NXP Semiconductors BZX284-B51,115

Overview

BZX284-B51,115 from NXP Semiconductors is a ±2% tolerance Zener voltage regulator diode in a SOD110 ceramic SMD package, rated for 51.0 V nominal working voltage at 5 mA test current, 400 mW total power dissipation, and 45 Ω typical differential resistance. It serves as a precision low-power voltage reference in power supply feedback loops, overvoltage protection circuits, and analog signal conditioning stages.

For engineers reviewing the BZX284-B51,115 datasheet, BZX284-B51,115 pinout, BZX284-B51,115 application, or BZX284-B51,115 equivalent, key selection considerations include its ±2% voltage tolerance, 51 V regulation point, SOD110 footprint compatibility, thermal resistance of 315 K/W, and reverse leakage of ≤2 µA at 2 V.

Technical Context

The BZX284-B51,115 operates as a two-terminal silicon Zener diode optimized for stable reverse-bias breakdown regulation. Its junction temperature range spans −65 °C to +150 °C, with a maximum non-repetitive peak reverse current of 0.4 A under 100 µs surge conditions.

It exhibits a positive temperature coefficient of +35 mV/K at 5 mA, enabling predictable voltage drift compensation in temperature-sensitive designs. The device's 51.0 V nominal Zener voltage is specified at I_Ztest = 5 mA, with differential resistance measured at 45 Ω (typ) and 350 Ω (max), supporting stable regulation under varying load currents.

Key Specifications

Pinout & Package

SOD110 is a two-terminal ceramic surface-mount package with cathode marked by a band on one end. No separate pin numbering applies-Terminal 1 is anode, Terminal 2 is cathode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX284-B51,115, the MMBZ5257B trades ±2% accuracy and 400 mW headroom for lower cost and smaller footprint, while the BZX84-C51 sacrifices leakage performance and thermal robustness for improved manufacturability-making the BZX284-B51,115 optimal for production-grade precision regulation where long-term stability and ceramic reliability are required.

Availability

BZX284-B51,115 is available at Aetrix Electronics and suitable for power supply feedback references, overvoltage clamp protection, analog signal level translation, and temperature-compensated bias networks requiring stable component supply and long-lifecycle support.

Supply support for BZX284-B51,115 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and consumer markets.

The BZX284 series was designed as a family of low-power, high-stability Zener diodes targeting precision voltage reference and protection functions in space-constrained, high-reliability applications such as telecom infrastructure and industrial control systems.

FAQ

What is the nominal Zener voltage and test condition for BZX284-B51,115?

The BZX284-B51,115 has a nominal Zener voltage of 51.0 V, specified at a test current of 5 mA (I_Ztest = 5 mA). This value falls within the ±2% tolerance band (50.0 V to 52.0 V), and the device achieves this regulation point with a typical differential resistance of 45 Ω. The BZX284-B51,115 must be operated in reverse bias above its knee voltage to maintain stable regulation behavior.

What package type does BZX284-B51,115 use and what are its key mechanical dimensions?

The BZX284-B51,115 uses the SOD110 very small ceramic surface-mount package, measuring 2.10 mm × 1.40 mm × 1.60 mm (length × width × height). It features a cathode identification band and is designed for reflow soldering on standard PCBs. The SOD110 package provides superior moisture resistance and long-term parameter stability compared to plastic alternatives like SOT-23, making the BZX284-B51,115 suitable for harsh-environment deployments.

How does the temperature coefficient of BZX284-B51,115 affect its regulation performance?

The BZX284-B51,115 exhibits a positive temperature coefficient of +35 mV/K at I_Z = 5 mA, meaning its Zener voltage increases predictably with junction temperature. This characteristic allows designers to compensate for negative-tempco components (e.g., transistors or thermistors) in bias networks. Because the coefficient is well-characterized and stable across the −65 °C to +150 °C range, the BZX284-B51,115 supports repeatable thermal drift modeling in precision analog circuits.

What is the maximum allowable power dissipation for BZX284-B51,115 and how is it thermally limited?

The BZX284-B51,115 has a maximum total power dissipation of 400 mW at ambient temperature (T_amb = 25 °C), with a junction-to-ambient thermal resistance (R_{th j-a}) of 315 K/W. This means that at full 400 mW dissipation, the junction temperature rises approximately 126 °C above ambient-requiring careful derating above 25 °C. For example, at 70 °C ambient, the safe continuous power drops to ~275 mW to keep T_j ≤ 150 °C. The BZX284-B51,115 must be mounted on a standard 11 × 25 × 1.6 mm PCB for these ratings to apply.

Can BZX284-B51,115 be used as a direct replacement for BZX284-C51,115 in existing designs?

No-BZX284-B51,115 and BZX284-C51,115 share the same nominal voltage (51 V) and SOD110 package but differ critically in tolerance (±2% vs. ±5%) and electrical parameters including differential resistance and leakage. The BZX284-B51,115 has tighter regulation, lower leakage (≤2 µA vs. ≤5 µA), and higher power capability (400 mW vs. 400 mW, but with different thermal profiles due to variant-specific characterization). Substituting BZX284-B51,115 into a design originally qualified with BZX284-C51,115 requires revalidation of regulation accuracy, thermal margin, and transient response.