  A highly granular silicon-tungsten electromagnetic calorimeter (SiW-ECAL) is
the reference design of the ECAL for International Large Detector (ILD)
concept, one of the two detector concepts for the detector(s) at the future
International Linear Collider. Prototypes for this type of detector are
developed within the CALICE Collaboration. The final detector will comprise
about $10^{8}$ calorimeter cells that have to be integrated in a volume of
maximal 20 cm in depth. Detector components that in terms of size and channel
density come already close to the specifications for future large scale
experiments are progressively developed. This contribution will report on the
performance of a new 1.2 mm thick 9-layer PCB with wirebonded ASICs and
comparisons with PCBs with BGA packaged ASICs will be presented. A volume of
about $6\times18\times0.2$ cm$^{3}$ is available for the digital readout and
the power supply of the individual detector layers that feature up to 10000
calorimeter cells. We will present newly developed electronic cards that meet
these constraints.
