AOD508 N-Channel MOSFET 30V 22A/70A TO-252 Equivalent & Substitute Parts

Part Overview

The AOD508 is an N-Channel MOSFET manufactured by Alpha & Omega Semiconductor Inc., rated for 30V drain-to-source voltage with continuous drain current of 22A (Ta) and 70A (Tc) in a TO-252 (DPAK) surface mount package. The device is classified as "Not For New Designs," indicating it has reached end-of-life status. This designation necessitates identification of functionally equivalent alternatives for ongoing production support and design continuity.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	30	V
Continuous Drain Current @ 25°C (Tc)	70	A
Continuous Drain Current @ 25°C (Ta)	22	A
On-Resistance (Rds On Max) @ 20A, 10V	3	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	2.2	V
Gate Charge (Qg) @ 10V	49	nC
Input Capacitance (Ciss) @ 15V	2010	pF
Power Dissipation (Tc)	50	W
Operating Temperature Range	-55 to 175	°C
Package Type	TO-252-3 (DPAK)	—
FET Type	N-Channel	—
Technology	MOSFET (Metal Oxide)	—

Substitute Part Grouping Explanation

Substitution of the AOD508 is determined by strict equivalence across the following electrical and mechanical parameters:

Primary Equivalence Criteria:

Drain-to-Source Voltage (Vdss): Must equal 30V
FET Type: Must be N-Channel
Technology: Must be MOSFET (Metal Oxide)
Operating Temperature Range: Must support -55°C to 175°C
Package Type: Must be TO-252-3 (DPAK) or compatible surface mount variant
RoHS3 Compliance: Required
Moisture Sensitivity Level: MSL 1 (Unlimited)

Secondary Equivalence Criteria:

Continuous Drain Current (Tc): Must meet or exceed 70A
On-Resistance (Rds On): Must not exceed 3.3mOhm @ specified conditions
Gate Threshold Voltage: Must fall within ±0.3V of 2.2V
Gate Charge: Must not exceed 75nC @ 10V
Input Capacitance: Must not exceed 5300pF @ 15V

All substitute parts listed maintain electrical compatibility within these defined parameters while offering improved or equivalent performance characteristics.

Parameter Comparison

Parameter	AOD508	IPD031N03LGATMA1	IPD90N03S4L03ATMA1	IRLR7843TRLPBF	STB155N3LH6	STD150N3LLH6
Manufacturer	Alpha & Omega	Infineon	Infineon	Infineon	STMicroelectronics	STMicroelectronics
Vdss (V)	30	30	30	30	30	30
Id (Tc) (A)	70	90	90	161	80	80
Rds On Max (mOhm)	3.0	3.1	3.3	3.3	3.0	2.8
Vgs(th) (V)	2.2	2.2	2.2	2.3	2.5	2.5
Qg (nC)	49	51	75	50	80	29
Ciss (pF)	2010	5300	5100	4380	3800	3700
Power Dissipation (W)	50	94	94	140	110	110
Operating Temp (°C)	-55 to 175	-55 to 175	-55 to 175	-55 to 175	-55 to 175	-55 to 175
Package	TO-252-3 (DPAK)	PG-TO252-3-11	PG-TO252-3-11	TO-252AA (DPAK)	TO-263-3 (D2PAK)	TO-252-3 (DPAK)
Product Status	Not For New Designs	Active	Last Time Buy	Not For New Designs	Active	Obsolete
RoHS3 Compliant	Yes	Yes	Yes	Yes	Yes	Yes

Engineering Selection Recommendations

Recommended Primary Substitute: IPD031N03LGATMA1

The IPD031N03LGATMA1 (Infineon OptiMOS™ series) is the preferred substitute for the AOD508. This device maintains identical Vdss (30V) and Vgs(th) (2.2V) specifications while providing superior continuous drain current (90A vs. 70A) and increased power dissipation capability (94W vs. 50W). The part carries Active product status, ensuring long-term availability and supply chain stability. RoHS3 compliance and MSL 1 rating are maintained. The device is supplied in Tape & Reel packaging, suitable for automated assembly operations.

Secondary Substitute: STD150N3LLH6

The STD150N3LLH6 (STMicroelectronics DeepGATE™/STripFET™ VI series) provides equivalent electrical performance with superior on-resistance characteristics (2.8mOhm vs. 3.0mOhm). This device maintains the TO-252-3 (DPAK) package format, enabling direct mechanical compatibility. However, the part is classified as Obsolete, limiting its suitability for new production commitments. It remains available for legacy system support with current inventory of 10,300 units.

Alternative Substitute: STB155N3LH6

The STB155N3LH6 (STMicroelectronics DeepGATE™/STripFET™ VI series) offers Active product status with 80A continuous drain current and 110W power dissipation. This device is packaged in TO-263-3 (D2PAK), requiring PCB layout modification compared to the original TO-252-3 footprint. The part maintains all electrical equivalence criteria and provides robust long-term availability.

Not Recommended: IRLR7843TRLPBF

While the IRLR7843TRLPBF (Infineon HEXFET® series) meets all electrical equivalence criteria with superior current rating (161A), it carries "Not For New Designs" status, identical to the AOD508. This designation limits its utility as a forward-looking substitute. The device is suitable only for direct replacement in existing production runs where supply of the original part is exhausted.

Not Recommended: IPD90N03S4L03ATMA1

The IPD90N03S4L03ATMA1 (Infineon OptiMOS™ series) is classified as Last Time Buy, indicating imminent discontinuation. While electrically equivalent, this status precludes its selection for new designs or long-term production planning.

Frequently Asked Questions (FAQ)

Q: Can the AOD508 be directly replaced with the IPD031N03LGATMA1 without circuit modification?

A: Yes. Both devices share identical Vdss (30V), Vgs(th) (2.2V), and package format (TO-252-3 DPAK). The IPD031N03LGATMA1 provides superior current handling (90A vs. 70A) and power dissipation (94W vs. 50W), making it a direct electrical and mechanical substitute. No circuit redesign is required.

Q: What is the difference between the TO-252-3 (DPAK) and TO-263-3 (D2PAK) packages?

A: Both are surface mount packages with identical electrical pin configurations (Gate, Drain, Source). The primary difference is physical size and thermal performance. TO-263-3 (D2PAK) is larger and provides superior thermal dissipation due to increased copper contact area. PCB layout modification is required when substituting between these package types.

Q: Why is the AOD508 classified as "Not For New Designs"?

A: This designation indicates the part has reached end-of-life status and is no longer recommended for new product development. Existing inventory remains available for legacy system support, but long-term supply cannot be guaranteed. Active-status alternatives such as IPD031N03LGATMA1 or STB155N3LH6 should be selected for new designs.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed in this reference maintain RoHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating, matching the environmental and regulatory requirements of the AOD508.

Q: What is the significance of Gate Charge (Qg) differences between substitute parts?

A: Gate Charge affects switching speed and gate drive circuit requirements. The AOD508 specifies 49nC @ 10V. Substitute parts range from 29nC (STD150N3LLH6) to 80nC (STB155N3LH6). Lower Qg values enable faster switching with reduced gate drive power consumption. Higher Qg values require proportionally increased gate drive current but do not prevent functional substitution in standard applications.

Q: Can the STB155N3LH6 (D2PAK package) be used as a drop-in replacement?

A: The STB155N3LH6 is electrically equivalent but requires PCB layout modification due to its TO-263-3 (D2PAK) package format. The pin configuration is identical, but the physical footprint differs from the original TO-252-3 (DPAK). This substitution is suitable for redesigned layouts but not for direct PCB compatibility.

Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?

A: Both packaging formats contain identical components. Cut Tape is supplied in individual strips suitable for manual assembly or small-volume production. Tape & Reel is supplied on continuous reels optimized for automated pick-and-place assembly. Selection depends on production volume and assembly equipment capabilities, not electrical performance.

Q: Why does the IPD90N03S4L03ATMA1 have higher Gate Charge (75nC) than the AOD508 (49nC)?

A: Gate Charge correlates with input capacitance and switching characteristics. The IPD90N03S4L03ATMA1 exhibits higher input capacitance (5100pF vs. 2010pF), resulting in increased gate charge. This difference does not prevent substitution but requires verification that the gate drive circuit can supply the additional charge within acceptable switching time parameters.

Q: Is the STD150N3LLH6 suitable for new production despite Obsolete status?

A: The STD150N3LLH6 is not recommended for new production commitments. Obsolete classification indicates the manufacturer has discontinued active production and support. While current inventory (10,300 units) is available, future supply cannot be guaranteed. This part is suitable only for legacy system maintenance and repair operations.

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