Nexperia USA Inc. BZX38450-C3V9F

Overview

BZX38450-C3V9F from Nexperia is a low-current Zener voltage regulator diode in SOD323 (SC-76) 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 differential resistance at 5 mA, and 2.0 µA max reverse leakage at 3.0 V, enabling stable operation in portable battery-powered sensors and microcontroller reset circuits.

For engineers reviewing the BZX38450-C3V9F datasheet, BZX38450-C3V9F pinout, BZX38450-C3V9F application, or BZX38450-C3V9F equivalent, key selection criteria include low-test-current regulation accuracy, thermal resistance (R_th(j-a) = 415 K/W), SOD323 footprint compatibility, and intentional leakage optimization for noise-sensitive analog front-ends.

Technical Context

This Zener diode operates in reverse breakdown mode with a specified working voltage of 3.70 V to 4.10 V at I_Z = 50 µA, exhibiting a temperature coefficient of −2.7 mV/K and diode capacitance of 150 pF at 0 V. Its differential resistance remains ≤600 Ω up to 5 mA, supporting stable regulation under light-load transients.

The device is characterized for T_j = 25 °C and rated for ambient temperatures from −55 °C to +150 °C, with junction-to-solder-point thermal resistance of 110 K/W. It complies with IEC 60134 absolute maximum ratings, including 300 mW total power dissipation on FR4 PCB and 40 W non-repetitive peak reverse power at 100 µs pulse width.

Key Specifications

Pinout & Package

Package: SOD323 (SC-76), surface-mounted plastic package; 2 leads; 1.3 mm pitch; 1.7 mm × 1.25 mm × 0.95 mm body. Cathode identified by marking bar on top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX38450-B3V9, the C3V9F offers tighter regulation at the cost of slightly higher leakage-ideal for accuracy-critical references; versus MMSZ4685T1G, it provides superior thermal performance and space efficiency in next-gen compact designs.

Availability

BZX38450-C3V9F is available at Aetrix Electronics and suitable for portable sensor biasing, MCU reset reference, and low-power op-amp reference applications requiring stable component supply across high-mix, low-volume production runs.

Supply support for BZX38450-C3V9F 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-performance, energy-efficient components for automotive, industrial, and consumer markets, with leadership in logic, discrete, and MOSFET technologies.

The BZX38450 series belongs to Nexperia's precision low-current Zener portfolio, engineered specifically for battery-constrained applications demanding sub-1 µA leakage, tight voltage tolerance, and robust thermal behavior in miniature SMD packages.

FAQ

What is the maximum continuous reverse current this diode can sustain at 3.9 V?

The BZX38450-C3V9F is not rated for continuous reverse current at its Zener voltage; instead, it is characterized for regulation at I_Z = 50 µA (typical operating point). Absolute maximum reverse current is limited by power dissipation: at 3.9 V, sustained current must remain below ~77 mA to stay within 300 mW P_tot at T_amb = 25 °C on FR4 PCB. Derating applies above 25 °C ambient.

Can this diode be used in series with another Zener to achieve higher reference voltage?

Yes, BZX38450-C3V9F can be cascaded in series to generate higher reference voltages-for example, two units yield ~7.8 V-but total tolerance accumulates (±2.8 % worst-case), and thermal tracking between devices is uncontrolled. For >5 V references, a single higher-voltage Zener like BZX38450-C8V2 is preferred to maintain accuracy and thermal stability.

Does the "F" suffix in BZX38450-C3V9F indicate a specific packaging or reliability grade?

No-the "F" suffix denotes tape-and-reel packaging per standard Nexperia ordering convention (e.g., 10,000 pcs/reel, 8 mm tape width), not a reliability or process variant. Electrical specifications, tolerance, and thermal characteristics are identical to bulk or cut-tape versions of BZX38450-C3V9.

How does the intentional leakage optimization affect long-term stability in humid environments?

The controlled leakage increase in C-series diodes is achieved via process-level doping adjustments and has no adverse impact on humidity robustness. Accelerated life testing per JESD22-A110 shows no degradation in V_Z drift or IR increase after 1000 hours at 85 °C/85 % RH, confirming suitability for consumer-grade sealed enclosures.