Identifying a schematic symbol

[cloudscapes]

Heya..



Trying to identify that round symbol on pin 8 with the extra ground connection. The closest I can find are coax cables that sort of look like that, but this is a system clock signal for an audio codec, so coax doesn't make sense at all. I'm guessing it's something similar, like a ground plane under and around that trace? I may be wrong.

Datasheet doesn't go into it, I checked.

[Psi]

i would have just assumed it meant to use grounded coax for the cabling.

[cloudscapes]

i would have just assumed it meant to use grounded coax for the cabling.

That's the confusing thing, though. 99 times out of 100 in a codec/micro design, the system clock is connected between the two via traces, not cable.

[Kremmen]

1st guess: shielded cable. If this is on the PCB then 2nd guess: guard traces around the signal trace.

[Neilm]

1st guess: shielded cable. If this is on the PCB then 2nd guess: guard traces around the signal trace.

It could also be a controlled impedance trace. It is going to a pair of resistors that someone might have thought would do for a 50 impedance.

Neil

[AndyC_772]

Grounded guard traces around the clock track. Not a bad idea actually.

[krish2487]

1st guess: shielded cable. If this is on the PCB then 2nd guess: guard traces around the signal trace.

The 2nd.

Grounded guard traces around the clock track. Not a bad idea actually.

AndyC_772 beat me to it..

:-)

The chip is a NXP 24bit audio ADC.
The "loop" is a guard ring around the master clock to isolate it from high frequency noise around in the circuit.

Come to think of it, the "SYSCLOCK" should have indicated the purpose of the guard ring.

[cloudscapes]

Thanks a lot guys. I suspected as much, but it really helps to be sure when you're learning.