FDD6680AS N-Channel 30V 55A MOSFET Equivalent & Substitute Parts

Part Overview

The FDD6680AS is an N-Channel MOSFET manufactured by onsemi, rated for 30V drain-to-source voltage and 55A continuous drain current in a TO-252AA surface mount package. This device is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design support and procurement continuity. The part belongs to the PowerTrench® and SyncFET™ series and is suitable for applications requiring moderate voltage switching with high current capacity in compact form factors.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	30	V
Continuous Drain Current (Id) @ 25°C	55	A (Ta)
On-State Resistance (Rds On) @ 12.5A, 10V	10.5	mOhm
Gate Threshold Voltage (Vgs(th)) @ 1mA	3	V
Gate Charge (Qg) @ 10V	29	nC
Input Capacitance (Ciss) @ 15V	1200	pF
Power Dissipation (Max)	60	W (Ta)
Operating Temperature Range	-55 to 150	°C (TJ)
Package Type	TO-252-3, DPAK	Surface Mount
FET Type	N-Channel	MOSFET

Substitute Part Grouping Explanation

Substitution of the FDD6680AS is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): Minimum 30V
Continuous Drain Current (Id): Minimum 55A at rated temperature
On-State Resistance (Rds On): Maximum 10.5mOhm at specified gate voltage
Package Type: TO-252-3 / DPAK surface mount configuration
Gate Threshold Voltage (Vgs(th)): Compatible with 3V to 10V gate drive circuits
Operating Temperature Range: Minimum -55°C to 150°C

Substitution Logic: Parts are grouped into three categories based on current rating alignment:

Direct Current Equivalents (≥55A): Parts meeting or exceeding the 55A continuous drain current specification with comparable Rds On characteristics.
Reduced Current Substitutes (40A–54A): Parts with lower continuous current ratings but acceptable for applications with reduced thermal or current demands, provided Rds On and voltage ratings remain compatible.
Enhanced Performance Alternatives: Parts exceeding the original specifications in current capacity, Rds On efficiency, or temperature range, suitable for upgraded designs.

All substitute parts maintain the TO-252-3 DPAK package footprint and are RoHS3 compliant with MSL 1 rating.

Parameter Comparison

Parameter	FDD6680AS	FDD6690A	IPD090N03LGATMA1	IPD30N03S4L09ATMA1	IPD40N03S4L08ATMA1	STD70NS04ZL
Manufacturer	onsemi	onsemi	Infineon	Infineon	Infineon	STMicroelectronics
Vdss (V)	30	30	30	30	30	33
Id @ 25°C (A)	55 (Ta)	12 (Ta) / 46 (Tc)	40 (Tc)	30 (Tc)	40 (Tc)	70 (Tc)
Rds On (mOhm)	10.5 @ 12.5A, 10V	12 @ 12A, 10V	9 @ 30A, 10V	9 @ 30A, 10V	8.3 @ 40A, 10V	10.5 @ 30A, 10V
Vgs(th) (V)	3 @ 1mA	3 @ 250µA	2.2 @ 250µA	2.2 @ 13µA	2.2 @ 13µA	3 @ 1mA
Qg (nC)	29 @ 10V	18 @ 5V	15 @ 10V	20 @ 10V	20 @ 10V	32 @ 5V
Ciss (pF)	1200 @ 15V	1230 @ 15V	1600 @ 15V	1520 @ 15V	1520 @ 15V	1800 @ 25V
Power Dissipation (W)	60 (Ta)	3.3 (Ta) / 56 (Tc)	42 (Tc)	42 (Tc)	42 (Tc)	110 (Tc)
Operating Temp (°C)	-55 to 150	-55 to 175	-55 to 175	-55 to 175	-55 to 175	-55 to 175
Package	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK
Product Status	Obsolete	Obsolete	Active	Active	Discontinued at DiGi Electronics	Active
RoHS3 Compliant	Yes	Yes	Yes	Yes	Yes	Yes

Engineering Selection Recommendations

Primary Substitute (Best Availability & Performance):

STD70NS04ZL (STMicroelectronics) is the recommended primary substitute. This part exceeds the FDD6680AS specifications with 70A continuous drain current, 33V Vdss rating, and 110W power dissipation. The device maintains compatible Rds On characteristics (10.5mOhm @ 30A, 10V) and identical gate threshold voltage (3V @ 1mA). Product status is Active with established supply chain availability. Extended operating temperature range (-55°C to 175°C) provides enhanced thermal margin. RoHS3 compliance and MSL 1 rating ensure regulatory and manufacturing compatibility.

Secondary Substitutes (Active Status, Infineon OptiMOS™ Series):

IPD090N03LGATMA1 (Infineon) provides 40A continuous current with superior Rds On performance (9mOhm @ 30A, 10V) and lower gate charge (15nC @ 10V). Product status is Active with high inventory availability (5400 units). Lower gate threshold voltage (2.2V @ 250µA) requires gate drive circuit verification for compatibility with existing designs.

IPD30N03S4L09ATMA1 (Infineon) offers 30A continuous current with matching Rds On (9mOhm @ 30A, 10V) and extended temperature range. Product status is Active with highest inventory availability (48,787 units). Suitable for applications with reduced current requirements or as a cost-optimized alternative.

IPD40N03S4L08ATMA1 (Infineon) delivers 40A continuous current with optimized Rds On (8.3mOhm @ 40A, 10V). Includes AEC-Q101 automotive qualification. Product status is Discontinued at DiGi Electronics; use only if existing inventory is available through alternative distributors.

Tertiary Substitute (onsemi Alternative):

FDD6690A (onsemi) maintains manufacturer continuity with 12A (Ta) / 46A (Tc) current rating and comparable Rds On (12mOhm @ 12A, 10V). Product status is Obsolete; selection is not recommended for new designs due to limited future availability.

Selection Criteria Summary:

For new designs requiring ≥55A: Select STD70NS04ZL
For designs tolerating 40A: Select IPD090N03LGATMA1 (Active status, superior performance)
For cost-optimized designs at 30A: Select IPD30N03S4L09ATMA1 (highest availability)
For automotive-qualified designs at 40A: Select IPD40N03S4L08ATMA1 (if available)

Frequently Asked Questions (FAQ)

Q: Can I use STD70NS04ZL as a direct replacement for FDD6680AS?

A: Yes. STD70NS04ZL meets all electrical requirements with enhanced specifications. The 33V Vdss rating exceeds the 30V requirement. The 70A continuous current and 110W power dissipation exceed the original 55A and 60W ratings. Rds On characteristics are compatible (10.5mOhm @ 30A, 10V). Gate threshold voltage matches at 3V. Package footprint is identical TO-252-3 DPAK. No circuit modifications are required.

Q: What is the difference between Ta and Tc current ratings?

A: Ta (ambient temperature) ratings specify continuous current at 25°C ambient temperature with the device mounted on a PCB. Tc (case temperature) ratings specify continuous current with the device case maintained at 25°C, typically achieved through enhanced thermal management. Infineon parts list Tc ratings; onsemi parts list Ta ratings. For thermal design purposes, use the more conservative rating applicable to your thermal management approach.

Q: Are the Infineon OptiMOS™ parts compatible with existing gate drive circuits designed for FDD6680AS?

A: Infineon OptiMOS™ parts have lower gate threshold voltages (2.2V @ 250µA) compared to FDD6680AS (3V @ 1mA). This difference is within acceptable margins for standard gate drive circuits operating at 5V or 10V. However, verify gate drive voltage levels if operating near the 3V threshold. Lower Vgs(th) may result in slightly faster switching transitions.

Q: Why does STD70NS04ZL have higher gate charge than FDD6680AS?

A: Gate charge (Qg) increases with die size and current capacity. STD70NS04ZL's 32nC @ 5V reflects its higher 70A current rating and larger silicon die compared to FDD6680AS at 29nC @ 10V. Higher gate charge requires proportionally longer switching times but does not affect steady-state operation. Gate drive circuits must supply sufficient current to charge the gate within acceptable switching time windows.

Q: Can I substitute a 40A part for a 55A application?

A: No. The FDD6680AS is rated for 55A continuous drain current. Substituting a 40A-rated part (IPD090N03LGATMA1 or IPD40N03S4L08ATMA1) would violate the continuous current specification and create thermal stress. Use 40A parts only in applications with confirmed maximum current requirements below 40A.

Q: What is the significance of the TO-252-3 DPAK package designation?

A: TO-252-3 DPAK (Dual Pak) is a three-terminal surface mount package with two leads plus a thermal tab. All substitute parts use this identical package, ensuring PCB footprint compatibility without layout modifications. The thermal tab provides direct connection to the drain terminal and must be soldered to a copper pad for effective heat dissipation.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed are RoHS3 compliant with MSL 1 (Unlimited) moisture sensitivity level. This ensures compatibility with lead-free soldering processes and unrestricted storage conditions without desiccant requirements.

Q: What is the impact of operating temperature range differences?

A: FDD6680AS operates from -55°C to 150°C (TJ). All substitute parts extend to -55°C to 175°C (TJ), providing 25°C additional thermal margin. This extended range improves reliability in high-temperature applications but does not affect performance in designs operating within the original -55°C to 150°C window.

Q: Should I select IPD30N03S4L09ATMA1 or IPD090N03LGATMA1 for a new design?

A: Selection depends on current requirements. IPD30N03S4L09ATMA1 (30A) is suitable for applications with confirmed maximum current ≤30A and offers highest inventory availability (48,787 units). IPD090N03LGATMA1 (40A) provides additional current margin and superior Rds On efficiency (9mOhm vs. 9mOhm at different current levels) with lower gate charge (15nC vs. 20nC). For designs with current headroom requirements, select IPD090N03LGATMA1.

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