Part Number: THS4222
Hi,I have a big problems with THS4522. I got samples and used it in our project. You can see part of design in the attachment. The problem is after soldering, some chips doesn't work - it looks like they are broken. Some of them works for a while, but after that they crashed. We don't know what is going on with these chips. Can anyone help?
I think you need a 22uF cap between the R11 and GND on the Vin1- input side. This cap is required to balance out the differential inputs. Without this cap, you will see a huge offset at the outputs which will cause the device to not work reliably.
In reply to Rohit Bhat:
Hi Rohit,Thank you very much for reply. It seems that with that capacitor design will be better, but I am wondering if that will stop chip damage? I don't know if it is problem with design or failed chips? Almost is damaged now.
In reply to Mateusz Borowiec:
I would recommend to simulate your circuit in TINA-TI to better understand whether the design has a problem. You might want to simulate with the actual output load and do ac analysis to make sure there are no oscillations in your design.
Without the 22uF cap between the R11 and GND on the Vin1- input side, you are introducing an asymmetry in the differential inputs. As a result, one of outputs is railed with a huge offset and the device stops working. I think that might be what you are seeing in your setup.
I have attached the TINA-TI circuit if you want to take a look. sboma73a.TSC
Hi Rohit,Thank you for reply. I made a simulation in LTSpice also and now i see the offset (earlier i check it after capacitors on output lines so i didn't see DC offset). The problem is this design is in Texas Instruments datasheet. Can anyone explain that?
Thank you for the reply,I use electret microphone as input.I read documentation and power consumption should be about 1mA per channel, but my design take about 30mA. Am I doing something wrong?
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