FQU9N25TU Equivalent & Substitute Parts

Part Overview

The FQU9N25TU is an N-Channel MOSFET manufactured by onsemi, rated for 250V drain-to-source voltage with 7.4A continuous drain current. The device is packaged in a Through Hole IPAK (TO-251-3) configuration and is part of the QFET® series. This part carries an Obsolete product status, making identification of equivalent and substitute components necessary for ongoing design support, maintenance, and production continuity.

Key Parameters

Parameter	Value	Unit
Manufacturer Part Number	FQU9N25TU	—
Manufacturer	onsemi	—
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	250	V
Continuous Drain Current (Id) @ 25°C	7.4	A (Tc)
On-State Resistance (Rds On Max) @ Id, Vgs	420	mOhm @ 3.7A, 10V
Gate Threshold Voltage (Vgs(th) Max) @ Id	5	V @ 250µA
Gate Charge (Qg Max) @ Vgs	20	nC @ 10V
Maximum Gate Voltage (Vgs Max)	±30	V
Input Capacitance (Ciss Max) @ Vds	700	pF @ 25V
Power Dissipation (Max)	2.5 (Ta), 55 (Tc)	W
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-251-3 Short Leads, IPak, TO-251AA	—
Product Status	Obsolete	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the FQU9N25TU is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

FET Type: N-Channel topology must be maintained
Drain-to-Source Voltage (Vdss): Substitute must equal or exceed 250V
Continuous Drain Current (Id): Substitute must meet or exceed 7.4A at 25°C
On-State Resistance (Rds On): Substitute performance must be comparable or superior
Gate Threshold Voltage (Vgs(th)): Must fall within acceptable control voltage range
Maximum Gate Voltage (Vgs Max): Must accommodate ±30V or greater
Operating Temperature Range: Must support -55°C to 150°C minimum

Mechanical Compatibility Criteria:

Mounting Type: Through Hole configuration required
Package / Case: TO-251-3 Short Leads (IPAK) footprint required
Pin Configuration: TO-251AA standard pinout

Regulatory & Compliance Criteria:

RoHS3 Compliance required
REACH Unaffected status required

The substitute parts listed below satisfy these criteria within the allowed parameter ranges.

Parameter Comparison

Parameter	FQU9N25TU (Main)	FQU10N20CTU (Substitute)	STU7NF25 (Substitute)	Unit
Manufacturer	onsemi	onsemi	STMicroelectronics	—
FET Type	N-Channel	N-Channel	N-Channel	—
Drain to Source Voltage (Vdss)	250	200	250	V
Continuous Drain Current (Id) @ 25°C	7.4	7.8	8.0	A (Tc)
On-State Resistance (Rds On Max) @ Id, Vgs	420 @ 3.7A, 10V	360 @ 3.9A, 10V	420 @ 4.0A, 10V	mOhm
Gate Threshold Voltage (Vgs(th) Max) @ Id	5 @ 250µA	4 @ 250µA	4 @ 250µA	V
Gate Charge (Qg Max) @ Vgs	20 @ 10V	26 @ 10V	16 @ 10V	nC
Maximum Gate Voltage (Vgs Max)	±30	±30	±20	V
Input Capacitance (Ciss Max) @ Vds	700 @ 25V	510 @ 25V	500 @ 25V	pF
Power Dissipation (Max)	55 (Tc)	50 (Tc)	72 (Tc)	W
Operating Temperature Range	-55 to 150	-55 to 150	-55 to 175	°C (TJ)
Mounting Type	Through Hole	Through Hole	Through Hole	—
Package / Case	TO-251-3 Short Leads, IPak, TO-251AA	TO-251-3 Short Leads, IPak, TO-251AA	TO-251-3 Short Leads, IPak, TO-251AA	—
Product Status	Obsolete	Obsolete	Active	—
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

FQU10N20CTU (onsemi Substitute): This part is designated as the manufacturer-recommended substitute. Both devices are from the onsemi QFET® series and share identical product status (Obsolete). The FQU10N20CTU provides superior on-state resistance performance (360 mOhm vs. 420 mOhm) and higher continuous drain current (7.8A vs. 7.4A). However, the drain-to-source voltage rating is reduced to 200V, which limits its use to applications where the maximum operating voltage does not exceed 200V. Both parts are ROHS3 Compliant and carry identical regulatory status. This substitute is suitable for direct replacement in circuits operating at 200V or below.

STU7NF25 (STMicroelectronics Substitute): This part is from the STMicroelectronics STripFET™ II series and carries Active product status, providing superior long-term availability compared to the Obsolete FQU9N25TU. The STU7NF25 maintains the 250V drain-to-source voltage rating and exceeds the continuous drain current specification (8.0A vs. 7.4A). Power dissipation capability is enhanced (72W vs. 55W). The operating temperature range extends to 175°C, providing additional thermal margin. The maximum gate voltage is limited to ±20V compared to ±30V on the original part. This substitute is suitable for direct replacement in circuits where the ±20V gate voltage limit is acceptable. ROHS3 Compliance and REACH Unaffected status are maintained.

Selection Basis:

For applications requiring 250V operation with long-term availability: STU7NF25
For applications operating at 200V or below with onsemi product continuity: FQU10N20CTU
All substitutes maintain Through Hole IPAK packaging and TO-251-3 footprint compatibility
All substitutes are ROHS3 Compliant and REACH Unaffected

Frequently Asked Questions (FAQ)

Q: Can the FQU10N20CTU be used in place of the FQU9N25TU in all applications?

A: The FQU10N20CTU is suitable only for applications where the maximum drain-to-source voltage does not exceed 200V. The original FQU9N25TU is rated for 250V operation. If your circuit operates above 200V, the FQU10N20CTU will not provide adequate voltage margin and substitution is not permitted.

Q: What is the primary advantage of the STU7NF25 over the FQU9N25TU?

A: The STU7NF25 carries Active product status, ensuring continued availability and manufacturing support. The original FQU9N25TU is Obsolete. Additionally, the STU7NF25 provides higher continuous drain current (8.0A vs. 7.4A), superior power dissipation capability (72W vs. 55W), and an extended operating temperature range (-55°C to 175°C vs. -55°C to 150°C).

Q: Are the FQU10N20CTU and STU7NF25 pin-compatible with the FQU9N25TU?

A: Yes. All three devices use the TO-251-3 Short Leads (IPAK) package with TO-251AA pinout. Direct mechanical substitution is possible without PCB modification.

Q: Does the STU7NF25 have any limitations compared to the FQU9N25TU?

A: The STU7NF25 has a maximum gate voltage rating of ±20V, compared to ±30V on the FQU9N25TU. If your circuit applies gate voltages exceeding ±20V, the STU7NF25 is not suitable. Additionally, the STU7NF25 has a lower input capacitance (500 pF vs. 700 pF), which may affect gate drive timing in certain applications.

Q: Are all substitute parts RoHS3 Compliant?

A: Yes. The FQU10N20CTU and STU7NF25 are both ROHS3 Compliant and REACH Unaffected, matching the regulatory status of the original FQU9N25TU.

Q: Which substitute should I select for new designs?

A: For new designs, the STU7NF25 is recommended due to its Active product status, which ensures long-term availability and manufacturing support. The STU7NF25 maintains the 250V voltage rating and provides enhanced performance specifications. Use the FQU10N20CTU only if your application is constrained to 200V operation and requires onsemi product continuity.

Q: What is the difference in on-state resistance between these parts?

A: The FQU10N20CTU has the lowest on-state resistance at 360 mOhm (measured at 3.9A, 10V gate voltage). The FQU9N25TU and STU7NF25 both have 420 mOhm on-state resistance. Lower on-state resistance reduces power dissipation and heat generation during operation.

Q: Can I use the FQU10N20CTU in a 250V application if I derate the voltage?

A: No. The FQU10N20CTU is rated for a maximum drain-to-source voltage of 200V. Using this device in a 250V circuit, even with derating, violates the absolute maximum ratings and creates risk of device failure. The STU7NF25 must be used for 250V applications.

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