Nexperia USA Inc. BZX58550-B27-QX

Overview

BZX58550-B27-QX from Nexperia is a low-current Zener voltage regulator diode in SOD523 (SC-79) package, designed for precision biasing and voltage reference in space-constrained, low-power circuits. It delivers a nominal 27 V regulation at 50 µA test current, with ±2 % tolerance, 300 mW total power dissipation, and AEC-Q101 qualification for automotive use.

For engineers reviewing the BZX58550-B27-QX datasheet, BZX58550-B27-QX pinout, BZX58550-B27-QX application, or BZX58550-B27-QX equivalent, key selection criteria include its ultra-low test current operation, tight voltage tolerance, thermal resistance profile, and automotive-grade reliability in miniature SMD packaging.

Technical Context

This device operates as a two-terminal shunt voltage regulator, maintaining stable reverse breakdown voltage across a wide range of bias currents (50 µA to 5 mA). Its differential resistance is 300 Ω at 5 mA, and temperature coefficient is +0.05 mV/K - indicating minimal drift over temperature for low-power reference applications.

The diode exhibits 25.65 V minimum and 28.35 V maximum working voltage (V_Z) at T_j = 25 °C, with reverse current limited to ≤0.05 µA at 20.4 V (VR), enabling high-impedance node stabilization in battery-powered sensor interfaces and microcontroller reset circuits.

Key Specifications

Pinout & Package

Package: SOD523 (SC-79), plastic surface-mounted, 2-lead, 1.2 mm × 0.8 mm × 0.6 mm body. Cathode identified by marking bar.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX58550-C27-Q, the BZX58550-B27-QX offers tighter regulation critical for uncalibrated analog signal paths; versus MMSZ5258B-7-F, it provides 45 % smaller PCB area and lower leakage at the expense of 150 mW power headroom.

Availability

BZX58550-B27-QX is available at Aetrix Electronics and suitable for automotive cabin electronics, industrial sensor modules, portable medical devices, and smart meter backup circuits requiring stable component supply with AEC-Q101 assurance and consistent SOD523 sourcing.

Supply support for BZX58550-B27-QX 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 logic, discrete, and MOSFET solutions, with leadership in automotive-qualified components.

The BZX58550-Q series belongs to Nexperia's low-current Zener regulator product line, engineered specifically for precision voltage referencing in space- and power-constrained automotive and industrial edge nodes.

FAQ

What is the maximum reverse voltage this diode can withstand before breakdown?

The BZX58550-B27-QX has a nominal Zener voltage of 27 V with guaranteed range of 25.65 V to 28.35 V at 50 µA. Its absolute maximum reverse voltage is not defined separately - operation beyond V_Z + margin risks exceeding the 300 mW power limit or triggering non-repetitive surge limits (40 W for 100 µs pulses). Sustained reverse bias above 28.35 V must be current-limited to avoid thermal runaway.

Is this device suitable for use in a 12 V automotive system?

Yes - the BZX58550-B27-QX is AEC-Q101 qualified and rated for −55 °C to +150 °C ambient operation. In a 12 V system, it functions as a 27 V clamp or reference, commonly used in auxiliary 24 V subsystems, CAN transceiver bias rails, or ECU diagnostic voltage monitors where higher reference voltages are required alongside primary 12 V distribution.

How does the ±2 % tolerance affect circuit accuracy in a voltage reference design?

At 27 V nominal, ±2 % tolerance means the actual V_Z falls between 25.65 V and 28.35 V. For a resistor-divider-based reference, this introduces up to ±2 % error in the derived voltage. In closed-loop systems with ADC calibration, this variation is typically compensated; in open-loop analog circuits, it sets the fundamental accuracy bound for bias points and thresholds.

Can this Zener diode replace a TL431-based shunt regulator?

No - the BZX58550-B27-QX is a passive two-terminal device with fixed 27 V breakdown, whereas the TL431 is an adjustable three-terminal active shunt regulator with programmable 2.5 V reference and 100 mA sink capability. This Zener lacks feedback control, current gain, or adjustability; it serves only as a simple, low-power voltage clamp or reference, not as a regulated output stage.