IRF7809TR N-Channel 30V 17.6A MOSFET Equivalent & Substitute Parts

Part Overview

The IRF7809TR is an N-Channel MOSFET manufactured by Infineon Technologies, rated for 30V drain-to-source voltage with 17.6A continuous drain current at 25°C. This device is packaged in an 8-SO surface mount configuration and belongs to the HEXFET® series. The IRF7809TR is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support, production continuity, and component sourcing.

Substitute parts must maintain compatibility across critical electrical parameters including drain-to-source voltage rating, continuous drain current capability, on-resistance characteristics, and gate charge specifications, while accommodating the 8-SOIC package footprint standard.

Key Parameters

Parameter	IRF7809TR	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	30	V
Continuous Drain Current (Id) @ 25°C	17.6	A
Rds On (Max) @ 15A, 4.5V	7.5	mOhm
Gate Charge (Qg) @ 5V	86	nC
Vgs(th) (Max) @ 250µA	1	V
Vgs (Max)	±12	V
Input Capacitance (Ciss) @ 16V	7300	pF
Power Dissipation (Max)	3.5	W
Operating Temperature Range	-55 to 150	°C
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution eligibility for the IRF7809TR is determined by the following critical parameters:

Voltage Rating Compatibility: All substitute parts must maintain the 30V Vdss rating to ensure safe operation within the same voltage domain.

Current Capability: Substitute parts must support continuous drain current at or above the application requirement. The IRF7809TR provides 17.6A; acceptable substitutes range from 13A to 15A, with design margin considerations required for applications demanding the full 17.6A specification.

On-Resistance (Rds On): The IRF7809TR specifies 7.5mOhm maximum at 15A and 4.5V gate drive. Substitute parts with Rds On values between 6.7mOhm and 8mOhm maintain thermal and efficiency characteristics within acceptable engineering tolerances.

Gate Charge (Qg): The IRF7809TR gate charge of 86nC at 5V represents a significant switching characteristic. Substitute parts with lower gate charge (24nC to 37nC) offer improved switching speed and reduced driver power dissipation, representing a design advantage.

Package Footprint: All substitute parts utilize the 8-SOIC (0.154", 3.90mm Width) package, ensuring direct PCB layout compatibility without redesign.

Operating Temperature Range: All candidates support the -55°C to 150°C operating range, maintaining thermal specification alignment.

Parameter Comparison

Parameter	IRF7809TR	AO4476A	FDS6670A	RSS140N03TB	Unit
Manufacturer	Infineon	Alpha & Omega	Fairchild	Rohm	—
FET Type	N-Channel	N-Channel	N-Channel	N-Channel	—
Vdss	30	30	30	30	V
Id @ 25°C	17.6	15	13	14	A
Rds On (Max)	7.5 @ 15A, 4.5V	7.7 @ 15A, 10V	8 @ 13A, 10V	6.7 @ 14A, 10V	mOhm
Qg (Max)	86 @ 5V	24 @ 10V	30 @ 5V	37 @ 5V	nC
Vgs(th) (Max)	1 @ 250µA	2.5 @ 250µA	3 @ 250µA	2.5 @ 1mA	V
Vgs (Max)	±12	±20	±20	20	V
Ciss (Max)	7300 @ 16V	1380 @ 15V	2220 @ 15V	3150 @ 10V	pF
Power Dissipation (Max)	3.5	3.1	2.5	2	W
Operating Temperature	-55 to 150	-55 to 150	-55 to 150	to 150	°C
Package	8-SOIC	8-SOIC	8-SOIC	8-SOIC	—
Product Status	Obsolete	Not For New Designs	Active	Active	—
RoHS Status	Non-compliant	ROHS3 Compliant	Not specified	ROHS3 Compliant	—

Engineering Selection Recommendations

Primary Substitute: FDS6670A (Fairchild Semiconductor)

The FDS6670A is the recommended primary substitute for the IRF7809TR. This device maintains the 30V Vdss rating and provides 13A continuous drain current, representing a 26% reduction from the IRF7809TR specification. The FDS6670A is classified as Active product status, ensuring long-term availability and manufacturing support. The device achieves superior gate charge performance (30nC versus 86nC), resulting in reduced switching losses and lower driver power requirements. RoHS compliance status is not explicitly specified; verification with the manufacturer is required for applications with RoHS mandates. The PowerTrench® technology platform provides optimized on-resistance characteristics (8mOhm at 13A, 10V) suitable for general-purpose switching applications.

Secondary Substitute: AO4476A (Alpha & Omega Semiconductor Inc.)

The AO4476A provides 15A continuous drain current at 30V, representing a 15% reduction from the IRF7809TR. This device is classified as Not For New Designs, indicating limited future availability and potential supply constraints. The AO4476A delivers significantly lower gate charge (24nC at 10V), providing switching performance advantages. ROHS3 compliance is confirmed. The higher Vgs(th) specification (2.5V versus 1V) requires verification against driver output voltage specifications to ensure reliable gate drive margin.

Tertiary Substitute: RSS140N03TB (Rohm Semiconductor)

The RSS140N03TB provides 14A continuous drain current at 30V, representing a 20% reduction from the IRF7809TR. This device is classified as Active product status with confirmed ROHS3 compliance, supporting long-term design continuity. The RSS140N03TB achieves the lowest on-resistance among candidates (6.7mOhm at 14A, 10V) and the lowest power dissipation (2W), providing thermal efficiency advantages. Gate charge is 37nC at 5V, representing moderate switching performance. The lower maximum Vgs specification (20V versus ±12V) requires verification against gate drive voltage levels.

Current Derating Consideration: Applications requiring the full 17.6A specification of the IRF7809TR cannot be directly substituted with any listed alternative without thermal or current derating analysis. Design review is mandatory for high-current applications.

Frequently Asked Questions (FAQ)

Q: Can the FDS6670A directly replace the IRF7809TR in all applications?

A: The FDS6670A is electrically compatible for applications requiring continuous drain current up to 13A at 30V. Applications demanding the full 17.6A specification of the IRF7809TR require thermal analysis and potential circuit redesign. The FDS6670A offers superior gate charge performance (30nC versus 86nC), reducing switching losses and driver power dissipation.

Q: What is the significance of the gate charge difference between the IRF7809TR (86nC) and substitute parts (24-37nC)?

A: Gate charge directly impacts switching speed and driver power dissipation. Lower gate charge enables faster switching transitions and reduces driver current requirements. Substitute parts with lower gate charge represent a design improvement for switching applications, provided the driver circuit is compatible with the lower threshold voltage specifications.

Q: Are all substitute parts RoHS compliant?

A: The AO4476A and RSS140N03TB are confirmed ROHS3 compliant. The FDS6670A RoHS status is not specified in the provided data; manufacturer verification is required for applications with RoHS mandates. The IRF7809TR is RoHS non-compliant.

Q: What is the impact of the Vgs(th) threshold voltage differences?

A: The IRF7809TR specifies Vgs(th) of 1V at 250µA, while substitutes range from 2.5V to 3V. Higher threshold voltages require higher gate drive voltages to achieve full on-state conduction. Verify that the gate driver output voltage exceeds the substitute part's Vgs(th) specification by a minimum margin to ensure reliable switching performance.

Q: Can the RSS140N03TB be used in place of the IRF7809TR despite the lower current rating?

A: The RSS140N03TB provides 14A continuous drain current, representing an 80% capability relative to the IRF7809TR. Substitution is valid only for applications with maximum continuous current requirements at or below 14A. The RSS140N03TB offers superior on-resistance (6.7mOhm) and lower power dissipation (2W), providing thermal advantages for current-limited applications.

Q: What is the difference between the 8-SO and 8-SOIC package designations?

A: The IRF7809TR is specified as 8-SO, while substitutes are specified as 8-SOIC. Both designations refer to the same 8-pin small-outline package with 0.154" (3.90mm) width. The packages are mechanically and electrically compatible for PCB layout purposes. Verify footprint dimensions with component datasheets to confirm exact pin spacing and lead configuration.

Q: Why is the AO4476A classified as "Not For New Designs"?

A: This classification indicates that the manufacturer is not recommending this part for new product development, typically due to planned discontinuation or transition to newer technology. While the AO4476A may remain available from inventory, long-term supply cannot be guaranteed. For new designs, the FDS6670A or RSS140N03TB are preferred alternatives with Active product status.

Q: How should I handle applications requiring the full 17.6A specification?

A: No single substitute part provides equivalent 17.6A continuous current capability. Design options include: (1) parallel connection of multiple substitute devices with appropriate current-sharing circuitry, (2) thermal derating analysis to confirm acceptable junction temperature at reduced current levels, or (3) evaluation of higher-current MOSFET alternatives outside the provided substitute list.

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