CY7C64225 Datasheet, PDF (7/19 Pages) Cypress Semiconductor – USB-to-UART Bridge Controller

CY7C64225
Bus Powered Design using External Regulator
Figure 4 illustrates the use of CY7C64225 in bus powered mode
but running at 3.3 V. This design can be adopted when the circuit
operating at 3.3 V is desired (RX, TX, RTS, CTS, DSR, DTR at
3.3 V).
This design uses an external 5 V to 3.3 V regulator to supply the
3.3 V to CY7C64225 from VBUS. The 3.3 V to CY7C64225 can
also be provided from a regulator which is already available on
the circuit board, being used for other components on the board.
Since the circuit is operating at 3.3 V, a voltage divider is used to
provide 3.3 V from VBUS of USB port to ‘VBUS’ pin of
CY7C64225.
Figure 4. Bus Powered Design using External Regulator
VDD
VBUS
5V to 3.3V
Regulator
VDD
VDD
VBUS ^VBUS
10k
VDD
VBUS
VDD
Rx_LED
D+
D-
GND
20k
D+
24
D-
24
560
VCFG
560
Tx_LED
560
SUSPEND
VDD _SW2
0.01uF
VDD _SW1
0.01uF
CY7C64225
WAKEUP
TxD
RxD
1k
RTS
CTS
RESET
GND
DTR
DSR
GND
1k
Document Number: 001-76294 Rev. *B
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