Bypass capacitor in order to isolate BJT array on a single substrate.

Thread Starter

Ngô Đình Nhân

Joined Jan 8, 2017
45
Hi all
I am using CA3083 ( BJT array chip) to build my circuit.
However I am wondering about pin 5 connection as my figure.
Could anyone let me know my connection to pin 5(SUB) is correct or not ?
by pass.jpg
 

Bordodynov

Joined May 20, 2015
2,469
No, this is not correct. The voltage on the substrate will float capacitance of the parasitic diode can reach a maximum value, and this will worsen the frequency parameters. If you have unipolar power, then connect the substrate to earth (GND). Why don't you want to follow the manufacturer’s order?
 

Thread Starter

Ngô Đình Nhân

Joined Jan 8, 2017
45
No, this is not correct. The voltage on the substrate will float capacitance of the parasitic diode can reach a maximum value, and this will worsen the frequency parameters. If you have unipolar power, then connect the substrate to earth (GND). Why don't you want to follow the manufacturer’s order?
Hello Bordodynov, thanks so much for reply. So I have to remove that capacitor, and then connect directly pin5 to GND. Right ?

One more thing is that I am considering a sentence in datasheet that " A suitable bypass capacitor can be used to establish a signal ground ". (as my highlight - blue color)

Can you help me to clear the meaning of this sentence ?

 
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