The CAIRO+ tool allows the designer of analog circuits to automate his flow, and permits the reuse. However, it doesn’t prevent him from controlling the generation. CAIRO+ is based on a library of smart generators which can handle the analog specific constraints, related to the electrical synthesis or to the design rules for a reliable layout. Here we present what are these device generators and how they can be used in a complex design automation. The example of a simple OTA using some of the available generators is shown.