  TARGET~5 is a new application-specific integrated circuit (ASIC) of the
TARGET family, designed for the readout of signals from photosensors in the
cameras of imaging atmospheric Cherenkov telescopes (IACTs) for ground-based
gamma-ray astronomy. TARGET~5 combines sampling and digitization on 16 signal
channels with the formation of trigger signals based on the analog sum of
groups of four channels. We describe the ASIC architecture and performance.
TARGET~5 improves over the performance of the first-generation TARGET ASIC,
achieving: tunable sampling frequency from $<0.4$~GSa/s to $>1$~GSa/s; a
dynamic range on the data path of 1.2 V with effective dynamic range of 11~bits
and DC noise of ${\sim}0.6$~mV; 3-dB bandwidth of 500 MHz; crosstalk between
adjacent channels $<1.3\%$; charge resolution improving from 40\% to $<4\%$
between 3 photoelectrons (p.e.) and $>100$~p.e. (assuming 4 mV per p.e.); and
minimum stable trigger threshold of 20 mV (5 p.e.) with trigger noise of 5 mV
(1.2 p.e.), which is mostly limited by interference between trigger and
sampling operations. TARGET~5 is the first ASIC of the TARGET family used in an
IACT prototype, providing one development path for readout electronics in the
forthcoming Cherenkov Telescope Array (CTA).
