LTC6943 datasheet wtf

[CopperCone]

I want to build the programmable gain amplifier listed in the datasheet. I have no clue what they are referring to however:

What is 14A and 14B?

http://cds.linear.com/docs/en/datasheet/6943f.pdf

[CopperCone]

never mind, I understand, you need two chips. Most of the other examples use only one part. 

[The Soulman]

 

[RandallMcRee]

The 6943 is a "clone" of the ltc1043. So look into that datasheet for more information/confusion.

There is a similar circuit there which might guide you.

The only reasonable thing given the functionality is that 14A is the clock input. (But 14B is the same in that case, so definitely strange!).

The ltc1043 datasheet has the same circuit using labels 16A and 16B. Again, it seems to refer to the clock.

So, right, it seems to be a roundabout way of telling us that, even though you only need two switches, each has a separate clock, so you actually need two devices. You end up with two unused switches. Oh well.

Good luck! Let us know if you get it to work.

[CopperCone]

What does the SHA pin even do? I cant find it in either datasheet (lt1043 or 6943).

Going to be a while before I get any thing working. Months before I have a PCB made.

[harry dB]

If anyone has any information on the purpose of the SHa and SHb pins, do please let us know. I've gone through the datasheet of both the LTC1043 and the [LTC6943](https://www.analog.com/media/en/technical-documentation/data-sheets/1043fa.pdf) and the purposes are nowhere to be found. It's kind of implied that they are shorted to the Ca- and Cb- pins, but that doesn't make sense of course

[moffy]

If anyone has any information on the purpose of the SHa and SHb pins, do please let us know. I've gone through the datasheet of both the LTC1043 and the [LTC6943](https://www.analog.com/media/en/technical-documentation/data-sheets/1043fa.pdf) and the purposes are nowhere to be found. It's kind of implied that they are shorted to the Ca- and Cb- pins, but that doesn't make sense of course

Hard to find, but it is used to provide a guard ring in the CMRR test, see attached photo from the datasheet:
P.S. The SH probably stands for 'shield'.