Tiny diodes provide big ESD protection

A new series of high-performance, micro-packaged ESD protection diodes is designed for single-line protection of voltage-sensitive components in portable and battery-operated applications.

ON Semiconductor has a new series of high-performance, micro-packaged electrostatic discharge (ESD) protection diodes designed for single-line protection of voltage-sensitive components in portable and battery-operated applications.

The five ESD5Z devices in the new series include the ESD5Z2.5T1 (2.5V), ESD5Z3.3T1 (3.3V), ESD5Z5.0T1 (5.0V), ESD5Z6.0T1 (6.0V) and ESD5Z7.0T1 (7.0V).

These devices are designed to clamp fast-rising ESD pulses, preventing damage to voltage sensitive components on the board.

An input waveform of 30kV - per the IEC61000-4-2 standard - will be clamped to less than 7V in a matter of nanoseconds by the ESD5Z series devices.

Their small size facilitates placement near input/output ports where ESD can enter the system, thus suppressing the transient voltage event before it can be coupled into the rest of the board.

In their off state, these ESD5Z devices exhibit very low leakage current of 5nA, making them ideal for applications where power efficiency is paramount.

The devices are also suitable for protecting voltage-sensitive components from load-switching transients on the power line, and can dissipate up to 200W with an 8 x 20us pulse waveform.

Offered in an ultrasmall SOD-523 package measuring 1.6 x 0.8 x 0.7mm, the ESD5Z devices are ideal for cellphones, PDAs and MP3 players where board space is at a premium and ESD events are a common occurrence.

They offer the designer maximum flexibility to protect a single line where board space or layout considerations preclude the use of multiline protection devices.

The ESD5Z series outperforms the commonly used multilayer varistors (MLVs) in several areas, while maintaining the small size advantage.

The maximum clamping voltage of the devices is less than half that of an MLV, thus providing superior protection to sensitive ICs.

With an off-state leakage level of 5nA, the ESD5Z diodes offer a clear advantage over the higher leakage MLVs with regard to battery life.

Another advantage offered is their ability to withstand multiple ESD strikes without shifts in electrical characteristics.

"As ICs continue to evolve to smaller, denser geometries for portable applications, they are increasingly more sensitive to ESD voltage", said Mamoon Rashid, ON Semiconductor General Manager of the Small Signal Division.

"ON Semiconductor will continue to develop high-performance solutions to suppress ESD voltage in this challenging application space".

The ESD5Z2.5T1, ESD5Z3.3T1, ESD5Z5.0T1, ESD5Z6.0T1 and ESD5Z7.0T1 are available in the SOD-523 package and are priced at $0.038 per unit in 10,000-unit quantities.

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