VASE: A 256-Channel Readout ASIC for Column- Parallel CCDs with 14b Dynamic Range

A 256-channel readout ASIC called VASE, intended for the readout of Column-Parallel Charge-Coupled Devices (CP-CCD), is presented. Each channel employs a chargesensitive amplifier and a first-order Sigma Delta ADC that acts as the front end of an Extended Counting ADC. To reduce the noise due to input capacitance and to ensure a compact camera, each VASE channel is pitch matched to the CP-CCD to allow chip-to-chip bonding with minimal parasitic capacitance. VASE, with a die area of approximately 38.1 mm
²
and fabricated in 180 nm CMOS technology, achieves approximately 22 e
^-
ENC at a 4 MHz pixel rate while dissipating 1.1 mW per channel. The prototype has been used to successfully image X-ray diffraction at a soft X-ray synchrotron.