2.2 Common Readout Electronics
15
Table 2.2 Summary of tested specifications for the ALTRO [2] and S-ALTRO [6]
Parameter
ALTRO
S-ALTRO
Voltage supply
2.5 V
2.5 V
Technology
ST 0.25 µm
IBM 0.13 µm
Channels per chip
16
16
ADC effective input range
2 Vpp
2 Vpp
ADC resolution
10-bit
10-bit
ADC max sampling frequency 25 MSps
40 MSps
Integrated Non-Linearity
<0.8 LSB
0.71 LSB
Differential Non-Linearity
<0.2 LSB
0.58 LSB
Spurious Free Dynamic Range 78 dBc
N/A
Signal-to-Noise And
Distortion
60 dB
56 dB
Effective Number Of Bits
9.7 bit
9.07 bit
Crosstalk
0.005%
0.7%
Noise
0.35 LSB
547 e
Power consumption (per ch)
20 mW
47 mW
Die size
64 mm 2
50 mm 2
ALTRO ADC parameters obtained at 10 MSps sampling speed
S-ALTRO ADC parameters obtained at 40 MSps sampling speed
2.2 Common Readout Electronics
Some common projects have been developed in the ALICE and CERN community to increase development efficiency and reduce costs. The Gigabit Transceiver
(GBTx) [11] is one of these and provides radiation hardened time-divisionmultiplexing of multiple serial links to and from a high-speed serial link. Combined with a radiation hardened electrical-to-optical transceiver like the Versatile
Transceiver (VTRx) [13], it is possible to communicate over optical links with offdetector electronics that are positioned away from the radiation field of the detector,
avoiding the need to design the controller with radiation effect mitigation in mind.
This lowers both the development time and cost of a new front-end system. The
Common Readout Unit (CRU) [14] is such an off-detector controller, which is being
designed as a common project for the Run 3 upgrade of the ALICE detector. The CRU
acts as the physical and logical interface to the ALICE online farm, to the Detector
Control System (DCS) and to the trigger system for the front-end electronics.
For slow-control and monitoring of front-end cards, a device called the GBT Slow
Control ASIC (GBT-SCA) [15] is available. It provides commonly used protocols
like SPI, I
2 C as well as General Purpose Input/Output (GPIO) and ADCs. The GBTSCA can be used in conjunction with the GBTx to let off-detector electronics easily
interface with devices on the front-end cards, without the need for the detectors to
design their own front-end board-controller.
15
Table 2.2 Summary of tested specifications for the ALTRO [2] and S-ALTRO [6]
Parameter
ALTRO
S-ALTRO
Voltage supply
2.5 V
2.5 V
Technology
ST 0.25 µm
IBM 0.13 µm
Channels per chip
16
16
ADC effective input range
2 Vpp
2 Vpp
ADC resolution
10-bit
10-bit
ADC max sampling frequency 25 MSps
40 MSps
Integrated Non-Linearity
<0.8 LSB
0.71 LSB
Differential Non-Linearity
<0.2 LSB
0.58 LSB
Spurious Free Dynamic Range 78 dBc
N/A
Signal-to-Noise And
Distortion
60 dB
56 dB
Effective Number Of Bits
9.7 bit
9.07 bit
Crosstalk
0.005%
0.7%
Noise
0.35 LSB
547 e
Power consumption (per ch)
20 mW
47 mW
Die size
64 mm 2
50 mm 2
ALTRO ADC parameters obtained at 10 MSps sampling speed
S-ALTRO ADC parameters obtained at 40 MSps sampling speed
2.2 Common Readout Electronics
Some common projects have been developed in the ALICE and CERN community to increase development efficiency and reduce costs. The Gigabit Transceiver
(GBTx) [11] is one of these and provides radiation hardened time-divisionmultiplexing of multiple serial links to and from a high-speed serial link. Combined with a radiation hardened electrical-to-optical transceiver like the Versatile
Transceiver (VTRx) [13], it is possible to communicate over optical links with offdetector electronics that are positioned away from the radiation field of the detector,
avoiding the need to design the controller with radiation effect mitigation in mind.
This lowers both the development time and cost of a new front-end system. The
Common Readout Unit (CRU) [14] is such an off-detector controller, which is being
designed as a common project for the Run 3 upgrade of the ALICE detector. The CRU
acts as the physical and logical interface to the ALICE online farm, to the Detector
Control System (DCS) and to the trigger system for the front-end electronics.
For slow-control and monitoring of front-end cards, a device called the GBT Slow
Control ASIC (GBT-SCA) [15] is available. It provides commonly used protocols
like SPI, I
2 C as well as General Purpose Input/Output (GPIO) and ADCs. The GBTSCA can be used in conjunction with the GBTx to let off-detector electronics easily
interface with devices on the front-end cards, without the need for the detectors to
design their own front-end board-controller.