Diodes Incorporated BZX84C18T-7-F

Overview

BZX84C18T-7-F from Diodes Incorporated is a 150 mW, 18 V nominal Zener diode in SOT-523 package, with ±0.6 V tolerance (16.8–19.1 V), 45 Ω maximum Zener impedance at 5 mA test current, and 0.1 µA maximum reverse leakage at 14 V. It provides precision voltage regulation in low-power analog reference and overvoltage protection circuits.

For engineers reviewing the BZX84C18T-7-F datasheet, BZX84C18T-7-F pinout, BZX84C18T-7-F application, or BZX84C18T-7-F equivalent, key selection criteria include Zener voltage tolerance, dynamic impedance at I_ZT, thermal resistance (833 °C/W), reverse leakage at VR, and SOT-523 footprint compatibility for space-constrained PCB layouts.

Technical Context

This device uses planar die construction to ensure stable Zener breakdown characteristics and tight voltage distribution across production lots. Its ultra-small SOT-523 package supports high-density mounting while maintaining thermal performance up to +150 °C junction temperature.

The diode operates with a specified test current of 5 mA for Zener voltage measurement and exhibits a temperature coefficient of +12.4 to +16.0 mV/°C - enabling predictable drift compensation in temperature-sensitive references.

Key Specifications

Pinout & Package

Package: SOT-523 - ultra-compact surface-mount plastic case (1.60 mm × 0.80 mm × 0.50 mm), UL 94V-0 rated, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener diode applications.

Compared with MMBZ5245B-7-F and BZX84-C18LT1G, BZX84C18T-7-F uniquely balances ultra-compact size, full RoHS compliance, and verified 150 mW derating behavior - making it optimal for new designs targeting miniaturization and regulatory alignment.

Availability

BZX84C18T-7-F is available at Aetrix Electronics and suitable for portable power management, industrial sensor signal conditioning, and automotive body control module designs requiring stable component supply and long-term lifecycle support.

Supply support for BZX84C18T-7-F includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, serving industrial, computing, consumer, and communications markets.

The BZX84 series belongs to Diodes' standard Zener diode product line, engineered specifically for cost-effective, high-volume voltage regulation and protection in space-constrained surface-mount applications.

FAQ

What is the maximum reverse voltage (VR) at which leakage current is guaranteed?

The datasheet specifies 0.1 µA maximum reverse current at VR = 14 V. This is not the absolute maximum reverse voltage - the device is rated for 18 V nominal Zener operation, and its absolute maximum reverse voltage before breakdown is defined by the 16.8–19.1 V range at I_ZT = 5 mA. Operation above 19.1 V risks uncontrolled conduction or thermal runaway without current limiting.

Can BZX84C18T-7-F be used in series or parallel configurations?

Series connection is acceptable for higher-voltage references if matched units are used and thermal coupling is ensured. Parallel use is strongly discouraged due to mismatched Zener impedances causing current hogging - even small V_Z variations (±0.6 V) result in unequal current sharing and potential thermal failure of the lower-V_Z unit.

Is the SOT-523 package compatible with standard reflow profiles?

Yes - the SOT-523 package is qualified for lead-free reflow per J-STD-020D Level 1 moisture sensitivity. Recommended peak temperature is 260 °C for ≤10 seconds, with ramp rates and soak profiles matching IPC/JEDEC J-STD-020. The 0.002 g mass enables rapid, uniform heating without tombstoning.

How does temperature affect Zener voltage accuracy in practical use?

At 5 mA test current, the temperature coefficient is +12.4 to +16.0 mV/°C - meaning a +50 °C rise from 25 °C increases V_Z by ~0.62–0.80 V. For high-accuracy applications, this drift must be compensated via circuit design (e.g., using complementary TC components) or limited to narrow ambient ranges (<10 °C variation).