Reconfigurable ASIC for a Low Level Trigger System in Cherenkov Telescope Cameras

TL;DR

This paper introduces a reconfigurable ASIC designed for low level trigger systems in Cherenkov telescope cameras, capable of implementing multiple trigger concepts with high speed and linearity, suitable for CTA prototypes.

Contribution

The paper presents a versatile ASIC that supports two trigger concepts and processes up to 7 inputs, with high-speed differential circuitry for Cherenkov telescope applications.

Findings

Achieves 500 MHz operation speed.

Supports two trigger concepts: Majority and Sum trigger.

Suitable for CTA prototype cameras.

Abstract

A versatile and reconfigurable ASIC is presented, which implements two different concepts of low level trigger (L0) for Cherenkov telescopes: the Majority trigger (sum of discriminated inputs) and the Sum trigger concept (analogue clipped sum of inputs). Up to 7 input signals can be processed following one or both of the previous trigger concepts. Each differential pair output of the discriminator is also available as a LVDS output. Differential circuitry using local feedback allows the ASIC to achieve high speed (500 MHz) while maintaining good linearity in a 1 Vpp range. Experimental results are presented. A number of prototype camera designs of the Cherenkov Telescope Array (CTA) project will use this ASIC.