Motorola MC14053B

 

The MC14053B is an analog multiplexer or more precisely a digitally controlled triple SPDT switch. It was one of the many chips in the 1994 Panasonic camcorder.

 

 

Die Photo

The die is 2.1 x 1.88 mm fabricated in a single metal Bipolar process with 10μm minimum geometry tracksMC15053 Die PhotoThe elements of the three switches can be clearly seen in the right side of the die photo.

Process

When you increase the magnification (See below) you can see the dielectric material (the green/grey area) has a mottled/textured appearance.  It looks like the surface has been attacked.  I doubt very much that this left the wafer fab looking like this and I am pretty sure it is not package residue as the metal tracks are clean. In nearly all chips this final dielectric layer is either a silicon nitride, silicon oxide, or a mixed ‘silicon oxynitride’.  In old chips it is possible that this is silicon oxide doped with ~2-4% Phosphorus that was added to improve the step coverage over the metal tracks at low temperatures used for the deposition (and thus improve the integrity of the film.)  Anyway I speculate that this has a Phosphorus content in the dielectric layer and the surface has been affected by the hot sulphuric acid I used to remove the plastic mould compound, which is unusual.

In the image you can also see the outline of diffusions or buried layers used in the process (But no colour variations in the different areas).

Layout

The datasheet for this part is still available from ON Semi who started as a Motorola spin-off and still manufacture the Motorola discrete, standard analog and logic parts.  It appears from the datasheet this part is still available today.

This is the functional diagram for the part, together with the logic truth table 🙂

Here is my take on the blocks with the pin out.  (The pin out threw me out at first as I expected the external large rail to be Vss (Ground) when in fact it is Vdd (+ve rail).

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