FDMS8558S N-Channel MOSFET 25V 33A/90A Equivalent & Substitute Parts

Part Overview

The FDMS8558S is an N-Channel MOSFET manufactured by onsemi, rated for 25V drain-to-source voltage with continuous drain current of 33A at Ta and 90A at Tc. This device is housed in an 8-PQFN (5x6) surface mount package and belongs to the PowerTrench® and SyncFET™ series. The part is currently classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Drain-to-Source Voltage (Vdss)	25 V
Continuous Drain Current @ 25°C (Ta)	33 A
Continuous Drain Current @ 25°C (Tc)	90 A
RDS(on) Max @ Id, Vgs	1.5 mOhm @ 33A, 10V
Gate Threshold Voltage Vgs(th) Max @ Id	2.2 V @ 1 mA
Gate Charge (Qg) Max @ Vgs	81 nC @ 10 V
Input Capacitance (Ciss) Max @ Vds	5118 pF @ 13 V
Power Dissipation Max (Ta)	2.5 W
Power Dissipation Max (Tc)	78 W
Operating Temperature Range	-55°C to 150°C (TJ)
Package Type	8-PQFN (5x6)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the FDMS8558S is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

Drain-to-Source Voltage (Vdss): Must equal or exceed 25 V
Continuous Drain Current (Ta): Must meet or exceed 33 A at ambient temperature
Continuous Drain Current (Tc): Must meet or exceed 90 A at case temperature
RDS(on) Max: Must not exceed 1.5 mOhm at rated conditions to maintain thermal performance
Gate Threshold Voltage: Must be compatible with 4.5V to 10V drive voltage range
Operating Temperature Range: Must span -55°C to 150°C (TJ)

Mechanical Compatibility Criteria:

Mounting Type: Surface Mount required
Package Classification: 8-pin PowerTDFN family packages acceptable
Pin Configuration: Must support N-Channel MOSFET functionality

Compliance Requirements:

RoHS3 Compliant
MSL 1 (Unlimited) preferred for handling flexibility
REACH Unaffected status

The substitute parts listed below meet these criteria within the allowed electrical and mechanical parameters for this product category.

Parameter Comparison

Parameter	FDMS8558S (onsemi)	CSD16401Q5T (TI)	CSD16401Q5 (TI)	BSC014NE2LSIATMA1 (Infineon)	BSC018NE2LSIATMA1 (Infineon)	BSZ018NE2LSATMA1 (Infineon)
Vdss (V)	25	25	25	25	25	25
Id @ Ta (A)	33	100	38	33	29	23
Id @ Tc (A)	90	100	100	100	100	40
RDS(on) Max (mOhm)	1.5 @ 33A, 10V	1.6 @ 40A, 10V	1.6 @ 40A, 10V	1.4 @ 30A, 10V	1.8 @ 30A, 10V	1.8 @ 30A, 10V
Vgs(th) Max (V)	2.2 @ 1 mA	1.9 @ 250 µA	1.9 @ 250 µA	2.0 @ 250 µA	2.0 @ 250 µA	2.0 @ 250 µA
Qg Max (nC)	81 @ 10V	29 @ 4.5V	29 @ 4.5V	39 @ 10V	36 @ 10V	39 @ 10V
Ciss Max (pF)	5118 @ 13V	4100 @ 12.5V	4100 @ 12.5V	2700 @ 12V	2500 @ 12V	2800 @ 12V
Pd Max @ Ta (W)	2.5	3.1	3.1	2.5	2.5	2.1
Pd Max @ Tc (W)	78	Not specified	Not specified	74	69	69
Operating Temp Range (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package	8-PQFN (5x6)	8-VSON-CLIP (5x6)	8-VSON-CLIP (5x6)	PG-TDSON-8-7	PG-TDSON-8-6	PG-TSDSON-8-FL
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS3 Compliant	Yes	Yes	Yes	Yes	Yes	Yes
MSL	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

CSD16401Q5T and CSD16401Q5 (Texas Instruments NexFET™ Series) are the preferred substitutes for the FDMS8558S. Both devices are manufactured by Texas Instruments and maintain active product status. The CSD16401Q5T variant offers 100A continuous drain current at Ta, exceeding the original 33A specification. The CSD16401Q5 provides 38A at Ta and 100A at Tc, closely matching the thermal performance envelope of the FDMS8558S. Both parts feature lower gate charge (29 nC @ 4.5V) compared to the original device, resulting in improved switching efficiency. The 8-VSON-CLIP (5x6) package is mechanically compatible with the original 8-PQFN footprint. Both devices maintain RoHS3 compliance and MSL 1 rating.

Secondary Substitutes (Infineon OptiMOS™ Series):

BSC014NE2LSIATMA1 provides electrical performance closely aligned with the FDMS8558S, offering 33A at Ta and 100A at Tc with superior RDS(on) of 1.4 mOhm. This device is actively manufactured and maintains full compliance certifications. The PG-TDSON-8-7 package is mechanically compatible within the 8-PowerTDFN family.

BSC018NE2LSIATMA1 offers 29A at Ta and 100A at Tc with RDS(on) of 1.8 mOhm. This part is suitable for applications where the Ta current requirement can be relaxed while maintaining Tc performance. Active product status and full compliance certifications apply.

BSZ018NE2LSATMA1 is a lower-current variant rated for 23A at Ta and 40A at Tc. This substitute is appropriate only for applications with reduced thermal and current demands. The PG-TSDSON-8-FL package maintains 8-PowerTDFN family compatibility.

Selection Basis:

All substitute parts meet the mandatory electrical criteria: 25V Vdss, continuous drain current specifications, compatible gate drive voltage ranges, and full operating temperature coverage from -55°C to 150°C. All devices maintain RoHS3 compliance and MSL 1 moisture sensitivity ratings. The primary distinction between substitutes is product status (all active versus obsolete original) and specific current/thermal performance characteristics. Selection should be based on application-specific current and thermal requirements within the provided electrical parameters.

Frequently Asked Questions (FAQ)

Q: Can the CSD16401Q5T directly replace the FDMS8558S in existing PCB layouts?

A: The CSD16401Q5T uses an 8-VSON-CLIP (5x6) package while the FDMS8558S uses 8-PQFN (5x6). Both packages share the same 5x6 mm footprint dimensions and are mechanically compatible. Pin configuration for N-Channel MOSFET operation is identical. PCB layout compatibility is confirmed for direct substitution.

Q: What is the primary advantage of the Infineon BSC014NE2LSIATMA1 over the original FDMS8558S?

A: The BSC014NE2LSIATMA1 offers superior on-resistance (RDS(on) = 1.4 mOhm versus 1.5 mOhm) and lower gate charge (39 nC versus 81 nC), resulting in reduced conduction losses and improved switching speed. The device maintains equivalent voltage and current ratings while providing enhanced thermal efficiency.

Q: Are all substitute parts suitable for high-frequency switching applications?

A: The Texas Instruments CSD16401Q5 and CSD16401Q5T devices feature significantly lower gate charge (29 nC @ 4.5V) compared to the original FDMS8558S (81 nC @ 10V), making them superior for high-frequency applications. The Infineon OptiMOS™ devices offer moderate gate charge reduction (36-39 nC), providing intermediate switching performance.

Q: What is the impact of selecting BSZ018NE2LSATMA1 instead of higher-current alternatives?

A: The BSZ018NE2LSATMA1 is rated for 23A at Ta and 40A at Tc, significantly lower than the FDMS8558S specification of 33A at Ta and 90A at Tc. This substitute is only appropriate for applications with reduced current and thermal demands. Thermal performance at Tc is limited to 40A versus the original 90A capability.

Q: Do all substitute parts maintain the same compliance certifications as the original FDMS8558S?

A: Yes. All listed substitute parts are RoHS3 compliant, REACH unaffected, and carry MSL 1 (Unlimited) moisture sensitivity ratings, matching the original device certifications.

Q: What is the significance of the lower input capacitance (Ciss) in substitute parts?

A: The Infineon OptiMOS™ devices feature reduced input capacitance (2500-2800 pF) compared to the FDMS8558S (5118 pF), resulting in lower gate drive current requirements and improved switching efficiency. The Texas Instruments NexFET™ devices offer moderate reduction (4100 pF), providing a balance between performance and compatibility.

Q: Can the BSC018NE2LSIATMA1 be used in applications requiring 33A continuous current at Ta?

A: The BSC018NE2LSIATMA1 is rated for 29A at Ta, which is below the original 33A specification. This device is not suitable for applications with strict 33A continuous current requirements at ambient temperature. The BSC014NE2LSIATMA1 or CSD16401Q5 variants are recommended for maintaining the original 33A Ta specification.

Q: What packaging considerations apply when substituting the FDMS8558S?

A: The original FDMS8558S uses 8-PQFN (5x6) packaging. All substitute parts use alternative 8-pin PowerTDFN family packages (8-VSON-CLIP, PG-TDSON-8-7, PG-TDSON-8-6, PG-TSDSON-8-FL) with identical 5x6 mm footprint dimensions. PCB layout compatibility is maintained for all listed substitutes. Verify pin assignment compatibility with your specific circuit design before implementation.

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