Nexperia USA Inc. BZX79-C43,133

Overview

BZX79-C43,133 from Nexperia is a ±5% tolerance Zener voltage regulator diode with nominal working voltage 43 V at 2 mA test current, 85 Ω typical differential resistance, and −3.5 to −1.4 mV/K temperature coefficient. It delivers stable low-power voltage reference in compact hermetically sealed SOD27 (DO-35) glass package, rated for 500 mW total power dissipation at 50 °C ambient, and used in precision analog supply rails and sensor biasing circuits.

For engineers reviewing the BZX79-C43,133 datasheet, BZX79-C43,133 pinout, BZX79-C43,133 application, or BZX79-C43,133 equivalent, this page provides verified electrical parameters, thermal behavior, reverse leakage limits at VR = 0.7×VZnom, non-repetitive surge capability (40 W, 100 μs), and validated alternatives for ±5% Zener reference designs.

Technical Context

This device operates as a two-terminal passive voltage reference, relying on controlled Zener breakdown in silicon PN junction under reverse bias. Its regulation accuracy depends on test current (IZ = 2 mA), junction temperature (Tj = 25 °C unless specified), and thermal resistance (Rth j-a = 380 K/W).

The BZX79-C43,133 exhibits negative temperature coefficient (−3.5 to −1.4 mV/K), meaning output voltage decreases with rising temperature - critical for compensation design in mixed-signal systems. Its 40 pF diode capacitance at 1 MHz and 0 V reverse bias impacts high-frequency noise rejection in filtering applications.

Key Specifications

Pinout & Package

Hermetically sealed axial-leaded SOD27 (DO-35) glass package with cathode band marking. Dimensions: D = 4.25 mm max, L = 25.4 mm min, b = 0.56 mm max, G1 = 1.85 mm max. Lead spacing not standardized; intended for through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX79-C43,133, the 1N4749A offers +500 mW power headroom in through-hole format, while BZX84-C43 trades thermal robustness for miniaturization - choice depends on board area, cooling capability, and surge duty cycle.

Availability

BZX79-C43,133 is available at Aetrix Electronics and suitable for industrial sensor biasing, power supply overvoltage clamping, and portable instrumentation reference requiring stable component supply with guaranteed long-term continuity.

Supply support for BZX79-C43,133 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 semiconductors, formed in 2017 from the former NXP Standard Products division, specializing in high-volume, high-reliability components for automotive and industrial markets.

The BZX79 series belongs to Nexperia's legacy Zener diode portfolio designed specifically for cost-sensitive, low-power voltage regulation and reference applications where ±5% tolerance and hermetic reliability are prioritized over ultra-low leakage or ultra-tight TC.

FAQ

What is the maximum continuous reverse current the BZX79-C43,133 can handle at 25 °C?

The device has no specified maximum continuous reverse current - its operation is defined by power dissipation limits. At 25 °C ambient, it supports up to ~11.6 mA reverse current (43 V × 11.6 mA ≈ 500 mW), but derating applies above 50 °C per Rth j-a = 380 K/W. Continuous operation must stay within Ptot curves in Figure 3.

Can BZX79-C43,133 be used in series for higher voltage references?

Yes, but with caution: series connection multiplies temperature coefficients and increases total differential resistance. For example, two BZX79-C43,133 units yield ~86 V nominal, but rdif sums to ~170 Ω and SZ becomes more negative, worsening thermal drift. Matched units and thermal coupling are recommended for stability.

Is the cathode band polarity consistent across all SOD27-packaged Nexperia Zeners?

Yes - the colored band always denotes the cathode terminal across the entire BZX79 series, including BZX79-C43,133. This matches JEDEC DO-35 standard and is confirmed in the package outline diagram (page 8, "marking band indicates the cathode"). No exceptions exist in this family.

How does the 40 pF diode capacitance affect high-frequency performance?

At 1 MHz and 0 V bias, 40 pF forms a 4 kΩ impedance that shunts high-frequency noise away from sensitive nodes. However, above ~10 MHz, capacitive reactance drops below 400 Ω, reducing effectiveness as a filter - supplemental ceramic decoupling remains necessary for RF immunity in switching power supplies.