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CD4052B: why output decrease by around 0.1V?

Yuan Tan63
Expert 3280 points
Part Number: CD4052B
Other Parts Discussed in Thread: CD74HC4052

Hi,

Customer connect CD4052B with F28377S's ADC, and when sampling frequency is 30kHz or 40kHz, the output of CD4052B will decrease by 0.1V. That will influence the accuracy a lot. do you know what kind of reason will lead to this issue?

here is schematic and test waveform:

  • 0
    Guru 317250 points

    CD4000 family devices are optimized for higher supply voltages. As shown in figure 3 of the datasheet, the channel resistance increases with lower supply voltages, and it is not even specified at 3.3 V. I'd guess that the output impedance of the signal is too large for the ADC.

    Try using some other 4:1 analog switch with a lower Ron, e.g., CD74HC4052.

  • 0 in reply to Clemens Ladisch
    TI__Genius 9132 points

    Hi Yuan,

    Yes ,the high RON of CD4052 at 3.3V is high compared to at high voltages.

    does your application require dual supply? Depending on your requirements, as Clemens mentioned  CD74HC4052. is a lower supply switch.

    Also, TMUX1109 is precision 4:1, 2 ch mux with very low RON in similar configuration with more features (1.8-V compatible control inputs, Break-before-make, Fail-safe logic).

    Regards,

    Saminah