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AD5422 - Transient voltage protection

Question asked by della on Jan 8, 2014
Latest reply on Jan 10, 2014 by tjohnson

Hello,

we want to use the AD5422 in single supply mode (AVDD=17VDC) with voltage and current output on same terminal.

There is a input protection example in the datasheet of the AD5422 (page 37, figure 76).

Right at the input terminal we want to use a bi-directional TVS SMBJ18CA. We also use a current limiting resistor 18 Ohm.

At the input of the AD5422 we have two protection diodes to AVDD and GND.

 

What kind of diodes should be used there (type and power rating) ?

Do I have to use schottky diodes or can I use normal silicon diodes, e.g. LL4148 ?

Should I take care of the higher reverse current when using schottky diodes ?

What is the clamping voltage of the AD5422 internal ESD protection diodes ?

Is another resistor necessary between external clamping diodes and the AD5422 input ?

 

Regards

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