I’ve tried L78L33ACZ (different ICs from one tape,TO-92) with V(in)=5.0V with no success – only 3.0V output (multiple measurements done by oscilloscope and multimeter), with no load at all. With V(in)>5.3V output is stable, V(out)=3.3V. Defective IC?
In datasheet http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00000446.pdf there are no performance graphs for L78L33, and in the table “Table 13. Electrical characteristics of L78L33AB and L78L33AC” test conditions specified only beginning from V(in)=5.3V. Weird…