Has anyone used TDA7468 or friends?

[vkj]

I am trying to use the TDA7468 for a simple preamp. The part was obtained from digikey.

After soldering it up and driving it, there is no output. The output dc is 1/2 the supply, but there is zero signal. I can tell that the i2c routines are working because (a) I get an ack, and (2) I am able to switch the input source correctly. The input source is available at the mux output of the amp. I can also switch the gain as per the specs. But the signal doesnt seem to be getting past the volume and tone control stages. I tried different setting for the mute function but nothing works. Same with the volume.

The (badly written) datasheet doesnt say what the power-on settings are. It has some table giving a power on reset input code, but I have no idea how this is used.

Has anyone used this or the other chips of the same type? ANy ideas how to fix this problem?

Thanks,

vkj

[pacificblue]

Mute Off = Output On.

Volume1 and Volume2 must be set on both channels. So there are four settings for the volume control: Volume1 setting 1, Volume2 setting 1, Volume1 setting 2 and Volume2 setting 2. Volume 1 is before tone control, Volume2 after tone control, setting 1 means channel 1 and setting 2 means channel 2.

You can find the Power-On Reset Condition in Table 5.

[vkj]

Originally Posted by pacificblue

Mute Off = Output On.

Volume1 and Volume2 must be set on both channels. So there are four settings for the volume control: Volume1 setting 1, Volume2 setting 1, Volume1 setting 2 and Volume2 setting 2. Volume 1 is before tone control, Volume2 after tone control, setting 1 means channel 1 and setting 2 means channel 2.

You can find the Power-On Reset Condition in Table 5.

Thanks for your reply.

I did try both mute off and mute on (Table 14, sub-address 6, value 1/0). Didnt make any difference.

I tried a volume setting of 0 for L and R channels, which I assume is "full" volume, 0dB, acc. to the table. Am I right?

I dont understand Table 5. It is not referred to in the text. Is it a one-byte command to reset the chip? If so what is the reset setting?

Thanks

vkj.