FDB8453LZ N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The FDB8453LZ is an N-Channel MOSFET manufactured by onsemi, rated for 40V drain-to-source voltage with continuous drain current of 16.1A (Ta) and 50A (Tc). This device is housed in a Surface Mount TO-263 (D2PAK) package and belongs to the PowerTrench® series. The FDB8453LZ is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing design support and production continuity. Substitute parts must maintain electrical compatibility across voltage ratings, current handling, thermal characteristics, and package form factor to ensure direct replacement capability.

Substiute Parts

FDB8453LZ

onsemiIn Stock: 1470FDB8453LZ Datasheet

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FDB8447L

onsemiIn Stock: 24106FDB8447L Datasheet

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BUK765R2-40B,118

NXP USA Inc.In Stock: 24087BUK765R2-40B,118 Datasheet

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BUK9609-40B,118

Nexperia USA Inc.In Stock: 6360BUK9609-40B,118 Datasheet

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BUK9675-55A,118

Nexperia USA Inc.In Stock: 6661BUK9675-55A,118 Datasheet

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PHB21N06LT,118

NXP USA Inc.In Stock: 1931PHB21N06LT,118 Datasheet

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PSMN8R0-40BS,118

Nexperia USA Inc.In Stock: 1753PSMN8R0-40BS,118 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FDB8453LZ are evaluated based on the following critical parameters:

Voltage Compatibility: All substitute parts must support a minimum Vdss rating equal to or greater than 40V to ensure safe operation under the same voltage conditions.

Current Handling: Substitute parts must support continuous drain current (Tc) of at least 50A to maintain equivalent current-carrying capacity. Parts with lower Ta ratings (ambient temperature) may be acceptable if Tc ratings meet or exceed the original specification.

On-Resistance (Rds On): Substitute parts with Rds On values at or below 7mOhm @ 10V maintain electrical efficiency equivalent to the original device. Higher Rds On values result in increased power dissipation and heat generation.

Package Form Factor: All substitute parts must use the TO-263 (D2PAK) Surface Mount package to ensure mechanical and thermal compatibility with existing PCB layouts and thermal management solutions.

Temperature Range: Substitute parts must support the operating temperature range of -55°C to 150°C minimum. Extended temperature ranges (to 175°C) provide additional design margin.

Gate Charge (Qg): Gate charge values influence switching speed and driver circuit requirements. Substitute parts with Qg values between 21nC and 66nC are compatible with standard gate driver circuits.

Substitute parts are grouped into two categories: Direct Equivalents (same voltage and current class) and Higher-Performance Alternatives (higher current or voltage ratings suitable for applications requiring additional design margin).

Parameter Comparison

Engineering Selection Recommendations

Direct Equivalent (Same Voltage and Current Class):

FDB8447L is the closest direct equivalent to FDB8453LZ. Both devices are manufactured by onsemi, operate at 40V with 50A (Tc) continuous drain current, and use identical TO-263 (D2PAK) packaging. The FDB8447L features slightly higher on-resistance (8.5mOhm vs. 7mOhm) and lower gate charge (52nC vs. 66nC), resulting in marginally reduced switching losses. Both devices are classified as obsolete; however, FDB8447L maintains higher inventory availability (24,087 units vs. 1,389 units). This part is suitable for direct replacement in existing designs without circuit modification.

Higher-Performance Alternatives (40V Class):

BUK765R2-40B (NXP USA Inc.) and BUK9609-40B (Nexperia USA Inc.) both operate at 40V with 75A (Tc) continuous drain current, providing 50% higher current capacity than the FDB8453LZ. Both parts are active products with AEC-Q101 automotive qualification and ROHS3 compliance. BUK765R2-40B features superior on-resistance (5.2mOhm) and extended operating temperature to 175°C. BUK9609-40B offers lower gate charge (32nC) for faster switching response. These parts are suitable for applications requiring additional current margin or automotive-grade reliability.

PSMN8R0-40BS (Nexperia USA Inc.) provides 77A (Tc) continuous drain current at 40V with on-resistance of 7.6mOhm, matching the FDB8453LZ electrical characteristics while offering higher current capacity. This part is active, ROHS3 compliant, and rated to 175°C. Gate charge of 21nC enables faster switching compared to the original device.

Higher-Voltage Alternatives (55V Class):

BUK9675-55A and PHB21N06LT both operate at 55V, providing 37.5% higher voltage margin. These parts are suitable for applications where voltage headroom is required or where 40V-rated devices present insufficient safety margin. Both are active products with AEC-Q101 qualification and extended temperature ranges. However, continuous drain current is reduced to 20A (BUK9675-55A) and 19A (PHB21N06LT), making these parts unsuitable for applications requiring the full 50A capacity of the FDB8453LZ.

Compliance and Availability Considerations:

All active substitute parts (BUK765R2-40B, BUK9609-40B, BUK9675-55A, PHB21N06LT, PSMN8R0-40BS) are ROHS3 compliant and REACH unaffected. BUK765R2-40B, BUK9609-40B, and BUK9675-55A carry AEC-Q101 automotive qualification, suitable for automotive and industrial applications. FDB8447L, while obsolete, maintains substantial inventory (24,087 units) for legacy design support.

Frequently Asked Questions (FAQ)

Q: Can FDB8447L be used as a direct replacement for FDB8453LZ?

A: Yes. FDB8447L is a direct equivalent operating at identical voltage (40V) and current (50A Tc) ratings in the same TO-263 (D2PAK) package. The slightly higher on-resistance (8.5mOhm vs. 7mOhm) and lower gate charge (52nC vs. 66nC) result in negligible performance differences. No circuit modifications are required.

Q: What is the primary difference between 40V and 55V rated substitutes?

A: Voltage rating determines maximum safe drain-to-source voltage. 55V-rated devices (BUK9675-55A, PHB21N06LT) provide 37.5% higher voltage margin but typically feature reduced continuous drain current (19-20A vs. 50A). Select 55V devices only when applications require higher voltage headroom; otherwise, 40V-rated substitutes maintain full current capacity.

Q: Are automotive-qualified parts (AEC-Q101) required for all applications?

A: AEC-Q101 qualification is required for automotive and safety-critical applications. BUK765R2-40B, BUK9609-40B, and BUK9675-55A carry this qualification. For industrial and consumer applications, non-qualified parts (FDB8447L, PHB21N06LT, PSMN8R0-40BS) are acceptable. Verify application requirements before part selection.

Q: How does on-resistance (Rds On) affect circuit performance?

A: Lower on-resistance reduces power dissipation and heat generation during conduction. BUK765R2-40B (5.2mOhm) dissipates less heat than FDB8453LZ (7mOhm) at identical current levels. Higher on-resistance (BUK9675-55A at 68mOhm) increases power dissipation proportionally. Select parts based on thermal management capability and power budget requirements.

Q: What is the significance of gate charge (Qg) in substitute selection?

A: Gate charge determines the energy required to switch the device and influences switching speed. Lower gate charge (PSMN8R0-40BS at 21nC) enables faster switching and reduces driver circuit stress. Higher gate charge (FDB8453LZ at 66nC) requires more driver current but is compatible with standard gate driver circuits. Verify gate driver specifications before selecting parts with significantly different Qg values.

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

A: Yes. All substitute parts use TO-263 (D2PAK) Surface Mount packaging with identical pinout and thermal characteristics. PCB layout modifications are not required for mechanical compatibility. Verify thermal pad dimensions and solder pad patterns with device datasheets for specific manufacturing processes.

Q: What inventory considerations apply to obsolete vs. active parts?

A: FDB8453LZ (1,389 units) and FDB8447L (24,087 units) are obsolete but available from current inventory. Active parts (BUK765R2-40B, BUK9609-40B, BUK9675-55A, PHB21N06LT, PSMN8R0-40BS) are in continuous production with long-term availability. For new designs, select active parts to ensure supply chain continuity. For legacy design support, obsolete parts remain available while inventory exists.

Q: Can higher-current-rated parts (75A, 77A) be used in place of 50A-rated devices?

A: Yes. Higher current ratings provide design margin and thermal headroom without circuit modification. BUK765R2-40B (75A) and PSMN8R0-40BS (77A) are direct substitutes with superior current capacity. Lower on-resistance in these parts (5.2mOhm and 7.6mOhm respectively) may reduce power dissipation compared to the original 7mOhm specification. Verify gate driver compatibility before implementation.

Q: What is the impact of extended operating temperature range (175°C vs. 150°C)?

A: Extended temperature range to 175°C provides additional thermal margin for high-temperature applications. All active substitute parts support -55°C to 175°C operation, compared to FDB8453LZ at -55°C to 150°C. This extended range is beneficial for automotive and industrial environments but not required for standard consumer applications. Temperature derating curves in device datasheets must be consulted for specific thermal conditions.