AOT474 N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The AOT474 is an N-Channel MOSFET manufactured by Alpha & Omega Semiconductor Inc., rated for 75V drain-to-source voltage with 9A continuous drain current at 25°C (Ta) and 127A at case temperature (Tc). The device is housed in a TO-220-3 through-hole package and operates across a temperature range of -55°C to 175°C. The AOT474 is classified as obsolete, making identification of functionally equivalent active alternatives necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	AOT474 Value	Unit
Drain-to-Source Voltage (Vdss)	75	V
Continuous Drain Current @ 25°C (Ta)	9	A
Continuous Drain Current @ Case (Tc)	127	A
On-Resistance (Rds On) @ 30A, 10V	11.3	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	4	V
Gate Charge (Qg) @ 10V	60	nC
Input Capacitance (Ciss) @ 30V	3370	pF
Power Dissipation (Ta)	1.9	W
Power Dissipation (Tc)	417	W
Operating Temperature Range	-55 to 175	°C
Package Type	TO-220-3	Through Hole
FET Technology	MOSFET (Metal Oxide)	N-Channel

Substitute Part Grouping Explanation

Substitution of the AOT474 is determined by the following critical parameters:

Voltage Rating Compatibility: The substitute must support a Vdss rating equal to or greater than 75V. This ensures the device can withstand the same or higher voltage stress in the application circuit.

Current Handling Capability: The substitute must support continuous drain current (Tc) equal to or greater than 127A to maintain equivalent or superior current delivery capacity.

On-Resistance (Rds On): The substitute should maintain comparable or lower on-resistance at the specified gate voltage (10V) to ensure similar conduction losses and thermal performance.

Gate Charge (Qg): Lower gate charge values indicate faster switching characteristics and reduced driver power requirements. Substitutes with equal or lower gate charge are preferred.

Package and Mounting: All substitutes must use the TO-220-3 through-hole package to ensure mechanical and electrical compatibility with existing PCB layouts.

Operating Temperature Range: The substitute must support the full -55°C to 175°C operating range or a range that encompasses the application requirements.

Product Status and Compliance: Active product status ensures ongoing availability and support. RoHS3 compliance and REACH compliance status are documented where applicable.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ Tc (A)	Rds On (mOhm)	Qg (nC)	Ciss (pF)	Temp Range (°C)	Status	Package
AOT474	Alpha & Omega	75	127	11.3 @ 30A	60 @ 10V	3370 @ 30V	-55 to 175	Obsolete	TO-220-3
AOT288L	Alpha & Omega	80	46	9.2 @ 20A	38 @ 10V	1871 @ 40V	-55 to 175	Active	TO-220-3
DMT6009LCT	Diodes Inc.	60	37.2	12 @ 13.5A	33.5 @ 10V	1925 @ 30V	-55 to 150	Active	TO-220-3
FDP16AN08A0	Fairchild	75	58	16 @ 58A	42 @ 10V	1857 @ 25V	-55 to 175	Active	TO-220-3
FDP75N08A	onsemi	75	75	11 @ 37.5A	104 @ 10V	4468 @ 25V	-55 to 150	Obsolete	TO-220-3
IRFB3307PBF	Infineon	75	130	6.3 @ 75A	180 @ 10V	5150 @ 50V	-55 to 175	Active	TO-220-3
IXTP70N075T2	IXYS	75	70	12 @ 25A	46 @ 10V	2725 @ 25V	-55 to 175	Active	TO-220-3
PHP29N08T,127	NXP	75	27	50 @ 14A	19 @ 10V	810 @ 25V	-55 to 175	Active	TO-220-3
PHP79NQ08LT,127	Nexperia	75	73	16 @ 25A	30 @ 5V	3026 @ 25V	-55 to 175	Obsolete	TO-220-3
SQP60N06-15_GE3	Vishay	60	56	15 @ 30A	50 @ 10V	2480 @ 25V	-55 to 175	Obsolete	TO-220-3
STP140NF75	STMicroelectronics	75	120	7.5 @ 70A	218 @ 10V	5000 @ 25V	-55 to 175	Active	TO-220-3

Engineering Selection Recommendations

Primary Recommendation: IRFB3307PBF

The IRFB3307PBF from Infineon Technologies is the most direct functional equivalent. It maintains the 75V Vdss rating and exceeds the 127A Tc current requirement with 130A capability. The device is active in production, RoHS3 compliant, and supports the full -55°C to 175°C operating temperature range. The lower on-resistance of 6.3 mOhm at 75A provides improved thermal performance compared to the AOT474. The HEXFET® technology platform ensures reliable long-term availability.

Secondary Recommendation: STP140NF75

The STP140NF75 from STMicroelectronics provides 75V/120A ratings with superior on-resistance of 7.5 mOhm at 70A. This device is active, RoHS3 compliant, and rated for -55°C to 175°C operation. The STripFET™ III technology delivers enhanced performance characteristics. Higher gate charge (218 nC) requires consideration in driver circuit design.

Alternative for Lower Current Applications: IXTP70N075T2

The IXTP70N075T2 from IXYS maintains 75V/70A ratings with 12 mOhm on-resistance. This device is active, RoHS3 compliant, and supports -55°C to 175°C operation. The TrenchT2™ technology provides balanced performance with moderate gate charge (46 nC), suitable for applications requiring lower current delivery than the primary recommendations.

Voltage-Reduced Alternative: DMT6009LCT

For applications where 60V operation is acceptable, the DMT6009LCT from Diodes Incorporated provides 60V/37.2A ratings with 12 mOhm on-resistance. This device is active and RoHS3 compliant. The operating temperature range is -55°C to 150°C, which is acceptable for most industrial applications. This option is suitable only when the 75V rating is not a circuit requirement.

Obsolete Status Consideration:

The FDP75N08A and PHP79NQ08LT,127 are classified as obsolete and should not be selected for new designs despite their technical compatibility. The AOT288L, while active, provides lower current capability (46A Tc) and higher voltage rating (80V), making it suitable only for applications with reduced current requirements.

Frequently Asked Questions (FAQ)

Q: Can the AOT474 be directly replaced with any of these substitutes in existing designs?

A: Direct replacement depends on circuit requirements. All listed substitutes maintain the TO-220-3 package and 75V rating (except DMT6009LCT at 60V). However, differences in on-resistance, gate charge, and input capacitance may require verification of driver circuit compatibility and thermal management adequacy. Obsolete parts (FDP75N08A, PHP79NQ08LT,127, SQP60N06-15_GE3) should not be used in new designs.

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

A: Ta (ambient temperature) current rating of 9A represents the continuous current at 25°C ambient with natural convection cooling. Tc (case temperature) rating of 127A represents the maximum current when the device case is maintained at 25°C through active cooling or thermal management. Substitutes must meet or exceed the 127A Tc requirement to ensure equivalent current delivery capacity under worst-case thermal conditions.

Q: Why do some substitutes have lower gate charge than the AOT474?

A: Gate charge (Qg) determines the energy required to switch the MOSFET on and off. Lower gate charge values (such as PHP29N08T,127 at 19 nC) indicate faster switching speed and reduced driver power consumption. However, lower gate charge may correlate with higher on-resistance or other trade-offs. Driver circuit compatibility must be verified based on the specific gate drive voltage and current capability available in the application.

Q: Is the operating temperature range difference between -55°C to 175°C and -55°C to 150°C significant?

A: The 25°C difference in maximum junction temperature affects thermal margin and long-term reliability in high-temperature environments. For applications operating near 150°C, the reduced margin may impact device lifespan. For typical industrial applications operating below 125°C, the difference is not critical. DMT6009LCT and FDP75N08A are limited to 150°C maximum.

Q: What does RoHS3 compliance indicate?

A: RoHS3 compliance certifies that the device meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. This certification is required for products sold in the European Union and is increasingly required globally. All active substitutes listed are RoHS3 compliant.

Q: Can I use a substitute with higher Vdss rating in a 75V circuit?

A: Yes. A device rated for 80V (AOT288L) can be used in a 75V circuit without exceeding its voltage rating. However, higher voltage-rated devices may have different on-resistance, gate charge, and capacitance characteristics that affect circuit performance. Verify that these parameter differences are acceptable for the specific application.

Q: Why is on-resistance (Rds On) important for substitution?

A: On-resistance directly determines conduction losses (I²R) and heat generation during operation. Lower on-resistance reduces power dissipation and improves efficiency. The AOT474 specifies 11.3 mOhm at 30A/10V. Substitutes with comparable or lower on-resistance (such as IRFB3307PBF at 6.3 mOhm) provide equal or better thermal performance. Higher on-resistance substitutes increase heat generation and may require enhanced thermal management.

Q: What is the difference between TO-220 and TO-220-3 package designations?

A: TO-220-3 specifies a three-lead through-hole package with gate, drain, and source connections. TO-220 and TO-220AB are equivalent designations for the same package. All substitutes listed use TO-220-3 or equivalent three-lead through-hole packages, ensuring mechanical and electrical compatibility with existing PCB layouts.

Q: Should I prioritize active or obsolete substitute parts?

A: Active parts are strongly preferred for new designs and ongoing production. Active parts ensure long-term availability, ongoing manufacturer support, and continued compliance with evolving standards. Obsolete parts (FDP75N08A, PHP79NQ08LT,127, SQP60N06-15_GE3) should be used only for legacy system maintenance when no active alternatives are available. The AOT474 itself is obsolete, making transition to an active substitute necessary for production continuity.

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