Specifications

30 Maxim Industrial Solutions
Programmable logic controllers (PLCs)
Fieldbus functions
Benefits
• Reduces cost of high-speed communi-
cation interfaces
– 128-byte FIFOs
– Automatic half-duplex transceiver
control
– High 24Mbps (max) data rates
• High integration saves cost and space
– Integrated oscillator reduces need for an
external crystal
• Advance on-board clocking allows
near-limitless baud-rate generation
– Integrated PLL, divider, and a fractional
baud-rate generator yield high accuracy
and freedom in baud-rate programming
• Enables high density and compact PLC
designs
– Tiny 24-pin, TQFN (3.5mm x 3.5mm) and
standard SSOP packages
MAX3107
The MAX3107 serial UART bridges SPI or I
2
C to an asynchronous
communication interface like RS-485, RS-232, PROFIBUS DP, or IrDA®.
RS-485 and PROFIBUS DP work up to high data-rates which many
UARTs embedded on today’s microcontrollers cannot support. With
two 128-word FIFOs and an integrated oscillator, this UART requires
only a simple host controller for high-speed operation. Working at
these high rates, the MAX3107 supports today’s demanding high-
speed applications.
Advanced SPI/I
2
C UART enhances system flexibility and functionality, reduces load on
the microcontroller
The MAX3107 in an RS-485 half-duplex application.
A
B
DI
RO
RE
DE
TX
RX
XIN
XOUT
AGND
DGNDV
18
V
A
V
EXT
V
L
IRQ
I
2
C/SPI
LDOEN
RST
SPI
3.3V
MICROCONTROLLER
RTS/CLKOUT
10kΩ
0.1µF
0.1
µF
MAX3107
MAX14840