FMC Time to Digital Converter: FMC TDC 1ns 5cha
tdc_v1_before_review.GIF
System specifications
- 5 inputs, TTL with software selectable 50 Ohm termination.
- Time tags apply to rising edges of inputs. They are made of two parts: 32 bits for the UTC second and as many bits as needed for the fractional part within the second (will depend on final choice of resolution).
- 500 ps resolution or better.
- Accuracy (of time-tag differences between channels): /- (250 ps timebase accuracy).
- Timebase accuracy: +/- 4ppm.
- Implementation details: timebase from a local TCXO on FMC card and needs calibration. Much better accuracy will be reached when used on a White Rabbit enabled FMC carrier.
- External inputs need to be protected against +15V pulses with a pulse width of at least 10us @ 50Hz (with protection diodes if possible).
- LEMO 00 connectors for all inputs. SMC connectors may be mounted instead.
- Minimum input pulse width: 100 ns. Narrower pulses should be ignored.
- A circular buffer will contain time tags for at least the last 100 input pulses. These time tags will at first be rough UTC (counter initialized by SW) giving ~ms accuracy. Later, with a WR-enabled solution, they can be much more accurate. Differences between channels will not suffer from this accuracy problem because the offset with respect to UTC will cancel.
- Programmable (enable/disable) host interrupts on all 5 channels.
- FMC mezzanine using a Low Pin Count (LPC) connector.
- Vadj 2.5V or higher.
Project documents
- Official production documentation (schematics, PCB, etc.): EDMS: EDA-02290
- LHC Equipment name:
Project Status
Date | Event |
06-12-2010 | Project start. |
14-12-2010 | First specification available for comments. |
09-03-2011 | First schematic available. (need to replace LEDs) |
18-03-2011 | Second schematics design review held. |
05-04-2011 | First layout made. Will be reviewed. |
Javier Serrano, Erik van der Bij - 7 April 2011