Has anyone used TDA7468 or friends?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
V

vkj

Member
Joined 2011
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
 
P

pacificblue

Member
Joined 2008
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.
 
V

vkj

Member
Joined 2011
pacificblue said:
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.
Click to expand...

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.
 
T

thebrakshow

Member
Joined 2011
VKJ, have you had any luck with this? I saw this part and really would like to use it however, after reading ST's so called datasheet (extremely vague and lacking of anything useful) I am a bit apprehensive.

Pacificblue do you happen to have a working schematic with this part? I found a service manual with this part in it but I'd like to have a second reference.
Thanks guys!
 
B

bastien

Member
Joined 2016
Vkj said it all
I have the exact same problem
Meaning I tried so many config values, but never got any audio out (measuring in and out with oscilloscope)
"power on reset" condition is not clear for me either, how should it be used ? I'm currently using it by sending only command byte (no data). Is it required to operate ?
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom