  We report a concept low gain avalanche diode (LGAD) detector to be integrated
into TOPSiDE, which is being developed for EIC (Electron-Ion Collider) project.
The LGAD detector will be taking its place to resolve requirement of
time-of-flight measurement for the TOPSiDE project. To achieve the required
timing resolution of 10 ps, the LGAD will be completely monolithic structure,
eliminating the parasitic elements from hybridization. The detector itself will
be consist of the LGAD sensor, amplification and discrimination, and
time-over-threshold logic components. At this stage, we are optimizing the LGAD
sensor design and preparing a discrete component based readout circuitry. In
this work, we will present simulation result of a conceptual LGAD silicon
detector and constant-fraction discriminator (CFD) circuit implementation. The
timing resolution of the conceptual detector was simulated with EDA tools such
as Silvaco Atlas and LTSpice with conjunction of a Monte-Carlo simulator to
resolve Landau distribution into the circuit readout simulation. The best
timing resolution we achieved was 23 ps.
