How does this telephone “dock” work?

[Athosworld]

I have this telephone dock I teardowned and found that apparently, it is powered with 9 volts AC that seems to be rectified to DC.

There is something blobby going in the upper right, I decided to decap the chip.
The die photos:

 

[Pommie]

Do you brick many items with your need to deblob?

Mike.

 

[Athosworld]

Do you brick many items with your need to deblob?

Mike.

Yes, this one was not working since many years.

 

[AnalogKid]

I don't understand the question.

 

[Athosworld]

I don't understand the question.

Im asking how the telephone ASIC chip (decaped) works.

 

[rjenkinsgb]

Most likely a dedicated DECT base controller such as these

DigChip IC database

DigChip is a provider of integrated circuits documentation search engine, it is also distributor agent between buyers and distributors excess inventory stock.

www.digchip.com

http://pdf-html.ic37.com/pdf_file_A/20200531/pdf_pdf/pdf1/NSC/SC14428_datasheet_345081/562108/SC14428_datasheet.pdf

Or just a DSP class microcontroller.

https://www.ti.com/product/TMS320C203/part-details/TMS320C203PZ80

The board was made to take a conventional 100 pin flat pack TQFP style IC as an alternate to the COB construction, likely either for initial production and design proving or just as an alternate depending on what IC sources were available.

You can learn infinitely more from the ICs that have numbers than from "blobs"!

And you can learn nothing practical or useful for designing your own stuff by pulling ICs apart, whether normal package or bare die..

Other than the controller IC:
The area at the lower left of the PCB is the telephone line interface, middle area power supply & voltage regulation, lower right corner the radio [DECT] transceiver IC.

The top centre area with the TO92 transistors is likely audio amplification or buffering between the phone line interface and ICs.

And the 8 pin at the top right most probably a memory IC, either settings storage or voicemail (or both) depending on its capacity.

The photo is not good enough quality to read the part numbers.

 

[rjenkinsgb]

For comparison - this is the board from a Siemens DECT base, a bit better quality with a fully screened RF section.

Note the similar 100 pin main controller at the top right, with the 8 pin memory IC next to it; very possibly the same IC as was in the wrecked one...

The circuitry is roughly similar, just more compact components with packaged bridge rectifiers and mostly surface mount, rather less discrete components.