PCA9703 spice model or details of inputs

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PCA9703 spice model or details of inputs

Contributor I

I'm trying to evaluate the PCA9703 for use with higher input voltages. It would be helpful to have a basic SPICE model of the inputs, or at least a little more information on the input structure. A formula is given for simple resistor value, but I am trying to determine resulting switch thresholds, e.g. using a resistive divider on the inputs to tailor to needed thresholds.

Anything available?


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NXP TechSupport
NXP TechSupport


It is very unfortunate for me to let you know that NXP does not have an available SPICE model or any other simulation model for the PCA9703. There is no further information about the internal structure of the input pins other than the information you can find on device datasheet.


But, the input structure allows for elevated voltages to be applied through a series resistor. The series resistor is required when the input voltage is above 5.5 V. The series resistor is required for two reasons: first, to prevent damage to the input avalanche diode, and second, to prevent the ESD protection circuitry from creating an excessive current flow.


The minimum required series resistance for applications with input voltages above 5.5 V is 100 kW. For applications requiring an applied voltage above 27 V, Equation 1on page 9 of the datasheet is recommended to determine the series resistor. Failure to include the appropriate input series resistor may result in product failure and will void the warranty.

Have a great day,

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