  We present a programmable 16 channel, mixed signal, low power readout ASIC,
having the project historically named Gigasample Recorder of Analog waveforms
from a PHotodetector (GRAPH). It is designed to read large aperture single
photon imaging detectors using micro channel plates for charge multiplication,
and measuring the detector's response on crossed strips anodes to extrapolate
the incoming photon position. Each channel consists of a fast, low power and
low noise charge sensitive amplifier, which provides a myriad of coarse and
fine programmable options for gain and shaping settings. Further, the amplified
signal is recorded using, to our knowledge novel, the Hybrid Universal sampLing
Architecture (HULA), a mixed signal double buffer memory, that enables
concurrent waveform recording, and selected event digitized data extraction.
The sampling frequency is freely adjustable between few~kHz up to 125~MHz,
while the chip's internal digital memory holds a history 2048 samples for each
channel, with a digital headroom of 12 bits. An optimized region of interest
sample-read algorithm allows to extract the information just around the event
pulse peak, while selecting the next event, thus substantially reducing the
operational dead time. The chip is designed in 130~$n$m TSMC CMOS technology,
and its power consumption is around 47~$m$W per channel.
