... | ... | @@ -5,7 +5,7 @@ |
|
|
Here is a quick explanation of the design where each different part is
|
|
|
described in a few words. For more information, read the paper
|
|
|
[Realisation of a low noise acquisition board : design
|
|
|
choices](https://www.ohwr.org/project/r19-tdc-del-a/uploads/2de2fdf069410a4799144539158fcd45/Realisation_of_a_low_noise_acquisition_board__design_choices.pdf).
|
|
|
choices](https://ohwr.org/project/r19-tdc-del-a/uploads/2de2fdf069410a4799144539158fcd45/Realisation_of_a_low_noise_acquisition_board__design_choices.pdf).
|
|
|
All the design has been done on KiCAD. For a better experience, it is
|
|
|
advised to download the last KiCAD project from the repository and
|
|
|
explore
|
... | ... | @@ -15,7 +15,7 @@ it. |
|
|
|
|
|
## The whole board
|
|
|
|
|
|
[![](/uploads/a8e8adf16dbc98e8ebaaa87f89e080f8/top_small.jpg)](/uploads/f3d7d01ea75b53cbefadb523371c500f/top_big.jpg)
|
|
|
[![](https://ohwr.org/project/r19-tdc-del-a/uploads/a8e8adf16dbc98e8ebaaa87f89e080f8/top_small.jpg)](https://ohwr.org/project/r19-tdc-del-a/uploads/f3d7d01ea75b53cbefadb523371c500f/top_big.jpg)
|
|
|
|
|
|
On this card will be connected all the future analogue time measurement
|
|
|
elements. The output of these elements has first to be converted in
|
... | ... | @@ -47,7 +47,7 @@ The AD9253 is able to sample data at a rate of 125 MHz. Its resolution |
|
|
is 14
|
|
|
bits.
|
|
|
|
|
|
[![](/uploads/d167fc7519b5a77a27b03ad150ded720/adc_small.jpg)](/uploads/9220efeb3bf4382a369f8e56e77976a6/adc_big.jpg)
|
|
|
[![](https://ohwr.org/project/r19-tdc-del-a/uploads/d167fc7519b5a77a27b03ad150ded720/adc_small.jpg)](https://ohwr.org/project/r19-tdc-del-a/uploads/9220efeb3bf4382a369f8e56e77976a6/adc_big.jpg)
|
|
|
|
|
|
The AD9253 has four inputs. On the previous verion of the board, we
|
|
|
chose the AD9645 which has more or less the same properties. This one
|
... | ... | @@ -68,7 +68,7 @@ All the resistors are in metal film to give the best performance (less |
|
|
noisy, lower temperature
|
|
|
coefficient).
|
|
|
|
|
|
[![](/uploads/ff0184d8ed14950ebb4fc10887e18612/input_small.jpg)](/uploads/9b129d4588dcb549e918033d284f5128/input_big.jpg)
|
|
|
[![](https://ohwr.org/project/r19-tdc-del-a/uploads/ff0184d8ed14950ebb4fc10887e18612/input_small.jpg)](https://ohwr.org/project/r19-tdc-del-a/uploads/9b129d4588dcb549e918033d284f5128/input_big.jpg)
|
|
|
|
|
|
On each input are one SMA connector for ground referenced signals and
|
|
|
two others for differential ones. All inputs have an impedance around 50
|
... | ... | @@ -79,7 +79,7 @@ MHz. |
|
|
|
|
|
## The Clock Circuitry
|
|
|
|
|
|
[![](/uploads/00a105a2dd37bdf7aace13b4fdb679b0/clock_small.jpg)](/uploads/8874a5702ef84095073fb253c23bee6d/clock_big.jpg)
|
|
|
[![](https://ohwr.org/project/r19-tdc-del-a/uploads/00a105a2dd37bdf7aace13b4fdb679b0/clock_small.jpg)](https://ohwr.org/project/r19-tdc-del-a/uploads/8874a5702ef84095073fb253c23bee6d/clock_big.jpg)
|
|
|
|
|
|
By default, the sampling frequency is 100 MHz given by the local
|
|
|
oscillator. Another frequency can be set using an external oscillator.
|
... | ... | @@ -96,7 +96,7 @@ jumpers. |
|
|
|
|
|
## The power Supply
|
|
|
|
|
|
[![](/uploads/e929b88be82a7cc5b2f4553797e06a69/power1_small.jpg)](/uploads/34cbcc1afa0aa6a6e0362bde9881319b/power1_big.jpg)
|
|
|
[![](https://ohwr.org/project/r19-tdc-del-a/uploads/e929b88be82a7cc5b2f4553797e06a69/power1_small.jpg)](https://ohwr.org/project/r19-tdc-del-a/uploads/34cbcc1afa0aa6a6e0362bde9881319b/power1_big.jpg)
|
|
|
|
|
|
We need enough power to supply all the components on the board but also
|
|
|
the MicroZed board. Furthermore, these components need different voltage
|
... | ... | @@ -124,7 +124,7 @@ converter, we decided to use different values to catch the high |
|
|
harmonics and then improve the noise
|
|
|
rejection.
|
|
|
|
|
|
[![](/uploads/df06807ebf1d165facf32721eb8124f7/power2_small.jpg)](/uploads/61a2cf211895bcf4de5496a649b6640d/power2_big.jpg)
|
|
|
[![](https://ohwr.org/project/r19-tdc-del-a/uploads/df06807ebf1d165facf32721eb8124f7/power2_small.jpg)](https://ohwr.org/project/r19-tdc-del-a/uploads/61a2cf211895bcf4de5496a649b6640d/power2_big.jpg)
|
|
|
|
|
|
We then convert these 5 V in a 3.3 V one. This last is used to supply
|
|
|
the clock splitter. Finally, two LDO are used to regulate the digital
|
... | ... | @@ -135,7 +135,7 @@ ADC. |
|
|
|
|
|
## External connections
|
|
|
|
|
|
[![](/uploads/727841d84385ae27bc1cf51f62d36d2e/connections1_small.jpg)](/uploads/c53bdb22f6e8c398a8641539df607df5/connections1_big.jpg)
|
|
|
[![](https://ohwr.org/project/r19-tdc-del-a/uploads/727841d84385ae27bc1cf51f62d36d2e/connections1_small.jpg)](https://ohwr.org/project/r19-tdc-del-a/uploads/c53bdb22f6e8c398a8641539df607df5/connections1_big.jpg)
|
|
|
|
|
|
The connections to the MicroZed board are done via its FCI connectors.
|
|
|
All these inputs can be configured to work in LVDS. As the outputs of
|
... | ... | @@ -143,7 +143,7 @@ our ADC are already in LVDS, this configuration fits ideally with our |
|
|
project.
|
|
|
|
|
|
There are two connectors. Only one is represented here. The [other
|
|
|
connector](https://www.ohwr.org/project/r19-tdc-del-a/uploads/6841e4bd942c7a6d0e9700829c390d6d/connections2_big.jpg)
|
|
|
connector](https://ohwr.org/project/r19-tdc-del-a/uploads/6841e4bd942c7a6d0e9700829c390d6d/connections2_big.jpg)
|
|
|
is powered with the 3.3V and is used to communicate with the components
|
|
|
in the miscellaneous part and the external GPIO ports.
|
|
|
|
... | ... | @@ -155,7 +155,7 @@ GPIO. |
|
|
|
|
|
## Miscellaneous
|
|
|
|
|
|
[![](/uploads/ddd128b75f8885d37a1683e789c03316/misc_small.jpg)](/uploads/e1abc2d9aa7ad2e376f8cff41f9fe754/misc_big.jpg)
|
|
|
[![](https://ohwr.org/project/r19-tdc-del-a/uploads/ddd128b75f8885d37a1683e789c03316/misc_small.jpg)](https://ohwr.org/project/r19-tdc-del-a/uploads/e1abc2d9aa7ad2e376f8cff41f9fe754/misc_big.jpg)
|
|
|
|
|
|
Some other components have been added to the board. First, we have the
|
|
|
trigger. This trigger is used to send a clock synchronized signal to an
|
... | ... | |