Characterization of SBRC-190: a multi-gain, cryogenic readout multiplexer for IR detector arrays

A low noise 2×16 Ge:Sb focal-plane array: Paving the way for large format FPAs for far IR astronomy

“…The measurements were made in differential mode and the noise was determined as the standard deviation of 1000 integrations. The results were similar to SBRC190s we have tested in other setups [17]. The read noise was highest with the largest feedback capacitors, dropping down to a plateau for several of the smallest feedback capacitors.…”

“…The noise is perhaps dominated by the 1/f noise of the readout MOSFETs. Taking more samples per integration reduced the read noise but the improvement was not as great as one would expect from statistics, possibly because of the additional noise introduced by addressing [17]. Most of the noise benefit was gained when clocking up to 16 samples-up-the-ramp beyond which the improvement was not as substantial.…”

“…We have tested a number of these devices in the past and found a CDS (correlated double sampling) read-noise of about 250-350e À [17]; not stellar but a reasonable noise performance nonetheless. The unit cell is an active integrator, with eight capacitor in the feedback loop, which can be enabled sequentially to provide eight gain settings.…”

“…These readouts must be especially designed for far IR detectors requiring low bias levels to ensure uniformity across the array and adequate dynamic range. CRC696 [13][14][15], successfully used in Spitzer's MIPS instrument, and SBRC190 [16,17], originally developed for SOFIA's AIRES instrument, are capacitive transimpedance amplifiers (CTIA) suitable for far IR detectors.…”

Viability of layered-hybrid architecture for far IR focal-plane arrays

“…The finished device was a top-illuminated, longitudinal, 1 mm thick, 2 · 16 array with 800 lm pixel pitch and pixel-groove depth of about 90 lm. The readout we used is the 1 · 32 SBRC190 which is specifically designed for far IR photoconductors operating below 4 K. It was manufactured by Raytheon for SOFIA's AIRES instrument using a 0.8 lm cryo-CMOS process [22,23]. The unit cell is an active integrator with eight capacitors in the feedback loop which can be enabled sequentially to provide eight gain settings.…”