BZX84B18-TP Equivalent & Substitute Parts

Part Overview

The BZX84B18-TP is an 18 V, 350 mW Zener diode manufactured by Micro Commercial Co in a surface mount SOT-23 package. This component is classified as Active and is ROHS3 compliant. The BZX84B18-TP serves as a voltage regulation and transient protection element in electronic circuits requiring stable 18 V reference voltage with moderate power dissipation capability. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and design continuity across manufacturing environments.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	18	V
Tolerance	±2%	—
Power - Maximum	350	mW
Impedance (Maximum)	45	Ohms
Current - Reverse Leakage @ Vr	100	nA @ 12.6 V
Voltage - Forward (Maximum) @ If	900	mV @ 10 mA
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Supplier Device Package	SOT-23	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the BZX84B18-TP are identified based on strict electrical and mechanical parameter alignment. The primary substitution criteria are:

Critical Parameters for Substitution:

Zener voltage nominal value: 18 V
Package type: SOT-23 (TO-236-3, SC-59, SOT-23-3)
Mounting type: Surface Mount
Operating temperature range compatibility
RoHS3 compliance status

Parametric Equivalent Classification: The BZX84B18HE3-TP is classified as a parametric equivalent. This part maintains identical electrical specifications (18 V nominal, ±2% tolerance, 350 mW power rating, 45 Ohms impedance) and identical package configuration. The primary distinction is automotive-grade qualification (AEC-Q101) and higher inventory availability.

Similar Part Classification: The BZX84B18LT1G is classified as a similar part. While it maintains the 18 V nominal zener voltage and SOT-23 package compatibility, it differs in power rating (225 mW versus 350 mW), tolerance (±6% versus ±2%), and reverse leakage current (50 nA versus 100 nA). This part is suitable for applications with lower power dissipation requirements and less stringent voltage tolerance specifications.

Parameter Comparison

Parameter	BZX84B18-TP	BZX84B18HE3-TP	BZX84B18LT1G
Manufacturer	Micro Commercial Co	Micro Commercial Co	onsemi
Voltage - Zener (Nom)	18 V	18 V	18 V
Tolerance	±2%	±2%	±6%
Power - Max	350 mW	350 mW	225 mW
Impedance (Max)	45 Ohms	45 Ohms	45 Ohms
Current - Reverse Leakage @ Vr	100 nA @ 12.6 V	100 nA @ 12.6 V	50 nA @ 12.6 V
Voltage - Forward (Max) @ If	900 mV @ 10 mA	900 mV @ 10 mA	900 mV @ 10 mA
Operating Temperature	-55°C ~ 150°C	-55°C ~ 150°C	-65°C ~ 150°C
Package / Case	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3
Mounting Type	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Product Status	Active	Active	Active
Automotive Grade	—	AEC-Q101	—

Engineering Selection Recommendations

BZX84B18HE3-TP Selection Criteria: The BZX84B18HE3-TP is a direct parametric equivalent suitable for applications requiring identical electrical performance to the BZX84B18-TP. This part carries AEC-Q101 automotive qualification, making it appropriate for automotive and industrial applications subject to automotive-grade component requirements. Both parts maintain Active product status and ROHS3 compliance. The BZX84B18HE3-TP is selected when automotive-grade certification is a design requirement or when higher inventory availability is advantageous.

BZX84B18LT1G Selection Criteria: The BZX84B18LT1G is a similar part suitable for applications where power dissipation requirements are lower than 350 mW and voltage tolerance of ±6% is acceptable. This part is manufactured by onsemi and maintains Active product status with ROHS3 compliance. The extended operating temperature range (-65°C minimum versus -55°C) provides additional thermal margin in low-temperature environments. The BZX84B18LT1G is selected when circuit design permits reduced power rating and relaxed tolerance specifications, or when onsemi component qualification is required.

Frequently Asked Questions (FAQ)

Q: Can BZX84B18HE3-TP be used as a direct replacement for BZX84B18-TP?

A: Yes. The BZX84B18HE3-TP is a parametric equivalent with identical electrical specifications (18 V nominal, ±2% tolerance, 350 mW power rating) and identical package configuration (SOT-23). Both parts are manufactured by Micro Commercial Co and maintain identical operating temperature ranges and compliance certifications.

Q: What are the limitations of using BZX84B18LT1G as a substitute?

A: The BZX84B18LT1G differs in three key parameters: maximum power rating (225 mW versus 350 mW), voltage tolerance (±6% versus ±2%), and reverse leakage current (50 nA versus 100 nA). This part is suitable only for applications where these reduced specifications are acceptable. Circuits designed for 350 mW dissipation or requiring ±2% voltage accuracy must not use this substitute.

Q: Are all three parts compatible with the same PCB footprint?

A: Yes. All three parts use the SOT-23 package (TO-236-3, SC-59, SOT-23-3) and are surface mount components. PCB footprints are mechanically and electrically compatible across all three parts.

Q: What is the significance of AEC-Q101 qualification on the BZX84B18HE3-TP?

A: AEC-Q101 is an automotive industry qualification standard. The BZX84B18HE3-TP carries this certification, making it suitable for automotive applications and environments subject to automotive-grade component requirements. The BZX84B18-TP and BZX84B18LT1G do not carry this certification.

Q: Which part should be selected for high-reliability applications?

A: Selection depends on specific application requirements. The BZX84B18HE3-TP is appropriate for automotive and industrial high-reliability applications due to AEC-Q101 qualification. The BZX84B18-TP is appropriate for general commercial applications. The BZX84B18LT1G is appropriate for applications with lower power dissipation requirements and relaxed tolerance specifications.

Q: Are moisture sensitivity levels identical across all three parts?

A: Yes. All three parts carry Moisture Sensitivity Level 1 (Unlimited), indicating no moisture sensitivity restrictions during storage, handling, or assembly.

Q: What is the inventory status of each part?

A: BZX84B18-TP: 896 Pcs New Original In Stock. BZX84B18HE3-TP: 6360 Pcs New Original In Stock. BZX84B18LT1G: 23400 Pcs New Original In Stock.

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