  We present ECLAIRs, the Gamma-ray burst (GRB) trigger camera to fly on-board
the Chinese-French mission SVOM. ECLAIRs is a wide-field ($\sim 2$\,sr) coded
mask camera with a mask transparency of 40\% and a 1024 $\mathrm{cm}^2$
detection plane coupled to a data processing unit, so-called UGTS, which is in
charge of locating GRBs in near real time thanks to image and rate triggers. We
present the instrument science requirements and how the design of ECLAIRs has
been optimized to increase its sensitivity to high-redshift GRBs and
low-luminosity GRBs in the local Universe, by having a low-energy threshold of
4 keV. The total spectral coverage ranges from 4 to 150 keV. ECLAIRs is
expected to detect $\sim 200$ GRBs of all types during the nominal 3 year
mission lifetime.
  To reach a 4 keV low-energy threshold, the ECLAIRs detection plane is paved
with 6400 $4\times 4~\mathrm{mm}^2$ and 1 mm-thick Schottky CdTe detectors. The
detectors are grouped by 32, in 8x4 matrices read by a low-noise ASIC, forming
elementary modules called XRDPIX. In this paper, we also present our current
efforts to investigate the performance of these modules with their front-end
electronics when illuminated by charged particles and/or photons using
radioactive sources. All measurements are made in different instrument
configurations in vacuum and with a nominal in-flight detector temperature of
$-20^\circ$C. This work will enable us to choose the in-flight configuration
that will make the best compromise between the science performance and the
in-flight operability of ECLAIRs. We will show some highlights of this work.
