Nexperia USA Inc. BZX84W-B33F

Overview

BZX84W-B33F from Nexperia is a ±2 % tolerance Zener voltage regulator diode with 33 V nominal breakdown voltage, 325 Ω typical differential resistance at 2 mA, and 29.7 mV/K temperature coefficient, housed in a SOT323 (SC-70) package for space-constrained power rail stabilization in DC-DC feedback loops.

For engineers reviewing the BZX84W-B33F datasheet, BZX84W-B33F pinout, BZX84W-B33F application, or BZX84W-B33F equivalent, this page delivers verified Zener parameters, thermal derating guidance, SOT323 terminal mapping, and direct substitution options for precision voltage reference design.

Technical Context

This device operates as a reverse-biased voltage reference with 33 V nominal Zener voltage (V_Z) at I_Z = 2 mA, exhibiting 325 Ω differential resistance (r_dif) and +29.7 mV/K temperature coefficient (S_Z). Its non-repetitive peak reverse power dissipation reaches 40 W for 100 µs pulses.

Designed for surface-mount use on FR4 PCBs with single-sided copper, it delivers 275 mW total power dissipation at 25 °C ambient and junction temperatures up to 150 °C, with thermal resistance from junction to ambient of 455 K/W in free air.

Key Specifications

Pinout & Package

SOT323 (SC-70) leadless plastic surface-mount package with 3 terminals, 1.3 mm × 1.8 mm footprint, and 0.65 mm pitch; optimized for reflow soldering with defined land pattern per Figure 9.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84W-B33F, BZX84W-C33 trades regulation accuracy for lower cost and wider voltage spread, while MMSZ4703T1G offers identical nominal voltage but requires more PCB area and exhibits higher thermal resistance-making BZX84W-B33F optimal for compact, precision 33 V reference designs.

Availability

BZX84W-B33F is available at Aetrix Electronics and suitable for DC-DC converter feedback, overvoltage protection, and reference voltage source applications requiring stable component supply, consistent parametric performance, and SOT323 footprint compatibility.

Supply support for BZX84W-B33F 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 manufacturer headquartered in Nijmegen, Netherlands, specializing in high-volume logic, discrete, and MOSFET solutions with emphasis on efficiency, reliability, and miniaturization.

The BZX84W series belongs to Nexperia's general-purpose Zener diode product line, engineered for compact, high-precision voltage regulation in consumer, industrial, and communications equipment where SMT scalability and parametric consistency are essential.

FAQ

What is the maximum continuous forward current for BZX84W-B33F?

The BZX84W-B33F is not rated for continuous forward conduction; its absolute maximum forward current is 200 mA only for short pulses. In normal Zener operation, it functions in reverse bias, and forward voltage is specified at 0.9 V maximum at 10 mA-intended solely for polarity verification, not power dissipation.

How does the 29.7 mV/K temperature coefficient affect regulation accuracy over temperature?

At a 100 °C junction temperature rise, the Zener voltage shifts by +2.97 V (29.7 mV/K × 100 K), resulting in a 33 V nominal device drifting to ~35.97 V. This must be accounted for in wide-temperature-range applications; compensation techniques or tighter thermal management may be needed to maintain system-level accuracy.

Can BZX84W-B33F replace BZX84C33 in an existing design?

Yes, electrically and physically-both use SOT323 packaging and share identical pinout-but BZX84W-B33F offers ±2 % tolerance versus ±5 % for BZX84C33, delivering tighter regulation at the cost of higher unit price. No layout changes are required, but verify if the improved accuracy impacts downstream comparator thresholds or feedback stability.

What is the significance of the 'n.c.' terminal in the SOT323 package?

Pin 2 is internally not connected-no bond wire or die connection exists. It serves only as a mechanical anchor and thermal path; no electrical routing or grounding is required. Leaving it unconnected avoids unintended parasitic coupling, and soldering it provides no functional benefit or thermal improvement per Nexperia's thermal characterization data.