  Time-Division Multiplexing is the readout architecture of choice for many
ground and space experiments, as it is a very mature technology with proven
outstanding low-frequency noise stability, which represents a central challenge
in multiplexing. Once fully populated, each of the two BICEP Array high
frequency receivers, observing at 150GHz and 220/270GHz, will have 7776 TES
detectors tiled on the focal plane. The constraints set by these two receivers
required a redesign of the warm readout electronics. The new version of the
standard Multi Channel Electronics, developed and built at the University of
British Columbia, is presented here for the first time. BICEP Array operates
Time Division Multiplexing readout technology to the limits of its capabilities
in terms of multiplexing rate, noise and crosstalk, and applies them in
rigorously demanding scientific application requiring extreme noise performance
and systematic error control. Future experiments like CMB-S4 plan to use TES
bolometers with Time Division/SQUID-based readout for an even larger number of
detectors.
