12-23 October 2020
GMT timezone

The threshold voltage generation for CMS ETL readout ASIC

14 Oct 2020, 16:05
Mini Oral and Poster Front End Electronics and Fast Digitizers Poster session C-01


Ms ZHANG, Li (Southern Methodist University)


We present the threshold voltage generation for CMS Endcap-Timing-Layer (ELT) readout ASIC called ETROC. ETROC together with the chosen sensor, low gain avalanche diode (LGAD), aim to achieve time resolution of 30~40 ps per track. In the analog front-end of ETROC, a pre-amplifier amplifies the signal from LGAD sensor, and then a discriminator converts the pre-amplifier signal into digital pulses for succeeding time-to-digital conversion and readout. The discriminator requires a programmable precision threshold voltage to cover the possible pre-amplifier signal range from 0.6 V to 1.0 V with a fine step size. The proposed threshold voltage generation network includes a reference generation network and a threshold voltage generator.
The threshold voltage generator has been implemented in ETROC0, the first prototype of ETROC, in a 65 nm CMOS technology. It includes a 10-bit digital-to-analog converter (DAC) and a noise filter. A two-stage resistor string structure is used in the DAC to achieve a monotonic adjustment curve. The first stage implements the 5-bit most significant bits (MSB) and the second stage determines the 5-bit least significant bits (LSB). The noise filter is used to filter out high-frequency noise and limit the noise well below the pre-amplifier noise. The threshold voltage generator measures differential nonlinearity (DNL) and integral nonlinearity (INL) of ±0.15 LSB and ±1.2LSB, respectively. The power consumption is 80 uA.
The reference generation network has been implemented in a separate prototype recently. Test results are expected to be presented at the conference.

IEEE Member No
Minioral Yes
Are you a student? Yes

Primary authors

Ms ZHANG, Li (Southern Methodist University) Ms EDWARDS, Christopher (Fermi National Accelerator Laboratory) Dr GONG, Datao (Southern Methodist Univeristy) Prof. HUANG, Guanming (Central China Normal University) Mr HUANG, Xing (Southern Methodist University) Mr LIU, Chonghan (Southern Methodist University) Dr LIU, Tiankuan (Southern Methodist University (US)) OLSEN, Jamieson (Fermi National Accelerator Lab. (US)) Ms SUN, Hanhan (Southern Methodist University) Dr SUN, Quan (Fermi National Accelerator Laboratory,) Prof. SUN, Xiangming (Central China Normal University) Prof. WU, Jingyuan (Fermi National Accelerator Lab. (US)) Prof. YE, Jingbo (Southern Methodist University) Mr ZHANG, Wei (Southern Methodist University) Prof. LIU, Tiehui (Fermi National Accelerator Lab. (US))

Presentation materials