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ADM2682E Logic Inputs (DE, RE, TxD) Threshold


Logic Inputs DE, RE, TxD Thresholds defined in the Table 1, on page 3 of datasheet. But I'm a little confused about the min and max values of thresholds. 

In datasheet, 

Input Low Voltage (0.27Vcc) is specified as "min", 

Input High Voltage (0.7Vcc) is specified as "max". 

I know that

Input Low Voltage is usually defined as a "max" and 

Input High Voltage is defined as a "min" value. Am I wrong? 

I cannot understand the logic inputs thresholds in the datasheet.  

Best Regards, 

  • The digital input voltages in this datasheet are defined as the max/min thresholds of the input pin, rather than the max/min input voltages that should be applied to the pin,

    For input low, the threshold voltage is a minimum of 0.27Vcc, which means the input voltage should be a maximum of 0.27Vcc for a logic low

    Similarly for the input high, the threshold voltage is a maximum of 0.7Vcc, which means the input voltage should be a minimum of 0.7Vcc for a logic high

    Agree this is a little confusing, hope this helps, 



  • Thank you. Clear now digital inputs thresholds.

    I think I can put one more short question here about the same IC here, instead of open a new title;

    -Is there a minimum power supply Vcc voltage for generating internal isolated power? When I give 3.3V to Vcc, will Visoout be internally generated? Or should I give 5V to Vcc for internal isolated power generation? 

    Thank you. 

  • No problem, the minimum Vcc power supply is 3V. The Visoout will be internally generated as long as the Vcc voltage is between the 3V - 5.5V range. All max/min specifications will be met under this supply range. 

    If you're looking for where this is guaranteed in the datasheet, it's at the top of page 3 on the datasheet, in the text above Table 1