Nexperia USA Inc. BZX58550-B3V9X

Overview

BZX58550-B3V9X from Nexperia is a low-current Zener voltage regulator diode in SOD523 (SC-79) package, designed for precision biasing and voltage reference in ultra-low-power circuits. It delivers a nominal 3.9 V regulation at 50 µA test current, with ±2 % tolerance, 600 Ω max differential resistance at 5 mA, and 2.0 µA max reverse leakage at 3.0 V, enabling stable operation in portable battery-powered sensor nodes and wearable power management.

For engineers reviewing the BZX58550-B3V9X datasheet, BZX58550-B3V9X pinout, BZX58550-B3V9X application, or BZX58550-B3V9X equivalent, this page provides verified electrical characteristics, thermal behavior under PCB mounting conditions, SOD523 footprint compliance, and validated alternative Zeners for low-current regulation design.

Technical Context

This device operates as a two-terminal shunt voltage regulator, maintaining stable output voltage across its cathode-anode terminals when reverse-biased above its specified Zener voltage (3.9 V). Its low 50 µA test current enables accurate regulation in micro-power systems where quiescent current must remain below 100 µA.

The BZX58550-B3V9X exhibits a negative temperature coefficient of −2.7 mV/K and 150 pF junction capacitance at 0 V, making it suitable for noise-sensitive analog references and low-frequency stabilization-unlike higher-current Zeners with larger thermal drift or parasitic capacitance.

Key Specifications

Pinout & Package

SOD523 (SC-79) plastic surface-mount package: 1.2 mm × 0.8 mm × 0.6 mm body, ultra-small footprint optimized for space-constrained wearables and medical patches.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-current Zener regulation applications.

Compared with BZX58550-C3V9, the BZX58550-B3V9X offers tighter tolerance and lower leakage for precision biasing; versus MMSZ4685T1G, it trades off power capability and impedance for 60 % smaller footprint and lower quiescent drain-critical in sub-mA battery systems.

Availability

BZX58550-B3V9X is available at Aetrix Electronics and suitable for portable sensor biasing, low-power ADC reference, wearable power sequencing, and IoT node voltage clamp requiring stable component supply across high-mix, low-volume production runs.

Supply support for BZX58550-B3V9X 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 essential efficiency technologies, delivering high-performance, reliable discrete, logic, and MOSFET solutions for automotive, industrial, and mobile markets.

The BZX58550 series belongs to Nexperia's precision low-current Zener portfolio, engineered specifically for ultra-low-power voltage reference and biasing in battery-constrained edge devices-not general-purpose regulation.

FAQ

What is the maximum continuous reverse power dissipation for BZX58550-B3V9X at 70 °C ambient?

At T_amb = 70 °C, derated power dissipation is 210 mW, calculated using the 350 K/W R_th(j-a) value and 150 °C max junction temperature: P_max = (150 − 70) / 350 = 0.229 W. This ensures safe long-term operation in thermally constrained wearable enclosures without forced airflow.

Can BZX58550-B3V9X be used in forward conduction mode as a low-V_F diode?

Yes-it exhibits ≤0.9 V forward voltage at 10 mA, making it viable as a low-drop clamp or level-shifter in bidirectional signal paths. However, its 200 mA absolute maximum forward current and lack of fast-recovery optimization limit use to DC or <100 kHz applications where switching losses are non-critical.

How does the −2.7 mV/K temperature coefficient affect accuracy in a 0 °C to 60 °C operating range?

Over 0–60 °C, the Zener voltage shifts by −162 mV (60 × −2.7 mV/K), resulting in a 4.15 % deviation from nominal 3.9 V. For applications requiring <1 % total error, external compensation (e.g., series thermistor) or selection of a zero-TC Zener like BZX58550-B6V2 is necessary.

Is the SOD523 package compatible with standard reflow profiles for lead-free soldering?

Yes-the device is qualified for JEDEC J-STD-020D-compliant lead-free reflow, with peak temperature up to 260 °C for ≤30 seconds. The recommended footprint (Fig. 10) uses 0.5 mm pad width and 0.4 mm solder mask clearance to prevent bridging during automated assembly of high-density PCBs.