AO3415 P-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The AO3415 is a P-Channel MOSFET manufactured by Alpha & Omega Semiconductor Inc., rated for 20V drain-to-source voltage with 4A continuous drain current in a SOT-23-3 surface mount package. This device is classified as obsolete product status. Due to its obsolete classification, equivalent and substitute parts from active manufacturers are necessary to maintain design continuity and ensure long-term component availability for new production and field replacements.

Key Parameters

Parameter	Value	Unit
FET Type	P-Channel	—
Drain to Source Voltage (Vdss)	20	V
Continuous Drain Current (Id) @ 25°C	4	A
Rds On (Max) @ 4A, 4.5V	43	mOhm
Power Dissipation (Max)	1.5	W
Gate Charge (Qg) @ 4.5V	17.2	nC
Input Capacitance (Ciss) @ 10V	1450	pF
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package	SOT-23-3	—

Substitute Part Grouping Explanation

Substitution of the AO3415 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): 20V minimum
Continuous Drain Current (Id): 4A or greater
Package Type: SOT-23-3 surface mount configuration
FET Type: P-Channel MOSFET technology
Operating Temperature Range: -55°C to 150°C minimum

Secondary Compatibility Factors:

Rds On (Max): 43 mOhm or lower at rated current and gate voltage
Gate Charge (Qg): 17.2 nC or lower for switching performance equivalence
Input Capacitance (Ciss): Comparable to 1450 pF for circuit timing considerations
Power Dissipation: 1.5W or greater thermal capability

Substitute parts are grouped into two categories:

Category A - Direct Electrical Equivalents (Vdss 20V, Id ≥4A, SOT-23-3): Parts meeting or exceeding all primary criteria with minimal parameter deviation.

Category B - Functional Alternatives (Vdss 20V, Id <4A, SOT-23-3): Parts with reduced current ratings or different package variants that require circuit evaluation for specific applications.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On @ Id, 4.5V (mOhm)	Qg @ 4.5V (nC)	Ciss @ 10V (pF)	Power Diss. (W)	Package	Status
AO3415	Alpha & Omega	20	4.0	43	17.2	1450	1.5	SOT-23-3	Obsolete
AOSS21115C	Alpha & Omega	20	4.5	40	17	930	1.3	SOT-23-3	Active
DMG3415U-7	Diodes Inc.	20	4.0	39	9.1	294	0.9	SOT-23-3	Active
DMG3415UQ-7	Diodes Inc.	20	4.0	42.5	9.1	294	0.9	SOT-23-3	Active
DMP2035U-7	Diodes Inc.	20	3.6	35	15.4	1610	0.81	SOT-23-3	Active
DMP2066LSN-7	Diodes Inc.	20	4.6	40	10.1	820	1.25	SC-59-3	Active
FDN302P	onsemi	20	2.4	55	14	882	0.5	SOT-23-3	Active
FDN304P	onsemi	20	2.4	52	20	1312	0.5	SOT-23-3	Active
FDN304PZ	onsemi	20	2.4	52	20	1310	0.5	SOT-23-3	Active
FDN306P	onsemi	12	2.6	40	17	1138	0.5	SOT-23-3	Active
FDN340P	UMW	20	2.0	70	8	600	1.1	SOT-23	Active

Engineering Selection Recommendations

Recommended Primary Substitutes (Category A - Direct Equivalents):

AOSS21115C (Alpha & Omega Semiconductor Inc.) — Active product status. Provides superior electrical performance with 4.5A continuous drain current, lower Rds On of 40 mOhm, and reduced input capacitance of 930 pF. Maintains identical SOT-23-3 package and operating temperature range. RoHS3 compliant with MSL 1 rating. Recommended for direct replacement in new designs and field service applications.

DMG3415U-7 (Diodes Incorporated) — Active product status. Matches AO3415 electrical specifications with 4A continuous drain current and 20V Vdss. Offers improved Rds On of 39 mOhm and significantly reduced gate charge of 9.1 nC, resulting in faster switching performance. SOT-23-3 package configuration. RoHS3 compliant with MSL 1 rating. Suitable for applications requiring enhanced switching speed.

DMG3415UQ-7 (Diodes Incorporated) — Active product status with AEC-Q101 automotive qualification. Identical electrical specifications to DMG3415U-7 with Rds On of 42.5 mOhm. Recommended for automotive and mission-critical applications requiring formal qualification documentation. SOT-23-3 package. RoHS3 compliant.

Secondary Substitutes (Category B - Functional Alternatives):

DMP2035U-7 (Diodes Incorporated) — Active product status. Rated for 3.6A continuous drain current with 20V Vdss. Provides lower Rds On of 35 mOhm and higher input capacitance of 1610 pF. Suitable for applications where current requirement is 3.6A or less. SOT-23-3 package. RoHS3 compliant.

DMP2066LSN-7 (Diodes Incorporated) — Active product status. Rated for 4.6A continuous drain current with 20V Vdss, exceeding AO3415 current capability. Rds On of 40 mOhm. Package variant is SC-59-3 instead of SOT-23-3, requiring PCB layout modification. RoHS3 compliant. Recommended only when higher current capacity is required and package change is acceptable.

Not Recommended for Direct Substitution:

FDN302P, FDN304P, FDN304PZ (onsemi) — Rated for 2.4A continuous drain current, below the 4A requirement of AO3415. Higher Rds On values (52–55 mOhm) result in increased power dissipation. Suitable only for applications with reduced current demands.

FDN306P (onsemi) — Rated for 12V Vdss maximum, insufficient for 20V applications. Not suitable for AO3415 replacement.

FDN340P (UMW) — Rated for 2A continuous drain current with 20V Vdss. Significantly higher Rds On of 70 mOhm. Insufficient current capacity for AO3415 applications.

Frequently Asked Questions (FAQ)

Q: Can AOSS21115C replace AO3415 in all applications?

A: AOSS21115C meets or exceeds all critical electrical parameters of AO3415 (20V Vdss, 4.5A Id, SOT-23-3 package, -55°C to 150°C operating range). It is the recommended direct replacement. Verify circuit design does not depend on specific gate charge or input capacitance characteristics that differ between parts.

Q: What is the difference between DMG3415U-7 and DMG3415UQ-7?

A: Both parts have identical electrical specifications (20V Vdss, 4A Id, 39–42.5 mOhm Rds On). DMG3415UQ-7 includes AEC-Q101 automotive qualification and is supplied in Tape & Reel packaging. DMG3415U-7 is supplied in Cut Tape & Digi-Reel packaging. Select DMG3415UQ-7 for automotive applications requiring formal qualification documentation.

Q: Why is DMP2066LSN-7 listed as a substitute if it uses SC-59-3 package instead of SOT-23-3?

A: DMP2066LSN-7 provides superior current rating (4.6A) and meets 20V Vdss requirement. SC-59-3 and SOT-23-3 are mechanically compatible pinout variants, but PCB footprint and layout must be verified before implementation. Use only when higher current capacity justifies package change.

Q: Can FDN306P replace AO3415?

A: No. FDN306P is rated for 12V Vdss maximum, which is insufficient for applications requiring 20V operation. It is not suitable for AO3415 replacement.

Q: What does RoHS3 compliance mean for component selection?

A: RoHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead and other hazardous materials. All recommended substitutes are RoHS3 compliant, ensuring regulatory compliance for new product designs and manufacturing.

Q: Are all substitute parts rated for the same operating temperature range as AO3415?

A: All recommended substitutes operate across -55°C to 150°C temperature range, matching AO3415 specifications. Verify specific application temperature requirements before final selection.

Q: What is Moisture Sensitivity Level (MSL) and why is it important?

A: MSL 1 rating indicates unlimited shelf life and no moisture precautions required during storage or handling. All recommended substitutes carry MSL 1 classification, matching AO3415 specifications and simplifying supply chain management.

Q: How do gate charge differences affect circuit performance?

A: Gate charge (Qg) determines switching speed and driver circuit requirements. DMG3415U-7 and DMG3415UQ-7 have lower gate charge (9.1 nC) compared to AO3415 (17.2 nC), resulting in faster switching transitions. Verify driver circuit can accommodate reduced gate charge without instability.

Q: Is inventory availability a factor in substitute selection?

A: Inventory levels are provided for reference. AOSS21115C (6,425 pcs), DMG3415U-7 (134,300 pcs), and DMP2066LSN-7 (232,429 pcs) demonstrate strong availability. Consult with component distributors for current stock status and lead times.

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