Fernando Rios said:
You mean like the one I will attend to do my M.S. in Physics (SJSU)
No, SJSU is a state school (according to Wikipedia, "the oldest public university on the West Coast and the founding campus of the California State University system."). The schools I'm thinking of are mostly small and privately-owned:
List of liberal arts colleges in the United States (Wikipedia)
They depend on student tution and fees, and on donations from alumni etc., for financial support.
Most of them originally had "College" in their names, and some of them still do, but many have "upgraded" themselves to "Universities" by adding specialized master's degree programs, often in health-related fields (e.g. nursing, pharmacy, occupational therapy), in order to bring in more tuition and fees. (However,
my own alma mater is still a "College", even after adding a nursing program.)
Fernando Rios said:
Working there as a lecturer is still a full-time job? Do I need a PhD to get tenure at this type of institutions?
Yes, they have the normal tenure track: assistant, associate and full professors; and most require a PhD in order to get on the tenure track. Their accrediting agencies usually limit the percentage of class-hours for a bachelor's degree, that can be taught by faculty who do not have a "terminal degree" e.g. PhD.
When I started teaching at the college that I retired from, a professor's normal teaching schedule was four lecture courses per semester. In departments with labs (e.g. physics, chemistry, biology), labs didn't "count" as much as lectures, so my schedule was usually either three lectures and two labs, or two lectures and three labs. At some point this changed to seven lectures per year (three in one semester and four in the other), with some weird advanced mathematics for "counting" labs.

This was for freeing up some faculty time to do research, which had basically become required for students.
Colleges with greater expectations for faculty to do research have teaching loads of three classes per semester, or even fewer if you can "buy" teaching hours with research grant money.