AOD4128 Equivalent & Substitute Parts

Part Overview

The AOD4128 is an N-Channel MOSFET manufactured by Alpha & Omega Semiconductor Inc., rated for 25V drain-to-source voltage with 60A continuous drain current in a Surface Mount TO-252 (DPAK) package. This device is classified as Obsolete, making identification of equivalent and substitute parts necessary for ongoing production support and design continuity. The AOD4128 serves applications requiring moderate voltage switching with high current capacity in compact surface mount form factors.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	25	V
Current - Continuous Drain (Id) @ 25°C	60	A (Tc)
Rds On (Max) @ Id, Vgs	4	mOhm @ 20A, 10V
Vgs(th) (Max) @ Id	2.5	V @ 250µA
Gate Charge (Qg) (Max) @ Vgs	80	nC @ 10V
Vgs (Max)	±20	V
Input Capacitance (Ciss) (Max) @ Vds	4300	pF @ 12.5V
Power Dissipation (Max)	2 (Ta), 75 (Tc)	W
Operating Temperature	-55 to 175	°C (TJ)
Mounting Type	Surface Mount	—
Package / Case	TO-252-3, DPAK (2 Leads + Tab), SC-63	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the AOD4128 is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

Drain-to-Source Voltage (Vdss) must equal or exceed 25V
Continuous Drain Current (Id) must meet or exceed 60A at rated conditions
On-state resistance (Rds On) must not exceed the original specification to maintain thermal performance
Gate threshold voltage (Vgs(th)) must be compatible with existing drive circuitry
Gate charge (Qg) and input capacitance (Ciss) must not significantly degrade switching performance
Maximum gate voltage (Vgs) must accommodate the drive voltage range

Mechanical Compatibility Criteria:

Package type must be TO-252 (DPAK) with identical pinout
Surface mount mounting type required
Moisture Sensitivity Level (MSL) must be compatible with assembly processes

Identified Substitute Parts:

AOD508 (Alpha & Omega Semiconductor Inc.) — Direct manufacturer alternative with higher voltage rating (30V) and comparable current handling
STD95N2LH5 (STMicroelectronics) — Manufacturer-recommended substitute with matching voltage rating and superior current capacity

Parameter Comparison

Parameter	AOD4128	AOD508	STD95N2LH5	Unit
Manufacturer	Alpha & Omega Semiconductor Inc.	Alpha & Omega Semiconductor Inc.	STMicroelectronics	—
FET Type	N-Channel	N-Channel	N-Channel	—
Drain to Source Voltage (Vdss)	25	30	25	V
Current - Continuous Drain (Id) @ 25°C	60 (Tc)	70 (Tc)	80 (Tc)	A
Rds On (Max) @ Id, Vgs	4 @ 20A, 10V	3 @ 20A, 10V	4.5 @ 40A, 10V	mOhm
Vgs(th) (Max) @ Id	2.5 @ 250µA	2.2 @ 250µA	1 @ 250µA	V
Gate Charge (Qg) (Max) @ Vgs	80 @ 10V	49 @ 10V	13.4 @ 5V	nC
Vgs (Max)	±20	±20	±22	V
Input Capacitance (Ciss) (Max) @ Vds	4300 @ 12.5V	2010 @ 15V	1817 @ 25V	pF
Power Dissipation (Max)	2 (Ta), 75 (Tc)	2.5 (Ta), 50 (Tc)	70 (Tc)	W
Operating Temperature	-55 to 175	-55 to 175	-55 to 175	°C (TJ)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	—
Package / Case	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	—
Product Status	Obsolete	Not For New Designs	Active	—
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	—

Engineering Selection Recommendations

AOD508 Selection Criteria:

The AOD508 is a direct manufacturer alternative from Alpha & Omega Semiconductor Inc. with a higher voltage rating of 30V and continuous drain current of 70A (Tc). This part provides electrical headroom above the original AOD4128 specification. The AOD508 features lower on-state resistance (3 mOhm vs. 4 mOhm) and reduced gate charge (49 nC vs. 80 nC), resulting in improved switching efficiency. However, the AOD508 carries a product status of "Not For New Designs," limiting its suitability for new development. The part is ROHS3 compliant and maintains identical MSL rating and package configuration.

STD95N2LH5 Selection Criteria:

The STD95N2LH5 is the manufacturer-recommended substitute from STMicroelectronics, classified as Active product status. This part matches the original 25V voltage rating and exceeds the current specification with 80A continuous drain current (Tc). The STD95N2LH5 demonstrates superior performance characteristics: lower gate threshold voltage (1V vs. 2.5V), significantly reduced gate charge (13.4 nC vs. 80 nC), and lower input capacitance (1817 pF vs. 4300 pF). These characteristics enable faster switching transitions and reduced drive circuit complexity. The part is ROHS3 compliant, carries Active product status suitable for new designs, and maintains identical MSL rating and TO-252 DPAK package configuration. The STD95N2LH5 is part of the STripFET™ V series, indicating advanced process technology.

Recommendation Summary:

For new designs and ongoing production requiring long-term availability, the STD95N2LH5 is the preferred substitute due to Active product status and superior electrical performance. The AOD508 serves as an alternative for applications where manufacturer continuity within Alpha & Omega Semiconductor Inc. product lines is prioritized, despite its "Not For New Designs" status.

Frequently Asked Questions (FAQ)

Q: Can the AOD508 directly replace the AOD4128 in existing designs?

A: The AOD508 is electrically compatible as a substitute. Both parts share identical TO-252 DPAK package configuration, pinout, and MSL rating. The AOD508 provides higher voltage rating (30V vs. 25V) and comparable current capacity (70A vs. 60A). However, the AOD508 carries "Not For New Designs" status, making it suitable only for legacy production support.

Q: Is the STD95N2LH5 a pin-compatible replacement?

A: Yes. The STD95N2LH5 uses the identical TO-252-3 DPAK package with 2 leads plus tab configuration. Pinout compatibility is maintained across all three parts. No PCB layout modifications are required for mechanical substitution.

Q: What are the key electrical differences between the AOD4128 and STD95N2LH5?

A: The STD95N2LH5 offers superior switching characteristics: gate threshold voltage is significantly lower (1V vs. 2.5V), gate charge is reduced by approximately 83% (13.4 nC vs. 80 nC), and input capacitance is reduced by approximately 58% (1817 pF vs. 4300 pF). Continuous drain current is higher (80A vs. 60A). These differences result in faster switching speed and reduced drive circuit power consumption.

Q: Are there compliance or regulatory differences between the substitute parts?

A: Both substitute parts are ROHS3 compliant and REACH unaffected, matching the original AOD4128 compliance profile. All three parts carry ECCN EAR99 and HTSUS 8541.29.0095 classifications. MSL rating is identical across all parts (MSL 1, Unlimited).

Q: Which substitute part should be selected for new product development?

A: The STD95N2LH5 is the appropriate choice for new designs. This part carries Active product status, indicating long-term manufacturer support and availability. The STD95N2LH5 also demonstrates superior electrical performance with reduced gate charge and input capacitance, enabling more efficient drive circuit design.

Q: What is the impact of lower gate threshold voltage in the STD95N2LH5?

A: The lower gate threshold voltage (1V vs. 2.5V) in the STD95N2LH5 enables faster turn-on response at lower drive voltages. This characteristic reduces switching losses and allows operation with lower gate drive voltage levels, simplifying drive circuit design while maintaining reliable switching performance.

Q: Are thermal characteristics comparable between the three parts?

A: The AOD4128 and STD95N2LH5 share identical maximum junction temperature rating (-55°C to 175°C). Power dissipation ratings differ: AOD4128 is rated 75W (Tc), AOD508 is rated 50W (Tc), and STD95N2LH5 is rated 70W (Tc). Thermal design considerations must account for these differences in high-power applications.

Q: Can the AOD508 and STD95N2LH5 be used interchangeably?

A: Both parts are electrically compatible substitutes for the AOD4128 and share identical package configuration. However, they differ in product status, manufacturer, and electrical performance characteristics. Selection between these two substitutes depends on design requirements, supply chain preferences, and long-term availability considerations.

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