FQP7N40 Equivalent & Substitute Parts

Part Overview

The FQP7N40 is an N-Channel MOSFET manufactured by onsemi, rated for 400V drain-to-source voltage with 7A continuous drain current at 25°C. This device features a TO-220-3 through-hole package and is part of the QFET® series. The FQP7N40 is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across critical parameters including voltage rating, current capacity, and thermal characteristics while accommodating packaging and availability constraints.

Key Parameters

Parameter	FQP7N40	Unit
Drain to Source Voltage (Vdss)	400	V
Continuous Drain Current (Id) @ 25°C	7	A
Rds On (Max) @ Id, Vgs	800 mOhm @ 3.5A, 10V	mOhm
Gate Threshold Voltage (Vgs(th)) @ Id	5	V @ 250µA
Power Dissipation (Max)	98	W
Operating Temperature Range	-55 to 150	°C
Package Type	TO-220-3	Through Hole
FET Type	N-Channel	—
Technology	MOSFET (Metal Oxide)	—

Substitute Part Grouping Explanation

Substitute parts for the FQP7N40 are selected based on strict electrical and mechanical parameter compatibility. The primary substitution criteria are:

Critical Parameters for Substitution:

Drain to Source Voltage (Vdss): Must equal or exceed 400V
Continuous Drain Current (Id): Must support minimum 7A at 25°C
Package Type: Must be TO-220 or TO-220-3 through-hole configuration
Operating Temperature Range: Must span -55°C to 150°C
FET Type: Must be N-Channel MOSFET technology
Gate Drive Voltage: Must operate at 10V drive voltage

Secondary Compatibility Parameters:

Rds On characteristics at specified gate voltage
Gate threshold voltage within acceptable operating range
Power dissipation capability
Input capacitance and gate charge specifications

The substitute parts identified (AOT9N40 and STP7NK40Z) meet or exceed the critical electrical parameters while maintaining through-hole TO-220 package compatibility. Both substitutes support the full operating temperature range and are available in active product status or with established supply chains.

Parameter Comparison

Parameter	FQP7N40 (onsemi)	AOT9N40 (Alpha & Omega)	STP7NK40Z (STMicroelectronics)	Unit
Drain to Source Voltage (Vdss)	400	400	400	V
Continuous Drain Current (Id) @ 25°C	7	8	5.4	A
Rds On (Max) @ Id, Vgs	800 mOhm @ 3.5A, 10V	800 mOhm @ 4A, 10V	1 Ohm @ 2.7A, 10V	mOhm
Gate Threshold Voltage (Vgs(th)) @ Id	5 @ 250µA	4.5 @ 250µA	4.5 @ 50µA	V
Gate Charge (Qg) (Max) @ Vgs	22 @ 10V	16 @ 10V	26 @ 10V	nC
Input Capacitance (Ciss) (Max) @ Vds	780 @ 25V	760 @ 25V	535 @ 25V	pF
Power Dissipation (Max)	98	132	70	W
Operating Temperature Range	-55 to 150	-55 to 150	-55 to 150	°C
Vgs (Max)	±30	±30	±30	V
Package Type	TO-220-3	TO-220-3	TO-220-3	—
Mounting Type	Through Hole	Through Hole	Through Hole	—
Product Status	Obsolete	Active	Active	—

Engineering Selection Recommendations

AOT9N40 (Alpha & Omega Semiconductor Inc.): The AOT9N40 provides direct electrical substitution with enhanced current capacity (8A vs. 7A) and superior power dissipation (132W vs. 98W). This device is classified as active product status with established supply availability. The AOT9N40 maintains identical voltage rating (400V Vdss) and gate drive voltage (10V) while offering improved thermal performance. RoHS3 compliance and REACH unaffected status align with modern manufacturing standards. This substitute is suitable for applications requiring equal or higher current handling and thermal margin.

STP7NK40Z (STMicroelectronics): The STP7NK40Z is an active product from the SuperMESH™ series offering alternative electrical characteristics. While continuous drain current is reduced to 5.4A, the device maintains 400V voltage rating and full operating temperature range compatibility. The STP7NK40Z features lower input capacitance (535 pF vs. 780 pF) and improved Rds On characteristics at lower current levels (1 Ohm @ 2.7A). RoHS3 compliance and established supply chain support long-term availability. This substitute is appropriate for applications where lower current requirements and reduced capacitance provide design advantages.

Both substitutes are classified as REACH unaffected and carry EAR99 ECCN designation, matching the original part's regulatory status. Selection between AOT9N40 and STP7NK40Z depends on specific application current requirements and thermal design constraints.

Frequently Asked Questions (FAQ)

Q: Can the AOT9N40 directly replace the FQP7N40 in all applications? A: The AOT9N40 maintains identical voltage rating (400V) and gate drive voltage (10V) with higher current capacity (8A vs. 7A) and power dissipation (132W vs. 98W). Direct substitution is electrically valid for applications operating at or below 7A continuous drain current. Thermal design must accommodate the different package thermal characteristics.

Q: What are the current limitations when using STP7NK40Z as a substitute? A: The STP7NK40Z is rated for 5.4A continuous drain current, which is lower than the FQP7N40's 7A rating. This device is suitable only for applications requiring 5.4A or less. The 400V voltage rating and operating temperature range remain fully compatible.

Q: Are all three devices pin-compatible in TO-220-3 packages? A: All three devices use TO-220-3 through-hole packages with identical pin configurations for N-Channel MOSFETs. Physical mounting and PCB layout compatibility is maintained across all three parts.

Q: What is the significance of the different Rds On specifications? A: Rds On (on-state resistance) affects power dissipation and heat generation. The FQP7N40 specifies 800 mOhm @ 3.5A, 10V; AOT9N40 specifies 800 mOhm @ 4A, 10V; and STP7NK40Z specifies 1 Ohm @ 2.7A, 10V. Lower Rds On at higher currents reduces power loss. Application current levels determine which specification is most relevant.

Q: How do gate charge differences impact circuit design? A: Gate charge (Qg) affects gate drive circuit requirements and switching speed. FQP7N40 requires 22 nC @ 10V, AOT9N40 requires 16 nC @ 10V, and STP7NK40Z requires 26 nC @ 10V. Lower gate charge enables faster switching and reduces gate drive power consumption. Existing gate drive circuits must be verified for compatibility with the selected substitute.

Q: Why is the FQP7N40 classified as obsolete? A: Obsolete status indicates the manufacturer has discontinued production. Substitute parts with active product status (AOT9N40 and STP7NK40Z) ensure long-term supply availability and continued manufacturing support.

Q: Are there compliance or regulatory differences between the three devices? A: All three devices are REACH unaffected and carry EAR99 ECCN designation. AOT9N40 and STP7NK40Z include RoHS3 compliance certification. Moisture sensitivity level is 1 (Unlimited) for all three devices, indicating no special moisture handling requirements.

Q: What thermal considerations apply when substituting these devices? A: Power dissipation ratings differ: FQP7N40 (98W), AOT9N40 (132W), and STP7NK40Z (70W). Thermal design must account for these differences. Higher power dissipation devices may require enhanced heatsinking. Lower power dissipation devices may allow simplified thermal management but are limited to lower current applications.

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