MAX14827A Datasheet, PDF (24/42 Pages) Maxim Integrated Products – High Configurability and Integration Reduce SKUs

MAX14827A
Low-Power, Ultra-Small, Dual Driver,
IO-Link Device Transceiver
Detailed Description
The MAX14827A is an industrial sensor output driver/IO-
Link device transceiver. The IC integrates the high voltage
functions commonly found in sensors, including two 24V
line driver and two on-board linear regulators (LDOs).
The MAX14827A can be configured and monitored either
through the SPI interface or by setting logic interface pins.
The MAX14827A features multiple programmable
functions that allow the user to optimize operation and
power dissipation for various loads and application
scenarios.
The integrated 3.3V and 5V LDOs provide the power
needed for low noise analog and logic supply rails.
SPI, UART, or Pin-Mode Interface
Pin-Mode
The MAX14827A provides a selectable SPI or pin interface
to configure and monitor device operation. Drive the SPI/
PIN input high to use the SPI. Drive SPI/PIN low to use the
pin interface (pin-mode control).
When operating in pin mode, the following functionality is
set and cannot be changed:
• RX and DI are enabled (cannot be disabled)
• RX deglitch filter is enabled
• Weak pull-ups/pull-downs on C/Q and DO are
disabled
• Autoretry functionality is disabled
• The blanking time on C/Q and DO is 128μs
SPI Operation (Parallel Operating Mode)
When the MAX14827A is operated in SPI mode, an
external UART can be connected to separate UART
interface pins (TX, RX, TXEN). This is called the parallel
SPI/UART operating mode. This is the common approach
used when the microcontroller offers a UART and a
separate SPI port in the Typical Operating Circuit. Drive
UARTSEL low for operation in parallel mode.
SPI Operation (Multiplexed Mode)
In cases where only one microcontroller serial port
is available with both SPI and UART functions, the
MAX14827A can be operated in multiplexed SPI/UART
mode. This is feasible in IO-Link operation due to the
defined idle times in the IO-Link cycle time. In multiplexed
mode, the UART and SPI pins are shared. Two operating
modes are available in multiplexed mode, as selected by
the ENMPX bit.
When ENMPX = 0, UART and SPI operation are selected
by setting the CS/PP input. In this mode the SPI interface
is active when CS/PP is low and UART operation when
CS/PP is high.
When ENMPX = 1, UART and SPI operations are
selected by setting the UARTSEL input. To avoid glitches
on C/Q, CLK/TXEN/200MA and SDI/TX/NPN are sampled
on the falling edge of UARTSEL in this mode. See Mode
Selection Table for more information.
When entering multiplexed mode, set TXEN low and TX
high to disable the driver.
IRQ/OC is active in both multiplexed modes during UART
communication.
24V Interface
The MAX14827A features an IO-Link transceiver interface
capable of operating with voltages up to 60V. This is the
24V interface and includes the C/Q input/output, the logic-
level digital output (DO), the logic-level digital input (DI),
and the V24 supply.
The MAX14827A features selectable push-pull, high-side
(PNP), or low-side (NPN) switching drivers at C/Q and DO.
Configurable Drivers (Pin-Mode)
In pin-mode, use SDI/TX/NPN and CS/PP inputs to
configure the C/Q and DO drivers in push-pull, PNP, or
NPN modes (Table 3) In this mode, toggle TXEN, TX, and
LO to switch the C/Q and DO outputs.
Configurable Drivers (SPI Mode)
In SPI operation, the C/Q and DO drivers can be
configured independently. Set the bits in the CQConfig
register to configure the C/Q driver, enable/disable the
weak pull-up and pull-down currents on C/Q. Set the bits
in the DIOConfig register to configure the DO driver and
enable/disable the weak pull-up and pull-down currents
on DO. The C/Q and DO drivers can be disabled by
setting the CQ_Dis and DO_Dis bits. Driver outputs are
high impedance and power dissipation is reduced when
these bits are set. See the Register Functionality section
for more information on configuring the drivers.
For IO-Link operation, TX, TXEN, and RX are the UART
interface to control C/Q communication. Set CQ_Dis =
CQ_Q = 0 and drive TX and TXEN inputs for C/Q driver
control.
For lower rate switching on the C/Q and DO drivers,
register bits can be used for C/Q and DO control. For bit
control, drive TXEN, TX, and LO high and use the CQ_Q
and DO_Q bits to control the C/Q and DO driver states.
The CQ_Dis and DO_Dis bits are used to enable/disable
the drivers in this mode.
IO-Link is a registered trademark of Profibus User Organization (PNO).
SPI is a trademark of Motorola, Inc.
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