IRF8721PBF N-Channel 30V 14A MOSFET Equivalent & Substitute Parts

Part Overview

The IRF8721PBF is an N-Channel MOSFET manufactured by Infineon Technologies, rated for 30V drain-to-source voltage with 14A continuous drain current at 25°C. This device is housed in an 8-SOIC surface mount package and features a maximum on-resistance of 8.5mOhm at 14A and 10V gate-source voltage. The IRF8721PBF is part of the HEXFET® series and is currently discontinued at DiGi Electronics. Due to its discontinued status, equivalent substitute parts with compatible electrical and mechanical specifications are necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	30	V
Continuous Drain Current (Id) @ 25°C	14	A
On-Resistance (Rds On Max) @ 14A, 10V	8.5	mOhm
Gate-Source Threshold Voltage (Vgs(th)) @ 25µA	2.35	V
Gate Charge (Qg) @ 4.5V	12	nC
Input Capacitance (Ciss) @ 15V	1040	pF
Power Dissipation (Max)	2.5	W
Operating Temperature Range	-55 to 150	°C
Package Type	8-SOIC	-
Mounting Type	Surface Mount	-

Substitute Part Grouping Explanation

Substitute parts for the IRF8721PBF are selected based on strict electrical and mechanical compatibility criteria. All substitute candidates must meet the following requirements:

Critical Matching Parameters:

Drain-to-Source Voltage (Vdss): 30V (exact match required)
FET Type: N-Channel (exact match required)
Technology: MOSFET Metal Oxide (exact match required)
Package Type: 8-SOIC with 0.154" (3.90mm) width (exact match required)
Mounting Type: Surface Mount (exact match required)
Gate-Source Voltage Range (Vgs Max): ±20V or greater (must accommodate)
Operating Temperature Range: -55°C to 150°C (must accommodate)
RoHS3 Compliance: Required
Moisture Sensitivity Level: 1 (Unlimited)

Allowable Parameter Variations: Substitute parts may have different values for continuous drain current (Id), on-resistance (Rds On), gate charge (Qg), input capacitance (Ciss), and power dissipation, provided these differences do not compromise circuit functionality. Parts with lower drain current ratings require circuit-level verification. Parts with higher on-resistance may increase power dissipation and require thermal management review.

The following parts meet all critical matching criteria and are presented as valid substitutes for the IRF8721PBF.

Parameter Comparison

Parameter	IRF8721PBF (Main)	FDS6680A	FDS8880	SI4894BDY-T1-E3	STS10N3LH5	Unit
Manufacturer	Infineon	onsemi	onsemi	Vishay Siliconix	STMicroelectronics	-
Vdss	30	30	30	30	30	V
Id @ 25°C	14	12.5	11.6	8.9	10	A
Rds On (Max) @ Vgs 10V	8.5	9.5	10	11	21	mOhm
Vgs(th) (Max)	2.35	3	2.5	3	1	V
Gate Charge (Qg)	12	23	30	38	4.6	nC
Ciss @ 15V	1040	1620	1235	1580	475	pF
Power Dissipation (Max)	2.5	2.5	2.5	1.4	2.5	W
Operating Temperature	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	°C
Package	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	-
Product Status	Discontinued	Active	Active	Active	Not For New Designs	-
RoHS3 Compliant	Yes	Yes	Yes	Yes	Yes	-

Engineering Selection Recommendations

Primary Substitute: FDS6680A (onsemi)

The FDS6680A is the recommended primary substitute for the IRF8721PBF. This part is currently in active production status with 50,400 pieces in stock. It maintains the same 30V Vdss rating and 8-SOIC package configuration. The continuous drain current rating of 12.5A is within 89% of the original 14A specification. The on-resistance of 9.5mOhm at 10V is marginally higher than the IRF8721PBF at 8.5mOhm, resulting in approximately 12% increased conduction losses under identical operating conditions. The FDS6680A is part of the PowerTrench® series and carries full RoHS3 compliance with unlimited moisture sensitivity rating.

Secondary Substitute: FDS8880 (onsemi)

The FDS8880 is an active production alternative with 38,100 pieces in stock. It provides an 11.6A continuous drain current rating (83% of original specification) and 10mOhm on-resistance at 10V. This part exhibits slightly higher gate charge (30nC versus 12nC) and input capacitance (1235pF versus 1040pF), which may increase switching losses in high-frequency applications. The FDS8880 maintains full electrical and mechanical compatibility with identical package specifications and temperature range.

Tertiary Substitute: SI4894BDY-T1-E3 (Vishay Siliconix)

The SI4894BDY-T1-E3 is an active production part with 65,100 pieces in stock. This TrenchFET® series device provides an 8.9A continuous drain current rating (64% of original specification) and 11mOhm on-resistance. The power dissipation rating is reduced to 1.4W compared to the original 2.5W, indicating lower thermal capacity. This part is suitable for applications where the lower current rating does not compromise circuit performance. The significantly lower gate charge (38nC) and higher input capacitance (1580pF) require evaluation in switching-dependent circuits.

Not Recommended for New Designs: STS10N3LH5 (STMicroelectronics)

The STS10N3LH5 carries a "Not For New Designs" product status designation. While it meets all critical electrical and mechanical compatibility criteria with a 30V Vdss rating and 8-SOIC package, its 10A continuous drain current (71% of original) and significantly elevated on-resistance of 21mOhm at 10V (147% higher than original) make it unsuitable for new design implementations. This part is presented for reference only in legacy system maintenance scenarios.

Frequently Asked Questions (FAQ)

Q1: Can the FDS6680A directly replace the IRF8721PBF without circuit modifications?

A: The FDS6680A is mechanically and electrically compatible with the IRF8721PBF in terms of package type, pinout, voltage rating, and temperature range. However, the 12.5A continuous drain current rating is lower than the original 14A specification. Direct replacement is permissible only if the circuit design does not require the full 14A current capacity. Thermal analysis should be performed to verify that the marginally higher on-resistance (9.5mOhm versus 8.5mOhm) does not exceed thermal design limits.

Q2: What are the key differences between the substitute parts?

A: The primary differences among substitute parts are continuous drain current ratings (ranging from 8.9A to 12.5A), on-resistance values (ranging from 9.5mOhm to 21mOhm), and gate charge specifications (ranging from 4.6nC to 38nC). These variations affect maximum current handling capability, conduction losses, and switching speed. Selection depends on specific circuit requirements for current capacity, thermal dissipation, and switching frequency.

Q3: Are all substitute parts available in the same 8-SOIC package?

A: Yes. All substitute parts listed are manufactured in the 8-SOIC package with 0.154" (3.90mm) width specification, ensuring mechanical compatibility with the original IRF8721PBF footprint. PCB layout modifications are not required for package substitution.

Q4: Do all substitute parts meet RoHS3 compliance requirements?

A: Yes. All substitute parts listed carry RoHS3 compliance certification and unlimited moisture sensitivity level (MSL 1) ratings, meeting current environmental and reliability standards.

Q5: Which substitute part has the lowest on-resistance?

A: The FDS6680A has the lowest on-resistance among active production substitutes at 9.5mOhm at 14A and 10V gate-source voltage, representing only a 12% increase over the original IRF8721PBF specification of 8.5mOhm.

Q6: What is the impact of higher gate charge on circuit performance?

A: Higher gate charge values increase the energy required to switch the MOSFET on and off, resulting in increased switching losses in high-frequency applications. The FDS8880 (30nC) and SI4894BDY-T1-E3 (38nC) exhibit significantly higher gate charge compared to the IRF8721PBF (12nC). In applications operating above 100kHz, gate driver capability and switching frequency performance should be verified.

Q7: Can the SI4894BDY-T1-E3 be used in high-current applications?

A: The SI4894BDY-T1-E3 is rated for 8.9A continuous drain current, which is 64% of the original IRF8721PBF specification. This part is suitable only for applications where the circuit current requirement does not exceed 8.9A. The reduced power dissipation rating (1.4W versus 2.5W) further limits its use in high-power scenarios.

Q8: Why is the STS10N3LH5 marked as "Not For New Designs"?

A: The STS10N3LH5 carries a "Not For New Designs" status, indicating that the manufacturer has discontinued active development and marketing of this part. While it remains available in inventory (15,265 pieces), it is intended for legacy system support only. New designs should utilize active production alternatives such as FDS6680A or FDS8880.

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