FQB6N80TM Equivalent & Substitute Parts

Part Overview

The FQB6N80TM is an N-Channel MOSFET manufactured by onsemi, rated for 800V drain-to-source voltage with 5.8A continuous drain current at 25°C. The device is housed in a TO-263 (D2PAK) surface mount package and is part of the QFET® series. The FQB6N80TM is classified as obsolete, making identification of equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain compatibility with the TO-263 (D2PAK) package footprint and deliver equivalent electrical performance within the specified operating parameters.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	800	V
Continuous Drain Current (Id) @ 25°C	5.8	A (Tc)
On-State Resistance (Rds On Max) @ Id, Vgs	1.95	Ohm @ 2.9A, 10V
Gate Threshold Voltage (Vgs(th) Max) @ Id	5	V @ 250µA
Gate Charge (Qg Max) @ Vgs	31	nC @ 10V
Input Capacitance (Ciss Max) @ Vds	1500	pF @ 25V
Power Dissipation (Max)	3.13 / 158	W (Ta) / W (Tc)
Operating Temperature Range	-55 to 150	°C (TJ)
Package Type	TO-263 (D2PAK)	Surface Mount
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the FQB6N80TM are selected based on the following criteria:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): 800V or higher
Continuous Drain Current (Id): 5.2A or higher at 25°C
Package Type: TO-263 (D2PAK) surface mount
On-State Resistance (Rds On): Comparable or lower values
Operating Temperature Range: -55°C to 150°C or wider
RoHS3 Compliance and MSL Level 1

Substitution Logic: Parts with identical or superior Vdss ratings and drain current capabilities are considered direct substitutes. Parts with higher Vdss ratings (900V) are acceptable as they provide enhanced voltage margin. On-state resistance values at or below the original specification ensure equivalent or improved switching performance. All substitute parts maintain the same package footprint and thermal characteristics required for direct board-level replacement.

Parameter Comparison

Parameter	FQB6N80TM (Main)	FQB4N80TM	STB7NK80ZT4	STB9NK80Z	STB6NK90ZT4
Manufacturer	onsemi	onsemi	STMicroelectronics	STMicroelectronics	STMicroelectronics
Vdss (V)	800	800	800	800	900
Id @ 25°C (A)	5.8	3.9	5.2	5.2	5.8
Rds On Max (Ohm)	1.95 @ 2.9A, 10V	3.6 @ 1.95A, 10V	1.8 @ 2.6A, 10V	1.8 @ 2.6A, 10V	2.0 @ 2.9A, 10V
Vgs(th) Max (V)	5 @ 250µA	5 @ 250µA	4.5 @ 100µA	4.5 @ 100µA	4.5 @ 100µA
Qg Max (nC)	31 @ 10V	25 @ 10V	56 @ 10V	40 @ 10V	60.5 @ 10V
Ciss Max (pF)	1500 @ 25V	880 @ 25V	1138 @ 25V	1138 @ 25V	1350 @ 25V
Power Dissipation Max (W)	3.13 (Ta) / 158 (Tc)	3.13 (Ta) / 130 (Tc)	125 (Tc)	125 (Tc)	140 (Tc)
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package	TO-263 (D2PAK)	TO-263 (D2PAK)	D2PAK	D2PAK	D2PAK
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

FQB4N80TM (onsemi): This part is an onsemi QFET® series device with identical Vdss (800V) and package (TO-263 D2PAK). The FQB4N80TM is active and ROHS3 compliant. However, the continuous drain current is reduced to 3.9A, which is lower than the FQB6N80TM specification of 5.8A. This part is suitable only for applications where the lower current rating is acceptable. The on-state resistance is higher at 3.6 Ohm, resulting in increased power dissipation. Selection of this part requires verification that circuit current demands do not exceed 3.9A.

STB7NK80ZT4 (STMicroelectronics): This SuperMESH™ series device maintains 800V Vdss with 5.2A continuous drain current, providing near-equivalent current handling. The part is active and ROHS3 compliant. On-state resistance is 1.8 Ohm, which is lower than the FQB6N80TM, offering improved efficiency. Gate charge is higher at 56 nC, which may increase switching losses in high-frequency applications. The D2PAK package is footprint-compatible with TO-263.

STB9NK80Z (STMicroelectronics): This SuperMESH™ series device is qualified to AEC-Q101 automotive standards and maintains 800V Vdss with 5.2A continuous drain current. The part is active and ROHS3 compliant. On-state resistance is 1.8 Ohm. Gate charge is 40 nC, lower than STB7NK80ZT4. The automotive qualification provides additional reliability assurance for demanding applications.

STB6NK90ZT4 (STMicroelectronics): This SuperMESH™ series device provides 900V Vdss with 5.8A continuous drain current, matching the original current specification while offering enhanced voltage margin. The part is active and ROHS3 compliant. On-state resistance is 2.0 Ohm, comparable to the FQB6N80TM. Gate charge is higher at 60.5 nC. This part is suitable for applications requiring higher voltage headroom.

Frequently Asked Questions (FAQ)

Q: Can the FQB4N80TM be used as a direct replacement for the FQB6N80TM?

A: The FQB4N80TM shares the same package and voltage rating but has a reduced continuous drain current specification of 3.9A compared to 5.8A. Direct replacement is possible only if the circuit current demand does not exceed 3.9A. Higher current applications require selection of STB7NK80ZT4, STB9NK80Z, or STB6NK90ZT4.

Q: What is the difference between STB7NK80ZT4 and STB9NK80Z?

A: Both parts are STMicroelectronics SuperMESH™ devices with identical Vdss (800V) and Id (5.2A) specifications. The primary difference is that STB9NK80Z carries AEC-Q101 automotive qualification, making it suitable for automotive and high-reliability applications. Gate charge differs at 56 nC (STB7NK80ZT4) versus 40 nC (STB9NK80Z), affecting switching characteristics.

Q: Is the STB6NK90ZT4 suitable for 800V applications?

A: Yes. The STB6NK90ZT4 is rated for 900V Vdss, which exceeds the 800V requirement of the FQB6N80TM. The higher voltage rating provides additional safety margin and is fully compatible with 800V circuit designs. The 5.8A continuous drain current matches the original specification.

Q: Are all substitute parts in the same package?

A: All substitute parts use the D2PAK (TO-263) surface mount package, which is footprint-compatible with the original FQB6N80TM TO-263 (D2PAK) package. Direct board-level replacement is possible without layout modifications.

Q: Do all substitute parts meet RoHS3 compliance?

A: Yes. All substitute parts listed (FQB4N80TM, STB7NK80ZT4, STB9NK80Z, and STB6NK90ZT4) are ROHS3 compliant with MSL Level 1 (Unlimited moisture sensitivity level), matching the environmental and regulatory requirements of the original FQB6N80TM.

Q: Which substitute part has the lowest on-state resistance?

A: STB7NK80ZT4 and STB9NK80Z both have on-state resistance of 1.8 Ohm at 2.6A and 10V, which is lower than the FQB6N80TM specification of 1.95 Ohm at 2.9A and 10V. This results in reduced conduction losses and improved thermal performance.

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

A: Gate charge affects switching speed and driver power requirements. STB6NK90ZT4 (60.5 nC) and STB7NK80ZT4 (56 nC) have higher gate charge than the FQB6N80TM (31 nC), requiring higher driver current or longer switching times. STB9NK80Z (40 nC) provides a middle ground. Circuit driver capability must be verified for high-frequency switching applications.

Q: Can the FQB6N80TM be replaced in high-frequency switching applications?

A: STB9NK80Z is recommended for high-frequency applications due to its lower gate charge (40 nC) compared to other STMicroelectronics alternatives, reducing switching losses. The automotive-qualified STB9NK80Z also provides enhanced reliability for demanding applications.

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