How can I find the CA Datacom Server mainframe solutions for USS? 

z/OS
USS

The CA Datacom Server USS solutions are published with the z/OS solutions.

NOTE: that we recommend that ALL CA Datacom Server mainframe solutions be applied which will include all the USS related solutions.

Here is one way to narrow down the solution search...

To download the CA Datacom Server (DBSRV) USS solutions, select the desired version from the "CA Datacom/CA Ideal/CA IPC Maintenance Grid for z/OS"

https://techdocs.broadcom.com/us/product-content/status/detailed-service-pack-info/ca-datacom-ca-ideal-ca-ipc-maintenance-grid-for-zos.html?r=2&r=1

Then, you will see the mainframe (OS) solutions for CA Datacom Server 15.0. 

Note "USS:" in the solution title when it is a USS solution with only cadjdbc.jar driver. 

Note "MF/USS:" when both MVS modules and jar driver are included.

Again, we recommend that ALL CA Datacom Server mainframe solutions be applied which will include all the USS related solutions.

As of this article update (September 2019), the latest CA Datacom Server Version 15.0 USS mainframe solution PTF SO07533 and provides the latest

cadcjdbc.jar Driver Version: 15.00.014

For CA Datacom Server Windows and LINUX solutions, refer to

Article 11469 (formerly TEC1485884) "CA Datacom Server Windows and LINUX solutions"
https://ca-broadcomcsm.wolkenservicedesk.com/wolken/esd/knowledgebase_search?articleId=11469