AOI403 MOSFET P-Channel 30V Equivalent & Substitute Parts

Part Overview

The AOI403 is a P-Channel MOSFET rated for 30V drain-to-source voltage with continuous drain current of 15A at ambient temperature (Ta) and 70A at case temperature (Tc). This device is packaged in a TO-251A through-hole configuration and is designed for applications requiring moderate to high current switching in P-channel configurations.

The AOI403 carries an Obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for systems utilizing this component.

Substiute Parts

AOI403

Alpha & Omega Semiconductor Inc.In Stock: 3624AOI403 Datasheet

Current PartRFQ

AOI21357

Alpha & Omega Semiconductor Inc.In Stock: 1844AOI21357 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AOI403 is determined by strict equivalence across the following critical parameters:

Mandatory Equivalence Criteria:

• FET Type: P-Channel
• Drain-to-Source Voltage (Vdss): 30V minimum
• Package Type: TO-251A through-hole configuration
• Mounting: Through-hole compatible with TO-251-3 stub leads

Performance Compatibility Criteria:

• Continuous drain current capability at case temperature (Tc) must equal or exceed 70A
• Power dissipation at case temperature (Tc) must support thermal requirements
• Gate threshold voltage (Vgs(th)) must be within acceptable switching control range
• On-state resistance (Rds On) must not exceed application-specific current handling limits

The AOI21357 qualifies as a direct substitute based on matching voltage rating, package configuration, and thermal performance specifications. Both devices are manufactured by Alpha & Omega Semiconductor Inc. and share identical TO-251A packaging.

Parameter Comparison

Engineering Selection Recommendations

AOI21357 as Primary Substitute:

The AOI21357 is the direct substitute for the obsolete AOI403. Both devices share identical voltage ratings (30V Vdss), identical case temperature drain current (70A Tc), and identical TO-251A packaging. The AOI21357 carries Active product status, ensuring long-term availability and supply chain support.

The AOI21357 demonstrates improved ambient temperature performance with 23A continuous drain current at Ta compared to the AOI403's 15A, providing enhanced thermal margin in applications with elevated ambient conditions. Both devices maintain ROHS3 compliance and REACH unaffected status, supporting regulatory requirements.

The AOI21357 exhibits a lower gate threshold voltage (2.3V versus 3.5V), enabling faster switching response with reduced gate drive requirements. Input capacitance is reduced (2830 pF versus 3500 pF), resulting in lower gate charge requirements and improved switching efficiency.

On-state resistance increases marginally (8 mOhm versus 6.7 mOhm at 20A, 10V), representing a 1.3 mOhm differential. This difference is negligible in applications where the 70A case temperature rating is the limiting thermal factor.

The maximum operating temperature range of the AOI21357 extends to 150°C junction temperature, compared to 175°C for the AOI403. Applications requiring operation above 150°C junction temperature require thermal design verification.

Frequently Asked Questions (FAQ)

Q: Can the AOI21357 directly replace the AOI403 in existing PCB designs?

A: Yes. Both devices use identical TO-251A packaging with TO-251-3 stub leads configuration. Pin-to-pin compatibility is maintained. No PCB layout modifications are required.

Q: What is the significance of the different continuous drain current ratings at ambient temperature (Ta)?

A: The AOI403 is rated for 15A at Ta while the AOI21357 is rated for 23A at Ta. Both devices are rated for 70A at case temperature (Tc). The Ta rating reflects performance under free-air convection conditions. The AOI21357's higher Ta rating indicates improved thermal performance at ambient conditions. For applications operating at or near the 70A Tc limit, the Ta rating difference has minimal practical impact.

Q: Are there temperature range limitations when substituting the AOI21357 for the AOI403?

A: The AOI21357 maximum junction temperature is 150°C, while the AOI403 extends to 175°C. Applications designed to operate above 150°C junction temperature require thermal analysis to confirm the AOI21357 remains within safe operating limits. Most applications operating within standard industrial temperature ranges (-40°C to 85°C ambient) will not encounter this limitation.

Q: How do the on-state resistance differences affect circuit performance?

A: The AOI21357 exhibits 8 mOhm Rds On compared to 6.7 mOhm for the AOI403 at 20A and 10V gate voltage. The 1.3 mOhm increase results in proportionally higher conduction losses. For a 70A application, this represents approximately 6.4W additional power dissipation (70A² × 0.0013 Ohm). Thermal design must account for this difference.

Q: What are the gate drive implications of the lower threshold voltage in the AOI21357?

A: The AOI21357 gate threshold voltage is 2.3V compared to 3.5V for the AOI403. The lower threshold enables faster turn-on with reduced gate drive voltage. Gate charge increases from 61 nC to 70 nC, requiring slightly higher gate drive current for equivalent switching speed. Existing gate drive circuits designed for the AOI403 will operate the AOI21357 with improved switching performance.

Q: Are both devices compliant with current regulatory standards?

A: Yes. Both the AOI403 and AOI21357 are ROHS3 compliant and REACH unaffected. Both carry Moisture Sensitivity Level 1 (Unlimited), indicating no moisture sensitivity precautions are required during storage or handling.

Q: What is the inventory status for these parts?

A: The AOI403 (Obsolete) has 3558 pieces in stock. The AOI21357 (Active) has 1783 pieces in stock. The Active status of the AOI21357 ensures continued availability through normal supply channels.