onsemi SZESD9C3.3ST5G

Overview

SZESD9C3.3ST5G from onsemi is a unidirectional ESD protection diode designed for I/O line protection in space-constrained portable electronics. It features a 3.3 V working peak reverse voltage (VRWM), clamping voltage of 12.8 V at 1 A peak pulse current (IPP), 13 pF maximum capacitance at 1 MHz, and IEC 61000-4-2 Level 4 (±8 kV contact) ESD rating - enabling robust transient suppression in high-speed data interfaces like USB 2.0 and HDMI.

For engineers reviewing the SZESD9C3.3ST5G datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under IEC61000-4-2 waveform, low capacitance for signal integrity, SOD-923 footprint compatibility, and AEC-Q101 qualification for automotive infotainment and ADAS sensor interfaces.

Technical Context

This device operates as a unidirectional TVS diode with cathode-anode polarity, leveraging silicon avalanche breakdown to clamp transients before they reach downstream ICs. Its 3.3 V VRWM ensures compatibility with 3.3 V logic rails while maintaining sufficient margin above typical VDD levels.

The SOD-923 package enables sub-1 mm² board area usage, and its <1 ns response time ensures effective suppression of fast-rising ESD pulses defined in IEC 61000-4-2. Clamping behavior is characterized per the full IEC waveform - not just peak current - with oscilloscope screenshots provided in the datasheet for design validation.

Key Specifications

Pinout & Package

SZESD9C3.3ST5G is housed in the SOD-923 surface-mount package (Case 514AB), measuring 1.0 mm × 0.6 mm × 0.37 mm with a single-row, two-terminal configuration and cathode identification via a polarity band.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ESD protection applications.

Compared with ESD9C5.0ST5G, SZESD9C3.3ST5G offers tighter voltage matching to modern 3.3 V microcontrollers and sensors, while maintaining identical board footprint and thermal profile - making it preferred for new designs targeting low-voltage, high-speed interfaces where clamping margin must be minimized without sacrificing signal fidelity.

Availability

SZESD9C3.3ST5G is available at Aetrix Electronics and suitable for smartphone camera modules, automotive display interfaces, USB 2.0 OTG ports, and industrial handheld scanners requiring stable component supply and long-term production continuity.

Supply support for SZESD9C3.3ST5G 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 (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, medical, and IoT applications.

The ESD9C Series is part of onsemi's transient protection portfolio, engineered specifically for ultra-compact, high-fidelity ESD suppression in portable and automotive electronics with strict board-area and signal-integrity constraints.

FAQ

What is the clamping voltage specification for SZESD9C3.3ST5G under IEC 61000-4-2 testing?

The SZESD9C3.3ST5G exhibits a maximum clamping voltage (VC) of 12.8 V at 1 A peak pulse current (IPP), measured per the IEC 61000-4-2 waveform. This value is derived from oscilloscope screenshots included in the official datasheet and reflects actual voltage across the device during an 8 kV contact discharge event - not a theoretical calculation. The clamping performance is validated across temperature and process variation, ensuring consistent protection for downstream ICs in real-world conditions.

Is SZESD9C3.3ST5G suitable for bidirectional signal lines such as USB D+ and D−?

SZESD9C3.3ST5G is a unidirectional ESD protection diode, meaning it protects only against positive transients on the cathode side relative to anode (ground). For bidirectional lines like USB D+ and D−, two SZESD9C3.3ST5G devices are required per line - one oriented for positive ESD, and a second (or a dedicated bidirectional variant) for negative transients. The datasheet explicitly defines this device as unidirectional, and no internal back-to-back configuration is present.

Does SZESD9C3.3ST5G meet automotive qualification standards?

Yes, SZESD9C3.3ST5G is AEC-Q101 qualified and PPAP capable, confirming its suitability for automotive applications including infotainment displays, ADAS camera links, and body control modules. The "SZ" prefix denotes compliance with automotive-specific site and change control requirements, and the device is rated for junction temperatures from −55°C to +150°C - exceeding standard automotive ambient operating ranges.

What is the maximum capacitance of SZESD9C3.3ST5G and how does it affect high-speed interfaces?

The maximum capacitance of SZESD9C3.3ST5G is 13 pF at 1 MHz and 0 V bias. This low value ensures minimal impact on signal rise/fall times and impedance matching, supporting reliable operation on USB 2.0 (480 Mbps), MIPI CSI-2, and SDIO interfaces. Measured at zero bias, this capacitance remains stable across typical operating voltages, avoiding dynamic modulation that could cause jitter or bit errors in high-speed data transmission.

Can SZESD9C3.3ST5G replace older ESD diodes like PESD5V0S1BA in SOD-523 packages?

SZESD9C3.3ST5G uses the smaller SOD-923 package (1.0 × 0.6 mm) versus SOD-523 (1.2 × 0.8 mm), so direct PCB replacement requires layout modification. While both offer 3.3 V VRWM and IEC Level 4 protection, SZESD9C3.3ST5G has higher capacitance (13 pF vs. ~9 pF) but superior thermal dissipation due to optimized die attachment. It is not a drop-in replacement, but a next-generation option for new designs prioritizing miniaturization over marginal capacitance reduction.