Nexperia USA Inc. BZX384-A3V9-QX

Overview

BZX384-A3V9-Q from Nexperia is a ±1 % tolerance Zener voltage regulator diode in SOD323 (SC-76) package, rated for 3.9 V nominal breakdown at 5 mA, with 300 mW total power dissipation and 40 W non-repetitive peak reverse power capability. It operates across −65 °C to +150 °C ambient and is AEC-Q101 qualified for automotive voltage reference and overvoltage protection circuits.

For engineers reviewing the BZX384-A3V9-Q datasheet, BZX384-A3V9-Q pinout, BZX384-A3V9-Q application, or BZX384-A3V9-Q equivalent, key selection criteria include its tight ±1 % V_Z tolerance, low 3 Ω differential resistance at I_Z = 5 mA, 3 μA max reverse current at V_R = 1 V, −3.5 mV/K temperature coefficient, and SOD323 footprint compatibility with high-density PCB layouts.

Technical Context

This device functions as a precision shunt voltage reference operating in reverse breakdown mode. Its regulation relies on controlled avalanche and Zener mechanisms, with stable V_Z maintained under DC and transient reverse bias up to 40 W for 100 μs pulses.

The diode exhibits low thermal resistance (R_th(j-a) = 415 K/W in free air), enabling reliable operation in thermally constrained automotive modules. Its cathode-anode polarity is marked by a bar on the SOD323 body, and it delivers consistent performance across −65 °C to +150 °C ambient without derating below 150 °C junction temperature.

Key Specifications

Pinout & Package

Package: SOD323 (SC-76), surface-mount plastic case with 2 leads, 1.35 mm × 0.85 mm body size, 0.45 mm lead pitch, and cathode marked by a bar on the top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX384-B3V9-Q, the A-grade part offers 2× tighter V_Z tolerance at no footprint or thermal penalty; versus MMSZ4684T1G, it trades 200 mW higher continuous power for 30 % smaller area and superior regulation stability in space-constrained automotive modules.

Availability

BZX384-A3V9-Q is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, USB-C protection circuits, and consumer IoT battery monitoring requiring stable component supply and AEC-Q101 compliance.

Supply support for BZX384-A3V9-Q 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-volume, high-reliability discrete and logic devices, with leadership in automotive-qualified components and energy-efficient solutions.

The BZX384-Q series belongs to Nexperia's automotive-grade Zener diode product line, engineered specifically for precision voltage regulation and transient protection in harsh-environment electronic control units.

FAQ

What is the maximum continuous reverse current this diode can handle?

The BZX384-A3V9-Q has a maximum continuous forward current (I_F) of 250 mA, but as a Zener regulator, it operates in reverse bias. Its steady-state reverse current is limited by power dissipation: at 3.9 V, the maximum DC reverse current is ~77 mA (300 mW ÷ 3.9 V), assuming full derating at 25 °C ambient and no thermal enhancement.

Does this part support reflow soldering, and what profile is recommended?

Yes, the SOD323 package is qualified for lead-free reflow soldering per JEDEC J-STD-020. Nexperia recommends a peak temperature of 260 °C for ≤30 seconds, with ramp-up rate ≤3 °C/s and ramp-down rate ≤6 °C/s. The footprint in Figure 12 (0.5 mm pad width, 1.65 mm pad length) must be used to ensure reliable joint formation.

How does the temperature coefficient affect regulation accuracy over temperature?

With S_Z = −3.5 mV/K, the BZX384-A3V9-Q exhibits a predictable negative drift: V_Z decreases by 3.5 mV per Kelvin rise in junction temperature. Over −40 °C to +125 °C (ΔT = 165 K), total drift is ~578 mV - a 14.8 % shift from 3.9 V - which must be compensated in high-accuracy references using external circuitry or calibration.

Is the marking code '2Y' unique to BZX384-A3V9-Q, and how is it read on the device?

Yes, '2Y' is the exclusive marking code for BZX384-A3V9-Q per Table 4. It appears as a single-line laser mark on the top surface of the SOD323 package, adjacent to the cathode bar. The bar itself identifies Pin 1 (cathode); '2Y' confirms ±1 % tolerance and 3.9 V nominal breakdown, distinguishing it from BZX384-B3V9-Q (marked 'K6') and BZX384-C3V9-Q (marked 'T8').