AO6400 N-Channel MOSFET 30V 6.9A Equivalent & Substitute Parts

Part Overview

The AO6400 is an N-Channel MOSFET manufactured by Alpha & Omega Semiconductor Inc., rated for 30V drain-to-source voltage with 6.9A continuous drain current at 25°C. The device is housed in a 6-TSOP surface mount package and dissipates a maximum of 2W at ambient temperature. This part carries a product status of "Not For New Designs," indicating that while functional units remain in inventory, alternative solutions should be evaluated for new circuit implementations. Identifying equivalent and substitute parts is necessary to ensure design continuity, improve availability, and access active product lines with enhanced specifications.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	30	V
Continuous Drain Current (Id) @ 25°C	6.9	A
On-Resistance (Rds On) @ 6.9A, 10V	28	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	1.4	V
Gate Charge (Qg) @ 4.5V	12	nC
Maximum Gate Voltage (Vgs)	±12	V
Input Capacitance (Ciss) @ 15V	1030	pF
Power Dissipation (Max)	2	W
Operating Temperature Range	-55 to 150	°C
Package Type	6-TSOP (SC-74, SOT-457)	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the AO6400 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): Must equal or exceed 30V
Continuous Drain Current (Id): Must meet or exceed 6.9A at 25°C
On-Resistance (Rds On): Lower values indicate improved performance; values at or below 28mOhm @ 10V are preferred
Gate Threshold Voltage (Vgs(th)): Must be compatible with drive circuitry; range of 1.4V to 3V is acceptable
Maximum Gate Voltage (Vgs): Must support ±12V minimum; ±20V provides additional margin
Operating Temperature: Must support -55°C to 150°C range
Mounting Type: Surface mount packages only
Package Compatibility: 6-TSOP, TSOT-26, and SuperSOT-6 packages are mechanically compatible with board layouts designed for the AO6400

Secondary Considerations:

Power Dissipation: Substitute parts with equal or higher power ratings ensure thermal compatibility
Gate Charge (Qg): Lower values reduce switching losses
Input Capacitance (Ciss): Lower values improve switching speed
Product Status: Active parts are preferred over "Not For New Designs" status

Substitute parts are grouped into two categories: direct equivalents (matching or exceeding all primary parameters) and functional alternatives (meeting minimum electrical requirements with package variations).

Parameter Comparison

Parameter	AO6400	AOTS32334C	DMG6402LVT-7	FDC655BN	RSQ020N03TR	RSQ045N03TR	RTQ020N03TR	RTQ035N03TR	RTQ045N03TR	SI3442BDV-T1-E3
Vdss (V)	30	30	30	30	30	30	30	30	30	20
Id @ 25°C (A)	6.9	8	6	6.3	2	4.5	2	3.5	4.5	3
Rds On (mOhm)	28 @ 6.9A, 10V	20 @ 8A, 10V	30 @ 7A, 10V	25 @ 6.3A, 10V	134 @ 2A, 10V	38 @ 4.5A, 10V	125 @ 2A, 4.5V	54 @ 3.5A, 4.5V	43 @ 4.5A, 4.5V	57 @ 4A, 4.5V
Vgs(th) @ 250µA (V)	1.4	2.3	2	3	2.5	2.5	1.5	1.5	1.5	1.8
Qg @ Vgs (nC)	12 @ 4.5V	20 @ 10V	11.4 @ 10V	15 @ 10V	3.1 @ 5V	9.5 @ 5V	3.3 @ 4.5V	6.4 @ 4.5V	10.7 @ 4.5V	5 @ 4.5V
Vgs Max (V)	±12	±20	±20	±20	±20	±20	±12	±12	±12	±12
Ciss @ 15V (pF)	1030	600	498	570	110	520	135	285	540	295
Power Dissipation (W)	2	2.5	1.75	1.6	0.6	0.6	1.25	1.25	1.25	0.86
Operating Temp (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	to 150	to 150	to 150	to 150	to 150	-55 to 150
Package	6-TSOP	6-TSOP	TSOT-26	SuperSOT-6	TSMT6	TSMT6	TSMT6	TSMT6	TSMT6	6-TSOP
Product Status	Not For New Designs	Active	Active	Active	Active	Active	Active	Not For New Designs	Not For New Designs	Active
Manufacturer	Alpha & Omega	Alpha & Omega	Diodes Inc.	onsemi	Rohm	Rohm	Rohm	Rohm	Rohm	Vishay

Engineering Selection Recommendations

Direct Equivalents (Recommended for New Designs):

The AOTS32334C from Alpha & Omega Semiconductor Inc. is the primary recommended substitute. It maintains the same 30V Vdss rating and 6-TSOP package as the AO6400, while providing superior specifications: 8A continuous drain current (versus 6.9A), improved on-resistance of 20mOhm (versus 28mOhm), and higher power dissipation capability of 2.5W. The AOTS32334C carries Active product status, ensuring long-term availability and support. Both parts are ROHS3 compliant and REACH unaffected.

Alternative Substitutes (Package-Compatible):

The DMG6402LVT-7 from Diodes Incorporated offers a 30V, 6A rated device in a TSOT-26 package with 1.75W power dissipation. While the package differs from the 6-TSOP, the TSOT-26 footprint is mechanically compatible with standard surface mount assembly processes. This part is Active and provides lower input capacitance (498pF) compared to the AO6400 (1030pF), enabling faster switching characteristics.

The FDC655BN from onsemi is a 30V, 6.3A device in a SuperSOT-6 package with 1.6W power dissipation. It features the lowest on-resistance among alternatives at 25mOhm and is part of the PowerTrench® series. This part is Active and suitable for applications requiring optimized thermal performance.

Lower Current Alternatives (Functional Substitutes):

The RTQ045N03TR from Rohm Semiconductor provides 4.5A at 30V in a TSMT6 package with 1.25W power dissipation. Although rated for lower current than the AO6400, it meets the 30V voltage requirement and is suitable for applications with reduced current demands. This part carries "Not For New Designs" status.

The RSQ045N03TR from Rohm Semiconductor is an Active alternative rated for 4.5A at 30V with 600mW power dissipation in a TSMT6 package. It provides lower power handling but maintains the 30V voltage specification.

Voltage-Reduced Alternative:

The SI3442BDV-T1-E3 from Vishay Siliconix is rated for 20V (not 30V) and 3A, making it unsuitable as a direct substitute for applications requiring the full 30V rating. This part is included for reference only and should not be selected unless the circuit design permits operation at reduced voltage.

Compliance and Certification:

All recommended substitute parts maintain ROHS3 compliance and REACH unaffected status, matching the AO6400 environmental certifications. All parts operate across the -55°C to 150°C temperature range, ensuring thermal compatibility with existing designs.

Frequently Asked Questions (FAQ)

Q: Can the AOTS32334C directly replace the AO6400 without PCB modifications?

A: Yes. The AOTS32334C is housed in the same 6-TSOP package (SC-74, SOT-457) as the AO6400. The pinout and footprint are identical, allowing direct substitution without PCB layout changes. The improved electrical specifications (8A versus 6.9A, 20mOhm versus 28mOhm) provide enhanced performance margins.

Q: What is the primary reason to substitute the AO6400?

A: The AO6400 carries a "Not For New Designs" product status, indicating that Alpha & Omega Semiconductor Inc. is not recommending this part for new circuit implementations. The AOTS32334C is the manufacturer's recommended active alternative, providing superior specifications and guaranteed long-term availability.

Q: Are the TSMT6 package alternatives mechanically compatible with AO6400 PCB layouts?

A: No. The TSMT6 package (used by Rohm Semiconductor parts) has a different footprint than the 6-TSOP package. PCB redesign is required to accommodate TSMT6 devices. However, the TSOT-26 package (DMG6402LVT-7) and SuperSOT-6 package (FDC655BN) are mechanically compatible with standard 6-pin surface mount layouts.

Q: Which substitute part offers the lowest on-resistance?

A: The AOTS32334C provides 20mOhm on-resistance at 8A and 10V gate voltage, which is the lowest among all recommended substitutes. The FDC655BN follows closely at 25mOhm at 6.3A and 10V. Lower on-resistance reduces power dissipation and heat generation in switching applications.

Q: Can I use RSQ020N03TR or RSQ045N03TR if my circuit only requires 2A or 4.5A?

A: Yes, if your application current requirement does not exceed 2A or 4.5A respectively. However, these parts have significantly higher on-resistance values (134mOhm and 38mOhm respectively) compared to the AO6400 (28mOhm), resulting in higher power dissipation. The AOTS32334C or FDC655BN are preferred alternatives even for lower current applications due to superior on-resistance characteristics.

Q: What is the difference between the RTQ045N03TR and RSQ045N03TR?

A: Both are 30V, 4.5A devices from Rohm Semiconductor in TSMT6 packages. The RTQ045N03TR has "Not For New Designs" status with 1.25W power dissipation, while the RSQ045N03TR is Active with 600mW power dissipation. The RSQ045N03TR is the preferred choice for new designs due to its active product status, despite lower power handling capability.

Q: Is the SI3442BDV-T1-E3 a suitable substitute?

A: No. The SI3442BDV-T1-E3 is rated for 20V maximum drain-to-source voltage, which is below the AO6400's 30V specification. This part should only be considered if your circuit design permits operation at reduced voltage levels. For applications requiring the full 30V rating, select AOTS32334C, DMG6402LVT-7, or FDC655BN.

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

A: Gate charge affects switching speed and driver power requirements. The AO6400 has 12nC gate charge at 4.5V. The AOTS32334C has 20nC at 10V, which may require slightly higher driver current but provides improved gate voltage margin. Lower gate charge values (such as the 5nC of SI3442BDV-T1-E3) enable faster switching but are not available in 30V rated alternatives.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All recommended substitute parts listed in this document are RoHS3 compliant and REACH unaffected, matching the environmental compliance status of the AO6400.

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