STP9NM40N Equivalent & Substitute Parts

Part Overview

The STP9NM40N is an N-Channel MOSFET manufactured by STMicroelectronics, rated for 400V drain-to-source voltage with 5.6A continuous drain current at 25°C. This device is part of the MDmesh™ II series and features a Through Hole TO-220-3 package configuration. The part is classified as obsolete, necessitating identification of equivalent substitute components for ongoing design requirements and procurement planning. Substitute parts must maintain electrical compatibility across voltage, current, and thermal specifications while accommodating the through-hole mounting requirement.

Substiute Parts

STP9NM40N

STMicroelectronicsIn Stock: 1602STP9NM40N Datasheet

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STP8NM50N

STMicroelectronicsIn Stock: 2040STP8NM50N Datasheet

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AOT9N40

Alpha & Omega Semiconductor Inc.In Stock: 2279AOT9N40 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the STP9NM40N are selected based on the following electrical and mechanical compatibility criteria:

Primary Substitution Parameters:

• Drain to Source Voltage (Vdss): Equal to or greater than 400V
• Continuous Drain Current (Id): Equal to or greater than 5.6A at 25°C
• Package Type: TO-220-3 Through Hole configuration
• FET Type: N-Channel MOSFET
• Operating Temperature: Maximum junction temperature of 150°C or higher
• RoHS3 Compliance: Required for regulatory alignment

Substitution Logic: Parts meeting or exceeding the voltage and current ratings while maintaining the same package footprint and thermal operating range are classified as functional equivalents. The STP8NM50N represents a voltage-rated upgrade (500V) with comparable current handling and identical on-resistance characteristics. The AOT9N40 provides enhanced current capacity (8A) at the same voltage rating with superior power dissipation capability (132W), offering performance headroom for the same application envelope.

Parameter Comparison

Engineering Selection Recommendations

STP8NM50N (STMicroelectronics): This substitute is recommended for applications requiring voltage margin above the original 400V specification. The 500V rating provides additional design headroom while maintaining identical on-resistance and gate charge characteristics. Product status is active with established supply chain availability. RoHS3 compliance and REACH unaffected status align with regulatory requirements. The reduced power dissipation rating (45W versus 60W) requires thermal evaluation in high-power applications.

AOT9N40 (Alpha & Omega Semiconductor Inc.): This substitute is recommended for applications requiring enhanced current capacity or thermal performance. The 8A continuous drain current and 132W power dissipation provide significant performance margin over the original specification. The device maintains the 400V voltage rating and TO-220-3 package compatibility. Product status is active with confirmed inventory availability. RoHS3 compliance and REACH unaffected status satisfy regulatory requirements. The higher gate charge (16nC versus 14nC) and input capacitance (760pF versus 365pF) require driver circuit evaluation for switching frequency applications.

Both substitutes maintain through-hole TO-220-3 package compatibility, enabling direct mechanical and electrical integration without PCB redesign.

Frequently Asked Questions (FAQ)

Q: Can the STP8NM50N be used as a direct replacement for the STP9NM40N?

A: The STP8NM50N is electrically compatible for applications operating at or below 400V. The higher voltage rating (500V) provides additional margin. The identical on-resistance (790mOhm @ 2.5A, 10V) and gate charge (14nC @ 10V) ensure equivalent switching performance. The reduced power dissipation rating (45W versus 60W) requires verification that thermal conditions remain within acceptable limits for the specific application.

Q: What are the key differences between the STP8NM50N and AOT9N40 substitutes?

A: The STP8NM50N offers a higher voltage rating (500V) with lower current capacity (5A), while the AOT9N40 maintains the original 400V rating with enhanced current capacity (8A). The AOT9N40 provides superior power dissipation capability (132W). The AOT9N40 exhibits higher input capacitance (760pF @ 25V) and gate charge (16nC @ 10V), which may affect switching frequency performance. Both devices are pin-compatible in TO-220-3 packages.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. Both the STP8NM50N and AOT9N40 are RoHS3 compliant and REACH unaffected, matching the regulatory status of the original STP9NM40N.

Q: Can these substitutes be used in high-frequency switching applications?

A: The STP8NM50N maintains identical gate charge and input capacitance characteristics to the original part, supporting equivalent switching frequency performance. The AOT9N40 exhibits higher gate charge (16nC) and input capacitance (760pF), which may reduce maximum switching frequency. Driver circuit evaluation is required for applications exceeding 100kHz switching frequency.

Q: What is the impact of the AOT9N40's higher Vgs (Max) rating of ±30V?

A: The AOT9N40's ±30V gate voltage rating provides additional margin compared to the ±25V rating of the original part. This does not restrict compatibility; existing gate drive circuits designed for ±25V operation remain fully compatible.

Q: Are there thermal considerations when selecting between substitutes?

A: The STP8NM50N's reduced power dissipation rating (45W) requires thermal verification in applications approaching the original 60W specification. The AOT9N40's enhanced power dissipation capability (132W) provides thermal margin for high-current or high-frequency applications. Heatsink requirements should be re-evaluated based on actual application duty cycle.

Q: Do these substitutes require PCB modifications?

A: No. Both substitutes maintain TO-220-3 through-hole package compatibility with identical pin assignments, enabling direct mechanical and electrical integration without PCB redesign.