ALICE INDUSTRIAL AWARD

1

ALICE INDUSTRIAL AWARD
to STMicroelectronics
for its
collaboration to the ALTRO Chip
ALTRO, one of the worlds most advanced Data
Acquisition System-on-Chip for the ALICE
Experiment The ALICE Experiment involves high
energy collisions between various types of heavy
ions. In order to study the tens of thousands of
resulting particles created by a single
collision, the ALICE Collaboration is building a
sophisticated detector (the Time Projection
Chamber, or TPC) containing nearly 600,000 tiny
sensors, each capable of responding to the
presence of an individual electron. The signal
from each of these sensors must be amplified,
converted to digital format, and pre-processed by
the front-end electronics, which is located deep
underground on the Time Projection Chamber.
About STMicroelectronics STMicroelectronics, the
worlds third largest semiconductor company, is a
global leader in developing and delivering
semiconductor solutions across the spectrum of
microelectronics applications. An unrivalled
combination of silicon and system expertise,
manufacturing strength, Intellectual Property
(IP) portfolio and strategic partners positions
the company at the forefront of System-on-Chip
(SoC) technology and its produtucts play a key
role anabling todays convergence market.
STMicroelectronics has made available to the
ALICE Collaboration one of its most advanced
circuits (TSA1001). This circuit was integrated
into the ALTRO chip designed by the CERN PH-ED
group. About 50,000 ALTRO chips have been
produced in site of Crolles (France) with the
250nm CMOS process.
One of the most critical challenges in designing
the TPC was to minimize the size and power
consumption of the front-end electronics beyond
the present capability of the integrated circuits
(ICs) commercially available. This challenge
motivated the development of an dedicated IC
(Aplication Specific Integrated Circtuis, or
ASIC) that embeds in a single chip the circuits
to digitise, process, compress and store the
information of a high number of channels.
Production site in Crolles (France)
The result is ALTRO (ALice Tpc Read Out) chip,
which integrates in a single chip 16 low-power
Analogue-to-Digital Converters (ADC) plus more
than 6 millions transistors of digital processing
circtuitry and around 800 kbits of data memory.
The ALTRO chip In one single chip, the analogue
signals from 16 channels are digitised,
processed, compressed and stored in a
multi-acquisition memory.
The Result of 4 Years of Development
The Analogue-to-Digital converters embedded in
the chip have a 10-bit dynamic range and a
maximum sampling rate of 40MHz.
ALTRO has been developed in three steps 1) the
first implementation was entirely based on
commercial components (1998) 2) in 1999 the
first attempt to miniaturize the circuit was done
developing a 4-channel ALTRO, but still with
external ADCs 3) the design and the prototype of
the final version of the ALTRO chip were
accomplished in 2001.
ALTRO ARCHITECTURE
After digitisation, a pipelined Data Processor is
able to remove from the input signal a wide range
of perturbations, related to the non-ideal
behaviour of the detector, temperature variation
of the electronics, environmental noise, etc. The
signal is then compressed by removing all data
below a programmable threshold, except for a
specified number of pre- and post-samples around
each peak.
ALTRO CHIP LAYOUT
Eventually data is stored in a multi-acquisition
memory that has a readout bandwidth of
300Mbyte/sec. The chip, is implemented in a
0.25mm CMOS technology, has an area of 64mm2 and
a power consumption of 320mW.
On 19 June 2002, the ALICE Collaboration assigned
the first industrial award to ST Microelectronics
for the excellent collaboration in the design and
production of the ALTRO chip. STMicroelectronic
s made available to the ALICE collaboration the
design of one of its most advanced circuits
(TSA1001). This was integrated into the ALTRO
chip designed by the CERN PH-ED group.