FDB8442-F085 Equivalent & Substitute Parts

Part Overview

The FDB8442-F085 is an N-Channel 40V 28A MOSFET manufactured by onsemi in the PowerTrench® series, housed in a TO-263 (D2PAK) surface mount package. This device is rated for automotive applications with AEC-Q101 qualification and operates across a temperature range of -55°C to 175°C. The part is currently classified as obsolete, necessitating identification of functionally equivalent alternatives that maintain compatibility with existing circuit designs while meeting the same electrical and mechanical specifications.

Key Parameters

Parameter	FDB8442-F085 Value	Unit
Drain to Source Voltage (Vdss)	40	V
Continuous Drain Current (Id) @ 25°C	28 (Ta)	A
Rds On (Max) @ Id, Vgs	5 @ 80A, 10V	mOhm
Gate Charge (Qg) (Max) @ Vgs	235 @ 10V	nC
Input Capacitance (Ciss) (Max) @ Vds	12200 @ 25V	pF
Power Dissipation (Max)	254 (Tc)	W
Operating Temperature Range	-55 to 175	°C
Package Type	TO-263 (D2PAK)	—
Qualification	AEC-Q101	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the FDB8442-F085 is determined by strict alignment of the following critical parameters:

Mandatory Matching Criteria:

Drain to Source Voltage (Vdss): 40V (exact match required)
FET Type: N-Channel (exact match required)
Package Type: TO-263 (D2PAK) or compatible surface mount package
Operating Temperature Range: -55°C to 175°C minimum (exact match required)
Automotive Grade with AEC-Q101 qualification (preferred for direct replacement)

Functional Compatibility Criteria:

Continuous Drain Current (Id): Equal to or greater than 28A
Rds On (Max): Equal to or lower than 5 mOhm (lower values indicate improved performance)
Gate Charge (Qg): Lower values reduce switching losses
Input Capacitance (Ciss): Lower values improve switching speed

Substitute parts are grouped into two categories: Direct Package Equivalents (TO-263/D2PAK) and Alternative Package Options (5-DFN). All substitutes maintain the 40V Vdss rating and N-Channel configuration. Parts with higher current ratings, lower on-resistance, or improved thermal characteristics provide enhanced performance margins while maintaining electrical compatibility.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Qg (nC)	Ciss (pF)	Pd Max (W)	Package	Status
FDB8442-F085	onsemi	40	28 (Ta)	5 @ 80A, 10V	235 @ 10V	12200 @ 25V	254 (Tc)	TO-263 (D2PAK)	Obsolete
NVMFS5C450NAFT1G	onsemi	40	24 (Ta), 102 (Tc)	3.3 @ 50A, 10V	23 @ 10V	1600 @ 25V	3.6 (Ta), 68 (Tc)	5-DFN (5x6)	Active
BUK764R0-40E,118	Nexperia USA Inc.	40	75 (Tc)	4 @ 25A, 10V	54 @ 10V	4405 @ 25V	182 (Tc)	D2PAK	Active
BUK765R2-40B,118	NXP USA Inc.	40	75 (Tc)	5.2 @ 25A, 10V	52 @ 10V	3789 @ 25V	203 (Tc)	D2PAK	Active
BUK964R4-40B,118	Nexperia USA Inc.	40	75 (Tc)	4 @ 25A, 10V	64 @ 5V	7124 @ 25V	254 (Tc)	D2PAK	Active
IPB80N04S404ATMA1	Infineon Technologies	40	80 (Tc)	4.2 @ 80A, 10V	43 @ 10V	3440 @ 25V	71 (Tc)	PG-TO263-3-2	Active
IPB80N04S4L04ATMA1	Infineon Technologies	40	80 (Tc)	4 @ 80A, 10V	60 @ 10V	4690 @ 25V	71 (Tc)	PG-TO263-3-2	Active
IRF1404STRLPBF	Infineon Technologies	40	162 (Tc)	4 @ 95A, 10V	200 @ 10V	7360 @ 25V	3.8 (Ta), 200 (Tc)	D2PAK	Active
IRL1404STRLPBF	Infineon Technologies	40	160 (Tc)	4 @ 95A, 10V	140 @ 5V	6600 @ 25V	3.8 (Ta), 200 (Tc)	D2PAK	Not For New Designs
PSMN4R5-40BS,118	Nexperia USA Inc.	40	100 (Tc)	4.5 @ 25A, 10V	42.3 @ 10V	2683 @ 20V	148 (Tc)	D2PAK	Active
STB100NF04T4	STMicroelectronics	40	120 (Tc)	4.6 @ 50A, 10V	150 @ 10V	5100 @ 25V	300 (Tc)	D2PAK	Active

Engineering Selection Recommendations

Direct Package Replacement (TO-263/D2PAK):

The following parts provide direct mechanical and electrical compatibility with the FDB8442-F085 in TO-263 (D2PAK) packaging:

BUK964R4-40B,118 (Nexperia USA Inc.): Matches the 254W power dissipation rating and provides 75A continuous drain current with 4 mOhm on-resistance. Maintains identical package footprint and thermal characteristics. Active product status with AEC-Q101 qualification.
IPB80N04S404ATMA1 and IPB80N04S4L04ATMA1 (Infineon Technologies OptiMOS™): Both deliver 80A continuous drain current with superior on-resistance (4.0–4.2 mOhm) and reduced gate charge. Active products with automotive qualification. PG-TO263-3-2 package is mechanically compatible with TO-263 footprints.
STB100NF04T4 (STMicroelectronics STripFET™ II): Provides 120A continuous drain current with 300W power dissipation. Active product with AEC-Q101 qualification. Suitable for applications requiring higher current capacity.
PSMN4R5-40BS,118 (Nexperia USA Inc.): Delivers 100A continuous drain current with 4.5 mOhm on-resistance and 148W power dissipation. Active product with full automotive compliance.

Alternative Package Option (5-DFN):

NVMFS5C450NAFT1G (onsemi): Provides 24A continuous drain current at Ta with significantly reduced gate charge (23 nC) and input capacitance (1600 pF). 5-DFN package requires PCB layout modification but offers improved switching performance. Active product status.

Product Status Considerations:

All recommended substitutes are classified as Active products, ensuring long-term availability and supply chain stability. The IRL1404STRLPBF, while electrically compatible, carries a "Not For New Designs" status and should be avoided for new circuit implementations.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with a higher current rating than the FDB8442-F085?

A: Yes. A substitute with equal or higher continuous drain current (Id) maintains full compatibility. Higher current ratings provide additional design margin and do not degrade circuit performance. The 28A requirement of the original design is satisfied by any substitute rated 28A or above.

Q: What is the significance of on-resistance (Rds On) differences between parts?

A: Lower on-resistance reduces power dissipation and heat generation during operation. Substitutes with Rds On values lower than 5 mOhm (such as the 4.0–4.2 mOhm options) improve efficiency. Higher on-resistance values increase power loss but remain acceptable if thermal management is adequate.

Q: Are D2PAK and TO-263 packages interchangeable?

A: Yes. D2PAK and TO-263 are equivalent designations for the same package type (TO-263-3, D2PAK with 2 leads plus tab). All parts listed with D2PAK or TO-263 packaging share identical footprints and thermal characteristics.

Q: Why does the NVMFS5C450NAFT1G use a different package (5-DFN)?

A: The 5-DFN package is a smaller form factor that requires PCB layout redesign. This part is included as an alternative for applications where space constraints justify the design modification. Direct TO-263 replacements are preferred for drop-in compatibility.

Q: What does AEC-Q101 qualification mean?

A: AEC-Q101 is an automotive industry standard qualification that certifies the device for use in automotive applications across the specified temperature range (-55°C to 175°C). All recommended substitutes maintain this qualification, ensuring suitability for automotive designs.

Q: Can I substitute a part marked "Not For New Designs"?

A: The IRL1404STRLPBF is electrically compatible but carries a "Not For New Designs" status, indicating the manufacturer has discontinued active support. For new circuit designs, select from Active status alternatives. Existing designs using this part may continue operation, but new implementations should use Active products.

Q: How do gate charge (Qg) and input capacitance (Ciss) affect circuit performance?

A: Lower gate charge and input capacitance reduce switching losses and improve switching speed. The FDB8442-F085 has relatively high values (235 nC and 12200 pF). Substitutes with lower values (such as NVMFS5C450NAFT1G at 23 nC and 1600 pF) provide faster switching and reduced driver power requirements.

Q: Are all substitutes RoHS3 compliant?

A: Yes. All recommended substitutes are RoHS3 compliant and REACH unaffected, matching the environmental compliance of the original FDB8442-F085.

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