Author Topic: How does this IC work?  (Read 940 times)

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Offline fonographTopic starter

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How does this IC work?
« on: November 23, 2018, 06:11:08 pm »
Its supposed to be volume control,in datasheet I found word "resistor ladder",I also found word "amplifier",it have alot pins,wtf is this thing and how does it work?

Is it amplifier? Is it some kind of volume control IC? Is it some weird active hybrid volume  morphing op amp gizmo?
Does it decrease volume by passive resistance like potentiometer or is this case of active circuit sorcery?

https://www.google.sk/url?sa=t&source=web&rct=j&url=https://www.mouser.com/ds/2/294/NJW1195_E-69285.pdf&ved=2ahUKEwiT0L7RjuveAhWD6qQKHXHlCw8QFjAAegQIABAB&usg=AOvVaw2OVh08J254k-drNO6JOyzq&cshid=1542996774066
« Last Edit: November 23, 2018, 06:13:24 pm by fonograph »
 

Offline Benta

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Re: How does this IC work?
« Reply #1 on: November 23, 2018, 06:38:44 pm »
It's a combination of analog switches and digital potentiometers (and associated control logic).

 
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Online SiliconWizard

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Re: How does this IC work?
« Reply #2 on: November 23, 2018, 06:53:50 pm »
Yeah it is much like the PGA2320 except it has additional MUXes to handle 4 inputs.

The volume control itself is basically a resistor ladder and a series of switches. You can get a basic idea with this: https://en.wikipedia.org/wiki/Logarithmic_resistor_ladder
 
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Offline fonographTopic starter

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Re: How does this IC work?
« Reply #3 on: November 23, 2018, 07:03:07 pm »
Is this passive stepped attenuator with bunch of various matched resistors combined with digitaly controlled solid state relays? Is there some active amplifier in the signal path? Some op amp-ish ouput buffer or something like that...
 


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