This DS9503P is designed as an ESD protection device for 1-Wire MicroLAN interfaces. In contrast to the DS9502, the DS9503P includes two 5 ohm isolation resistors on chip. Although 5 ohm are negligible during communication, they represent a high impedance relative to the conducting diode during an ESD event. Thus, the diode absorbs the energy while the resistors further isolate and protect the circuit at the other side of the package.
If used with circuits that already have a strong ESD-protection at their I/O port, the ESD protection level is raised to more that 27 kV (IEC 801-2 Reference model). In case of abnormal ESD hits beyond its maximum ratings the DS9503P will eventually fail "short" thus preventing further damage.
During normal operation the DS9503P behaves like a regular Zener Diode. When the voltage exceeds the trigger voltage, the I/V characteristic of the device will "snapback" allowing the same or higher amount of current to flow, but at a significantly lower voltage. As long as a minimum current or voltage is maintained, the device will stay in the "snapback mode". If the voltage or the current falls below the holding voltage or holding current, the device will abruptly change to its normal mode and conduct only a small leakage current.
Features
- Zener characteristic with voltage snap-back to protect against ESD hits
- High avalanche voltage, low leakage and low capacitance avoid signal attenuation
- Compatible to all 5V logic families
- Space saving, low inductance TSOC surface mount package
- On-chip 5 ohm resistors for isolation at both anode and cathode terminals
