US1A-TP Equivalent & Substitute Parts

Part Overview

The US1A-TP is a general-purpose rectifier diode manufactured by Micro Commercial Co, 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 "Not For New Designs," indicating it has reached end-of-life status. Identifying equivalent and substitute parts is necessary for ongoing maintenance, repair, and legacy system support where the original component is no longer available or procurement is limited.

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	V @ A
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	—
Reverse Recovery Time (trr)	50	ns
Current - Reverse Leakage @ Vr	10	µA @ 50 V
Package / Case	DO-214AC, SMA	—
Operating Temperature - Junction	-65 to 175	°C
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the US1A-TP is determined by strict electrical and mechanical compatibility across the following parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): Must equal or exceed 50 V
Current - Average Rectified (Io): Must equal or exceed 1 A
Package / Case: Must be DO-214AC (SMA) or mechanically compatible surface mount package
Mounting Type: Must be Surface Mount
RoHS Status: Must maintain ROHS3 Compliance
Moisture Sensitivity Level: Must be MSL 1 (Unlimited) or equivalent

Secondary Compatibility Parameters:

Voltage - Forward (Vf) (Max) @ If: Acceptable range 0.92 V to 1.3 V @ 1 A
Speed Classification: Fast Recovery (≤ 500ns) or Standard Recovery (> 500ns) both acceptable
Reverse Recovery Time (trr): Acceptable range 25 ns to 2 µs
Current - Reverse Leakage @ Vr: Acceptable range 5 µA to 10 µA @ 50 V
Operating Temperature - Junction: Acceptable range -65°C to -55°C (minimum) and 150°C to 175°C (maximum)

Substitute parts meeting all primary criteria and falling within secondary parameter ranges are electrically and mechanically interchangeable with the US1A-TP in standard applications.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) @ If [V @ A]	Speed	trr [ns]	Ir @ Vr [µA @ V]	Package	Tj (°C)	Product Status
US1A-TP	Micro Commercial Co	50	1	1 @ 1	Fast Recovery ≤ 500ns	50	10 @ 50	DO-214AC (SMA)	-65 to 175	Not For New Designs
CGRA4001-G	Comchip Technology	50	1	1.1 @ 1	Standard Recovery > 500ns	—	5 @ 50	DO-214AC (SMA)	-55 to 150	Active
ES1A	YAGEO	50	1	0.95 @ 1	—	—	—	DO-214AC (SMA)	—	Active
ES1A-13-F	Diodes Incorporated	50	1	0.92 @ 1	Fast Recovery ≤ 500ns	25	5 @ 50	DO-214AC (SMA)	-55 to 150	Active
GF1A	onsemi	50	1	1 @ 1	Standard Recovery > 500ns	2000	5 @ 50	DO-214AC (SMA)	-65 to 175	Not For New Designs
GF1A-E3/67A	Vishay General Semiconductor - Diodes Division	50	1	1.1 @ 1	Standard Recovery > 500ns	2000	5 @ 50	DO-214BA	-65 to 175	Active
RS1A-M3/5AT	Vishay General Semiconductor - Diodes Division	50	1	1.3 @ 1	Fast Recovery ≤ 500ns	150	5 @ 50	DO-214AC (SMA)	-55 to 150	Active
RS1A-M3/61T	Vishay General Semiconductor - Diodes Division	50	1	1.3 @ 1	Fast Recovery ≤ 500ns	150	5 @ 50	DO-214AC (SMA)	-55 to 150	Active
RS1AHE3_A/H	Vishay General Semiconductor - Diodes Division	50	1	1.3 @ 1	Fast Recovery ≤ 500ns	150	5 @ 50	DO-214AC (SMA)	-55 to 150	Active
RS1AHE3_A/I	Vishay General Semiconductor - Diodes Division	50	1	1.3 @ 1	Fast Recovery ≤ 500ns	150	5 @ 50	DO-214AC (SMA)	-55 to 150	Active
S1A	YAGEO	50	1	1.1 @ 1	—	—	—	DO-214AC (SMA)	—	Active

Engineering Selection Recommendations

Direct Electrical Equivalents (Highest Compatibility):

ES1A-13-F (Diodes Incorporated) and RS1A-M3/5AT (Vishay) are the primary recommended substitutes. Both parts maintain the 50 V / 1 A electrical specification, operate within acceptable forward voltage and reverse recovery time parameters, and carry Active product status. ES1A-13-F offers superior reverse recovery time (25 ns) compared to the original US1A-TP (50 ns), resulting in improved switching performance. Both parts are ROHS3 compliant and MSL 1 rated.

Active Status Alternatives (DO-214AC Package):

CGRA4001-G (Comchip Technology), ES1A (YAGEO), S1A (YAGEO), RS1A-M3/61T (Vishay), RS1AHE3_A/H (Vishay), and RS1AHE3_A/I (Vishay) all meet the primary electrical and mechanical substitution criteria. These parts are in Active product status, ensuring long-term availability. RS1AHE3_A/H and RS1AHE3_A/I variants include AEC-Q101 automotive qualification, suitable for applications requiring automotive-grade reliability.

Package Consideration:

GF1A-E3/67A (Vishay) uses DO-214BA (GF1) package instead of DO-214AC (SMA). While electrically equivalent, this package variant requires PCB layout modification and is not a direct mechanical substitute without redesign.

Temperature Range Consideration:

The original US1A-TP operates across -65°C to 175°C. Most active substitutes operate within -55°C to 150°C. Applications requiring the full -65°C to 175°C range should select GF1A (onsemi) or GF1A-E3/67A (Vishay), both rated to these extended limits. GF1A carries "Not For New Designs" status; GF1A-E3/67A is Active.

Frequently Asked Questions (FAQ)

Q: Can ES1A-13-F directly replace US1A-TP without PCB modification?

A: Yes. Both parts use DO-214AC (SMA) package with identical pinout and footprint. No PCB layout changes are required. Electrical parameters fall within acceptable substitution ranges.

Q: What is the difference between Fast Recovery and Standard Recovery speed classifications?

A: Fast Recovery diodes (≤ 500ns) exhibit shorter reverse recovery time, reducing switching losses and improving efficiency in high-frequency applications. Standard Recovery diodes (> 500ns) are suitable for lower-frequency rectification. The US1A-TP is Fast Recovery; substitutes with either classification are electrically compatible for standard rectification applications.

Q: Why do some substitutes show higher forward voltage (Vf)?

A: Forward voltage varies with semiconductor manufacturing process and doping levels. RS1A variants show 1.3 V versus the original 1 V. This 0.3 V difference results in slightly higher power dissipation but does not affect circuit functionality in standard rectifier applications. Verify thermal design margins if operating near maximum current.

Q: Are RS1AHE3_A/H and RS1AHE3_A/I suitable for automotive applications?

A: Yes. Both variants carry AEC-Q101 automotive qualification and are rated for automotive-grade reliability. They are electrically and mechanically identical except for qualification status.

Q: What is the significance of MSL 1 (Unlimited) rating?

A: MSL 1 indicates unlimited shelf life without moisture baking requirements. Both the original US1A-TP and all listed substitutes carry this rating, ensuring consistent handling and storage procedures across all alternatives.

Q: Can GF1A-E3/67A be used as a substitute despite different package designation?

A: GF1A-E3/67A uses DO-214BA (GF1) package instead of DO-214AC (SMA). While electrically equivalent, the package footprint differs. Direct PCB substitution is not possible without layout redesign. This part is suitable only if PCB modification is acceptable.

Q: Which substitute offers the best reverse recovery time performance?

A: ES1A-13-F (Diodes Incorporated) provides the fastest reverse recovery time at 25 ns, compared to the original US1A-TP at 50 ns. This results in reduced switching losses and improved efficiency in switching applications.

Q: Are all substitutes ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance status, matching the original US1A-TP specification.

Q: What is the inventory status of recommended substitutes?

A: ES1A-13-F (Diodes Incorporated) has 70,300 pcs in stock. RS1A-M3/5AT and RS1A-M3/61T (Vishay) have 807 and 865 pcs respectively. YAGEO ES1A and S1A variants have 80,200 and 4,747 pcs in stock. Comchip CGRA4001-G has 10,226 pcs available. Inventory levels support both immediate and sustained procurement requirements.

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