Since few years, our group is developing a family of ASICs for space applications, named IDeF-X for Imaging Detector Front-end. IDeF-X HD is the new member of the IDeF-X family. It has been optimized for the readout of 16 x 16 pixels CdTe or CdZnTe pixelated detectors to build a new low power Caliste 256 module. This micro gamma-camera will be the elementary unit of the MAC SI (Modular Assembly of Caliste Spectro Imager) camera: A 2048-pixels 8 cm2 gamma camera designed with 8 identical Caliste modules.