Laut Datenblatt:
+1.8V to +5.25V supply to UART Interface and CBUS group pins (2,3, 6,
...,11, 21, 22, 30,..32). In USB bus powered designs connect to 3V3OUT
to drive out at 3.3V levels, or connect to VCC to drive out at 5V CMOS
level. This pin can also be supplied with an external 1.8V - 2.8V supply
in order to drive out at lower levels. It should be noted that in this
case this supply should originate from the same source as the supply to
Vcc. This means that in bus powered designs a regulator which is
supplied by the 5V on the USB bus should be used.
Im Schaltplan unter "Self-Powered" ist es auch so eingezeichnet wie ich
es hier habe. Hab ich einen Fehler gemacht?
Proktor