS9933A is suitable as a replacement when the following conditions are met:

1. Current Requirements: The application continuous drain current requirement does not exceed 3.8A. If the design requires the full 5A capability of the original FDS9933, the FDS9933A is not suitable.

2. Thermal Performance: The higher on-resistance of the FDS9933A (75mOhm versus 55mOhm) results in increased power dissipation at equivalent current levels. Thermal analysis must confirm that the 900mW maximum power rating is not exceeded under worst-case operating conditions.

3. Gate Drive Compatibility: The FDS9933A exhibits a higher gate threshold voltage (1.5V versus 1.2V). The gate drive circuit must supply sufficient voltage to reliably turn on the device. The lower gate charge (10nC versus 20nC) and input capacitance (600pF versus 825pF) reduce gate drive power requirements.

4. Temperature Operating Range: The FDS9933A maximum junction temperature is 150°C, compared to 175°C for the FDS9933. Applications operating above 150°C junction temperature require thermal derating or alternative components.

5. Compliance and Availability: The FDS9933A is RoHS3 compliant and actively stocked. The FDS9933 is obsolete with limited availability. Transition to FDS9933A is recommended for new designs and ongoing production.

Frequently Asked Questions (FAQ)

Q: Can the FDS9933A directly replace the FDS9933 in existing designs?

A: Direct replacement is possible only if the application current requirement does not exceed 3.8A and the maximum junction temperature does not exceed 150°C. The identical 8-SOIC package and pin configuration ensure mechanical and electrical compatibility at the board level. However, circuit performance differences due to higher on-resistance and gate threshold voltage must be evaluated.

Q: What is the impact of the higher on-resistance in the FDS9933A?

A: The FDS9933A on-resistance of 75mOhm (at 3.8A, 4.5V) compared to the FDS9933 at 55mOhm (at 3.2A, 4.5V) results in increased power dissipation during conduction. At equivalent current levels, power loss increases proportionally. Thermal analysis must confirm that total power dissipation remains within the 900mW maximum rating under worst-case conditions including ambient temperature and duty cycle.

Q: Are there pin compatibility concerns between FDS9933 and FDS9933A?

A: No. Both devices use the 8-SOIC package with identical pin assignments. The devices are pin-for-pin compatible and require no PCB layout modifications for substitution.

Q: How does the lower gate charge of FDS9933A affect circuit design?

A: The FDS9933A gate charge of 10nC (versus 20nC for FDS9933) reduces the total charge required to switch the device. This results in lower gate drive power consumption and faster switching transitions. Gate drive circuits designed for the FDS9933 will operate with improved efficiency when driving the FDS9933A.

Q: What is the significance of the different gate threshold voltages?

A: The FDS9933A gate threshold voltage of 1.5V (versus 1.2V for FDS9933) requires slightly higher gate drive voltage to ensure reliable device turn-on. Gate drive circuits must supply at least 1.5V to the gate terminal. Circuits designed with marginal gate drive voltage may require adjustment when substituting to FDS9933A.

Q: Is the FDS9933A suitable for applications requiring the full 5A continuous current rating?

A: No. The FDS9933A is rated for 3.8A continuous drain current at 25°C. Applications requiring 5A operation must use alternative components or the original FDS9933 if available. Exceeding the rated current will result in device failure or reduced reliability.

Q: What compliance certifications apply to the FDS9933A?

A: The FDS9933A is RoHS3 compliant and REACH unaffected. Both devices carry ECCN classification EAR99 and HTSUS code 8541.21.0095. The FDS9933A has moisture sensitivity level (MSL) rating of 1 (unlimited), indicating no moisture sensitivity constraints for storage and handling.

Q: Why is the FDS9933 classified as obsolete?

A: The FDS9933 is no longer in active production by onsemi. The FDS9933A represents the current active product in the PowerTrench® dual P-channel MOSFET family. Existing FDS9933 inventory is limited, and new designs should transition to FDS9933A for long-term supply assurance.

Q: Can the FDS9933A operate at the full 175°C junction temperature of the original FDS9933?

A: No. The FDS9933A maximum junction temperature is 150°C. Applications requiring operation above 150°C must use alternative components. Thermal design must ensure that junction temperature remains below 150°C under all operating conditions.