IRF3717TR N-Channel MOSFET 20V 20A Equivalent & Substitute Parts

Part Overview

The IRF3717TR is an N-Channel MOSFET manufactured by Infineon Technologies, part of the HEXFET® series. This device is rated for 20V drain-to-source voltage with 20A continuous drain current in a surface mount 8-SO package. The IRF3717TR is classified as obsolete, making identification of functionally equivalent substitute components necessary for ongoing design support and procurement continuity. Equivalent parts must maintain compatibility across electrical ratings, thermal characteristics, and mechanical packaging to ensure direct substitution in existing circuit applications.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	20	V
Continuous Drain Current (Id) @ 25°C	20	A
On-State Resistance (Rds On Max) @ 20A, 10V	4.4	mOhm
Gate Threshold Voltage (Vgs(th) Max) @ 250µA	2.45	V
Gate Charge (Qg Max) @ 4.5V	33	nC
Maximum Gate Voltage (Vgs Max)	±20	V
Power Dissipation (Max)	2.5	W
Operating Temperature Range	-55 to 150	°C
Package Type	8-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution eligibility for the IRF3717TR is determined by strict equivalence across the following critical parameters:

Primary Electrical Criteria:

Drain-to-Source Voltage (Vdss): Must equal 20V
Continuous Drain Current (Id): Must equal or exceed 20A at 25°C
On-State Resistance (Rds On): Must not exceed 4.4 mOhm at specified gate voltage
Gate Threshold Voltage (Vgs(th)): Must be compatible with existing gate drive circuits
Maximum Gate Voltage (Vgs Max): Must accommodate ±20V gate drive signals

Mechanical & Thermal Criteria:

Package: 8-SOIC surface mount configuration with 0.154" (3.90mm) width
Operating Temperature: -55°C to 150°C junction temperature range
Mounting Type: Surface mount compatibility

Compliance Criteria:

RoHS and REACH compliance status
Moisture Sensitivity Level (MSL): Level 1 (Unlimited)

Two substitute parts meet these criteria with documented electrical and mechanical compatibility to the IRF3717TR.

Parameter Comparison

Parameter	IRF3717TR (Main)	AO4402	SI4408DY-T1-E3	Unit
Manufacturer	Infineon Technologies	Alpha & Omega Semiconductor Inc.	Vishay Siliconix	—
FET Type	N-Channel	N-Channel	N-Channel	—
Vdss	20	20	20	V
Id @ 25°C	20	20	14	A
Rds On (Max)	4.4 @ 20A, 10V	5.5 @ 20A, 4.5V	4.5 @ 21A, 10V	mOhm
Vgs(th) Max @ 250µA	2.45	1.6	1.0 (Min)	V
Qg Max	33 @ 4.5V	43 @ 10V	32 @ 4.5V	nC
Vgs Max	±20	±12	±20	V
Power Dissipation (Max)	2.5	3.1	1.6	W
Operating Temperature	-55 to 150	-55 to 150	-55 to 150	°C
Package	8-SOIC	8-SOIC	8-SOIC	—
Product Status	Obsolete	Not For New Designs	Active	—
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

AO4402 (Alpha & Omega Semiconductor Inc.)

The AO4402 provides electrical equivalence at the 20V/20A rating with 8-SOIC packaging. This part maintains the same drain current specification and voltage rating as the IRF3717TR. The AO4402 achieves ROHS3 compliance, addressing regulatory requirements for new procurement. However, the AO4402 carries a "Not For New Designs" status, indicating limited long-term availability. The Rds On specification of 5.5 mOhm at 4.5V gate voltage is slightly higher than the IRF3717TR at 4.4 mOhm, resulting in marginally increased power dissipation. The maximum gate voltage rating of ±12V is lower than the IRF3717TR's ±20V, requiring verification of gate drive circuit compatibility. Inventory availability is substantial at 180,400 pieces.

SI4408DY-T1-E3 (Vishay Siliconix)

The SI4408DY-T1-E3 is classified as Active product status, providing the longest procurement and design support horizon. This device maintains 20V Vdss rating and 8-SOIC packaging with full ROHS3 compliance. The continuous drain current is rated at 14A, which is lower than the IRF3717TR's 20A specification. The Rds On of 4.5 mOhm at 10V gate voltage is comparable to the IRF3717TR. The SI4408DY-T1-E3 supports ±20V gate voltage, matching the IRF3717TR's gate drive requirements. Gate charge of 32 nC is nearly identical to the IRF3717TR. This part is suitable for applications where the 14A continuous current rating is sufficient. Current inventory is 29,230 pieces.

Selection Basis:

For applications requiring the full 20A continuous drain current specification, the AO4402 provides direct electrical equivalence despite its "Not For New Designs" status. For applications tolerating 14A continuous current with preference for long-term active product support, the SI4408DY-T1-E3 is the preferred selection. Both parts satisfy mechanical packaging and thermal operating range requirements.

Frequently Asked Questions (FAQ)

Q: Can the AO4402 directly replace the IRF3717TR in all applications?

A: The AO4402 maintains electrical equivalence at the 20V/20A rating and 8-SOIC package. However, the maximum gate voltage of ±12V versus the IRF3717TR's ±20V requires verification that existing gate drive circuits do not exceed ±12V. The slightly higher Rds On (5.5 mOhm vs. 4.4 mOhm) results in increased power dissipation, which must be evaluated against thermal design margins.

Q: Why is the SI4408DY-T1-E3 rated for only 14A when the IRF3717TR is 20A?

A: The SI4408DY-T1-E3 is a different device within the same voltage class. The 14A continuous current rating reflects its specific die design and thermal characteristics. This part is suitable only for applications where 14A continuous current is sufficient. Applications requiring 20A continuous current must use the AO4402 or identify alternative 20A-rated devices.

Q: Are both substitute parts available in the same packaging as the IRF3717TR?

A: Yes. Both the AO4402 and SI4408DY-T1-E3 are supplied in 8-SOIC packages with 0.154" (3.90mm) width, matching the IRF3717TR's mechanical footprint. Both are surface mount devices with identical lead spacing and PCB layout compatibility.

Q: What is the significance of the "Not For New Designs" status on the AO4402?

A: This status indicates the manufacturer is not recommending the AO4402 for new circuit designs, typically due to planned discontinuation or transition to newer products. However, the part remains available for existing design support and legacy system maintenance. Long-term availability cannot be guaranteed.

Q: Which substitute part has the best long-term availability?

A: The SI4408DY-T1-E3 carries Active product status, indicating ongoing manufacturing and support. This part provides the most favorable long-term procurement outlook. The AO4402, despite higher current inventory, has limited design-in recommendations.

Q: Do both substitute parts meet RoHS compliance requirements?

A: Yes. Both the AO4402 and SI4408DY-T1-E3 are ROHS3 compliant. The original IRF3717TR is RoHS non-compliant, making either substitute suitable for applications with RoHS compliance mandates.

Q: How do gate charge differences affect circuit performance?

A: The IRF3717TR specifies 33 nC gate charge at 4.5V. The AO4402 specifies 43 nC at 10V, and the SI4408DY-T1-E3 specifies 32 nC at 4.5V. Higher gate charge requires greater gate drive current or longer switching times. The SI4408DY-T1-E3 is nearly identical to the IRF3717TR in this parameter.

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