STD40NF3LLT4 Equivalent & Substitute Parts

Part Overview

The STD40NF3LLT4 is an N-Channel 30V 40A MOSFET manufactured by STMicroelectronics in the STripFET™ II series, housed in a DPAK (TO-252-3) surface mount package. This device is classified as obsolete, necessitating identification of functionally equivalent alternatives for new designs and production continuity. The part delivers 80W maximum power dissipation at case temperature and operates across the industrial temperature range of -55°C to 175°C. Equivalent substitutes must maintain compatibility with the 30V drain-source voltage rating, 40A continuous drain current specification, and DPAK package form factor while meeting RoHS3 compliance requirements.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	30	V
Continuous Drain Current (Id) @ 25°C	40	A (Tc)
On-Resistance (Rds On) @ 20A, 10V	11	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	1	V
Gate Charge (Qg) @ 4.5V	33	nC
Power Dissipation (Max)	80	W (Tc)
Operating Temperature Range	-55 to 175	°C (TJ)
Package Type	DPAK (TO-252-3)	Surface Mount
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution eligibility for the STD40NF3LLT4 is determined by the following critical parameters:

Primary Compatibility Criteria:

Drain-Source Voltage (Vdss): Must equal or exceed 30V
Continuous Drain Current (Id): Must equal or exceed 40A at 25°C case temperature
Package Type: Must be DPAK (TO-252-3) surface mount
FET Type: N-Channel MOSFET technology
Operating Temperature: Must support -55°C to 175°C range
Compliance: RoHS3 compliant

Secondary Compatibility Considerations:

On-Resistance (Rds On): Lower values indicate improved performance; values within 8–13 mOhm are functionally compatible
Gate Charge (Qg): Lower values reduce switching losses; range of 10–48 nC acceptable
Power Dissipation: Minimum 42W required; higher ratings provide thermal margin

Substitute parts are grouped into two categories: Direct Equivalents (matching all primary criteria with identical or superior electrical performance) and Similar Alternatives (meeting primary criteria with acceptable parameter variations for specific applications).

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Qg (nC)	Power Diss. (W)	Status	Package
STD40NF3LLT4	STMicroelectronics	30	40	11	33	80	Obsolete	DPAK
IRFR1205TRPBF	Infineon Technologies	55	44	27	65	107	Active	TO-252AA (DPAK)
BUK9214-30A,118	Nexperia USA Inc.	30	63	12	31	107	Obsolete	DPAK
DMN3010LK3-13	Diodes Incorporated	30	43	9.5	37	1.6	Active	TO-252-3
FDD6690A	onsemi	30	46	12	18	56	Obsolete	TO-252AA
FDD8876	onsemi	30	73	8.2	47	70	Obsolete	TO-252AA
FDD8880	onsemi	30	58	9	31	55	Active	TO-252AA
IPD090N03LGATMA1	Infineon Technologies	30	40	9	15	42	Active	PG-TO252-3-11
IPD135N03LGATMA1	Infineon Technologies	30	30	13.5	10	31	Active	PG-TO252-3
IPD40N03S4L08ATMA1	Infineon Technologies	30	40	8.3	20	42	Discontinued	PG-TO252-3-11
IPD70N03S4L04ATMA1	Infineon Technologies	30	70	4.3	48	68	Active	PG-TO252-3-11

Engineering Selection Recommendations

Direct Equivalent (Recommended for Drop-In Replacement):

IPD090N03LGATMA1 (Infineon Technologies OptiMOS™ series) is the primary recommended substitute. This part matches the STD40NF3LLT4 specification exactly: 30V Vdss, 40A continuous drain current at 25°C, and DPAK-compatible package (PG-TO252-3-11). The device is currently in active production status, ensuring long-term availability. Superior on-resistance (9 mOhm versus 11 mOhm) and lower gate charge (15 nC versus 33 nC) provide improved switching efficiency. RoHS3 compliance and unlimited moisture sensitivity level (MSL 1) match the original part. This substitute requires no circuit modifications.

Alternative Equivalents (Application-Dependent Selection):

IPD40N03S4L08ATMA1 (Infineon Technologies, Automotive-qualified AEC-Q101) provides identical electrical specifications with enhanced on-resistance (8.3 mOhm) and automotive-grade qualification. Status is discontinued at DiGi Electronics; verify availability before selection. Suitable for automotive and industrial applications requiring AEC-Q101 certification.

FDD8880 (onsemi PowerTrench® series, Active status) delivers 58A continuous drain current with 30V Vdss in DPAK package. Superior current handling (58A versus 40A) and lower on-resistance (9 mOhm) provide thermal margin for high-current applications. Acceptable for designs tolerating higher gate charge (31 nC).

Not Recommended for Direct Substitution:

IRFR1205TRPBF: 55V Vdss exceeds application requirement; higher on-resistance (27 mOhm) and gate charge (65 nC) degrade efficiency.

IPD135N03LGATMA1: 30A continuous current falls below 40A requirement; unsuitable for full-load operation.

BUK9214-30A,118 and FDD6690A: Obsolete status limits availability; prefer active-status alternatives.

Frequently Asked Questions (FAQ)

Q: Can the IRFR1205TRPBF replace the STD40NF3LLT4?

A: The IRFR1205TRPBF is not recommended as a direct substitute. Although it provides 44A continuous current and DPAK packaging, the 55V Vdss rating exceeds the 30V application requirement. The significantly higher on-resistance (27 mOhm versus 11 mOhm) and gate charge (65 nC versus 33 nC) result in increased power dissipation and switching losses, reducing circuit efficiency. Use only if the application can tolerate higher voltage rating and thermal performance degradation.

Q: What is the difference between DPAK and TO-252AA packaging?

A: DPAK and TO-252AA are equivalent package designations for the same physical form factor (TO-252-3, SC-63). Both feature identical lead spacing, thermal tab dimensions, and PCB footprints. Parts specified as DPAK or TO-252AA are mechanically and electrically interchangeable on the same circuit board layout.

Q: Why does IPD090N03LGATMA1 have lower gate charge than the original STD40NF3LLT4?

A: Gate charge (Qg) is a function of semiconductor process technology and die design. The IPD090N03LGATMA1 employs Infineon's OptiMOS™ technology, which optimizes gate structure for reduced charge accumulation. Lower gate charge reduces switching losses and improves high-frequency performance. This represents a performance improvement over the original part.

Q: Is the IPD40N03S4L08ATMA1 suitable for new production designs?

A: The IPD40N03S4L08ATMA1 is discontinued at DiGi Electronics, indicating limited future availability. For new production designs, select IPD090N03LGATMA1 (active status) or FDD8880 (active status) to ensure supply chain continuity and long-term component availability.

Q: Can I use FDD8876 (73A) instead of a 40A-rated part?

A: Yes, FDD8876 is functionally compatible. The higher current rating (73A versus 40A) provides thermal margin and does not create circuit incompatibility. However, FDD8876 is obsolete; prefer active-status alternatives such as FDD8880 or IPD090N03LGATMA1 for new designs.

Q: What does RoHS3 compliance mean for this part?

A: RoHS3 compliance certifies that the part contains no restricted substances (lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls, or polybrominated diphenyl ethers) beyond specified thresholds. All listed substitute parts maintain RoHS3 compliance, ensuring regulatory compatibility with EU and equivalent international standards.

Q: Are Infineon OptiMOS™ parts pin-compatible with the STD40NF3LLT4?

A: Yes. All OptiMOS™ parts listed (IPD090N03LGATMA1, IPD40N03S4L08ATMA1, IPD70N03S4L04ATMA1) use the standard DPAK/TO-252-3 pinout: Gate (pin 1), Drain (pin 2), Source (pin 3, tab). No PCB modifications are required for substitution.

Q: What is the significance of AEC-Q101 qualification on IPD40N03S4L08ATMA1?

A: AEC-Q101 is an automotive industry qualification standard requiring enhanced reliability testing, temperature cycling, and failure rate validation. This certification is mandatory for automotive applications and recommended for industrial environments with stringent reliability requirements. Non-automotive applications do not require AEC-Q101 qualification.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message