Nexperia USA Inc. BZX79-B4V3,133

Overview

BZX79-B4V3,133 from Nexperia is a ±2% tolerance Zener voltage regulator diode in a hermetically sealed SOD27 (DO-35) glass package, designed for low-power voltage reference and stabilization at 4.3 V nominal with 5 mA test current, 410 Ω typical differential resistance, and −2.5 mV/K temperature coefficient. It operates within −65 °C to +200 °C junction temperature range and supports applications requiring stable biasing in analog sensor interfaces and power supply feedback networks.

For engineers reviewing the BZX79-B4V3,133 datasheet, BZX79-B4V3,133 pinout, BZX79-B4V3,133 application, or BZX79-B4V3,133 equivalent, key selection criteria include Zener voltage tolerance, dynamic impedance, temperature coefficient, reverse leakage at 1 V, and thermal resistance in leaded-glass packaging - all critical for precision reference stability under varying ambient conditions.

Technical Context

This Zener diode functions as a two-terminal shunt voltage regulator, maintaining a stable 4.3 V reference by operating in reverse breakdown with controlled differential resistance (410 Ω typ. at 5 mA). Its negative temperature coefficient (−2.5 mV/K) enables predictable drift compensation in temperature-sensitive circuits.

Designed for low-power operation, it delivers 500 mW total power dissipation at Tamb = 50 °C with 380 K/W junction-to-ambient thermal resistance (lead length ≤8 mm), and withstands non-repetitive peak reverse power surges up to 40 W for 100 μs pulses.

Key Specifications

Pinout & Package

Hermetically sealed axial-leaded SOD27 (DO-35) glass package with cathode indicated by a colored band; leads are tinned copper-clad steel, suitable for wave or hand soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ4685,115 and BZX55C4V3, the BZX79-B4V3,133 offers superior voltage accuracy (±2% vs. ±5%), lower dynamic impedance (410 Ω vs. ≥500 Ω), and proven surge robustness (40 W) - making it optimal for industrial-grade reference and stabilization where long-term stability and thermal predictability are required.

Availability

BZX79-B4V3,133 is available at Aetrix Electronics and suitable for industrial sensor biasing, microcontroller reset circuits, linear power supply feedback, and ESD-protected analog interface applications requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for BZX79-B4V3,133 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 leader in discrete, logic, and PowerMOS semiconductors, serving automotive, industrial, computing, consumer, and wearable markets with high-volume, high-reliability components.

The BZX79 series belongs to Nexperia's standard Zener diode product line, engineered specifically for low-power voltage regulation and precision reference applications in cost-sensitive yet thermally demanding environments.

FAQ

What is the maximum continuous power dissipation for BZX79-B4V3,133 at 70 °C ambient?

The datasheet specifies 500 mW at Tamb = 50 °C and 400 mW at Tamb = 50 °C with note 1 (no metallization pad). At 70 °C, derating applies: using R_{th j-a} = 380 K/W, maximum P_tot ≈ 368 mW to maintain T_j ≤ 200 °C. This value is calculated from (T_jmax − T_amb) / R_{th j-a}, not interpolated from tabulated points.

Does BZX79-B4V3,133 have a specified Zener impedance at 1 mA test current?

No - the BZX79-B4V3,133 differential resistance is characterized at I_Z = 5 mA (410 Ω typ., 600 Ω max). At 1 mA, impedance rises significantly; Table 1 shows rdif values at 1 mA only for types ≤3.9 V, and BZX79-B4V3 is not included in that subset. No guaranteed specification exists for 1 mA operation.

Can BZX79-B4V3,133 be used in place of a 4.3 V TL431 shunt regulator?

No - the BZX79-B4V3,133 is a passive two-terminal Zener diode, while the TL431 is an active three-terminal programmable shunt regulator with adjustable output (2.5–36 V), lower dynamic impedance (~0.2 Ω), and built-in reference/amp/comparator. They serve different functional roles and are not interchangeable without circuit redesign.

Is the cathode marking visible on the physical BZX79-B4V3,133 device?

Yes - the SOD27 (DO-35) package uses a distinct colored band (typically black or dark gray) applied near one end of the glass body to identify the cathode terminal, consistent with JEDEC DO-35 mechanical drawings and Nexperia's packaging standards.