This appendix lists the parameters of the Beetle chip as described in the original work by S. Löchner and M. Schmelling (The Beetle Reference Manual, LHCb-2005-105).
Name | Range | Step | Nominal | Reg. content | Description |
---|---|---|---|---|---|
Itp | 0-2 mA | 7.8 μA | 0 μA | 0x00 | test pulse bias current |
Ipre | 0-2 mA | 7.8 μA | 600 μA | 0x4C | preamplifier bias current |
Isha | 0-2 mA | 7.8 μA | 80 μA | 0x0A | shaper bias current |
Ibuf | 0-2 mA | 7.8 μA | 80 μA | 0x0A | front-end buffer bias current |
Vfp | 0-2.5 V | 9.8 mV | 0 mV | 0x00 | preamplifier feedback voltage |
Vfs | 0-2.5 V | 9.8 mV | 0 mV | 0x00 | shaper feedback voltage |
Icomp | 0-2 mA | 7.8 μA | 40 μA | 0x05 | comparator bias current |
Ithdelta | 0-2 mA | 7.8 μA | -- | -- | current defining incremental comparator threshold |
Ithmain | 0-2 mA | 7.8 μA | -- | -- | current defining common comparator threshold |
Vrc | 0-1.25 V | 4.9 mV | 0 mV | 0x00 | comparator RC time constant |
Ipipe | 0-2 mA | 7.8 μA | 100 μA | 0x0D | pipeamp bias current |
Vd | 0-2.5 V | 9.8 mV | 1275 mV | 0x82 | pipeamp reset potential |
Vdcl | 0-2.5 V | 9.8 mV | 1030 mV | 0x69 | pipeamp reference voltage |
Ivoltbuf | 0-2 mA | 7.8 μA | 160 μA | 0x14 | pipeamp buffer bias current |
Isf | 0-2 mA | 7.8 μA | 200 μA | 0x1A | multiplexer buffer bias current |
Icurrbuf | 0-2 mA | 7.8 μA | 800 μA | 0x66 | output buffer bias current |
Latency | 10-160 | -- | 160 | 0xA0 | trigger latency |
ROCtrl | -- | -- | cf. table C.11 | readout control | |
RclkDiv | 0-255 | -- | 0 | 0x00 | ratio between Rclk and Sclk |
CompCtrl | -- | -- | See Table A-2 | comparator control | |
CompChTh | 0-31 | -- | -- | -- | comparator channel threshold shift register implementation and Beetle revision Id. |
CompMask | -- | -- | 0 | 0x00 | comparator mask shift register implementation |
TpSelect | -- | -- | 0 | 0x00 | test pulse selection shift register implementation |
SEUcounts | 0-255 | -- | -- | -- | sum of Single Event Upsets |
The following table describes the bits in the CompCtrl reagister
Bit | Function | Description |
---|---|---|
0 | DisableCompLVDS | 0: enable comparator LVDS output ports 1: disable comparator LVDS output ports |
1 | CompPolarity | 0: inverting 1: non-inverting |
2 | PipelineMode | 0: analogue readout 1: binary readout |
3 | CompDisable | 0: enable comparator 1: disable comparator |
4 | CompMode | 0: track mode 1: pulse mode |
5-7 | not used | -- |