The LBNE Project is developing a design for multiple 20 kiloton liquid argon (LAr) time projection chambers to be used as the far detector for the Long Baseline Neutrino Experiment. An essential component of this design is a complete electronic readout system designed to operate in LAr (at 90K). This system is being implemented as a CMOS ASIC, in 180nm commercial technology, that will provide low-noise readout of the signals induced on the TPC wires, digitization of those signals at 2 MS/s, zero-suppression, buffering and output multiplexing to a small number of cryostat feed-throughs. A resolution better than 1000 rms electrons at 200 pF input capacitance for an input range of 300 fC is required, along with low power (<15mW/channel) and operation in LAr with a lifetime greater than 15 years. An analog-only frontend has been successfully completed and fully evaluated, and will be used in the MicroBooNE LAr TPC. A prototype of the digital section has been fabricated and is being evaluated. The results demonstrate that CMOS transistors have lower noise and much improved dc characteristics at LAr temperature. We will describe the progress to date and plans for the remaining development.