  We report on the development and characterization of the low-noise, low
power, mixed analog-digital SIRIUS ASICs for both the LAD and WFM X-ray
instruments of LOFT. The ASICs we developed are reading out large area silicon
drift detectors (SDD). Stringent requirements in terms of noise (ENC of 17 e-
to achieve an energy resolution on the LAD of 200 eV FWHM at 6 keV) and power
consumption (650 {\mu}W per channel) were basis for the ASICs design. These
SIRIUS ASICs are developed to match SDD detectors characteristics: 16 channels
ASICs adapted for the LAD (970 microns pitch) and 64 channels for the WFM (145
microns pitch) will be fabricated. The ASICs were developed with the 180nm
mixed technology of TSMC.
