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Ground Analog and Digital

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caringin

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Hi,

I want to make a PCB for my design. It consists of Microcontroller, Analog-to-Digital Converter, motor driver, and amplifier. Should I separate their Ground since the micro is digital and the others are analog? Thanks.
 

bimbla

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Treat the microcontroller , Digital GND of ADC, Motor driver, Amplifier and Analog GND of ADC as seperate sub ciruits. Use seperate ground 'paths' for the sub circuits and tie them all at one single point.

I hope that this helps.

bimbla.
 

    caringin

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wwfeda

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It is always good practice to separate them and have them join at one point. Becareful the motor driver, as they tend to draw spike currents which could be distruptive to your grounds. Heavily bypass that power line too. Capacitor values ranging from 47uF to 0.01uF are good.
 

    caringin

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caringin

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Hi,

I use IC motor driver, L293D H-bridge. Do I still need to use bypass caps? Do I also need optoisolator to separate output from the micro and the H-bridge? A friend told me that there is a chance that high current from H-bridge flows enter the micro? I use 12 V for H-bridge and 5 V for micro.
 

tyty

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HI caringin

Use by-pass capacitor. Listen to your friend. Best regards! tyty
 

yangxh

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wwfeda said:
It is always good practice to separate them and have them join at one point. Becareful the motor driver, as they tend to draw spike currents which could be distruptive to your grounds. Heavily bypass that power line too. Capacitor values ranging from 47uF to 0.01uF are good.
It's really,but you may use photoelectricity isolation technology,as well as use a inductance across the two point.Thank you!
 

mayu_wakui

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to tie analog gnd to digital gnd, use ferrite beads. the rite impedence would suppress the spikes esp from starting currents of the motor. all the best for the project.
 

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