MAX14826 Datasheet, PDF (17/32 Pages) Maxim Integrated Products – IO-Link Device Transceiver

MAX14826
IO-Link Device Transceiver
Detailed Description
The MAX14826 is a sensor/actuator transceiver designed
for IO-Link^® device applications supporting all the speci-
fied IO-Link data rates. In IO-Link applications, the devices
act as the physical layer interface to a microcontroller run-
ning the data-link layer protocol. The device contains an
additional 24V digital input and an additional 24V digital
output. Two internal linear regulators generate common
sensor and actuator power requirements: 5V and 3.3V.
The device detects IO-Link wake-up conditions on the
C/Q line and generates a wake-up signal on the WU/
THSD output. The C/Q and DO drivers are independently-
configurable to any one of three driver output types: push-
pull, high-side (PNP), or low-side (NPN).
This device is configured and monitored through a pin-
selectable parallel or SPI™ interface. Extensive alarms
are available through SPI.
24V Interface
The device features an IO-transceiver interface capable
of operating with voltages up to 36V. This is the 24V
interface and includes the C/Q input/output, the logic-level
digital output (DO), and the logic-level digital input (DI).
Configurable Drivers
The device features selectable push-pull, high-side (PNP),
or low-side (NPN) switching drivers at C/Q and DO.
Parallel Mode
In parallel mode, the C/Q and DO drivers are indepen-
dently-configurable using the CQPP/SCLK, DOPP/SDI,
and PNP/CS inputs. Set CQPP/SCLK high to select push-
pull operation on the C/Q driver. Set DOPP/SDI high to
select the push-pull operation on the DO driver.
The PNP/CS input selects NPN or PNP operation for driv-
ers configured for open-drain operation. Set PNP/CS high
for PNP operation. Set PNP/CS low for NPN operation.
See Table 1.
Table 1. Parallel Mode Select Truth Table
CQPP/SCLK DOPP/SDI
Low
Low
High
High
Low
Low
High
Low
Low
Low
Low
High
High
High
PNP/CS
Low
High
Low
High
Low
High
x
C/Q
MODE
NPN
PNP
Push-pull
Push-pull
NPN
PNP
Push-pull
DO MODE
NPN
PNP
NPN
PNP
Push-pull
Push-pull
Push-pull
X = Don’t care
IO-Link is a registered trademark of Profibus User Organization (PNO).
SPI is a trademark of Motorola, Inc.
SPI Mode
In SPI mode, write to the CQConfig and DIOConfig regis-
ters to configure the C/Q and DO drivers.
Set the C/Q_N/P and C/Q_PP bits in the CQConfig reg-
ister to select the driver mode for the C/Q driver. When
configured as a push-pull output, C/Q switches between
VP and ground. Set the C/Q_PP bit to 1 to select push-
pull operation at C/Q. Set the C/Q_PP bit to 0 to configure
the C/Q output for open-drain operation. The C/Q_N/P bit
selects NPN or PNP operation when C/Q is configured as
an open-drain output.
Set the DoN/P and DoPP bits in the DIOConfig regis-
ter to select the driver mode for the DO output. When
configured as a push-pull output, DO switches between
V_CC and ground. Set the DoPP bit to 1 for push-pull oper-
ation. The DoN/P bit selects NPN or PNP operation when
DO is configured as an open-drain output. Set the DoPP
bit to 0 to select high-side or low-side operation at DO.
C/Q Driver and Receiver
The C/Q driver can be enabled/disabled in either parallel-
input mode or SPI mode.
The device’s C/Q driver is specified for 200mA to drive
large capacitive loads of up to 1µF and dynamic imped-
ances like incandescent lamps. The maximum load cur-
rent for C/Q is limited to 480mA.
The C/Q receiver is always on. In SPI mode, the RX out-
put through the RxDis bit in the CQConfig register. Set the
RxDis bit to 1 to set the RX output high. Set the RxDis bit
to 0 for normal receive operation.
The C/Q receiver has an analog lowpass filter to reduce
high-frequency noise present on the line.
C/Q Fault Detection
The device registers a C/QFault condition under either of
two conditions:
1) When it detects a short-circuit for longer than 214µs
(typ). A short condition exists when the C/Q driver’s
load current exceeds the 350mA (typ) current limit.
2) When it detects a voltage level error at the C/Q output.
A voltage level error occurs when the C/Q driver is
configured for open-drain operation (NPN or PNP), the
driver is turned off, and the C/Q voltage is not pulled to
exceed the C/Q receiver’s threshold levels (< 8V or >
13V) by the external supply.
When a C/QFault error occurs, the C/QFault and
C/QFaultInt bits are set, IRQ/CQOC asserts, and the
driver is turned off after the start of the fault condition.
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