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DAC121S101: input Logic level thershold

Dino Mason
Prodigy 20 points
Part Number: DAC121S101

I am using a DAC121S101 Dac  which is power by a 5Volt rail.  My question is can I operate the digital control lines with a 3.3 Volt logic swing. The datasheet only specify a minimum input logic level of 2.4V.It does not specify the maximum level require to recognize a logic high

  • 0
    TI__Mastermind 46290 points
    Dino,

    Conventionally this is how logic input thresholds are defined. Input high voltages are defined with a minimum voltage, so as to say that as long as the input logic level is at least X volts communication is successful. From part to part the threshold could be lower to actually register a logic high. The specification is given from the perspective of the input voltage itself, not that of the DAC.

    Similarly the logic low level voltage says that as long as you are below a maximum of Y volts, you will successfully communicate a logic low. Part to part the threshold could be higher, but this is the protected / guard-banded specification.

    To put it directly - any voltage lower than 0.8V will register as logic low in 5V Va mode for all parts and any voltage higher than 2.4V will register as a logic high in 5V va mode for all parts. Depending on the tolerance of your 3.3V MCU logic, you should be fine.