1N5231B-TP Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N5231B-TP is a 5.1 V, 500 mW Zener diode manufactured by Micro Commercial Co in a DO-35 through-hole package. This component is classified as obsolete, necessitating identification of equivalent and substitute parts for ongoing design support and procurement. The 1N5231B-TP serves voltage regulation and protection applications requiring precise 5.1 V Zener characteristics with 500 mW power dissipation capability.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	5.1	V
Tolerance	±5%	%
Power - Max	500	mW
Impedance (Max)	17	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 2 V
Voltage - Forward (Vf) (Max) @ If	1.1	V @ 200 mA
Operating Temperature	-55 to 150	°C
Mounting Type	Through Hole
Package / Case	DO-204AH, DO-35, Axial

Substitute Part Grouping Explanation

Substitution of the 1N5231B-TP is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nom): 5.1 V (exact match required)
Power - Max: 500 mW (minimum requirement)
Tolerance: ±5% (electrical specification match)
Mounting Type: Through Hole (mechanical compatibility)
Package / Case: DO-35 or DO-204AH (physical form factor)

Substitution Categories:

Parametric Equivalents maintain all electrical and mechanical specifications identical to the 1N5231B-TP, differing only in manufacturer or product status.

Upgrade Substitutes provide identical electrical performance with enhanced operating temperature ranges (-65°C to 200°C versus -55°C to 150°C) and active product status, enabling long-term availability.

Similar Substitutes share the 5.1 V Zener voltage and DO-35 package but differ in power rating, impedance, or other secondary parameters. These are suitable only when application requirements permit deviation from the 500 mW specification.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Vf @ If (V)	Temp Range (°C)	Product Status	RoHS Status
1N5231B-TP	Micro Commercial Co	5.1	±5%	500	17	1.1 @ 200 mA	-55 to 150	Obsolete	ROHS3 Compliant
1N5231B BK PBFREE	Central Semiconductor Corp	5.1	±5%	500	17	1.1 @ 200 mA	-65 to 200	Active	ROHS3 Compliant
1N5231B TR PBFREE	Central Semiconductor Corp	5.1	±5%	500	17	1.1 @ 200 mA	-65 to 200	Active	ROHS3 Compliant
1N4625 TR PBFREE	Central Semiconductor Corp	5.1	±5%	250	1500	1.0 @ 200 mA	-65 to 200	Active	ROHS3 Compliant
1N5231B	Microchip Technology	5.1	±5%	500	17	1.5 @ 200 mA	-65 to 175	Active	RoHS non-compliant
1N5231BTR	onsemi	5.1	±5%	500	17	1.2 @ 200 mA	-65 to 200	Active	ROHS3 Compliant
BZX55C5V1-TR	Vishay General Semiconductor - Diodes Division	5.1	-	500	35	1.5 @ 200 mA	-65 to 175	Active	ROHS3 Compliant
BZX79C5V1-T50A	onsemi	5.1	±5%	500	60	1.5 @ 100 mA	-65 to 200	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Replacement (Parametric Equivalents):

The 1N5231B BK PBFREE and 1N5231B TR PBFREE from Central Semiconductor Corp are parametric equivalents with identical electrical specifications (5.1 V, 500 mW, 17 Ohms impedance, ±5% tolerance). Both are active products with ROHS3 compliance. The TR PBFREE variant in cut tape packaging offers higher inventory availability (5213 units) compared to the BK PBFREE bulk variant (923 units). These parts are suitable for direct substitution without circuit redesign.

Upgrade Substitutes (Enhanced Operating Range):

The 1N5231BTR from onsemi provides identical electrical performance with extended operating temperature range (-65°C to 200°C) and active product status. This part is suitable for applications requiring enhanced thermal performance or long-term supply assurance.

Conditional Substitutes (Power Rating Reduction):

The 1N4625 TR PBFREE from Central Semiconductor Corp shares the 5.1 V Zener voltage but operates at 250 mW maximum power (50% of the 1N5231B-TP rating). This part is suitable only for applications where the circuit design permits reduced power dissipation capability. The significantly higher impedance (1500 Ohms versus 17 Ohms) indicates different dynamic characteristics and requires circuit validation.

Alternative Manufacturers (Equivalent Performance):

The 1N5231B from Microchip Technology and BZX55C5V1-TR from Vishay provide 5.1 V, 500 mW operation in DO-35 packages. The Microchip variant carries RoHS non-compliance status. The Vishay BZX55C5V1-TR includes AEC-Q101 automotive qualification and higher impedance (35 Ohms), suitable for automotive applications requiring qualification documentation.

The BZX79C5V1-T50A from onsemi operates at 5.1 V, 500 mW with higher impedance (60 Ohms) and reduced reverse leakage (2 µA @ 2 V), providing alternative performance characteristics for specific circuit requirements.

Frequently Asked Questions (FAQ)

Q: Can the 1N5231B-TP be directly replaced with the 1N4625 TR PBFREE?

A: The 1N4625 TR PBFREE shares the 5.1 V Zener voltage and DO-35 package but operates at 250 mW maximum power versus 500 mW for the 1N5231B-TP. Direct substitution is not recommended without circuit analysis confirming that the application does not require the full 500 mW power dissipation capability. The impedance difference (1500 Ohms versus 17 Ohms) also affects voltage regulation characteristics.

Q: What is the difference between 1N5231B BK PBFREE and 1N5231B TR PBFREE?

A: Both parts are from Central Semiconductor Corp with identical electrical specifications (5.1 V, 500 mW, ±5% tolerance, 17 Ohms impedance). The difference is packaging: BK PBFREE is supplied in bulk, while TR PBFREE is supplied in cut tape. The TR PBFREE variant has significantly higher inventory availability (5213 units versus 923 units). Selection depends on procurement and assembly requirements.

Q: Is the 1N5231B from Microchip Technology a suitable replacement?

A: The Microchip 1N5231B provides identical electrical specifications (5.1 V, 500 mW, ±5% tolerance, 17 Ohms impedance) and active product status. However, this variant carries RoHS non-compliance status, whereas the original 1N5231B-TP is ROHS3 compliant. Use of the Microchip variant requires verification that RoHS non-compliance is acceptable for the application and end-use market.

Q: What are the advantages of the 1N5231BTR from onsemi?

A: The 1N5231BTR maintains identical electrical specifications to the 1N5231B-TP (5.1 V, 500 mW, ±5% tolerance, 17 Ohms impedance) while providing an extended operating temperature range (-65°C to 200°C versus -55°C to 150°C). Active product status ensures long-term availability. This part is suitable for applications requiring enhanced thermal performance or extended temperature operation.

Q: Can the BZX55C5V1-TR from Vishay be used as a substitute?

A: The BZX55C5V1-TR operates at 5.1 V, 500 mW in a DO-35 package, meeting the primary electrical and mechanical requirements. However, the impedance is 35 Ohms versus 17 Ohms for the 1N5231B-TP, and reverse leakage is significantly lower (100 nA @ 1 V versus 5 µA @ 2 V). The part includes AEC-Q101 automotive qualification. Substitution is suitable for applications where the different impedance and leakage characteristics are acceptable or beneficial.

Q: What does the impedance parameter indicate for Zener diode substitution?

A: Impedance (Zzt) affects the dynamic voltage regulation characteristics of the Zener diode. Lower impedance (17 Ohms for 1N5231B-TP) provides better voltage regulation under varying load conditions. Higher impedance (1500 Ohms for 1N4625, 60 Ohms for BZX79C5V1-T50A) results in greater voltage variation with load changes. Substitution with different impedance values requires circuit analysis to confirm acceptable performance.

Q: Are all substitute parts available in the same DO-35 package?

A: All substitute parts listed are available in DO-35 or DO-204AH packages, which are mechanically compatible. Packaging variants (bulk, cut tape) differ by supplier but do not affect electrical performance or physical form factor compatibility with through-hole PCB designs.

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