Hello Gonzalo,
You can download jConnect driver as follows.
SAP Service Marketplace -> SAP Support Portal -> Download -> Installation and Upgrade -> A-Z -> S -> SDK FOR SAP ASE
This link may help you locate the driver: https://service.sap.com/sap/support/notes/2093510Information
Please see the followling document.
http://dcx.sap.com/index.html#sqla170/en/html/3bd588c76c5f10149824867aa281fadd.html
Regards,
Koichi