BZX84C12 Equivalent & Substitute Parts

Part Overview

The BZX84C12 is a surface mount Zener diode rated at 12 V nominal with 350 mW maximum power dissipation in a SOT-23-3 package. Manufactured by onsemi, this component is classified as obsolete. The BZX84C12 is used in voltage regulation and protection circuits where a 12 V reference voltage is required in compact surface mount applications.

Due to its obsolete product status, equivalent and substitute parts from active manufacturers are necessary for new designs and ongoing production requirements. Substitute components maintain the core electrical specifications while offering improved availability and compliance certifications.

Substiute Parts

BZX84C12

onsemiIn Stock: 44199BZX84C12 Datasheet

Current PartRFQ

BZX84C12LT1G

onsemiIn Stock: 312625BZX84C12LT1G Datasheet

SimilarRFQ

BZX84C12 TR PBFREE

Central Semiconductor CorpIn Stock: 10719BZX84C12 TR PBFREE Datasheet

DirectRFQ

BZX84C12-7-F

Diodes IncorporatedIn Stock: 20341BZX84C12-7-F Datasheet

UpgradeRFQ

BZX84-C12,215

Nexperia USA Inc.In Stock: 407074BZX84-C12,215 Datasheet

SimilarRFQ

BZX84-C12,235

Nexperia USA Inc.In Stock: 19476BZX84-C12,235 Datasheet

SimilarRFQ

BZX84C12_R1_00001

Panjit International Inc.In Stock: 4039BZX84C12_R1_00001 Datasheet

SimilarRFQ

CMPZ5242B BK PBFREE

Central Semiconductor CorpIn Stock: 774CMPZ5242B BK PBFREE Datasheet

SimilarRFQ

CMPZ5242B TR PBFREE

Central Semiconductor CorpIn Stock: 25604CMPZ5242B TR PBFREE Datasheet

SimilarRFQ

BZX84B12-TP

Micro Commercial CoIn Stock: 924BZX84B12-TP Datasheet

Parametric EquivalentRFQ

BZX84C12-TP

Micro Commercial CoIn Stock: 43704BZX84C12-TP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BZX84C12 is determined by the following critical parameters:

Electrical Specifications:

• Zener voltage: 12 V nominal (core requirement)
• Tolerance: ±5% (acceptable range for voltage regulation)
• Power dissipation: 350 mW maximum (or lower ratings acceptable for reduced power applications)
• Impedance: 25 Ohms maximum
• Reverse leakage current: 100 nA @ 8 V (or lower acceptable)
• Forward voltage: 900 mV @ 10 mA maximum

Mechanical & Environmental:

• Package: SOT-23-3 / TO-236-3 / SC-59 (identical physical form factor)
• Mounting: Surface Mount (required for PCB compatibility)
• Operating temperature: -55°C to 150°C minimum (extended range acceptable)
• Moisture sensitivity: MSL 1 (Unlimited)

Substitute parts are grouped by their relationship to the main part:

Direct Substitutes: Parts with identical electrical specifications and packaging from different manufacturers.

Similar Substitutes: Parts with equivalent core specifications but variations in power rating, tolerance, or temperature range that remain functionally compatible.

Parametric Equivalents: Parts with enhanced specifications (tighter tolerance, higher power rating, or extended temperature range) that provide superior performance while maintaining backward compatibility.

Parameter Comparison

Engineering Selection Recommendations

Direct Replacement (Identical Specifications):

BZX84C12-TP (Micro Commercial Co) and BZX84C12 TR PBFREE (Central Semiconductor Corp) are direct functional replacements for the obsolete BZX84C12. Both maintain 12 V nominal voltage, ±5% tolerance, 350 mW power rating, and SOT-23-3 packaging. Both are ROHS3 compliant and active products with extended temperature ranges (-65°C to 150°C or -55°C to 150°C).

Active Manufacturer Alternatives with Reduced Power Rating:

BZX84C12LT1G (onsemi), BZX84-C12,215 (Nexperia), and BZX84-C12,235 (Nexperia) are active products with identical voltage and tolerance specifications but reduced power dissipation (250 mW). These are suitable for applications where the full 350 mW rating is not required. Nexperia parts include AEC-Q101 automotive qualification. All are ROHS3 compliant with extended temperature ranges.

Enhanced Tolerance Option:

BZX84B12-TP (Micro Commercial Co) provides tighter voltage tolerance (±2% versus ±5%) while maintaining 350 mW power rating and SOT-23-3 packaging. This part is suitable for applications requiring improved voltage regulation accuracy.

Higher Power Rating Option:

BZX84C12_R1_00001 (Panjit International Inc.) offers 410 mW maximum power dissipation, providing additional thermal margin for high-current applications while maintaining 12 V nominal voltage and ±5% tolerance.

Impedance Consideration:

CMPZ5242B variants (Central Semiconductor Corp) have 30 Ohms maximum impedance compared to 25 Ohms for other options. This represents a 20% increase in dynamic impedance and may affect voltage regulation performance in sensitive applications.

All substitute parts are ROHS3 compliant, MSL 1 (Unlimited), and available in active production status.

Frequently Asked Questions (FAQ)

Q: Can BZX84C12LT1G replace the obsolete BZX84C12 in all applications?

A: BZX84C12LT1G is electrically compatible for voltage regulation and protection functions. The primary difference is reduced power dissipation (250 mW versus 350 mW). Applications requiring continuous power dissipation below 250 mW can use this part directly. Applications requiring the full 350 mW rating require BZX84C12-TP or BZX84C12 TR PBFREE.

Q: What is the difference between BZX84-C12,215 and BZX84-C12,235?

A: Both parts are manufactured by Nexperia with identical electrical specifications (12 V, ±5%, 250 mW, SOT-23-3). The difference is packaging format: BZX84-C12,215 is supplied in Cut Tape (CT) & Digi-Reel format, while BZX84-C12,235 is supplied in Tape & Reel (TR) format. Both include AEC-Q101 automotive qualification.

Q: Is BZX84B12-TP a suitable replacement for BZX84C12?

A: BZX84B12-TP is functionally compatible with identical 12 V voltage, 350 mW power rating, and SOT-23-3 packaging. The key difference is tighter voltage tolerance (±2% versus ±5%). This part is suitable for all BZX84C12 applications and provides improved voltage regulation accuracy.

Q: Why do some substitute parts have different impedance values?

A: Impedance (Zzt) is a dynamic parameter affecting voltage regulation under load changes. The BZX84C12 specifies 25 Ohms maximum. CMPZ5242B variants specify 30 Ohms maximum. For applications with strict voltage regulation requirements, parts with 25 Ohms impedance are preferred. For general voltage reference applications, 30 Ohms impedance is acceptable.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. The obsolete BZX84C12 does not have RoHS status specified. All substitutes are suitable for applications requiring RoHS compliance.

Q: What is the temperature range difference between substitute parts?

A: The original BZX84C12 operates from -55°C to 150°C. Most active substitutes extend the lower temperature limit to -65°C, providing improved cold-temperature performance. BZX84B12-TP and BZX84C12-TP maintain the -55°C lower limit. For applications operating below -55°C, extended-range parts are required.

Q: Can CMPZ5242B parts be used as direct replacements?

A: CMPZ5242B variants are electrically compatible with 12 V nominal voltage, ±5% tolerance, and 350 mW power rating in SOT-23-3 packaging. The 30 Ohms maximum impedance (versus 25 Ohms) and 1 µA reverse leakage current (versus 100 nA) represent minor parameter variations. These parts are suitable for general voltage regulation applications but may not be optimal for precision voltage reference circuits.

Q: What packaging options are available for substitute parts?

A: Substitute parts are available in multiple packaging formats: Cut Tape (CT) & Digi-Reel, Tape & Reel (TR), and Bulk. All maintain the SOT-23-3 physical form factor. Selection depends on production volume and assembly equipment compatibility. High-volume production typically uses Tape & Reel format.