FDS6609A P-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The FDS6609A is a P-Channel MOSFET manufactured by onsemi, rated for 30V drain-to-source voltage with 6.3A continuous drain current at 25°C. This device is housed in an 8-SOIC surface mount package and is part of the PowerTrench® series. The FDS6609A is classified as obsolete, making identification of equivalent and substitute parts necessary for ongoing design support and procurement continuity. Substitute parts must maintain compatibility across voltage ratings, current handling, package form factor, and thermal characteristics to ensure direct replacement capability in existing circuit designs.

Key Parameters

Parameter	FDS6609A
Drain-to-Source Voltage (Vdss)	30 V
Continuous Drain Current (Id) @ 25°C	6.3 A
On-Resistance (Rds On Max) @ Id, Vgs	32 mOhm @ 7A, 10V
Gate Threshold Voltage (Vgs(th) Max) @ Id	3 V @ 250 µA
Gate Charge (Qg Max) @ Vgs	29 nC @ 10 V
Power Dissipation (Max)	2.5 W
Operating Temperature Range	-55°C to 150°C (TJ)
Package Type	8-SOIC
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution eligibility for the FDS6609A is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Drain-to-Source Voltage (Vdss): Must equal or exceed 30V
Package Type: Must be 8-SOIC form factor
Mounting Type: Must be Surface Mount
FET Type: Must be P-Channel
Technology: Must be MOSFET (Metal Oxide)
Operating Temperature Range: Must support -55°C to 150°C (TJ)

Performance Parameters:

Continuous Drain Current (Id): Substitute must support minimum 6.3A at 25°C
On-Resistance (Rds On): Lower or equivalent values are acceptable
Gate Charge (Qg): Lower or equivalent values are acceptable
Power Dissipation: Must support minimum 2.5W

All four substitute parts listed meet these mandatory criteria and are therefore qualified as direct replacements for the obsolete FDS6609A.

Parameter Comparison

Parameter	FDS6609A	FDS4435BZ	SI4431BDY-T1-GE3	STS6P3LLH6	ZXMP3A16N8TA
Manufacturer	onsemi	onsemi	Vishay Siliconix	STMicroelectronics	Diodes Incorporated
Drain-to-Source Voltage (Vdss)	30 V	30 V	30 V	30 V	30 V
Continuous Drain Current (Id) @ 25°C	6.3 A	8.8 A	5.7 A	6 A	5.6 A
Rds On (Max) @ Id, Vgs	32 mOhm @ 7A, 10V	20 mOhm @ 8.8A, 10V	30 mOhm @ 7.5A, 10V	30 mOhm @ 3A, 10V	40 mOhm @ 4.2A, 10V
Gate Threshold Voltage (Vgs(th) Max) @ Id	3 V @ 250 µA	3 V @ 250 µA	3 V @ 250 µA	1 V @ 250 µA (Min)	1 V @ 250 µA
Gate Charge (Qg Max) @ Vgs	29 nC @ 10 V	40 nC @ 10 V	20 nC @ 5 V	12 nC @ 4.5 V	29.6 nC @ 10 V
Power Dissipation (Max)	2.5 W	2.5 W	1.5 W	2.7 W	1.9 W
Operating Temperature Range	-55°C to 150°C (TJ)	-55°C to 150°C (TJ)	-55°C to 150°C (TJ)	150°C (TJ)	-55°C to 150°C (TJ)
Package Type	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

FDS4435BZ (onsemi)

The FDS4435BZ is an active product from onsemi with enhanced current handling capability (8.8A versus 6.3A) and improved on-resistance characteristics (20 mOhm versus 32 mOhm). This part maintains identical voltage ratings and thermal specifications while offering superior performance margins. The FDS4435BZ is ROHS3 compliant and carries active product status, ensuring long-term availability and supply chain stability. This substitute is optimal for applications requiring higher current capacity or lower conduction losses.

SI4431BDY-T1-GE3 (Vishay Siliconix)

The SI4431BDY-T1-GE3 is a Vishay Siliconix TrenchFET® device with active product status and ROHS3 compliance. This part operates within the specified voltage and temperature ranges with 5.7A continuous drain current. The SI4431BDY-T1-GE3 features lower gate charge (20 nC) compared to the FDS6609A, resulting in faster switching characteristics. Power dissipation is rated at 1.5W, which is lower than the FDS6609A specification. This substitute is suitable for applications where switching speed and reduced power dissipation are beneficial.

STS6P3LLH6 (STMicroelectronics)

The STS6P3LLH6 is an active STMicroelectronics product utilizing DeepGATE™ and STripFET™ VI technology. This part meets the 30V voltage requirement and supports 6A continuous drain current. The STS6P3LLH6 exhibits significantly lower gate charge (12 nC) and lower gate threshold voltage (1V minimum) compared to the FDS6609A, enabling faster switching response and reduced drive requirements. Power dissipation is rated at 2.7W. The operating temperature specification lists 150°C (TJ) without a lower bound; verification of minimum operating temperature is required for applications requiring full -55°C to 150°C range support.

ZXMP3A16N8TA (Diodes Incorporated)

The ZXMP3A16N8TA is an active Diodes Incorporated product with ROHS3 compliance and REACH compliance confirmation. This part maintains 30V voltage rating and supports 5.6A continuous drain current. The ZXMP3A16N8TA features gate charge characteristics (29.6 nC) comparable to the FDS6609A with lower gate threshold voltage (1V). Power dissipation is rated at 1.9W. This substitute provides a balanced alternative with active product status and full temperature range support (-55°C to 150°C).

Frequently Asked Questions (FAQ)

Q: Can the FDS4435BZ directly replace the FDS6609A in all applications?

A: The FDS4435BZ meets all mandatory compatibility criteria for direct substitution. The higher current rating (8.8A versus 6.3A) and lower on-resistance (20 mOhm versus 32 mOhm) provide performance enhancement. Applications operating at or below 6.3A will function identically or with improved efficiency. No circuit modifications are required.

Q: What is the primary difference between the SI4431BDY-T1-GE3 and the FDS6609A?

A: The SI4431BDY-T1-GE3 features lower gate charge (20 nC versus 29 nC) and lower power dissipation (1.5W versus 2.5W). These characteristics result in faster switching transitions and reduced thermal load. The continuous drain current is slightly lower (5.7A versus 6.3A). Applications operating below 5.7A will function within specification; applications requiring the full 6.3A rating should use FDS4435BZ or STS6P3LLH6.

Q: Does the STS6P3LLH6 support the full operating temperature range of the FDS6609A?

A: The STS6P3LLH6 datasheet specifies 150°C (TJ) as the maximum operating temperature without explicitly stating a minimum temperature. The FDS6609A specifies -55°C to 150°C (TJ). Applications requiring operation below 0°C should confirm STS6P3LLH6 minimum temperature capability with the manufacturer or select an alternative substitute.

Q: Are all substitute parts available in the same packaging format?

A: All substitute parts are housed in 8-SOIC surface mount packages with identical physical dimensions (0.154", 3.90mm width). PCB layout and footprints are directly compatible. No board redesign is required for package accommodation.

Q: Which substitute part offers the lowest on-resistance?

A: The FDS4435BZ provides the lowest on-resistance at 20 mOhm (measured at 8.8A, 10V gate-source voltage). This characteristic reduces conduction losses and heat generation in high-current applications.

Q: What is the significance of gate charge differences among the substitute parts?

A: Gate charge (Qg) determines the energy required to switch the transistor. Lower gate charge values enable faster switching transitions and reduce driver power consumption. The STS6P3LLH6 exhibits the lowest gate charge (12 nC), followed by SI4431BDY-T1-GE3 (20 nC). Applications with high switching frequencies benefit from lower gate charge specifications.

Q: Are all substitute parts RoHS compliant?

A: All four substitute parts are ROHS3 compliant. The FDS6609A compliance status is not specified in the provided data. For applications requiring RoHS certification, FDS4435BZ, SI4431BDY-T1-GE3, STS6P3LLH6, and ZXMP3A16N8TA all meet this requirement.

Q: Which substitute part is recommended for new designs?

A: All substitute parts carry active product status, ensuring long-term availability. Selection should be based on specific application requirements: FDS4435BZ for maximum current capacity, SI4431BDY-T1-GE3 for lowest power dissipation, STS6P3LLH6 for fastest switching response, or ZXMP3A16N8TA for balanced performance across all parameters.

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