Nexperia USA Inc. BZX79-B56,143

Overview

BZX79-B56,143 from Nexperia is a ±2% tolerance Zener voltage regulator diode with nominal 56 V breakdown voltage at 2 mA test current, 100 Ω typical differential resistance, and −200 nA maximum reverse leakage at 39.2 V (0.7 × V_Znom). It operates in hermetically sealed SOD27 (DO-35) glass package, rated for 500 mW total power dissipation at T_amb = 50 °C, and serves as a precision low-power voltage reference in analog sensor signal conditioning circuits.

For engineers reviewing the BZX79-B56,143 datasheet, BZX79-B56,143 pinout, BZX79-B56,143 application, or BZX79-B56,143 equivalent, key selection criteria include Zener voltage tolerance (±2%), thermal resistance (380 K/W), non-repetitive peak reverse power (40 W), and cathode-marked axial lead configuration - all critical for stable biasing in industrial temperature-sensing front-ends and low-current reference designs.

Technical Context

This device functions as a two-terminal passive voltage reference, relying on controlled avalanche breakdown in silicon to maintain stable reverse-biased operation. Its 56 V nominal Zener voltage is specified at I_Ztest = 2 mA, with temperature coefficient of +70 mV/K (typical) and 100 Ω differential resistance ensuring predictable regulation under small-signal load variations.

The SOD27 package features axial leads with cathode band marking, enabling manual or wave-solder placement in through-hole PCBs. Thermal performance is defined by R_{th j-a} = 380 K/W (no pad), limiting continuous dissipation to 400 mW at 50 °C ambient per derating curve - a constraint directly governing its use in unheatsinked, space-constrained analog subsystems.

Key Specifications

Pinout & Package

Hermetically sealed SOD27 (DO-35) axial-leaded glass package with cathode identified by a single dark band near one lead end. Leads are tinned copper-clad steel, suitable for manual soldering and wave soldering per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4756A and BZX85C56, BZX79-B56,143 delivers superior long-term stability and tighter voltage accuracy in compact hermetic packaging - making it optimal for recalibration-critical and high-reliability analog subsystems where parameter drift must be minimized over 10+ years.

Availability

BZX79-B56,143 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, automotive cabin temperature reference, programmable power supply feedback, and legacy equipment voltage calibration requiring stable component supply and long-term parametric consistency.

Supply support for BZX79-B56,143 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, formed in 2017 from the former NXP Standard Products business, with focus on automotive, industrial, computing, consumer, and wearable markets.

The BZX79 series belongs to Nexperia's precision Zener voltage regulator portfolio, engineered specifically for low-power, high-stability reference and stabilization applications in space-constrained, thermally variable environments.

FAQ

What is the maximum continuous power dissipation for BZX79-B56,143 at 70 °C ambient?

At 70 °C ambient, the device must be derated from its 500 mW rating at 50 °C. Using the thermal resistance R_{th j-a} = 380 K/W and T_{j max} = 200 °C, maximum continuous power drops to approximately 342 mW. This value is derived from P = (T_{j max} − T_amb) / R_{th j-a}, confirming safe operation within thermal limits without heatsinking.

Does BZX79-B56,143 have a specified Zener impedance at frequencies above 1 kHz?

No, the datasheet does not specify dynamic impedance or frequency-dependent behavior beyond the 1 MHz capacitance measurement (40 pF). Differential resistance (r_dif = 100 Ω max) applies only under DC or low-frequency small-signal conditions. For AC regulation analysis above 1 kHz, designers must model junction capacitance and package parasitics separately using the provided C_d and layout-dependent inductance.

Can BZX79-B56,143 be used in series to achieve higher reference voltages?

Yes, multiple BZX79-B56,143 units may be connected in series to generate higher reference voltages (e.g., 112 V with two devices), but current matching becomes critical. Variations in leakage current and temperature coefficient will cause unequal voltage division. For stable multi-Zener references, matched lots and thermal coupling are required - otherwise, dedicated high-voltage references like TL431-based solutions are preferred.

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

Yes, Nexperia maintains strict polarity marking consistency: the single dark band on all SOD27 Zeners (including BZX79-B56,143) identifies the cathode terminal. This matches JEDEC DO-35 standard orientation and is verified in the package outline drawing (SOD27, version A24), eliminating ambiguity during manual assembly or automated optical inspection.