STB40NF10T4 N-Channel MOSFET 100V 50A D2PAK Equivalent & Substitute Parts

Part Overview

The STB40NF10T4 is an N-Channel MOSFET manufactured by STMicroelectronics in the STripFET™ II series. This device operates at 100V drain-to-source voltage with a continuous drain current of 50A at 25°C and dissipates up to 150W. The part is housed in a D2PAK (TO-263-3) surface mount package with two leads plus tab configuration.

The STB40NF10T4 is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this MOSFET topology.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	100	V
Continuous Drain Current (Id) @ 25°C	50	A (Tc)
On-State Resistance (Rds On) @ 25A, 10V	28	mOhm
Gate-to-Source Threshold Voltage (Vgs(th)) @ 250µA	4	V
Gate Charge (Qg) @ 10V	80	nC
Input Capacitance (Ciss) @ 25V	1780	pF
Power Dissipation (Max)	150	W (Tc)
Operating Temperature Range	-50 to 175	°C (TJ)
Package Type	D2PAK (TO-263-3)	Surface Mount
FET Type	N-Channel	—
Technology	MOSFET (Metal Oxide)	—

Substitute Part Grouping Explanation

Substitution of the STB40NF10T4 is determined by strict alignment of the following electrical and mechanical parameters:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): 100V (exact match required)
Package Type: D2PAK / TO-263-3 surface mount (exact match required)
FET Type: N-Channel (exact match required)
Technology: MOSFET Metal Oxide (exact match required)

Secondary Compatibility Parameters:

Continuous Drain Current (Id): 46A to 59A range (within acceptable operating envelope)
On-State Resistance (Rds On): 15.4 to 39 mOhm @ 10V (performance variation acceptable within thermal limits)
Gate-to-Source Threshold Voltage (Vgs(th)): 2V to 4V @ specified test current (functional compatibility)
Power Dissipation: 100W to 200W (thermal capability variation)
Operating Temperature Range: -55°C to 175°C minimum (covers or exceeds STB40NF10T4 range)

Substitute parts must maintain identical package footprint and pinout configuration to ensure direct board-level replacement without layout modification. All listed substitutes meet these criteria and are available in active or obsolete product status with full RoHS3 compliance and MSL Level 1 rating.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On @ 10V (mOhm)	Vgs(th) (V)	Qg @ 10V (nC)	Ciss @ 25V (pF)	Power Diss. (W)	Temp Range (°C)	Status
STB40NF10T4	STMicroelectronics	100	50	28	4	80	1780	150	-50 to 175	Obsolete
BUK7626-100B,118	Nexperia USA Inc.	100	49	26	4	38	2891	157	-55 to 175	Obsolete
BUK9629-100B,118	Nexperia USA Inc.	100	46	27	2	33	4360	157	-55 to 175	Active
BUK9640-100A,118	Nexperia USA Inc.	100	39	39	2	48	3072	158	-55 to 175	Active
FDB3672-F085	onsemi	100	44	28	4	31	1710	120	-55 to 175	Obsolete
FQB55N10TM	onsemi	100	55	26	4	98	2730	155	-55 to 175	Active
HUF75639S3ST	Fairchild Semiconductor	100	56	25	4	130	2000	200	-55 to 175	Active
HUF76639S3ST	onsemi	100	51	26	3	86	2400	180	-55 to 175	Active
IPB50N10S3L16ATMA1	Infineon Technologies	100	50	15.4	2.4	64	4180	100	-55 to 175	Active
IRF3710STRLPBF	Infineon Technologies	100	57	23	4	130	3130	200	-55 to 175	Active
IRF3710ZSTRLPBF	Infineon Technologies	100	59	18	4	120	2900	160	-55 to 175	Active

Engineering Selection Recommendations

Active Product Substitutes (Recommended for New Designs):

The following parts are in active production status and provide direct functional equivalence with enhanced or comparable electrical performance:

BUK9629-100B,118 (Nexperia): 46A continuous drain current, 27mOhm Rds On, AEC-Q101 automotive qualified. Suitable for applications where current rating of 46A meets design requirements.
BUK9640-100A,118 (Nexperia): 39A continuous drain current, 39mOhm Rds On, AEC-Q101 automotive qualified. Appropriate for lower current applications within the 100V class.
FQB55N10TM (onsemi): 55A continuous drain current, 26mOhm Rds On, active status. Provides higher current capability with comparable on-state resistance.
HUF75639S3ST (Fairchild Semiconductor): 56A continuous drain current, 25mOhm Rds On, 200W power dissipation, active status. Offers superior thermal performance and current handling.
HUF76639S3ST (onsemi): 51A continuous drain current, 26mOhm Rds On, 180W power dissipation, active status. Close electrical match to STB40NF10T4 with active product support.
IPB50N10S3L16ATMA1 (Infineon OptiMOS™): 50A continuous drain current, 15.4mOhm Rds On, active status. Lowest on-state resistance option; suitable for applications prioritizing efficiency and thermal performance.
IRF3710STRLPBF (Infineon HEXFET®): 57A continuous drain current, 23mOhm Rds On, 200W power dissipation, active status. High current capability with excellent thermal characteristics.
IRF3710ZSTRLPBF (Infineon HEXFET®): 59A continuous drain current, 18mOhm Rds On, active status. Highest current rating with lowest on-state resistance in the substitute list.

Obsolete Product Substitutes (Legacy System Support Only):

BUK7626-100B,118 (Nexperia): 49A continuous drain current, 26mOhm Rds On. Obsolete status; use only for direct replacement in existing production where active alternatives are not feasible.
FDB3672-F085 (onsemi): 44A continuous drain current, 28mOhm Rds On, 120W power dissipation. Obsolete status; lower power dissipation rating may limit thermal headroom in high-power applications.

Compliance and Certification:

All substitute parts listed maintain RoHS3 compliance and MSL Level 1 moisture sensitivity rating, ensuring compatibility with modern manufacturing processes and long-term storage requirements. Parts designated as AEC-Q101 automotive qualified (BUK9629-100B,118, BUK9640-100A,118, FDB3672-F085) meet automotive reliability standards and are suitable for automotive and industrial applications requiring enhanced qualification.

Frequently Asked Questions (FAQ)

Q: Can the STB40NF10T4 be directly replaced with any of the listed substitute parts?

A: Direct replacement is possible only with parts sharing identical D2PAK (TO-263-3) package configuration and pinout. All listed substitutes meet this requirement. However, electrical performance variations exist; verify that the substitute part's continuous drain current (Id), on-state resistance (Rds On), and power dissipation ratings meet or exceed your application requirements.

Q: What is the primary difference between active and obsolete substitute parts?

A: Active parts are in current production with ongoing manufacturer support, quality assurance, and supply availability. Obsolete parts are no longer manufactured and should be used only for legacy system maintenance or direct replacement in existing production runs where supply exists. For new designs, active substitutes are strongly preferred.

Q: How do I determine which substitute part is best for my application?

A: Selection depends on three factors: (1) Required continuous drain current—choose a part with Id rating equal to or greater than your design requirement; (2) Thermal performance—applications with high power dissipation benefit from parts with lower Rds On values (such as IPB50N10S3L16ATMA1 or IRF3710ZSTRLPBF); (3) Supply availability and cost—active parts offer better long-term availability than obsolete alternatives.

Q: Are there any gate drive voltage differences between the STB40NF10T4 and its substitutes?

A: The STB40NF10T4 specifies a maximum gate-to-source voltage (Vgs Max) of ±20V. Most substitutes maintain this specification; however, BUK9629-100B,118 and BUK9640-100A,118 specify ±15V maximum. Verify your gate drive circuit does not exceed the substitute part's Vgs Max rating. FQB55N10TM specifies ±25V, providing additional margin.

Q: What is the significance of gate charge (Qg) differences?

A: Gate charge affects switching speed and gate drive circuit power consumption. The STB40NF10T4 specifies 80nC @ 10V. Substitutes range from 31nC to 130nC. Lower gate charge (FDB3672-F085 at 31nC) results in faster switching and lower drive power; higher gate charge (HUF75639S3ST at 130nC) may require higher gate drive current but does not prevent functional substitution.

Q: Can I use a substitute part with lower continuous drain current rating than the STB40NF10T4?

A: No. The BUK9640-100A,118 (39A) and FDB3672-F085 (44A) have lower current ratings than the STB40NF10T4 (50A). These parts are suitable only if your application's actual current requirement is lower than the STB40NF10T4's 50A rating. Operating at or above the substitute part's Id rating will cause thermal stress and potential device failure.

Q: Are automotive-qualified parts (AEC-Q101) required for my application?

A: AEC-Q101 qualification is required only for automotive and safety-critical applications. BUK9629-100B,118, BUK9640-100A,118, and FDB3672-F085 carry this certification. For industrial, consumer, or non-automotive applications, non-qualified parts are acceptable and may offer cost advantages.

Q: What is the impact of on-state resistance (Rds On) variation on circuit performance?

A: Lower Rds On reduces conduction losses and heat generation. The STB40NF10T4 specifies 28mOhm @ 25A, 10V. Substitutes range from 15.4mOhm (IPB50N10S3L16ATMA1) to 39mOhm (BUK9640-100A,118). Lower Rds On improves efficiency; higher Rds On increases power dissipation. Select based on your thermal budget and efficiency requirements.

Q: Is the operating temperature range important for substitution?

A: The STB40NF10T4 operates from -50°C to 175°C. All listed substitutes operate from -55°C to 175°C, providing equal or superior temperature coverage. This ensures functional compatibility across the full operating range of the original part.

Q: Can I substitute the STB40NF10T4 with a part having higher power dissipation rating?

A: Yes. Higher power dissipation ratings (such as HUF75639S3ST at 200W versus STB40NF10T4 at 150W) indicate improved thermal capability and do not create compatibility issues. The substitute will operate cooler under identical load conditions. Lower power dissipation ratings (such as FDB3672-F085 at 120W) may limit thermal headroom in high-power applications.

Q: What packaging considerations apply to these substitutes?

A: All listed substitutes use D2PAK (TO-263-3) surface mount package with identical footprint and pinout to the STB40NF10T4. No PCB layout modification is required for direct substitution. Verify that your board assembly process supports the substitute part's moisture sensitivity level (all listed parts are MSL Level 1, unlimited shelf life).

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