Performance and quality control of a radiation-hard 12-bit 40 MSPS ADC for the ATLAS Liquid Argon calorimeter trigger readout electronics Phase-I upgrade at the LHC

Abstract

A : A radiation-hard quad-channel 12-bit 40 MSPS pipeline analog-to-digital converter (ADC) has been designed for the trigger readout electronics Phase-I upgrade of the ATLAS Liquid Argon calorimeter, at the CERN Large Hadron Collider. The final version of the custom design, fabricated in a commercial 130 nm CMOS process, is presented and found to meet the system requirements for analog performance and radiation tolerance. The procedure for quality control of 17200 ADCs is described and the results are presented.

The Phase-I trigger readout electronics upgrade of the ATLAS Liquid Argon calorimeters

“…An internal Phase Lock Loop (PLL) generates a 640 MHz clock from a 40 MHz input clock (provided by the LTDB), of which both edges are used for the SAR operation. The MDAC stages operate with a supply voltage of 2.5 V and a common-mode voltage of 1.25 V, while for the SAR a supply voltage of 1.2 V with a common-mode of 0.6 V is used [20]. A digital data processing unit (DDPU) applies the calibration, forming the digital output, and the data are serialized and sent off the chip over a Scalable Low-Voltage Signaling (SLVS) driver at 320 MHz.…”

“…Proton SEE cross-sections were measured to be of the order of 10 −12 cm 2 per ADC channel. In addition to the proton radiation tests, SEE cross-sections were measured using four different species of heavy ions at the Cyclotron Resource Centre at Louvain-la-Neuve, Belgium, targeting a larger range of deposited energies and complementing the existing studies with protons [20].…”

“…The functionality, dynamic range and precision, evaluated by the effective number of bits (ENOB), were measured. A total of 12838 chips were identified as having four channels with a dynamic range greater than 3600 counts and an ENOB larger than 9.9 bits (using the limited-precision socketed board) [20], and thus were qualified to be used for LTDB production.…”