FDMS7700S Equivalent & Substitute Parts

Part Overview

The FDMS7700S is a dual N-channel MOSFET array manufactured by onsemi, designed for power switching applications requiring 30V drain-to-source voltage capability and continuous drain current ratings of 12A to 22A. The device features logic-level gate drive, making it suitable for direct microcontroller interfacing in power management circuits.

This part carries a Last Time Buy status, indicating that onsemi has discontinued or will discontinue production. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support long-term product availability for applications currently utilizing the FDMS7700S.

Substiute Parts

FDMS7700S

onsemiIn Stock: 6419FDMS7700S Datasheet

Current PartRFQ

CSD86350Q5D

Texas InstrumentsIn Stock: 34869CSD86350Q5D Datasheet

SimilarRFQ

STL66DN3LLH5

STMicroelectronicsIn Stock: 22720STL66DN3LLH5 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the FDMS7700S is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Drain-to-Source Voltage (Vdss) must be equal to or greater than 30V
• Continuous Drain Current (Id) must meet or exceed the application requirement (12A or 22A)
• Gate Threshold Voltage (Vgs(th)) must support logic-level gate drive operation (typically ≤ 3V @ 250µA)
• On-Resistance (Rds On) must be compatible with thermal and efficiency requirements
• Configuration must be dual N-channel to maintain circuit topology

Mechanical Compatibility Criteria:

• Mounting type must be Surface Mount
• Package must accommodate the 8-pin power package footprint
• Moisture Sensitivity Level must be MSL 1 or equivalent

Compliance Criteria:

• RoHS3 compliance required
• Operating temperature range must support -55°C to 150°C minimum

The substitute parts identified below satisfy these criteria with variations in current rating, power dissipation, and package geometry that allow functional replacement in the target application.

Parameter Comparison

Engineering Selection Recommendations

STL66DN3LLH5 (STMicroelectronics)

The STL66DN3LLH5 provides the closest electrical match to the FDMS7700S. Both devices maintain 30V Vdss rating and dual N-channel configuration. The STL66DN3LLH5 offers significantly higher continuous drain current (78.5A versus 12A/22A) and power dissipation capability (72W versus 1W), making it suitable for applications requiring higher current handling or thermal performance. Gate threshold voltage remains at 3V, ensuring compatible logic-level gate drive. The extended operating temperature range (-55°C to 175°C) provides additional thermal margin. This device carries Active product status and holds AEC-Q101 automotive qualification, supporting long-term availability and reliability in automotive and industrial applications. Package geometry differs (PowerFlat 5x6 versus Power56), requiring PCB layout verification.

CSD86350Q5D (Texas Instruments)

The CSD86350Q5D offers an alternative with 25V Vdss rating and 40A continuous drain current. While the voltage rating is 5V lower than the FDMS7700S, this device remains suitable for applications operating at or below 25V. The lower gate threshold voltage (2.1V) provides improved gate drive efficiency. Reduced gate charge (10.7nC) and lower input capacitance support faster switching performance. The 13W power dissipation rating exceeds the FDMS7700S capability. This device carries Active product status and is available in high inventory quantities. Package geometry differs (8-LSON 5x6 versus Power56), requiring PCB layout verification. The half-bridge configuration differs from the dual configuration of the FDMS7700S; circuit topology compatibility must be confirmed.

Product Status Consideration

Both substitute parts carry Active product status, ensuring continued manufacturing and long-term supply availability. The FDMS7700S Last Time Buy status necessitates transition planning to one of these alternatives for new designs or production continuity.

Frequently Asked Questions (FAQ)

Q: Can the STL66DN3LLH5 directly replace the FDMS7700S in existing PCB designs?

A: Electrical substitution is feasible due to matching Vdss (30V) and dual N-channel configuration. However, package geometry differs (PowerFlat 5x6 versus Power56), requiring PCB footprint modification. Pin assignment and thermal pad layout must be verified against the STL66DN3LLH5 datasheet before implementation.

Q: Is the CSD86350Q5D suitable for 30V applications?

A: The CSD86350Q5D is rated for 25V Vdss maximum. Applications requiring 30V operation must use the STL66DN3LLH5 or confirm that actual operating voltage does not exceed 25V. Using a 25V-rated device in a 30V circuit violates absolute maximum ratings and voids reliability.

Q: What is the difference between dual and half-bridge MOSFET configurations?

A: Dual configuration provides two independent N-channel MOSFETs in a single package. Half-bridge configuration integrates one high-side and one low-side MOSFET optimized for complementary switching. Circuit topology determines which configuration is appropriate. Verify gate drive requirements and switching logic before substituting between configurations.

Q: Do all substitute parts require the same gate drive voltage?

A: All three devices feature logic-level gate drive with gate threshold voltages between 2.1V and 3V, supporting direct microcontroller interfacing. Gate charge differs (28nC for FDMS7700S, 12nC for STL66DN3LLH5, 10.7nC for CSD86350Q5D), affecting gate driver current requirements. Verify gate driver capability for the selected substitute.

Q: Are there thermal considerations when substituting to higher-power devices?

A: The STL66DN3LLH5 (72W) and CSD86350Q5D (13W) offer significantly higher power dissipation than the FDMS7700S (1W). Applications with identical current and voltage stress will generate less heat in the substitute devices due to lower on-resistance. Thermal design may be simplified, but PCB layout and thermal management must be re-evaluated for the new package geometry.

Q: What is the impact of different input capacitance values?

A: Input capacitance (Ciss) affects gate charge and switching speed. The FDMS7700S has 1750pF at 15V, while substitutes range from 1500pF to 1870pF. These variations are minor and typically do not require gate driver redesign. Verify gate driver slew rate capability if switching frequency is critical.

Q: Are all parts RoHS3 compliant and MSL 1?

A: Yes. All three devices (FDMS7700S, STL66DN3LLH5, and CSD86350Q5D) are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity. No additional handling or storage precautions are required beyond standard ESD protection.

Q: Which substitute is recommended for new designs?

A: Selection depends on application voltage and current requirements. For 30V applications requiring current up to 22A, the STL66DN3LLH5 is recommended due to matching voltage rating, active product status, and automotive qualification. For applications operating at 25V or below with current requirements up to 40A, the CSD86350Q5D offers excellent performance and availability. Verify package compatibility with existing PCB designs.