LZ52C18WS Equivalent & Substitute Parts

Part Overview

The LZ52C18WS is a Zener diode manufactured by Diodes Incorporated, rated at 18 V nominal with 500 mW maximum power dissipation. This component is packaged in a 1206 surface mount configuration and features ±2% voltage tolerance. The part is classified as obsolete, necessitating identification of active equivalent components that maintain functional compatibility while meeting current supply chain requirements. Substitute parts must satisfy the core electrical specifications: 18 V Zener voltage, surface mount technology, and comparable power handling characteristics.

Substiute Parts

LZ52C18WS

Diodes IncorporatedIn Stock: 957LZ52C18WS Datasheet

Current PartRFQ

BZT52C18S-7-F

Diodes IncorporatedIn Stock: 7920BZT52C18S-7-F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LZ52C18WS is determined by the following critical electrical and mechanical parameters:

Primary Matching Criteria:

• Zener voltage: 18 V nominal (core functional requirement)
• Surface mount technology (mechanical compatibility)
• RoHS3 compliance (regulatory requirement)

Secondary Compatibility Factors:

• Power dissipation rating (affects thermal performance and circuit reliability)
• Voltage tolerance (affects circuit precision)
• Operating temperature range (affects application suitability)
• Package form factor (affects PCB layout compatibility)

The substitute part BZT52C18S-7-F maintains the 18 V Zener voltage specification and surface mount technology. However, this substitute operates at reduced maximum power (200 mW versus 500 mW) and features a different package form (SOD-323 versus 1206). These differences establish a conditional substitution relationship where the substitute is suitable for applications with lower power requirements and compatible PCB layouts.

Parameter Comparison

Engineering Selection Recommendations

LZ52C18WS (Obsolete): The LZ52C18WS is classified as obsolete and no longer in active production. While 896 pieces remain in inventory, this part is not recommended for new designs or long-term production commitments due to supply discontinuation.

BZT52C18S-7-F (Active Substitute): The BZT52C18S-7-F is an active product with 7908 pieces in current inventory. This substitute maintains the 18 V Zener voltage specification and RoHS3 compliance. Selection of this substitute is appropriate when:

• Circuit power dissipation requirements do not exceed 200 mW
• PCB layout accommodates SOD-323 package dimensions
• Voltage tolerance of ±6% satisfies circuit precision requirements
• Operating temperature range of -65°C to 150°C is sufficient for the application

The reduced maximum power rating and narrower operating temperature range represent the primary design constraints when implementing this substitute.

Frequently Asked Questions (FAQ)

Q: Can BZT52C18S-7-F directly replace LZ52C18WS in all applications?

A: No. The substitute operates at 200 mW maximum power versus 500 mW for the original part. Direct substitution is limited to applications where power dissipation does not exceed 200 mW. Additionally, the SOD-323 package requires PCB layout modification compared to the 1206 package.

Q: What is the impact of the ±6% tolerance on BZT52C18S-7-F compared to ±2% on LZ52C18WS?

A: The wider tolerance on the substitute introduces greater variation in Zener voltage. For applications requiring precise voltage regulation, this difference may affect circuit performance. The original ±2% tolerance provides tighter voltage control.

Q: Are both parts RoHS3 compliant?

A: Yes. Both LZ52C18WS and BZT52C18S-7-F are RoHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: What is the difference between the 1206 and SOD-323 packages?

A: The 1206 package (3216 Metric) is a larger surface mount component suitable for higher power dissipation. The SOD-323 package is a smaller form factor designed for space-constrained applications with lower power requirements. PCB footprints are not interchangeable.

Q: Why is the operating temperature range different?

A: The LZ52C18WS operates from -65°C to 175°C, while BZT52C18S-7-F operates from -65°C to 150°C. Applications requiring operation above 150°C cannot use the substitute without thermal management modifications.

Q: Is the impedance difference significant?

A: The impedance values are comparable (50 Ohms versus 45 Ohms), representing a 10% difference. This minor variation does not typically affect circuit functionality in standard Zener diode applications.

Q: What is the reverse leakage current specification?

A: Both parts specify 100 nA reverse leakage current at slightly different reference voltages (13 V for LZ52C18WS, 12.6 V for BZT52C18S-7-F). This leakage characteristic is equivalent for practical circuit applications.