Northern Telecom Meridian Handset …part 2

Nortel QMV491

Lets look at the other QMV part number.

The QMV491BT5 oddly with no manufacturer logo





De-capping the part and I confirm this is another Nortel fabricated part and alongside the copyright and mask registration we have the designers initials ‘MT’




Oddly this has two internal code numbers (Split personality) is it a B65 or D67?

Here is the die photoThis one is a very similar size to the QMV493/B44 at 4.7 mm x 4.47 mm (21 mm2) but it was made on a more advanced process.  I measure the gate length to be ~1.3μm (It is too small to be accurate, but they are a bit bigger than 1μm) so I think this is a 1.25μm CMOS process again with two metal layers.

Here is an area of logic imaged with my 80x objective (Multiple focus stacked image)As you can see the chip is laid out as 3 blocks of CMOS digital logic together with two memory blocks.  Again I have no idea of chip function, it might be the chip that provides the handset functionality to the selected buttons (I suppose a forerunner of what is an application processor in a modern smartphone).

Looking at the large memory block, I can see it is a metal encoded ROM.  Imaging it at 20X it is easy to see the different bits in M1.Oddly when you zoom in with the 80x objective the programmed bits are much harder to seeThe other array looks like an SRAM either 6T or 8T (The polysilicon layer is almost complete obscured by the metal layers) with an interesting complex metal layout.

Motorola MC145447

I also looked at the Motorola MC145447 “Calling Line Identification Receiver with Ring Detector”.  Designed in 1991 with internal die code D15H

This is a smaller die 3.5 mm x 3 mm (10.5 mm2This is the block diagram of the functions on this chip, its a bit beyond my skill to map them to the die photo.The Motorola chip appears to be fabricated in a very similar process to the Nortel QMV493 i.e.. A double poly, double metal 3μm CMOS process.  Again there are large amounts of poly-poly capacitors on the die, though there layout is different to the Nortel chip.And here is what I think is a bandage reference circuit with lateral PNP’s and a interesting metal layout with lots of symmetry

Motorola MC34119

And last as a bonus die photo I took a look at the package just labeled 34119.  De-caping part reveals it is also a Motorola chip and searching reveals this datasheet for an MC34119 Low power audio amp.  The die itself is a tiny thing just 1.4 mm x 1.16 mm (1.6 mm2) and according to the datasheet contains 45 active transistors 🙂

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