FDT86256 Equivalent & Substitute Parts

Part Overview

The FDT86256 is an N-Channel MOSFET manufactured by onsemi, rated for 150V drain-to-source voltage with continuous drain current of 1.2A (Ta) or 3A (Tc) in a surface mount SOT-223-4 package. This device is part of the PowerTrench® series and operates across a temperature range of -55°C to 150°C.

The FDT86256 has reached obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this MOSFET.

Substiute Parts

FDT86256

onsemiIn Stock: 25211FDT86256 Datasheet

Current PartRFQ

FDT86246

onsemiIn Stock: 7544FDT86246 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FDT86256 is determined by electrical and mechanical compatibility across the following critical parameters:

Voltage Rating Compatibility: The substitute part must maintain the 150V Vdss rating to ensure safe operation within the same voltage domain.

Current Rating Compatibility: The substitute part must support continuous drain current specifications that meet or exceed the application requirements. The FDT86256 provides 1.2A (Ta) or 3A (Tc); substitute parts must accommodate these current levels.

Gate Voltage Compatibility: The Vgs(th) threshold voltage and maximum Vgs rating must remain within ±20V to ensure compatible gate drive circuitry.

On-State Resistance: The Rds On parameter directly affects power dissipation and thermal performance. Substitute parts with lower Rds On values provide improved efficiency and reduced heat generation.

Package Compatibility: Both the main part and substitute must use the SOT-223-4 surface mount package to ensure mechanical and electrical compatibility with existing PCB layouts.

Temperature Range: Operating temperature specifications must span -55°C to 150°C to maintain thermal performance across the intended application environment.

Compliance and Status: Substitute parts must maintain RoHS3 compliance, REACH unaffected status, and preferably active product status for long-term availability.

Parameter Comparison

Engineering Selection Recommendations

FDT86246 as Primary Substitute

The FDT86246 is the manufacturer-recommended substitute for the FDT86256. Both devices share identical voltage ratings (150V Vdss), gate threshold specifications (4V @ 250µA), and maximum gate voltage (±20V). Both operate across the full temperature range of -55°C to 150°C and are packaged in SOT-223-4 surface mount configuration.

The FDT86246 provides superior electrical performance with continuous drain current of 2A (Ta), exceeding the FDT86256's 1.2A rating. The on-state drain resistance is significantly lower at 236mOhm compared to 845mOhm, resulting in reduced power dissipation and improved thermal efficiency.

Compliance and Availability

Both parts maintain RoHS3 compliance and REACH unaffected status, ensuring regulatory compatibility. The FDT86246 holds active product status, providing assured long-term availability and supply chain continuity compared to the obsolete FDT86256.

Application Suitability

The FDT86246 is suitable for applications where the FDT86256 was previously deployed, provided that the application current requirements do not exceed 2A (Ta). The improved Rds On characteristic of the FDT86246 makes it particularly advantageous for power-sensitive applications where thermal management is a design consideration.

Frequently Asked Questions (FAQ)

Q: Can the FDT86246 directly replace the FDT86256 in existing designs?

A: Yes. Both devices share identical voltage ratings (150V Vdss), gate threshold voltage (4V), maximum gate voltage (±20V), operating temperature range (-55°C to 150°C), and SOT-223-4 package configuration. No PCB layout modifications are required.

Q: What are the key electrical differences between these parts?

A: The FDT86246 provides higher continuous drain current (2A Ta versus 1.2A Ta) and significantly lower on-state drain resistance (236mOhm versus 845mOhm at 10V). These improvements result in reduced power dissipation and better thermal performance. The FDT86246 has higher gate charge (4nC versus 2nC) and input capacitance (215pF versus 73pF), which may affect gate drive circuit timing.

Q: Are there any thermal performance considerations?

A: The FDT86246 exhibits lower on-state resistance, which reduces I²R losses and heat generation during conduction. Power dissipation at Ta is comparable (2.2W versus 2.3W), but the improved Rds On characteristic provides better thermal efficiency in continuous operation scenarios.

Q: What is the impact of higher gate charge on circuit design?

A: The FDT86246 requires 4nC of gate charge compared to 2nC for the FDT86256. Gate drive circuits must supply sufficient current to charge the gate within the required switching time. Existing gate drive circuits designed for the FDT86256 may require evaluation to ensure adequate drive capability for the FDT86246.

Q: Are both parts available in the same packaging options?

A: Both the FDT86256 and FDT86246 are supplied in SOT-223-4 surface mount packages. The FDT86256 is available in Cut Tape (CT) packaging, while the FDT86246 is supplied in Tape & Reel (TR) format. Both are compatible with standard surface mount assembly processes.

Q: What is the regulatory compliance status of the substitute part?

A: The FDT86246 maintains RoHS3 compliance and REACH unaffected status, identical to the FDT86256. Both parts meet current environmental and regulatory requirements for electronic component manufacturing and use.

Q: Why is the FDT86256 listed as obsolete?

A: The FDT86256 has reached end-of-life status. The FDT86246 represents the active product line continuation within the PowerTrench® series, offering improved electrical characteristics and assured long-term availability.