US1B/1 General Purpose Rectifier Diode – Equivalent & Substitute Parts

Part Overview

The US1B/1 is a general-purpose rectifier diode manufactured by Vishay General Semiconductor - Diodes Division, rated for 100 V DC reverse voltage and 1 A average rectified current in a DO-214AC (SMA) surface mount package. This component is classified as Obsolete, which necessitates identification of functionally equivalent alternatives for ongoing production and repair applications. The fast recovery characteristic (≤500 ns) and 50 ns reverse recovery time position this diode for applications requiring rapid switching performance in standard rectification circuits.

Key Parameters

Parameter	Value	Unit
Voltage – DC Reverse (Vr) (Max)	100	V
Current – Average Rectified (Io)	1	A
Voltage – Forward (Vf) (Max) @ If	1 V @ 1 A	V @ A
Speed Classification	Fast Recovery ≤500 ns, >200 mA (Io)	–
Reverse Recovery Time (trr)	50	ns
Current – Reverse Leakage @ Vr	10 µA @ 100 V	µA
Capacitance @ Vr, F	15 pF @ 4 V, 1 MHz	pF
Package / Case	DO-214AC, SMA	–
Operating Temperature – Junction	–65°C to 175°C	°C
RoHS Status	RoHS non-compliant	–

Substitute Part Grouping Explanation

Substitution of the US1B/1 is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage – DC Reverse (Vr) rating must equal or exceed 100 V
Current – Average Rectified (Io) must equal or exceed 1 A
Package / Case must be DO-214AC (SMA) for mechanical and thermal compatibility
Mounting Type must be Surface Mount

Secondary Compatibility Factors:

Speed classification (Fast Recovery ≤500 ns preferred for equivalent performance)
Reverse Recovery Time (trr) – lower values indicate faster switching
Operating Temperature range – minimum –55°C to 150°C acceptable for most applications
RoHS compliance status – ROHS3 compliant alternatives preferred for new designs

Substitute parts are grouped into three categories based on voltage rating and product status:

Direct Equivalents (100 V rating) – GS1B-LTP, ES1B-13-F, ES1B-LTP, GF1B, S1B – provide identical voltage performance with varying recovery characteristics and compliance certifications.
Upgraded Voltage Ratings (200 V, 400 V, 1000 V) – CURA103-G, CURA104-G, CURA107-G – suitable for applications requiring higher voltage margin or operating in elevated voltage environments while maintaining 1 A current rating.
Active Product Alternatives – EGF1B (Fairchild Semiconductor) – offers matching electrical specifications with Active product status and improved compliance profile.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) @ If [V @ A]	Speed	trr [ns]	Ir @ Vr [µA]	Package	Temp Range [°C]	Product Status	RoHS
US1B/1	Vishay	100	1	1 @ 1	Fast ≤500 ns	50	10 @ 100	DO-214AC	–65 to 175	Obsolete	Non-compliant
GS1B-LTP	Micro Commercial Co	100	1	1 @ 1	Standard >500 ns	–	10 @ 100	DO-214AC	–55 to 150	Not For New Designs	ROHS3
EGF1B	Fairchild Semiconductor	100	1	1 @ 1	Fast ≤500 ns	50	10 @ 100	DO-214AC	–65 to 175	Active	–
CURA103-G	Comchip Technology	200	1	1 @ 1	Fast ≤500 ns	50	5 @ 200	DO-214AC	–55 to 150	Active	ROHS3
CURA104-G	Comchip Technology	400	1	1.3 @ 1	Fast ≤500 ns	50	5 @ 400	DO-214AC	–55 to 150	Active	ROHS3
CURA107-G	Comchip Technology	1000	1	1.7 @ 1	Fast ≤500 ns	75	5 @ 1000	DO-214AC	–55 to 150	Active	ROHS3
ES1B	YAGEO	100	1	0.95 @ 1	–	–	–	DO-214AC	–	Active	ROHS3
ES1B-13-F	Diodes Incorporated	100	1	0.92 @ 1	Fast ≤500 ns	25	5 @ 100	DO-214AC	–55 to 150	Active	ROHS3
ES1B-LTP	Micro Commercial Co	100	1	0.95 @ 1	Fast ≤500 ns	35	5 @ 100	DO-214AC	–65 to 175	Not For New Designs	ROHS3
GF1B	onsemi	100	1	1 @ 1	Standard >500 ns	2000	5 @ 100	DO-214AC	–65 to 175	Not For New Designs	ROHS3
S1B	YAGEO	100	1	1.1 @ 1	–	–	–	DO-214AC	–	Active	ROHS3

Engineering Selection Recommendations

For Active Production (New Designs):

Select EGF1B (Fairchild Semiconductor) as the primary replacement for the obsolete US1B/1. This part maintains identical electrical specifications including 100 V reverse voltage, 1 A current rating, fast recovery characteristics (≤500 ns), and 50 ns reverse recovery time. EGF1B carries Active product status and operates across the full temperature range (–65°C to 175°C), ensuring long-term availability and design continuity.

For RoHS3 Compliance Requirement:

Select ES1B-13-F (Diodes Incorporated) or CURA103-G (Comchip Technology). ES1B-13-F provides 100 V rating with superior reverse recovery time (25 ns) and lower forward voltage (920 mV @ 1 A), delivering improved switching performance. CURA103-G offers 200 V rating with ROHS3 compliance and Active status, suitable for applications requiring voltage margin above 100 V.

For Voltage Margin Applications:

Select CURA104-G (400 V) or CURA107-G (1000 V) from the Comchip CURA series. These parts maintain 1 A current rating and fast recovery characteristics while providing elevated voltage ratings. Forward voltage increases with voltage rating (1.3 V @ 1 A for 400 V; 1.7 V @ 1 A for 1000 V), which must be evaluated against circuit requirements.

For Legacy System Repair (Obsolete Equipment):

Select ES1B-LTP (Micro Commercial Co) or GF1B (onsemi) for direct form-fit-function replacement. Both parts maintain DO-214AC packaging and operate across –65°C to 175°C. ES1B-LTP provides fast recovery (35 ns) with ROHS3 compliance. GF1B offers standard recovery characteristics (2 µs) with ROHS3 compliance and extended availability through onsemi distribution channels.

Avoid for New Designs:

Parts marked "Not For New Designs" (GS1B-LTP, ES1B-LTP, GF1B) are suitable only for repair and legacy applications. These parts have limited future availability and should not be selected for new product development.

Frequently Asked Questions (FAQ)

Q: Can I use a 200 V rated diode (CURA103-G) in place of the 100 V US1B/1?

A: Yes. The CURA103-G operates at 200 V reverse voltage, which exceeds the 100 V requirement of the US1B/1. The higher voltage rating provides additional safety margin and does not degrade performance in 100 V applications. However, forward voltage is identical (1 V @ 1 A), and reverse leakage is lower (5 µA vs. 10 µA), resulting in improved efficiency. Verify circuit design does not depend on the specific reverse leakage characteristic of the original part.

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

A: Fast Recovery diodes (≤500 ns reverse recovery time) switch off more rapidly than Standard Recovery diodes (>500 ns). The US1B/1 specifies Fast Recovery with 50 ns reverse recovery time. Substitutes with Standard Recovery (GS1B-LTP, GF1B) exhibit slower switching and higher reverse recovery time (2 µs for GF1B), which may cause increased switching losses in high-frequency applications. For equivalent performance, select Fast Recovery alternatives (EGF1B, ES1B-13-F, ES1B-LTP, CURA series).

Q: Are all substitute parts compatible with the DO-214AC (SMA) footprint?

A: Yes. All listed substitute parts use the DO-214AC (SMA) package, ensuring mechanical and thermal compatibility with existing PCB layouts. No footprint modification is required for direct substitution.

Q: What does "Not For New Designs" product status mean?

A: Parts designated "Not For New Designs" are in mature or declining production phases with limited future availability. These parts are suitable for repair of existing equipment and legacy system maintenance but should not be selected for new product development. For new designs, select parts with Active product status: EGF1B, CURA103-G, CURA104-G, CURA107-G, ES1B, ES1B-13-F, or S1B.

Q: How does RoHS compliance affect part selection?

A: The original US1B/1 is RoHS non-compliant. For applications subject to RoHS3 regulations (EU Directive 2015/863/EU), select ROHS3 compliant alternatives: GS1B-LTP, CURA103-G, CURA104-G, CURA107-G, ES1B, ES1B-13-F, ES1B-LTP, GF1B, or S1B. RoHS3 compliance ensures the part contains no restricted substances (lead, cadmium, mercury, hexavalent chromium, PBBs, PBDEs) and meets environmental and safety standards for regulated markets.

Q: What is the significance of reverse recovery time (trr) in diode selection?

A: Reverse recovery time is the interval required for a diode to transition from forward conduction to reverse blocking after the applied voltage reverses. Lower trr values indicate faster switching and reduced switching losses. The US1B/1 specifies 50 ns. Alternatives with lower trr (ES1B-13-F at 25 ns) provide improved efficiency in switching applications. Parts with significantly higher trr (GF1B at 2 µs) are unsuitable for high-frequency switching circuits.

Q: Can I substitute the US1B/1 with a higher current rated diode?

A: The provided substitute list contains only 1 A rated parts, matching the US1B/1 current specification. Higher current alternatives are not included in this reference. If a higher current rating is required, consult the manufacturer's full product portfolio or contact a component distributor for extended options.

Q: What is the operating temperature range significance?

A: The US1B/1 operates from –65°C to 175°C junction temperature. Most substitutes operate from –55°C to 150°C, representing a narrower range. For applications requiring full –65°C to 175°C operation, select EGF1B, ES1B-LTP, or GF1B. For standard industrial applications (–55°C to 150°C), all alternatives are acceptable.

Q: How do I verify electrical compatibility before substitution?

A: Verify the following parameters match or exceed the original specification: (1) Voltage – DC Reverse (Vr) ≥ 100 V, (2) Current – Average Rectified (Io) ≥ 1 A, (3) Package / Case = DO-214AC (SMA), (4) Speed classification appropriate for circuit switching frequency. Forward voltage (Vf) and reverse leakage (Ir) variations are typically acceptable in rectification circuits but should be evaluated if the circuit design is sensitive to these parameters.

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