US1AHM2G Equivalent & Substitute Parts

Part Overview

The US1AHM2G is a general-purpose rectifier diode manufactured by Taiwan Semiconductor Corporation, rated for 50 V DC reverse voltage and 1 A average rectified current in a DO-214AC (SMA) surface mount package. This part is classified as discontinued at DiGi Electronics, though 987 pieces remain in stock as new original inventory. The device features fast recovery characteristics with a 50 ns reverse recovery time and automotive-grade qualification under AEC-Q101 standard.

Identification of equivalent and substitute parts is necessary due to the discontinued product status. Alternative sources from active manufacturers provide functional equivalents that maintain electrical and mechanical compatibility within specified parameters.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	50	V
Current - Average Rectified (Io)	1	A
Voltage - Forward (Vf) (Max) @ If	1	V @ 1 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	—
Reverse Recovery Time (trr)	50	ns
Current - Reverse Leakage @ Vr	5	µA @ 50 V
Capacitance @ Vr, F	15	pF @ 4V, 1MHz
Package / Case	DO-214AC, SMA	—
Operating Temperature - Junction	-55 to 150	°C
Grade	Automotive	—
Qualification	AEC-Q101	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the US1AHM2G is determined by strict equivalence in the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): 50 V
Current - Average Rectified (Io): 1 A
Package / Case: DO-214AC (SMA)
Mounting Type: Surface Mount
Operating Temperature Range: -55°C to 150°C minimum

Secondary Compatibility Factors:

Voltage - Forward (Vf) (Max) @ If: 1 V @ 1 A or lower
Speed Classification: Fast Recovery ≤ 500ns or Standard Recovery
Reverse Recovery Time (trr): 50 ns or lower
Current - Reverse Leakage @ Vr: 5 µA @ 50 V or lower
RoHS Status: ROHS3 Compliant

Substitute parts are grouped into three categories:

Parametric Equivalents (HS1A, US1A, US1AH): Identical electrical specifications with active product status. These parts maintain all critical parameters including fast recovery speed and automotive qualification where applicable.

Direct Manufacturer Equivalents (CGRA4001-G): Functionally equivalent from alternative manufacturer with minor parameter variations (standard recovery speed, forward voltage 1.1 V). Maintains 50 V / 1 A rating and DO-214AC package.

Similar Parts (ES1A-13-F, ES1A-E3/5AT, RS1A-13-F, RS1AB-13-F, S1A-13-F, GS2A-LTP): Parts with matching voltage and package specifications but with variations in recovery characteristics, forward voltage, or current rating. GS2A-LTP operates at 2 A and represents an upgraded current capability option.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) @ If [V]	Speed	trr [ns]	Package	Temp Range [°C]	Product Status	Grade
US1AHM2G	Taiwan Semiconductor	50	1	1 @ 1A	Fast Recovery ≤ 500ns	50	DO-214AC (SMA)	-55 to 150	Discontinued	Automotive AEC-Q101
HS1A	Taiwan Semiconductor	50	1	1 @ 1A	Fast Recovery ≤ 500ns	50	DO-214AC (SMA)	-55 to 150	Active	—
US1A	Taiwan Semiconductor	50	1	1 @ 1A	Fast Recovery ≤ 500ns	50	DO-214AC (SMA)	-55 to 150	Active	—
US1AH	Taiwan Semiconductor	50	1	1 @ 1A	Fast Recovery ≤ 500ns	50	DO-214AC (SMA)	-55 to 150	Active	Automotive AEC-Q101
CGRA4001-G	Comchip Technology	50	1	1.1 @ 1A	Standard Recovery >500ns	—	DO-214AC (SMA)	-55 to 150	Active	—
ES1A-13-F	Diodes Incorporated	50	1	0.92 @ 1A	Fast Recovery ≤ 500ns	25	DO-214AC (SMA)	-55 to 150	Active	—
ES1A-E3/5AT	Vishay General Semiconductor	50	1	0.92 @ 1A	Fast Recovery ≤ 500ns	25	DO-214AC (SMA)	-55 to 155	Active	—
RS1A-13-F	Diodes Incorporated	50	1	1.3 @ 1A	Fast Recovery ≤ 500ns	150	DO-214AC (SMA)	-65 to 150	Active	—
RS1AB-13-F	Diodes Incorporated	50	1	1.3 @ 1A	Fast Recovery ≤ 500ns	150	DO-214AA (SMB)	-65 to 150	Active	—
S1A-13-F	Diodes Incorporated	50	1	1.1 @ 1A	Standard Recovery >500ns	3000	DO-214AC (SMA)	-65 to 150	Active	—
GS2A-LTP	Micro Commercial Co	50	2	1.1 @ 2A	Standard Recovery >500ns	—	DO-214AC (SMA)	-55 to 150	Active	—

Engineering Selection Recommendations

For Direct Replacement (Discontinued Product Mitigation):

The US1A and US1AH from Taiwan Semiconductor Corporation provide the most direct substitution path. Both parts maintain identical electrical specifications to the US1AHM2G, including 50 V reverse voltage, 1 A current rating, fast recovery speed (≤ 500ns), and 50 ns reverse recovery time. US1AH additionally carries automotive AEC-Q101 qualification matching the original part's grade. Both are active products with substantial inventory availability (17,187 and 827 pieces respectively).

For Automotive Applications Requiring AEC-Q101:

US1AH is the recommended substitute when automotive qualification is mandatory. This part maintains all electrical parameters of the US1AHM2G while offering active product status and continued supply assurance.

For General-Purpose Applications with Relaxed Recovery Requirements:

CGRA4001-G from Comchip Technology provides functional equivalence with 50 V / 1 A specifications in DO-214AC package. The forward voltage is slightly elevated at 1.1 V, and recovery speed is standard (>500ns) rather than fast. This part is suitable for applications where recovery speed is not performance-critical.

For Applications Prioritizing Lower Forward Voltage:

ES1A-13-F and ES1A-E3/5AT from Diodes Incorporated and Vishay respectively offer reduced forward voltage (0.92 V) and faster recovery (25 ns trr). These parts are suitable for power-sensitive applications. ES1A-E3/5AT extends the upper operating temperature to 155°C.

For Extended Temperature Range:

RS1A-13-F and S1A-13-F extend the lower operating temperature to -65°C. RS1A-13-F maintains fast recovery characteristics, while S1A-13-F operates with standard recovery speed.

For Increased Current Capacity:

GS2A-LTP provides 2 A current rating in the same DO-214AC package, suitable for applications requiring higher current handling with the same voltage specification.

Frequently Asked Questions (FAQ)

Q: Can US1A be used as a direct replacement for US1AHM2G?

A: Yes. US1A is a parametric equivalent with identical electrical specifications: 50 V reverse voltage, 1 A current rating, fast recovery speed (≤ 500ns), and 50 ns reverse recovery time. The primary difference is product status (US1A is active with 17,187 pieces in stock versus US1AHM2G discontinued status). Both use DO-214AC (SMA) packaging and are ROHS3 compliant.

Q: What is the difference between US1AH and US1A?

A: US1AH carries automotive-grade qualification (AEC-Q101) identical to the original US1AHM2G, while US1A does not specify a grade designation. Electrical parameters are identical. US1AH is the preferred choice for automotive applications where qualification documentation is required.

Q: Why does ES1A-13-F have a lower forward voltage than US1AHM2G?

A: Forward voltage variation (0.92 V versus 1 V) reflects different semiconductor manufacturing processes and die designs between manufacturers. Both values are within acceptable ranges for 50 V / 1 A rectifier diodes. The lower forward voltage of ES1A-13-F results in reduced power dissipation, which may be advantageous in power-sensitive applications.

Q: Can RS1AB-13-F replace US1AHM2G despite the different package?

A: RS1AB-13-F uses DO-214AA (SMB) packaging instead of DO-214AC (SMA). While electrical specifications are compatible (50 V / 1 A), the different package footprint requires PCB layout modification. This substitution is not recommended for direct board-level replacement without design revision.

Q: Is GS2A-LTP suitable as a substitute for US1AHM2G?

A: GS2A-LTP is electrically compatible in voltage (50 V) and package (DO-214AC), but operates at 2 A current rating versus 1 A. This part functions as a higher-capacity alternative suitable for applications requiring increased current handling. It is not a direct replacement but rather an upgraded option.

Q: What does "Fast Recovery ≤ 500ns" mean in practical terms?

A: Reverse recovery time (trr) indicates how quickly the diode transitions from conducting to blocking state when reverse voltage is applied. Fast recovery (≤ 500ns) is critical in high-frequency switching applications and power conversion circuits. Standard recovery (>500ns) is acceptable for lower-frequency or non-switching applications.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance status, matching the original US1AHM2G specification. All parts also maintain REACH unaffected status and EAR99 export classification.

Q: What is the significance of the -55°C to 150°C operating temperature range?

A: This range defines the junction temperature limits within which the diode maintains specified electrical characteristics. All primary substitutes (US1A, US1AH, HS1A) match this range. Some alternatives extend the lower limit to -65°C (RS1A-13-F, S1A-13-F) or upper limit to 155°C (ES1A-E3/5AT), providing flexibility for extreme temperature environments.

Q: Can I use S1A-13-F in a high-frequency switching application?

A: S1A-13-F is not recommended for high-frequency switching applications. This part operates with standard recovery speed (>500ns) and exhibits 3 µs reverse recovery time, significantly slower than the US1AHM2G (50 ns). Use S1A-13-F only in low-frequency rectification or general-purpose applications.

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