The ESD9X5.0ST5G belongs to onsemi's ESD9X series of voltage-sensitive components designed to protect circuit nodes from electrostatic discharge. The series spans stand-off voltages from 3.3V to 12V; this member is the 5V device (marking code B), matching 5V signal and supply lines in cellular phones, MP3 players, digital cameras and other portable applications where board space sells at a premium.

Despite its size, the protection numbers are substantial: ESD withstand is ±30kV for both contact and air discharge per IEC 61000-4-2 (Level 4 standard) and greater than 16kV Human Body Model (Class 3), with a response time typically below 1ns - fast enough to catch the sub-nanosecond edge of a real strike. Maximum reverse peak pulse current is 9.7A, clamping at 12.3V maximum at that full current with 107W typical peak pulse power (8x20µs waveform).

The device is unidirectional: Pin 1 is the cathode (line side) and Pin 2 the anode (ground side), giving a low clamping voltage on positive transients and standard diode conduction below ground. Working voltage VRWM is 5.0V with leakage of no more than 1µA, and breakdown is at least 6.2V (1mA). Housed in the void-free thermosetting epoxy SOD-923 (CASE 514AB) at 0.43mm maximum height, it operates from -55°C to +150°C; the T5G suffix denotes 8,000 units on tape and reel, Pb-free. An SZ-prefixed version (SZESD9X5.0ST5G) covers AEC-Q101 automotive requirements.

Note: Refer to the official onsemi ESD9X series datasheet for full electrical parameters and curves. Subject to change without notice; verify all parameters before final design.

The ESD9X5.0ST5G uses onsemi's SOD-923 (CASE 514AB) outline: a two-terminal micro package with a 0.039in x 0.024in (1.0mm x 0.6mm) footprint and a maximum body height of just 0.017in (0.43mm). The case is void-free, transfer-molded thermosetting epoxy rated UL 94V-0, with 100% matte-tin lead finish over the leadframe; mounting position is any, and the device meets MSL 1 with a 260°C qualified reflow temperature.

Marking is two characters - the device-specific code B (for the 5.0V member) plus a date code - and the T5G suffix means 8,000 units on tape and reel, Pb-free. Being unidirectional, orientation must follow the cathode marking toward the protected line.

The device is unidirectional with two terminals - polarity matters:

• Pin 1 - CATHODE: Connect to the protected signal or supply line.
• Pin 2 - ANODE: Connect to ground.

In this orientation positive transients on the line are clamped at the reverse breakdown characteristic (12.3V max at full 9.7A surge), while negative transients are shunted by forward diode conduction. Place the device directly at the connector pin with the shortest possible ground return. Confirm the polarity against the datasheet image below before layout.

The following ESD protection diodes are listed for reference. Verify working voltage, direction, capacitance, clamping and footprint before substituting.

onsemi (ON Semiconductor, NASDAQ: ON), headquartered in Scottsdale, Arizona, USA, is a leading supplier of power and protection semiconductors. The ESD9X micro-packaged protection family targets space-critical portable designs, and SZ-prefixed versions extend the same silicon to AEC-Q101 automotive qualification with PPAP capability under unique site and control change requirements.

onsemi provides complete datasheets, application notes (AND8308/D, AND8307/D) and long-term supply, with authorized distribution and technical support across China for both prototype and volume programs.