  We developed a new front-end application specific integrated circuit (ASIC)
for the upgrade of the Maia x-ray microprobe. The ASIC instruments 32
configurable front-end channels that perform either positive or negative charge
amplification, pulse shaping, peak amplitude and time extraction along with
buffered analog storage. At a gain of 3.6 V/fC, 1 $\mu$s peaking time and a
temperature of 248 K, an electronic resolution of 13- and 10 electrons rms was
measured with and without a SDD sensor respectively. A spectral resolution of
170 eV FWHM at 5.9 keV was obtained with an $^{55}$Fe source. The channel
linearity was better than $\pm$ 1 % with rate capabilities up to 40 kcps. The
ASIC was fabricated in a commercial 250 nm process with a footprint of 6.3 mm x
3.9 mm and dissipates 167 mW of static power.
