FDMS8660S N-Channel 30V 25A/40A MOSFET Equivalent & Substitute Parts

Part Overview

The FDMS8660S is an N-Channel MOSFET manufactured by onsemi, rated for 30V drain-to-source voltage with continuous drain current of 25A at Ta and 40A at Tc. The device is housed in an 8-PQFN (5x6) surface mount package and belongs to the PowerTrench® series. This part is classified as obsolete, making equivalent and substitute components necessary for new designs and ongoing production support. Substitute parts must maintain compatibility across drain-to-source voltage, continuous drain current ratings, gate charge characteristics, and thermal performance parameters while accommodating modern active product alternatives.

Key Parameters

Parameter	FDMS8660S	Unit
Drain-to-Source Voltage (Vdss)	30	V
Continuous Drain Current @ 25°C (Ta)	25	A
Continuous Drain Current @ Tc	40	A
Rds On (Max) @ 25A, 10V	2.4	mOhm
Gate Charge (Qg) @ 10V	113	nC
Input Capacitance (Ciss) @ 15V	4345	pF
Power Dissipation (Ta)	2.5	W
Power Dissipation (Tc)	83	W
Operating Temperature Range	-55 to 150	°C
Package Type	8-PowerTDFN	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the FDMS8660S is determined by the following critical parameters:

Voltage Rating Compatibility: All substitute parts must maintain a minimum Vdss rating of 30V to ensure safe operation within the original design envelope.

Continuous Drain Current: Substitute parts must support a minimum continuous drain current of 25A at Ta (ambient temperature) to meet or exceed the original specification. Parts with higher current ratings at Tc provide enhanced thermal performance.

On-Resistance (Rds On): The maximum on-resistance at rated current and gate voltage must not exceed the original specification to maintain power efficiency and thermal characteristics.

Gate Charge (Qg): Gate charge values determine switching speed and driver requirements. Substitute parts with lower gate charge reduce switching losses and driver stress.

Input Capacitance (Ciss): Input capacitance affects gate drive circuit design and switching performance. Comparable values ensure consistent circuit behavior.

Package and Mounting: All substitutes must use surface mount technology in 8-pin PowerTDFN or equivalent packages to maintain PCB layout compatibility.

Product Status and Compliance: Active product status and RoHS3 compliance are preferred for new designs. Obsolete parts are listed for reference only in legacy system support.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ Ta (A)	Id @ Tc (A)	Rds On @ 10V (mOhm)	Qg @ 10V (nC)	Ciss @ 15V (pF)	Product Status	Package
FDMS8660S	onsemi	30	25	40	2.4	113	4345	Obsolete	8-PowerTDFN
BSC020N03LSGATMA1	Infineon	30	28	100	2.0	93	7200	Active	8-PowerTDFN
BSC020N03MSGATMA1	Infineon	30	25	100	2.0	124	9600	Active	8-PowerTDFN
BSC025N03LSGATMA1	Infineon	30	25	100	2.5	74	6100	Not For New Designs	8-PowerTDFN
BSC025N03MSGATMA1	Infineon	30	23	100	2.5	98	7600	Active	8-PowerTDFN
BSC030N03LSGATMA1	Infineon	30	23	100	3.0	55	4300	Active	8-PowerTDFN
BSC030N03MSGATMA1	Infineon	30	21	100	3.0	73	5700	Active	8-PowerTDFN
BSZ019N03LSATMA1	Infineon	30	22	40	1.9	44	2800	Active	8-PowerTDFN
BSZ0901NSATMA1	Infineon	30	22	40	2.0	45	2850	Active	8-PowerTDFN
CSD16407Q5	Texas Instruments	25	31	100	2.4	18	2660	Active	8-PowerTDFN
CSD17576Q5B	Texas Instruments	30	100	100	2.0	68	4430	Active	8-PowerTDFN

Engineering Selection Recommendations

Primary Substitutes for Active Designs:

The BSC020N03MSGATMA1 (Infineon OptiMOS™) is the preferred substitute for the FDMS8660S. This part maintains the 30V Vdss rating, matches the 25A continuous drain current at Ta, and provides superior thermal performance with 100A at Tc. The on-resistance of 2.0 mOhm at 10V is lower than the original specification, reducing power dissipation. The part carries Active product status and RoHS3 compliance, making it suitable for new designs. Gate charge of 124 nC is slightly elevated compared to the original 113 nC, requiring verification of gate driver capability in high-frequency switching applications.

The CSD17576Q5B (Texas Instruments NexFET™) offers the highest continuous drain current rating at 100A Ta and exceptional thermal performance at 125W Tc. This part maintains 30V Vdss and delivers 2.0 mOhm on-resistance. The lower gate charge of 68 nC provides faster switching characteristics. This substitute is appropriate for applications requiring maximum thermal headroom and switching efficiency.

The BSZ0901NSATMA1 (Infineon OptiMOS™) provides a direct current-matched alternative with 22A Ta and 40A Tc ratings closely aligned to the original 25A/40A specification. This part features the lowest gate charge at 45 nC and minimal input capacitance at 2850 pF, resulting in reduced switching losses and simplified gate drive requirements. Active product status and RoHS3 compliance support new design implementation.

Secondary Substitutes for Legacy Support:

The BSC025N03LSGATMA1 carries a "Not For New Designs" status but remains available for legacy system maintenance. This part meets the 25A Ta and 30V Vdss requirements with comparable thermal performance.

Voltage-Rated Alternative:

The CSD16407Q5 operates at 25V Vdss, which is below the original 30V specification. This part is suitable only for applications where the design voltage margin permits operation at 25V maximum. The 31A continuous drain current at Ta exceeds the original requirement, and the part maintains active product status with RoHS3 compliance.

Frequently Asked Questions (FAQ)

Q: Can the BSC020N03MSGATMA1 directly replace the FDMS8660S in existing designs?

A: Yes, the BSC020N03MSGATMA1 is a direct functional replacement. Both parts maintain 30V Vdss and 25A continuous drain current at Ta. The substitute offers improved on-resistance (2.0 mOhm vs. 2.4 mOhm) and superior thermal performance (100A at Tc vs. 40A). Gate charge is slightly higher at 124 nC, requiring confirmation that the gate driver can supply the additional charge without exceeding switching time specifications. PCB layout compatibility is maintained through identical 8-PowerTDFN packaging.

Q: What is the primary difference between the Infineon BSC020N03LSGATMA1 and BSC020N03MSGATMA1?

A: Both parts share identical electrical specifications at 30V Vdss, 2.0 mOhm on-resistance, and 100A Tc current rating. The primary difference is packaging: the LSGATMA1 variant uses Cut Tape (CT) & Digi-Reel® packaging, while the MSGATMA1 uses Tape & Reel (TR) packaging. Electrical performance and thermal characteristics are equivalent. Selection depends on procurement and assembly requirements.

Q: Why does the CSD16407Q5 have a lower Vdss rating of 25V compared to the original 30V?

A: The CSD16407Q5 is rated for 25V maximum drain-to-source voltage, which is 5V below the FDMS8660S specification. This part is suitable only for applications where the circuit design operates at 25V or lower. If the original design requires 30V operation, this substitute is not appropriate. The CSD17576Q5B from the same manufacturer provides the required 30V rating.

Q: How does gate charge affect circuit performance when substituting the FDMS8660S?

A: Gate charge (Qg) determines the total charge the gate driver must supply to switch the MOSFET. The FDMS8660S requires 113 nC at 10V. Substitutes with lower gate charge (such as BSZ0901NSATMA1 at 45 nC) reduce switching losses and driver stress, improving efficiency. Substitutes with higher gate charge (such as BSC020N03MSGATMA1 at 124 nC) require the gate driver to supply additional charge, potentially increasing switching time. Verify that the gate driver circuit can accommodate the substitute's gate charge specification without exceeding maximum current or voltage ratings.

Q: Are all substitute parts RoHS3 compliant?

A: All substitute parts listed carry RoHS3 compliance status. The original FDMS8660S does not specify RoHS status. For applications requiring RoHS3 certification, all listed substitutes are acceptable from a compliance perspective.

Q: What is the significance of the "Not For New Designs" status on the BSC025N03LSGATMA1?

A: Parts designated "Not For New Designs" are in mature production phases and may be discontinued in the future. While the BSC025N03LSGATMA1 meets the electrical requirements for substitution, Infineon recommends using active alternatives for new product development. For legacy system support and maintenance, this part remains available. The BSC020N03MSGATMA1 or BSC025N03MSGATMA1 are preferred alternatives with Active product status.

Q: Can the BSZ019N03LSATMA1 be used as a substitute despite its lower continuous drain current rating?

A: The BSZ019N03LSATMA1 is rated for 22A continuous drain current at Ta, which is below the FDMS8660S specification of 25A. This part is suitable only for applications where the actual circuit current demand does not exceed 22A at ambient temperature. If the design requires the full 25A capability, this substitute is not appropriate. However, the 40A Tc rating matches the original specification, and the superior on-resistance (1.9 mOhm) and minimal gate charge (44 nC) provide performance advantages in lower-current applications.

Q: What packaging considerations apply when substituting these parts?

A: All substitute parts use 8-pin PowerTDFN surface mount packages, maintaining PCB layout compatibility with the original FDMS8660S. Specific package variants (PG-TDSON-8-1, PG-TDSON-8-5, PG-TSDSON-8-FL) are mechanically and electrically compatible within the 8-PowerTDFN family. Verify footprint dimensions with the substitute datasheet to confirm PCB reflow compatibility. Moisture sensitivity level (MSL) is 1 (Unlimited) for all parts, eliminating special storage or handling requirements.

Q: Which substitute offers the best thermal performance for high-power applications?

A: The CSD17576Q5B provides the highest thermal performance with 125W power dissipation at Tc and 100A continuous drain current. This part is optimized for applications requiring maximum heat dissipation capability. The BSC020N03LSGATMA1 and BSC020N03MSGATMA1 also deliver excellent thermal performance at 96W Tc with 100A current ratings. Selection depends on specific thermal management requirements and circuit current demands.

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