Datasheet

SPI/I
2
C UART with 128-Word FIFOs
MAX3107
49Maxim Integrated
Connector Pin Sharing
The TX and RTS/CLKOUT outputs can be programmed
to be high impedance. This can be used in cases where
the MAX3107 shares a common connector with other
communication devices. Set the output of the MAX3107
to high impedance when the other communication
devices are active. Program MODE1[2]: TxHiZ high to
set TX to a high-impedance state. Program MODE1[3]:
RTSHiZ high to set RTS/CLKOUT to a high-impedance
state. Figure 25 shows an example of connector sharing
with a USB transceiver.
RS-232 5x3 Application
The four GPIOs can be used to implement the other flow-
control signals defined in ITU V.24. Figure 26 shows how
the GPIOs create the DSR, DTR, DCD, and RI signals
found on some RS-232/V.28 interfaces.
Set FlowCtrl[1:0] high to enable auto hardware RTS/CTS
flow control.
Typical Application Circuit
Figure 27 shows the MAX3107 being used in a half-
duplex RS-485 application. The microcontroller, the
RS-485 transceiver, and the MAX3107 are powered
by 3.3V. SPI is used as the controller’s communication
interface.
The MAX14840 receiver is continually enabled so that
echoing occurs. Enable auto echo suppression in the
MAX3107 UART by setting MODE2[7]: EchoSuprs to 1.
Set MODE1[4]: TranscvCtrl high to enable auto trans-
ceiver direction control to automatically control the DE
input of the transceiver.
Chip Information
PROCESS: BiCMOS
Figure 24. Logic-Level Translation
Figure 25. Connector Sharing with a USB Transceiver
MAX3107
TX
RX
RTS/CLKOUT
AGND
DGND
V
L
V
A
V
EXT
RST
IRQ
SPI/I
2
C
MAX3078
TRANSCEIVER
V
CC
DI
DE
RO
V
DD
2.5V
1.8V 3.3V
MICROCONTROLLER
MAX3107
TX
RX
MAX13481E
D+
D-
OE
TX/D+
RX/D-
SHARED
CONNECTOR