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Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi, CERN ATLAS CMOS WG1 f2f meeting 20 th February 2014 - CERN
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Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

Feb 23, 2016

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ATLAS CMOS WG1 f2f meeting 20 th February 2014 - CERN. Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN. Tony’s slides on 27/1/14. Tony’s slides on 27/1/14. 4. Z-encoding. - PowerPoint PPT Presentation
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Page 1: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

Readout options.Some ideasR. Turchetta, STFC-RAL, UK

F.Anghinolfi, CERN

ATLAS CMOS WG1 f2f meeting20th February 2014 - CERN

Page 2: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

Tony’s slides on 27/1/14

Page 3: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

Tony’s slides on 27/1/14

Page 4: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

4

Pixel: 74.5umx50um

Segment: 74.5umx800umNumber of pixel/segments: 16

Number of segments: 32Number of contiguous segments in X: 256

Size of sensing area: 19.1mmx25.6mm

Number of bits per segmentM (X pos.) = 8N (Z pos.) = 5Total = 13

Z-encoding

Z

X

Only what I would call the basic unit is considered below. It is close to reticle size, so good for both stitched and non-stitched sensors. All coordinates below list first X dimension then Z.

Page 5: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

5

Z-encoding

The next slides will try to answer the following main questions:

1) How do we get the digital information out of the pixels?

2) What should go in the periphery of the sensor?

3) How do we interface with the ABCxxx and what are the

implications for the ASIC?

Page 6: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

6How do we get the digital

information out of the pixels? Option 1.

16 input OR

Distributed priority encoderUse asynchronous “toggle” per segment: No clock propagation less power consumption and substrate noise; Asynchronous hit encodingUse priority encoding, for example 4:2 building blocks to build the 32:5 encoding.

(see Alice-ITS)

Page 7: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

7How do we get the digital

information out of the pixels? Option 2.

16 input OR

Straight wiring32-bit wide bus from pixels, then priority encoder in the periphery.The bus could be driven by a digital buffer or a current method could be adopted.

The trade-off is between power and noise. Need some accurate design to be studied.

It would then need an encoder in the periphery

Page 8: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

8

Options review

Option 1 Option 2

Pros Cons Pros Cons

Data in periphery decoded

More complicated design in the pixel area

Minimal in pixel electronics

Pixel area not used for encoding electronics

Complicated electronics only in

periphery gives more options for trade-off

Page 9: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

9What should go in the

periphery of the sensor?

Option 1.Each strip generates 5-bit per hit.It needs an additional 256:8 encoder to generate the X position.After this, one hit would be coded over 5+8=13 bits.

Option 2.Each strip needs a 32:5 encoder. Then, as for option 1, it needs an additional 256:8 encoder to generate the X position.After this, one hit would be coded over 5+8=13 bits.

Page 10: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

10How do we interface with the ABCxxx and what are the implications for the

ASIC?

Both options are going to generate 13 bits per hit.The information is already encoded, so no need for decoding within the ABCxx DCL not needed.

Pipeline size: at the moment 256 bits per BCO. They would become 13*max. number of hits per BCO

Data transmission.

Q: Would the ABCxxx need to process clusters?

Page 11: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

Tony’s slides on 27/1/14

Page 12: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

12Standard stereo

As in Z-encoding, pixel outputs are ORed to generate a single output. Then they connect straight into ABCxxx = ABC130 – front-end

Page 13: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

Tony’s slides on 27/1/14

Page 14: Readout options. Some ideas R. Turchetta, STFC-RAL, UK F.Anghinolfi , CERN

14Binary stereo

As in Z-encoding, pixel outputs are ORed to generate a single output.256:8 encoder is integrated in the peripheryThe ABCxxx receives 8 bits per hit

Pipeline size: at the moment 256 bits per BCO. They would become 8*max. number of hits per BCO

Data transmission.

Q: Would the ABCxxx need to process clusters?