Equivalent & Substitute Parts for US2AA General Purpose Rectifier Diode

Part Overview

The US2AA is a general purpose rectifier diode manufactured by onsemi, rated for 50V DC reverse voltage and 1.5A average rectified current in a Surface Mount DO-214AC (SMA) package. This component is classified as "Not For New Designs," indicating it has reached end-of-life status. Finding equivalent or substitute parts is necessary for ongoing production support, maintenance applications, and design continuity where this diode was previously specified.

The US2AA features fast recovery characteristics with a reverse recovery time of 50 nanoseconds and is qualified to AEC-Q101 automotive standards. It operates across a junction temperature range of -55°C to 150°C and maintains ROHS3 compliance.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) Maximum	50	V
Current - Average Rectified (Io)	1.5	A
Voltage - Forward (Vf) Maximum @ If	1	V @ 1.5 A
Reverse Recovery Time (trr)	50	ns
Current - Reverse Leakage @ Vr	5	µA @ 50 V
Capacitance @ Vr, F	50	pF @ 4V, 1MHz
Package / Case	DO-214AC, SMA	—
Operating Temperature - Junction	-55 to 150	°C
Technology	Standard	—
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	—

Substitute Part Grouping Explanation

Substitution of the US2AA is determined by strict alignment of electrical and mechanical parameters. The following criteria establish valid substitute relationships:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) Maximum: Must equal or exceed 50V
Current - Average Rectified (Io): Must equal or exceed 1.5A
Package / Case: Must be DO-214AC or SMA (mechanically compatible)
Mounting Type: Must be Surface Mount
Speed Classification: Must maintain Fast Recovery characteristics (≤ 500ns, > 200mA)

Secondary Compatibility Factors:

Forward voltage (Vf) characteristics within acceptable operating margins
Reverse leakage current performance
Operating temperature range compatibility
RoHS and compliance status alignment

Substitute parts are grouped into two categories:

Direct Parametric Equivalents: Parts with identical or near-identical electrical specifications and the same package format. These include HS2AA and HS2AA R3G from Taiwan Semiconductor Corporation, and RS2AA-13-F from Diodes Incorporated. All maintain the 50V/1.5A rating with compatible forward voltage and recovery characteristics.

Upgraded Substitutes: Parts with superior current ratings (2A) while maintaining the 50V reverse voltage specification. These include MURA205T3G from onsemi and BYG22A-E3/TR from Vishay. These parts provide enhanced current capacity and improved reverse recovery performance, making them suitable for applications requiring higher current margins or improved switching speed.

Parameter Comparison

Parameter	US2AA	HS2AA	HS2AA R3G	RS2AA-13-F	MURA205T3G	BYG22A-E3/TR
Manufacturer	onsemi	Taiwan Semiconductor	Taiwan Semiconductor	Diodes Incorporated	onsemi	Vishay
Vr (Max)	50V	50V	50V	50V	50V	50V
Io (Average Rectified)	1.5A	1.5A	1.5A	1.5A	2A	2A
Vf (Max) @ If	1V @ 1.5A	1V @ 1.5A	1V @ 1.5A	1.3V @ 1.5A	940mV @ 2A	1.1V @ 2A
Reverse Recovery Time (trr)	50ns	50ns	50ns	150ns	30ns	25ns
Reverse Leakage @ Vr	5µA @ 50V	5µA @ 50V	5µA @ 50V	5µA @ 50V	2µA @ 50V	1µA @ 50V
Capacitance @ Vr, F	50pF @ 4V, 1MHz	50pF @ 4V, 1MHz	50pF @ 4V, 1MHz	30pF @ 4V, 1MHz	—	—
Package / Case	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA
Operating Temp Range	-55 to 150°C	-55 to 150°C	-55 to 150°C	-65 to 150°C	-65 to 175°C	-55 to 150°C
Technology	Standard	Standard	Standard	Standard	Standard	Avalanche
Product Status	Not For New Designs	Active	Discontinued at DiGi Electronics	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical Performance):

HS2AA from Taiwan Semiconductor Corporation is the preferred direct parametric equivalent. It maintains identical voltage, current, forward voltage, and reverse recovery specifications as the US2AA while offering Active product status. The HS2AA is available in Tape & Reel packaging with 829 pieces in current inventory. This part is suitable for applications requiring exact electrical performance matching without design modification.

RS2AA-13-F from Diodes Incorporated provides an alternative direct replacement option with Active product status and higher inventory availability (25,100 pieces). This part maintains the 50V/1.5A rating and fast recovery characteristics. The forward voltage specification is slightly elevated at 1.3V versus 1V, and reverse recovery time is longer at 150ns versus 50ns. These differences are acceptable in applications where the original design margins accommodate such variations.

For Enhanced Performance Applications:

MURA205T3G from onsemi is recommended where increased current capacity is beneficial. This 2A-rated part maintains the 50V reverse voltage specification while providing superior reverse recovery time (30ns) and lower reverse leakage current (2µA). It is suitable for designs requiring higher current margins or improved switching performance. Active product status and high inventory (23,933 pieces) ensure long-term availability.

BYG22A-E3/TR from Vishay General Semiconductor - Diodes Division offers the most aggressive performance profile with 2A current rating, 25ns reverse recovery time, and 1µA reverse leakage current. This Avalanche-technology diode provides superior transient suppression characteristics. It maintains the 50V rating and DO-214AC package compatibility. Active product status and highest inventory level (30,200 pieces) support production continuity.

Compliance and Qualification:

All recommended substitute parts maintain ROHS3 compliance and REACH Unaffected status, matching the original US2AA environmental qualification. The HS2AA and BYG22A-E3/TR maintain the -55°C to 150°C operating temperature range of the original part. MURA205T3G and RS2AA-13-F extend the lower temperature limit to -65°C, providing enhanced cold-temperature performance.

Packaging Considerations:

All substitute parts are available in Surface Mount configuration with DO-214AC (SMA) package compatibility. HS2AA R3G is available in Cut Tape (CT) packaging rather than Tape & Reel, which may affect automated assembly processes. This part is noted as Discontinued at DiGi Electronics and should not be selected for new production commitments.

Frequently Asked Questions (FAQ)

Q: Can RS2AA-13-F be used as a direct replacement for US2AA despite the higher forward voltage specification?

A: Yes, RS2AA-13-F is electrically compatible for direct replacement. The forward voltage difference (1.3V versus 1V at 1.5A) represents a 0.3V increase. This difference is acceptable in most rectifier applications where the original design included adequate voltage margin. The longer reverse recovery time (150ns versus 50ns) may affect switching performance in high-frequency applications but is acceptable for standard rectification circuits. Verify that your circuit design accommodates these parameter variations before implementation.

Q: What is the advantage of using MURA205T3G or BYG22A-E3/TR over direct equivalents?

A: Both upgraded substitutes provide 2A current rating versus the original 1.5A specification. This provides a 33% current margin improvement, reducing thermal stress and extending component life in current-limited applications. MURA205T3G and BYG22A-E3/TR also feature significantly faster reverse recovery times (30ns and 25ns respectively versus 50ns), improving switching efficiency in rectifier circuits. Lower reverse leakage current (2µA and 1µA versus 5µA) reduces standby power consumption. These improvements are particularly valuable in power supply and switching applications.

Q: Why is HS2AA R3G not recommended despite identical electrical specifications?

A: HS2AA R3G is marked as Discontinued at DiGi Electronics, indicating limited future availability. While it maintains identical electrical specifications to the original US2AA, the discontinuation status creates supply chain risk for ongoing production. Additionally, HS2AA R3G is supplied in Cut Tape (CT) packaging rather than Tape & Reel (TR), which may require manual handling or tape conversion for automated assembly processes. The standard HS2AA in Tape & Reel packaging is the preferred alternative.

Q: Are there temperature range differences between substitute options?

A: Yes. The original US2AA, HS2AA, HS2AA R3G, and BYG22A-E3/TR all operate across -55°C to 150°C. RS2AA-13-F and MURA205T3G extend the lower temperature limit to -65°C, providing 10°C additional cold-temperature capability. MURA205T3G further extends the upper temperature limit to 175°C, providing 25°C additional high-temperature margin. Select MURA205T3G or RS2AA-13-F if your application requires operation below -55°C or if enhanced thermal margin is desired.

Q: What is the difference between Standard and Avalanche technology in BYG22A-E3/TR?

A: BYG22A-E3/TR uses Avalanche technology, which provides controlled breakdown characteristics under reverse bias overvoltage conditions. This technology offers superior transient suppression and is particularly valuable in circuits subject to voltage spikes or switching transients. Standard technology diodes (US2AA, HS2AA, RS2AA-13-F, MURA205T3G) do not provide this controlled breakdown feature. Select BYG22A-E3/TR if your application requires enhanced transient protection or if the circuit experiences voltage overshoot conditions.

Q: Can I use these substitutes interchangeably in automotive applications?

A: All recommended substitute parts maintain ROHS3 compliance and REACH Unaffected status. However, automotive application suitability depends on specific qualification requirements. The original US2AA carries AEC-Q101 automotive qualification. Verify that your specific automotive application accepts the substitute part's qualification status before implementation. Contact the component manufacturer or your quality assurance department to confirm automotive qualification acceptance for MURA205T3G, BYG22A-E3/TR, RS2AA-13-F, or HS2AA in your particular application.

Q: What inventory considerations should guide my selection?

A: Current inventory levels vary significantly: BYG22A-E3/TR (30,200 pieces), MURA205T3G (23,933 pieces), RS2AA-13-F (25,100 pieces), HS2AA (829 pieces), and HS2AA R3G (2,600 pieces). For long-term production continuity, BYG22A-E3/TR and MURA205T3G offer the highest inventory security. HS2AA and HS2AA R3G have limited stock and should not be selected for high-volume or extended-duration production programs.

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