LM49450 pop noise at headphone

Hi Thomas,

Unfortunately there is no EVM for this device, so it might be difficult to verify this issue. I can try to contact my colleague to see whether we can offer you some solution.

Andy

Hi Andy: Any updated?
I have tried to capture I2C of LM49450 by TAS5717 main board.
But we could not access it by some I2C address: 0x7D, 0xFA or 0xFB, do you kow the real I2C address?

Hi Thomas,

The 7-bit i2c address is 1111101(0x7d), which could be found on Page 22 of LM49450 datasheet. As I told you before, I couldn't find any EVM for this device, so I am not able to verify this address.

Although it might be a bit late, I still would like to suggest you not recommend this device for any new projects because this device is going to be "starved". See my supervisor's comment in this thread:
e2e.ti.com/.../268956

Andy

DearAndy: I used USB toGPIO tools to get LM49450 address(0x7d).
Becasue it is reference design with C-media chip, I could not promote another chips to them.

Hi, Thomas,

What can you tell me about this C-Media Reference Design?

This part came from National, so I don't have any history on it, but looking at the d/s, it seems like it shouldn't have bad pop from the HP output. Can you capture a scope plot of the pop so we might have a better idea of what is causing it?

You might also try changing the volume control of HP to minimum before powering off. See Table 16. Headphone Volume Control Register.

-d2

Hi Don: The project is Monitor for Acer and Dell.
The reference design isfrom n-vedia not C-media.
The pop noise when mute turn on/off.