SLLSEB1D February 2012 – November 2015 TPD1E10B06
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
When a system contains a human interface connector, the system becomes vulnerable to large system-level ESD strikes that standard ICs cannot survive. TVS ESD protection diodes are typically used to suppress ESD at these connectors. TPD1E10B06 is a single-channel ESD protection device containing back-to-back TVS diodes, which is typically used to provide a path to ground for dissipating ESD events on bidirectional signal lines between a human interface connector and a system. As the current from ESD passes through the device, only a small voltage drop is present across the diode structure. This is the voltage presented to the protected IC. The low RDYN of the triggered TVS holds this voltage, VCLAMP, to a tolerable level to the protected IC.
For this design example, two TPD1E10B06s will be used to protect left and right audio channels. For this audio application, the following system parameters are known.
|Audio Amplifier Class||AB|
|Audio signal voltage range||–3 V to 3 V|
|Audio frequency content||20 Hz to 20 kHz|
|Required IEC 61000-4-2 ESD Protection||±20-kV Contact/ ±25-kV Air-Gap|
To begin the design process, some parameters must be decided upon; the designer should make sure:
For this application, the audio signal voltage range is –3 V to 3 V. The VRWM for the TVS is –5.5 V to 5.5 V; therefore, the bidirectional TVS will not break down during normal operation, and therefore normal operation of the audio signal will not be effected due to the signal voltage range. In this application, a bidirectional TVS like TPD1E10B06 is required.
Next, consider the frequency content of this audio signal. In this application with the class AB amplifier, the frequency content is from 20 Hz to 20 kHz; ensure that the TVS I/O capacitance will not distort this signal by filtering it. With TPD1E10B06 typical capacitance of 12 pF, which leads to a typical 3-dB bandwidth of 400 MHz, this diode has sufficient bandwidth to pass the audio signal without distorting it.
Finally, the human interface in this application requires above standard Level 4 IEC 61000-4-2 system-level ESD protection (±20-kV Contact/ ±25-kV Air-Gap). A standard TVS cannot survive this level of IEC ESD stress. However, TPD1E10B06 can survive at least ±30-kV Contact/ ±30-kV Air-Gap. Therefore, the device can provide sufficient ESD protection for the interface, even though the requirements are stringent. For any TVS diode to provide the full range of ESD protection capabilities, as well as to minimize the noise and EMI disturbances the board will see during ESD events, a system designer must use proper board layout of their TVS ESD protection diodes. See Layout for instructions on properly laying out TPD1E10B06.