1N4685-TP Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N4685-TP is a 3.6 V, 500 mW Zener diode in DO-35 axial through-hole package manufactured by Micro Commercial Co. This component is classified as obsolete, indicating discontinuation from the original manufacturer. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for applications utilizing this diode specification.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	3.6	V
Tolerance	±5%	-
Power - Max	500	mW
Current - Reverse Leakage @ Vr	7.5	µA @ 2 V
Voltage - Forward (Vf) (Max) @ If	1.5	V @ 100 mA
Operating Temperature	200	°C (TJ)
Mounting Type	Through Hole	-
Package / Case	DO-204AH, DO-35, Axial	-
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution of the 1N4685-TP is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nom): 3.6 V
Power - Max: 500 mW
Tolerance: ±5%
Package / Case: DO-204AH, DO-35, Axial
Mounting Type: Through Hole

Secondary Compatibility Factors:

Current - Reverse Leakage @ Vr
Voltage - Forward (Vf) (Max) @ If
Operating Temperature range
RoHS compliance status
Product status (Active vs. Obsolete)

Substitute parts are classified into two categories:

Direct Substitutes: Parts with identical nominal Zener voltage (3.6 V), power rating (500 mW), tolerance (±5%), and package configuration (DO-35 axial through-hole). These parts are functionally interchangeable in circuit applications.

Similar Substitutes: Parts meeting the core electrical specifications (3.6 V, 500 mW, DO-35) but with variations in impedance, reverse leakage current, or forward voltage characteristics. These parts maintain functional compatibility while offering alternative performance characteristics suitable for specific application requirements.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Vf Max @ If	Ir @ Vr	Temp Range (°C)	Product Status	RoHS
1N4685-TP	Micro Commercial Co	3.6	±5%	500	1.5 V @ 100 mA	7.5 µA @ 2 V	-65 to 200	Obsolete	ROHS3
1N4685 TR PBFREE	Central Semiconductor Corp	3.6	±5%	500	1.5 V @ 100 mA	7.5 µA @ 2 V	-65 to 200	Active	ROHS3
1N5227B TR PBFREE	Central Semiconductor Corp	3.6	±5%	500	1.1 V @ 200 mA	15 µA @ 1 V	-65 to 200	Active	ROHS3
1N5227B-T	Vishay General Semiconductor - Diodes Division	3.6	±5%	500	1.1 V @ 200 mA	15 µA @ 1 V	-65 to 175	Obsolete	ROHS3
1N747A BK TIN/LEAD	Central Semiconductor Corp	3.6	±5%	500	1.5 V @ 200 mA	10 µA @ 1 V	-65 to 200	Active	Non-compliant
1N747A TR TIN/LEAD	Central Semiconductor Corp	3.6	±5%	500	1.5 V @ 200 mA	10 µA @ 1 V	-65 to 200	Active	Non-compliant
TZX3V6B-TAP	Vishay General Semiconductor - Diodes Division	3.6	-	500	1.5 V @ 200 mA	5 µA @ 1 V	-65 to 175	Active	ROHS3
TZX3V6B-TR	Vishay General Semiconductor - Diodes Division	3.6	-	500	1.5 V @ 200 mA	5 µA @ 1 V	-65 to 175	Active	ROHS3
TZX3V6C-TAP	Vishay General Semiconductor - Diodes Division	3.6	-	500	1.5 V @ 200 mA	5 µA @ 1 V	-65 to 175	Active	ROHS3
TZX3V6C-TR	Vishay General Semiconductor - Diodes Division	3.6	-	500	1.5 V @ 200 mA	5 µA @ 1 V	-65 to 175	Active	ROHS3

Engineering Selection Recommendations

Primary Recommendation: 1N4685 TR PBFREE

The 1N4685 TR PBFREE manufactured by Central Semiconductor Corp is the direct equivalent to the obsolete 1N4685-TP. This part maintains identical electrical specifications including 3.6 V nominal Zener voltage, 500 mW power rating, ±5% tolerance, and forward voltage characteristics. The part is currently in active production status, ensuring supply chain availability. RoHS3 compliance is maintained, and the extended operating temperature range (-65°C to 200°C) matches the original specification. Tape & Reel packaging is suitable for automated assembly processes.

Secondary Recommendation: 1N5227B TR PBFREE

The 1N5227B TR PBFREE from Central Semiconductor Corp provides functional equivalence with active product status and RoHS3 compliance. This part shares the 3.6 V nominal voltage and 500 mW power rating. Differences include lower forward voltage (1.1 V @ 200 mA versus 1.5 V @ 100 mA) and higher reverse leakage current (15 µA @ 1 V versus 7.5 µA @ 2 V). These characteristics are within acceptable substitution parameters for most circuit applications. High inventory availability (9990 Pcs) supports production continuity.

Automotive-Grade Alternative: TZX3V6B-TR or TZX3V6C-TR

The TZX series from Vishay General Semiconductor - Diodes Division offers automotive-qualified alternatives (AEC-Q101) with active product status and RoHS3 compliance. Both TZX3V6B-TR and TZX3V6C-TR maintain 3.6 V nominal voltage and 500 mW power rating. These parts feature lower reverse leakage current (5 µA @ 1 V) and are suitable for applications requiring automotive-grade reliability. Operating temperature range is -65°C to 175°C. Extensive inventory availability (40532 Pcs for TZX3V6B-TR and 30525 Pcs for TZX3V6C-TR) ensures supply security.

Legacy Compatibility: 1N747A Series

The 1N747A BK TIN/LEAD and 1N747A TR TIN/LEAD from Central Semiconductor Corp provide functional equivalence with active product status. These parts maintain 3.6 V nominal voltage and 500 mW power rating with extended operating temperature range (-65°C to 200°C). RoHS non-compliance status requires evaluation against application regulatory requirements. Tin/lead finish may be restricted in certain markets or applications subject to RoHS directives.

Obsolete Status Consideration: 1N5227B-T

The 1N5227B-T from Vishay General Semiconductor - Diodes Division is classified as obsolete. While this part meets electrical specifications (3.6 V, 500 mW, ±5% tolerance) and carries AEC-Q101 automotive qualification, its discontinued status limits long-term supply availability. This part is suitable only for replacement or repair applications where existing inventory exists.

Frequently Asked Questions (FAQ)

Q: Can the 1N4685-TP be directly replaced with the 1N4685 TR PBFREE?

A: Yes. The 1N4685 TR PBFREE is the direct equivalent manufactured by Central Semiconductor Corp. Both parts share identical nominal Zener voltage (3.6 V), power rating (500 mW), tolerance (±5%), and package configuration (DO-35 axial through-hole). The primary difference is packaging format (Tape & Reel versus bulk) and active product status of the substitute.

Q: What is the difference between the 1N4685-TP and 1N5227B TR PBFREE?

A: Both parts maintain 3.6 V nominal Zener voltage and 500 mW power rating. The 1N5227B TR PBFREE exhibits lower forward voltage (1.1 V @ 200 mA) compared to the 1N4685-TP (1.5 V @ 100 mA), and higher reverse leakage current (15 µA @ 1 V versus 7.5 µA @ 2 V). These differences are within acceptable substitution parameters for standard circuit applications. The 1N5227B TR PBFREE offers superior supply availability with 9990 Pcs in stock.

Q: Are the TZX3V6 series parts suitable replacements for the 1N4685-TP?

A: Yes. The TZX3V6B-TR and TZX3V6C-TR maintain 3.6 V nominal voltage and 500 mW power rating in DO-35 package. These Vishay parts feature lower reverse leakage current (5 µA @ 1 V) and carry AEC-Q101 automotive qualification. Operating temperature range is -65°C to 175°C. These parts are suitable for applications requiring automotive-grade reliability and are currently in active production with extensive inventory availability.

Q: What is the significance of RoHS compliance in selecting a substitute?

A: The 1N4685-TP is ROHS3 compliant. Substitute parts should maintain equivalent RoHS status to ensure regulatory compliance in target markets. The 1N4685 TR PBFREE, 1N5227B TR PBFREE, and TZX series parts are ROHS3 compliant. The 1N747A series parts are RoHS non-compliant and require regulatory evaluation before selection.

Q: Does packaging format affect electrical performance?

A: No. Packaging format (Bulk, Tape & Reel, Cut Tape, Tape & Box) does not affect electrical performance. Packaging selection is determined by assembly process requirements. Tape & Reel and Cut Tape formats support automated assembly. Bulk packaging is suitable for manual assembly or repair applications.

Q: Can I use 1N747A parts as substitutes despite RoHS non-compliance?

A: The 1N747A BK TIN/LEAD and 1N747A TR TIN/LEAD are functionally equivalent to the 1N4685-TP with identical 3.6 V nominal voltage and 500 mW power rating. However, RoHS non-compliance status requires evaluation against application regulatory requirements and target market restrictions. Applications subject to RoHS directives should select ROHS3-compliant alternatives.

Q: What is the difference between TZX3V6B and TZX3V6C variants?

A: Both TZX3V6B and TZX3V6C variants maintain identical electrical specifications (3.6 V nominal voltage, 500 mW power rating, 5 µA reverse leakage @ 1 V). The designation difference reflects internal design variations within the Vishay TZX series. Both variants are suitable for direct substitution and carry AEC-Q101 automotive qualification.

Q: Why is the 1N4685-TP classified as obsolete?

A: The 1N4685-TP is discontinued from the original manufacturer (Micro Commercial Co). Obsolete status indicates that new production has ceased. Active equivalent parts such as 1N4685 TR PBFREE from Central Semiconductor Corp and TZX series from Vishay ensure continued availability for new designs and production requirements.

Q: What operating temperature range should I consider for substitute selection?

A: The 1N4685-TP specifies maximum junction temperature of 200°C. The 1N4685 TR PBFREE and 1N747A series maintain -65°C to 200°C operating range. The TZX series and 1N5227B-T specify -65°C to 175°C. For applications requiring full 200°C maximum junction temperature operation, select 1N4685 TR PBFREE or 1N747A series parts.

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