S1A Equivalent & Substitute Parts Reference

Part Overview

The onsemi S1A is a general-purpose rectifier diode rated for 50 V DC reverse voltage and 1 A average rectified current in a DO-214AC (SMA) surface mount package. This component is classified as "Not For New Designs," indicating it has been superseded in the manufacturer's product portfolio. Identifying equivalent and substitute parts is necessary for applications requiring continued supply, design updates, or performance optimization while maintaining electrical and mechanical compatibility.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	50	V
Current - Average Rectified (Io)	1	A
Voltage - Forward (Vf) (Max) @ If	1.1 V @ 1 A	V
Reverse Recovery Time (trr)	1.8	µs
Current - Reverse Leakage @ Vr	1	µA @ 50 V
Package / Case	DO-214AC, SMA	—
Mounting Type	Surface Mount	—
Operating Temperature - Junction	-55 to 150	°C
Technology	Standard	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the S1A is determined by the following critical parameters:

Electrical Compatibility Requirements:

Voltage - DC Reverse (Vr) rating must equal or exceed 50 V
Current - Average Rectified (Io) rating must equal or exceed 1 A
Forward voltage (Vf) must be compatible with circuit design tolerances
Reverse recovery time (trr) and leakage current affect switching performance and power dissipation

Mechanical Compatibility Requirements:

Package / Case must be DO-214AC (SMA) or mechanically equivalent
Mounting Type must be Surface Mount
Operating temperature range must accommodate application requirements

Compliance Requirements:

RoHS3 Compliant status required
Moisture Sensitivity Level (MSL) 1 (Unlimited) preferred for manufacturing flexibility

Substitute parts are grouped into three categories based on these criteria:

Category 1: Direct Electrical & Mechanical Equivalents (1 A, 50 V, DO-214AC) Parts with identical current and voltage ratings in the same package.

Category 2: Enhanced Performance Substitutes (Higher Current or Voltage) Parts with upgraded electrical specifications that maintain backward compatibility.

Category 3: Alternative Technology Substitutes (Schottky Diodes) Parts with different semiconductor technology offering different performance characteristics.

Parameter Comparison

Part Number	Manufacturer	Vr (Max)	Io	Vf @ 1A	trr	Package	Technology	Product Status
S1A	onsemi	50 V	1 A	1.1 V	1.8 µs	DO-214AC	Standard	Not For New Designs
ES1A	YAGEO	50 V	1 A	0.95 V	—	DO-214AC	Standard	Active
RS1A	Taiwan Semiconductor Corporation	50 V	1 A	1.3 V	150 ns	DO-214AC	Standard	Active
ES1A-13-F	Diodes Incorporated	50 V	1 A	0.92 V	25 ns	DO-214AC	Standard	Active
ES1A-E3/5AT	Vishay General Semiconductor	50 V	1 A	0.92 V	25 ns	DO-214AC	Standard	Active
ES1A-LTP	Micro Commercial Co	50 V	1 A	0.95 V	35 ns	DO-214AC	Standard	Not For New Designs
EGF1A-E3/5CA	Vishay General Semiconductor	50 V	1 A	1.0 V	50 ns	DO-214BA	Standard	Active
EGF1A-E3/67A	Vishay General Semiconductor	50 V	1 A	1.0 V	50 ns	DO-214BA	Standard	Active
MURA105T3G	onsemi	50 V	2 A	0.875 V	30 ns	DO-214AC	Standard	Active
CMSH1-60M BK PBFREE	Central Semiconductor Corp	60 V	1 A	0.7 V	≤500 ns	DO-214AC	Schottky	Active
CMSH1-60M TR13 PBFREE	Central Semiconductor Corp	60 V	1 A	0.7 V	≤500 ns	DO-214AC	Schottky	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical & Mechanical Specifications):

ES1A-13-F (Diodes Incorporated) and ES1A-E3/5AT (Vishay General Semiconductor) are recommended as primary substitutes. Both parts maintain 50 V / 1 A ratings in DO-214AC packages with Active product status. These parts offer improved reverse recovery time (25 ns versus 1.8 µs) and lower forward voltage (0.92 V versus 1.1 V), resulting in reduced power dissipation and improved switching performance. Both are ROHS3 Compliant with MSL 1 rating.

ES1A (YAGEO) provides an alternative direct equivalent with Active status and lower forward voltage (0.95 V), suitable for applications where supply continuity from a different manufacturer is required.

For Applications Tolerating Package Variation:

EGF1A-E3/5CA and EGF1A-E3/67A (Vishay General Semiconductor, SUPERECTIFIER® series) maintain electrical specifications (50 V / 1 A) but use DO-214BA package instead of DO-214AC. These parts are suitable only if PCB layout accommodates the different package footprint. Both offer improved reverse recovery time (50 ns) and are Active status with ROHS3 compliance.

For Current Upgrade Applications:

MURA105T3G (onsemi) provides 2 A current rating at 50 V in DO-214AC package with Active status. This part is suitable for applications requiring increased current capacity while maintaining the same package and voltage rating. Forward voltage is reduced to 0.875 V, and reverse recovery time is 30 ns.

For Schottky Technology Applications:

CMSH1-60M TR13 PBFREE (Central Semiconductor Corp, Tape & Reel) offers Schottky technology with 60 V / 1 A rating in DO-214AC package. This part is suitable only for applications where Schottky characteristics (lower forward voltage of 0.7 V, higher reverse leakage of 500 µA @ 60 V) are acceptable. Active status and ROHS3 compliance confirmed.

Parts Not Recommended for New Designs:

ES1A-LTP (Micro Commercial Co) carries "Not For New Designs" status and should be avoided for new applications despite electrical compatibility.

Frequently Asked Questions (FAQ)

Q: Can ES1A-13-F directly replace S1A without PCB modification?

A: Yes. ES1A-13-F maintains identical electrical ratings (50 V / 1 A) and uses the same DO-214AC (SMA) package. No PCB layout changes are required. The part offers improved performance characteristics with lower forward voltage and faster reverse recovery time.

Q: What is the difference between DO-214AC and DO-214BA packages?

A: DO-214AC and DO-214BA are both surface mount packages for diodes but have different physical dimensions and footprints. EGF1A-E3/5CA and EGF1A-E3/67A use DO-214BA and require different PCB pad layouts. These parts are not pin-compatible with S1A without PCB redesign.

Q: Why does MURA105T3G have a higher current rating (2 A) than S1A (1 A)?

A: MURA105T3G is designed for higher current applications. The 2 A rating indicates the part can handle twice the average rectified current. It maintains the same 50 V voltage rating and DO-214AC package, making it suitable for applications requiring increased current capacity. Existing circuits designed for 1 A operation will function correctly with this part, but it is not required unless higher current is needed.

Q: Are Schottky diodes (CMSH1-60M) suitable replacements for standard rectifier diodes (S1A)?

A: Schottky diodes have different electrical characteristics. CMSH1-60M offers lower forward voltage (0.7 V versus 1.1 V) and higher reverse leakage current (500 µA versus 1 µA). These differences affect power dissipation and circuit performance. Schottky substitution is only appropriate if the application circuit design accounts for these characteristic differences. Reverse leakage current in particular may impact high-impedance circuits.

Q: What does "Not For New Designs" status mean for S1A?

A: "Not For New Designs" indicates that onsemi has superseded this part in their product portfolio. While existing inventory remains available, the manufacturer recommends using alternative parts for new circuit designs. This status does not affect the functionality of existing applications but signals that long-term supply may be limited.

Q: Which substitute part offers the best performance improvement over S1A?

A: ES1A-13-F and ES1A-E3/5AT both provide significant improvements: forward voltage reduced from 1.1 V to 0.92 V (16% reduction) and reverse recovery time reduced from 1.8 µs to 25 ns (98% reduction). These improvements reduce power dissipation and enable faster switching. Both parts are Active status with full ROHS3 compliance.

Q: Can I use a 60 V rated diode (CMSH1-60M) in a circuit designed for 50 V (S1A)?

A: Yes, from a voltage rating perspective. A 60 V rated diode can safely operate in a 50 V circuit. However, CMSH1-60M is a Schottky diode with different forward voltage and reverse leakage characteristics. Circuit performance will differ

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