AwaXe_v2 (Athena Warm Asic for the X-ifu Electronics - Version2) is an upgrade of a demonstration performance and technology design for the Warm Front End Electronics (WFEE) of a future X-ray space telescope ATHENA. The main studied part of this ASIC, is an ultra low gain drift LNA (Low Noise Amplifier) for the readout chain of the X-ray Integral Field Unit (X-IFU) instrument of the ATHENA space observatory. This ASIC also includes series bus RS485/I2C for slow control using RadHard by Design digital library, a differential thermometer for high common-mode noise rejection HK and other test vehicules used for radiation effects study. This ASIC is one of the AwaXe and SQmux ASIC families developed at APC for the SQUID/TES readout. This development is funded by CNES and CNRS.Gain drift as low as 300ppm/°C is optained by post-simulation. The input voltage noise is simulated to an uptodate level of 0.7 nV/Hz in the goal bandwidth of 1-6MHz. The non-linearity is better than 1% over the whole dynamic range of 1 Vpp.