FR3B Equivalent & Substitute Parts Reference

Part Overview

The FR3B is a general-purpose rectifier diode manufactured by SMC Diode Solutions, rated for 100 V DC reverse voltage and 3 A average rectified current in a Surface Mount SMC (DO-214AB) package. This component is classified as obsolete, indicating that direct procurement from the original manufacturer may be limited or unavailable. Identifying equivalent and substitute parts ensures design continuity and maintains supply chain reliability for applications requiring this diode specification.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	100	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	1.3	V @ 3 A
Reverse Recovery Time (trr)	150	ns
Current - Reverse Leakage @ Vr	5	µA @ 100 V
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
Operating Temperature - Junction	-65°C ~ 150°C	—
Technology	Standard	—
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	—

Substitute Part Grouping Explanation

Substitute parts for the FR3B are classified based on strict electrical and mechanical parameter alignment. The primary substitution criteria are:

Critical Parameters for Substitution:

Voltage - DC Reverse (Vr) (Max): 100 V
Current - Average Rectified (Io): 3 A
Package / Case: DO-214AB, SMC
Mounting Type: Surface Mount
Technology: Standard
Speed Classification: Fast Recovery ≤ 500ns, > 200mA (Io)

All substitute parts listed maintain these core electrical ratings and physical package specifications. Variations in secondary parameters such as forward voltage, reverse recovery time, reverse leakage current, and operating temperature range are noted but do not preclude substitution when the critical parameters align.

Substitution Categories:

Direct Manufacturer Substitute (RS3B): Identical electrical ratings with active product status and improved availability. Manufactured by Taiwan Semiconductor Corporation.

Similar Manufacturer Substitute (CMR3U-01 BK PBFREE): Meets core electrical and package requirements with enhanced performance characteristics (lower reverse recovery time, extended temperature range). Manufactured by Central Semiconductor Corp.

Parametric Equivalent (RS3B-13-F): Exact electrical parameter match with highest inventory availability. Manufactured by Diodes Incorporated.

Parameter Comparison

Parameter	FR3B (SMC)	RS3B (TSC)	CMR3U-01 BK PBFREE (CSC)	RS3B-13-F (Diodes Inc.)
Voltage - DC Reverse (Vr) (Max)	100 V	100 V	100 V	100 V
Current - Average Rectified (Io)	3 A	3 A	3 A	3 A
Voltage - Forward (Vf) (Max) @ If	1.3 V @ 3 A	1.3 V @ 3 A	1 V @ 3 A	1.3 V @ 3 A
Reverse Recovery Time (trr)	150 ns	150 ns	50 ns	150 ns
Current - Reverse Leakage @ Vr	5 µA @ 100 V	10 µA @ 100 V	5 µA @ 100 V	5 µA @ 100 V
Package / Case	DO-214AB, SMC	DO-214AB, SMC	DO-214AB, SMC	DO-214AB, SMC
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Operating Temperature - Junction	-65°C ~ 150°C	-55°C ~ 150°C	-65°C ~ 175°C	-65°C ~ 150°C
Product Status	Obsolete	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

RS3B-13-F (Diodes Incorporated) is the primary recommended substitute. This part provides exact electrical parameter matching across all critical specifications including forward voltage, reverse recovery time, and reverse leakage current. The part is ROHS3 compliant, carries active product status, and maintains the highest inventory availability (9,100 pieces in stock). The operating temperature range (-65°C ~ 150°C) is identical to the FR3B, ensuring thermal compatibility in existing designs.

RS3B (Taiwan Semiconductor Corporation) serves as an alternative direct substitute with active product status and substantial inventory (2,300 pieces). This part matches all critical electrical ratings and package specifications. The reverse leakage current specification (10 µA @ 100 V) is slightly elevated compared to the FR3B (5 µA @ 100 V), and the minimum operating temperature is -55°C rather than -65°C. These differences are acceptable for applications not requiring the extended low-temperature performance of the original part.

CMR3U-01 BK PBFREE (Central Semiconductor Corp) provides enhanced performance characteristics with a lower reverse recovery time (50 ns versus 150 ns) and extended maximum operating temperature (175°C versus 150°C). The forward voltage is reduced to 1 V @ 3 A, resulting in lower power dissipation. This part is ROHS3 compliant and active. Selection of this substitute is appropriate for applications benefiting from improved switching speed or elevated temperature operation.

All three substitute parts are ROHS3 compliant and REACH unaffected, meeting modern regulatory requirements. Selection should be based on specific application requirements regarding temperature range, switching speed, and power dissipation characteristics.

Frequently Asked Questions (FAQ)

Q: Can RS3B-13-F directly replace FR3B in existing PCB designs?

A: Yes. RS3B-13-F maintains identical package geometry (DO-214AB, SMC), mounting type (Surface Mount), and all critical electrical parameters. No PCB layout modifications are required.

Q: What is the difference between the three substitute options?

A: All three substitutes meet the core electrical and package requirements. RS3B-13-F provides exact parameter matching. RS3B offers active status with slightly higher reverse leakage. CMR3U-01 BK PBFREE provides enhanced performance with lower reverse recovery time and extended temperature range.

Q: Does the reverse leakage current difference between FR3B (5 µA) and RS3B (10 µA) affect circuit performance?

A: The 5 µA difference is within typical application tolerances for general-purpose rectifier applications. Circuit-specific analysis is required only if reverse leakage current is a critical design parameter.

Q: Are all substitute parts RoHS compliant?

A: Yes. RS3B-13-F, RS3B, and CMR3U-01 BK PBFREE are all ROHS3 compliant. The original FR3B RoHS status was not specified in available documentation.

Q: Which substitute has the best availability?

A: RS3B-13-F (Diodes Incorporated) has the highest inventory with 9,100 pieces in stock, followed by RS3B with 2,300 pieces and CMR3U-01 BK PBFREE with 902 pieces.

Q: Can CMR3U-01 BK PBFREE be used in applications requiring the -65°C minimum operating temperature?

A: Yes. CMR3U-01 BK PBFREE operates from -65°C to 175°C, matching the FR3B minimum temperature and exceeding the maximum. This part is suitable for extended temperature range applications.

Q: What is the significance of the "Fast Recovery" speed classification?

A: Fast Recovery classification (≤ 500ns, > 200mA) indicates the diode is optimized for switching applications. All substitute parts maintain this classification, ensuring compatibility with high-frequency rectification circuits.

Q: Is tape and reel packaging compatible with bulk packaging in manufacturing?

A: Tape and reel (TR) and bulk packaging formats are compatible for assembly operations. The physical component specifications remain identical; packaging format affects only handling and automated placement processes.

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