STB45NF06 N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The STB45NF06 is an N-Channel MOSFET manufactured by STMicroelectronics, rated for 60V drain-to-source voltage with 38A continuous drain current at 25°C. This device is packaged in D2PAK (TO-263-3) surface mount configuration and is designed for general-purpose switching and amplification applications. The part is classified as Obsolete, necessitating identification of functionally equivalent alternatives for new designs and ongoing production support.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	60	V
Continuous Drain Current (Id) @ 25°C	38	A
On-State Resistance (Rds On) @ 19A, 10V	28	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	4	V
Gate Charge (Qg) @ 10V	58	nC
Input Capacitance (Ciss) @ 25V	980	pF
Power Dissipation (Max)	80	W
Operating Temperature Range	-55 to 175	°C
Package Type	D2PAK (TO-263-3)	Surface Mount
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution of the STB45NF06 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): Minimum 60V required
Continuous Drain Current (Id): Minimum 38A at 25°C
On-State Resistance (Rds On): Lower or equivalent values preferred for thermal performance
Package Type: D2PAK (TO-263-3) surface mount configuration
Gate Threshold Voltage (Vgs(th)): 4V nominal
Operating Temperature Range: -55°C to 175°C minimum
RoHS Compliance: ROHS3 Compliant

Substitute parts are grouped into two categories:

Category A - Direct Electrical Equivalents (Vdss ≥ 60V, Id ≥ 38A, D2PAK Package): Parts meeting or exceeding all primary electrical specifications while maintaining identical packaging.

Category B - Functional Alternatives (Vdss ≥ 55V, Id ≥ 35A, D2PAK Package): Parts with slightly reduced voltage or current ratings that remain functionally compatible for applications not requiring maximum specifications.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Qg (nC)	Package	Status
STB45NF06	STMicroelectronics	60	38	28 @ 19A, 10V	58 @ 10V	D2PAK	Obsolete
IRFS3806TRLPBF	Infineon Technologies	60	43	15.8 @ 25A, 10V	30 @ 10V	D2PAK	Active
IRFZ44ESTRLPBF	Infineon Technologies	60	48	23 @ 29A, 10V	60 @ 10V	D2PAK	Not For New Designs
IRFZ44SPBF	Vishay Siliconix	60	50	28 @ 31A, 10V	67 @ 10V	D2PAK	Active
IRFZ44STRLPBF	Vishay Siliconix	60	50	28 @ 31A, 10V	67 @ 10V	D2PAK	Active
IRFZ44NSTRLPBF	Infineon Technologies	55	49	17.5 @ 25A, 10V	63 @ 10V	D2PAK	Active
IRFZ46NSTRLPBF	Infineon Technologies	55	53	16.5 @ 28A, 10V	72 @ 10V	D2PAK	Not For New Designs
BUK7635-55A,118	Nexperia USA Inc.	55	35	35 @ 20A, 10V	N/A	D2PAK	Obsolete
IRFZ34NSTRLPBF	Infineon Technologies	55	29	40 @ 16A, 10V	34 @ 10V	D2PAK	Active

Engineering Selection Recommendations

Recommended Primary Substitutes (Active Status, Full Electrical Equivalence):

IRFS3806TRLPBF - Infineon Technologies
- Meets all primary electrical specifications with Vdss 60V and Id 43A
- Superior on-state resistance (15.8 mOhm) provides improved thermal performance
- Active product status ensures long-term availability
- ROHS3 compliant with identical operating temperature range
- Recommended for new designs requiring direct replacement
IRFZ44SPBF / IRFZ44STRLPBF - Vishay Siliconix
- Vdss 60V with Id 50A exceeds STB45NF06 specifications
- Active product status with established supply chain
- ROHS3 compliant
- Identical on-state resistance (28 mOhm) to original part
- Available in both tube and tape & reel packaging options

Secondary Substitutes (Reduced Voltage Rating, Functional Compatibility):

IRFZ44NSTRLPBF - Infineon Technologies
- Vdss 55V with Id 49A provides functional equivalence for applications not requiring full 60V rating
- Active product status
- Improved on-state resistance (17.5 mOhm) reduces power dissipation
- ROHS3 compliant
IRFZ46NSTRLPBF - Infineon Technologies
- Vdss 55V with Id 53A suitable for reduced-voltage applications
- Higher current capability than original part
- Not For New Designs status limits long-term viability

Not Recommended:

BUK7635-55A,118 - Obsolete status and reduced current rating (35A) below original specification
IRFZ34NSTRLPBF - Current rating (29A) below STB45NF06 specification; suitable only for downrated applications
IRFZ44ZPBF - Through-hole TO-220AB package incompatible with D2PAK surface mount requirement

Frequently Asked Questions (FAQ)

Q: Can IRFZ44NSTRLPBF replace STB45NF06 in all applications?

A: IRFZ44NSTRLPBF operates at 55V maximum drain-to-source voltage compared to STB45NF06's 60V rating. This part is suitable for applications where the supply voltage does not exceed 55V. For circuits designed for 60V operation, IRFS3806TRLPBF or IRFZ44SPBF are preferred.

Q: What is the difference between IRFZ44SPBF and IRFZ44STRLPBF?

A: Both parts are electrically identical with Vdss 60V and Id 50A. The primary difference is packaging: IRFZ44SPBF is supplied in tube format, while IRFZ44STRLPBF is supplied in tape & reel format. Selection depends on assembly process requirements.

Q: Why is IRFS3806TRLPBF recommended over IRFZ44ESTRLPBF despite similar ratings?

A: IRFS3806TRLPBF maintains Active product status, ensuring long-term availability and supply continuity. IRFZ44ESTRLPBF is classified as Not For New Designs, indicating limited future support. Additionally, IRFS3806TRLPBF exhibits superior on-state resistance (15.8 mOhm vs. 23 mOhm), resulting in lower power dissipation and improved thermal performance.

Q: Is the D2PAK package critical for substitution?

A: Yes. The STB45NF06 is specified for D2PAK (TO-263-3) surface mount configuration. Substitutes must maintain this package type to ensure PCB compatibility and thermal management characteristics. IRFZ44ZPBF, while electrically similar, uses TO-220AB through-hole packaging and is not a direct substitute.

Q: What does "Not For New Designs" status mean?

A: Parts marked "Not For New Designs" are in mature or declining production phases. While functional, these parts may have limited availability and extended lead times. For new product development, Active status parts such as IRFS3806TRLPBF or IRFZ44STRLPBF are preferred to ensure supply security.

Q: Can I use a lower-rated part like IRFZ34NSTRLPBF as a substitute?

A: IRFZ34NSTRLPBF with 29A continuous drain current is below the STB45NF06's 38A specification. This part is suitable only for applications where the actual current requirement is below 29A. Using an underrated device in a circuit designed for 38A operation will result in thermal stress and potential failure.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All recommended substitute parts listed are ROHS3 compliant, matching the original STB45NF06 environmental compliance status. This ensures compatibility with RoHS-regulated supply chains and end-use applications.

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

A: Gate charge affects switching speed and driver circuit requirements. IRFS3806TRLPBF has lower gate charge (30 nC vs. 58 nC), enabling faster switching with lower driver power consumption. IRFZ44 series parts have similar or slightly higher gate charge, requiring equivalent driver capability to the original part.

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