onsemi SZBZX84C51ET1G

Overview

SZBZX84C51ET1G from onsemi is a 51 V, 250 mW surface-mount Zener diode in SOT-23 package, designed for precision voltage regulation and overvoltage protection in space-constrained circuits. It delivers ±5% nominal Zener voltage tolerance at 5 mA test current, exhibits 180 Ω dynamic impedance at 5 mA, and supports 100 µA maximum reverse leakage at 38.3 V, making it suitable for voltage reference and clamping in portable power management.

For engineers reviewing the SZBZX84C51ET1G datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage accuracy (48–54 V range), thermal coefficient (+35.7 mV/°C), junction-to-ambient thermal resistance (500 °C/W on FR-5 board), and AEC-Q101 qualification for automotive use.

Technical Context

This device operates as a two-terminal, silicon planar Zener diode with avalanche breakdown mechanism optimized for stable reverse-bias regulation. Its electrical behavior is defined by three test points: 48 V min / 51 V nom / 54 V max at I_ZT = 5 mA, 47.6 V min / 54 V max at I_ZT = 1 mA, and 48.1 V min / 54.6 V max at I_ZT = 20 mA - confirming tight voltage consistency across operating currents.

The SOT-23 package features a cathode-indicated polarity band, no internal connection on pin 2, and is rated for 260 °C soldering temperature for 10 seconds. With ESD rating >16 kV (HBM Class 3) and peak pulse power handling of 225 W (8 × 20 µs), it supports robust transient suppression in battery-powered systems.

Key Specifications

Pinout & Package

Package: SOT-23 (TO-236), 2.90 × 1.30 × 1.00 mm, void-free thermosetting plastic case with corrosion-resistant finish; polarity indicated by cathode band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SZBZX84C51ET1G, BZX84C51ET1G offers identical electrical specs but no automotive qualification, while MMSZ5256B-TP provides double the power rating in a different package - requiring layout revision but enabling higher reliability in thermally demanding environments.

Availability

SZBZX84C51ET1G is available at Aetrix Electronics and suitable for automotive electronics, portable medical devices, and high-density industrial PCBs requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for SZBZX84C51ET1G 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

onsemi is a global semiconductor manufacturer specializing in energy-efficient silicon solutions for automotive, industrial, cloud, and IoT applications.

SZBZX84C51ET1G belongs to the BZX84CxxxET1G family - engineered for compact, reliable voltage regulation in space-constrained, high-reliability systems where AEC-Q101 compliance is mandatory.

FAQ

What is the Zener voltage tolerance of SZBZX84C51ET1G at 5 mA test current?

The SZBZX84C51ET1G has a Zener voltage range of 48 V (min) to 54 V (max) at I_ZT = 5 mA, yielding a nominal 51 V with ±5% tolerance. This specification is measured under controlled 25 °C ambient conditions and defines the guaranteed regulation window for design margining and worst-case analysis in voltage reference circuits.

Is SZBZX84C51ET1G qualified for automotive applications?

Yes, SZBZX84C51ET1G is AEC-Q101 qualified and PPAP capable, with the "SZ" prefix explicitly indicating compliance for automotive and other high-reliability applications requiring unique site and process controls. It is approved for use in engine control, body electronics, and ADAS subsystems meeting stringent automotive quality standards.

What is the thermal resistance of SZBZX84C51ET1G on FR-5 board?

The junction-to-ambient thermal resistance (R_JA) of SZBZX84C51ET1G is 500 °C/W when mounted on FR-5 board at 25 °C ambient. This value assumes standard JEDEC 2s2p pad layout and determines the maximum allowable power dissipation before junction temperature exceeds 150 °C - critical for thermal derating in enclosed enclosures.

Does SZBZX84C51ET1G have a connected pin 2?

No, pin 2 of SZBZX84C51ET1G is internally unconnected (NC). The device uses a 3-pin SOT-23 package with active terminals only on pin 1 (anode) and pin 3 (cathode); pin 2 must remain electrically floating in PCB layout and must not be tied to ground, power, or any signal net to avoid malfunction or damage.

What is the maximum reverse leakage current for SZBZX84C51ET1G?

The maximum reverse leakage current for SZBZX84C51ET1G is 100 µA at V_R = 38.3 V and T_A = 25 °C. This parameter defines the upper bound of off-state conduction prior to Zener breakdown and is essential for low-power standby circuit design where quiescent current must remain below microamp thresholds.