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Question on 5146 and CMOS camera grounding

Anonymous
Anonymous

Other Parts Discussed in Thread: TVP5146

Hi All,

 

I would like to ask a question on grounding.

 

 

 

 

Does each analog or analog involved device require a separate grounding? The basically question is

1.    One TVP5146 or 5150

2.    One digital CMOS camera

Are both placed on the board, so do I need separate analog ground and analog power supply for them?

I searched all grounding in EVM6437 schematics and found there are four separate grounds:

1.    GND: devices

2.    GND_AIC: audio

3.    GND_DENC: 5146

a.    D_ENC= digital encoder?

4.    GND_DAC: video

 

So this seems to suggest that each, at least each type, analog involved device needs a separate grounding?

 

So regarding my question: one 5146 and one CMOS camera, which are both essentially A-D encoders (Am I correct here with CMOS camera?), do they require separate grounds?

 

 

Another question is on AGND, which is highlighted in yellow in the picture. Doesn’t there need to exist an inductor or ferrite bead between it and the Vdd? I searched the schematics and found all devices’ ground connection to this net are marked as GND, never AGND. So why is this AGND net label still provided here? Does it suggest anything?

 

 

 

 

Thanks,

Zheng

  • 0
    TI__Mastermind 43875 points

    Zheng,

    Grounding is a very complex topic and the perticular topology implemented depends very much on the characteristics of the board design and layout. Experience is usually the biggest factor in implementing a grounding scheme.

    Regarding the AGND, if you look at the schematics you will see that the AGND node is also connected to the other ground symbol with the horozontal lines (immediately above the highlighted triangle AGND identifier). This actually makes a connection between the 2 ground nets.

    BR,

    Steve