Nexperia USA Inc. BZX84-C15/DG/B3,21

Overview

BZX84-C15/DG/B3,21 from Nexperia is a ±5 % tolerance Zener voltage regulator diode in SOT23 (TO-236AB) package, rated for 15 V nominal breakdown at 5 mA, with 250 mW total power dissipation and 75 Ω typical differential resistance - used for precision low-power voltage reference and overvoltage clamping in power supply feedback paths and sensor biasing circuits.

For engineers reviewing the BZX84-C15/DG/B3,21 datasheet, BZX84-C15/DG/B3,21 pinout, BZX84-C15/DG/B3,21 application, or BZX84-C15/DG/B3,21 equivalent, this part supports stable 15 V regulation under 5 mA test current, operates up to +150 °C junction temperature, and delivers <1 μA reverse leakage at 12 V - critical for low-quiescent-current LDO supervision and analog front-end protection.

Technical Context

This Zener diode operates in reverse-biased avalanche mode to maintain a stable 15 V reference across its cathode-anode terminals when reverse current exceeds the knee threshold (~1 mA). Its ±5 % tolerance (13.8 V–15.6 V range at I_Z = 5 mA) and 0.05 mV/K temperature coefficient enable predictable drift behavior in ambient-temperature-varying circuits.

The device features non-repetitive peak reverse power dissipation of 40 W (100 μs pulse), thermal resistance from junction to ambient of 500 K/W on FR4 PCB, and forward voltage ≤0.9 V at 10 mA - supporting both regulation and transient suppression roles without external heatsinking in space-constrained designs.

Key Specifications

Pinout & Package

SOT23 (TO-236AB) plastic surface-mounted package with 3 leads; 1.3 mm × 2.9 mm footprint, 1.1 mm height, and gull-wing lead form compatible with standard reflow soldering profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ5245BS and BZX84-C15-TP, the BZX84-C15/DG/B3,21 offers optimal balance of low dynamic impedance (75 Ω), industry-standard 250 mW rating, and proven long-term stability in Nexperia's production process - making it ideal for cost-sensitive, volume-manufactured industrial controls.

Availability

BZX84-C15/DG/B3,21 is available at Aetrix Electronics and suitable for power supply feedback references, sensor biasing networks, overvoltage clamp protection, and low-power voltage monitors requiring stable component supply and consistent parametric performance across manufacturing lots.

Supply support for BZX84-C15/DG/B3,21 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability discrete and logic devices, with leadership in advanced packaging and automotive-grade qualification.

The BZX84 series belongs to Nexperia's general-purpose Zener diode product line, designed specifically for cost-effective, space-efficient voltage regulation and protection in consumer, industrial, and computing applications.

FAQ

What is the maximum continuous reverse current for stable 15 V regulation?

The BZX84-C15/DG/B3,21 maintains stable regulation at I_Z = 5 mA per datasheet test condition. Continuous operation up to 20 mA is permitted within its 250 mW power limit (T_amb ≤ 25 °C), but voltage drift increases beyond 10 mA due to self-heating and r_dif effects - design should target 2–8 mA for optimal accuracy and thermal margin.

Can this Zener be used in series for higher voltage references?

Yes - two BZX84-C15/DG/B3,21 diodes in series provide ~30 V regulation, but tolerance compounds to ±10 % (27–33 V), and thermal tracking between devices is uncontrolled. For >20 V references, a single higher-voltage Zener (e.g., BZX84-C30) is preferred to minimize drift and layout complexity.

Is the n.c. pin electrically isolated or thermally coupled?

Pin 2 is internally not connected - no bond wire or die attachment exists. It is electrically isolated and provides no thermal conduction path; however, its metal pad may slightly reduce local thermal resistance if soldered to a large copper pour, though this effect is not characterized or guaranteed in the datasheet.

How does temperature affect regulation accuracy at 15 V?

At I_Z = 5 mA, the temperature coefficient is +0.05 mV/K (typical), meaning output voltage increases by ~0.75 mV per °C rise from 25 °C. Over –40 °C to +125 °C, total drift is approximately ±7.5 mV - negligible for most 15 V applications but relevant in precision analog systems requiring sub-0.1 % stability.