MAX14827A Datasheet, PDF (25/42 Pages) Maxim Integrated Products – High Configurability and Integration Reduce SKUs

MAX14827A
Low-Power, Ultra-Small, Dual Driver,
IO-Link Device Transceiver
C/Q Driver Enable/Disable
In pin-mode, the C/Q driver is enabled/disabled with the
TXEN input. Drive TXEN high to enable the C/Q driver.
C/Q is the logic inverse of the TX input.
In SPI mode, the C/Q driver can also be enabled/disabled,
configured, and controlled in the CQConfig register.
C/Q Current Limit
The C/Q driver is optimized for driving large capacitive
loads and dynamic impedances like incandescent
lamps. In pin-mode, the driver current limit is selectable
by setting the CLK/TXEN/200MA input high or low. Set
CLK/TXEN/200MA low for 100mA maximum load current.
Set CLK/TXEN/200MA high for a 200mA maximum load
current.
In SPI operation, the maximum driver current limit is
selectable as 50mA, 100mA, 200mA, or 250mA by setting
the CL1 and CL0 bits in the CURRLIM register.
C/Q Driver Fault Detection
The MAX14827A senses a fault condition on the C/Q driver
when it detects a short circuit for longer than the blanking
time. A short condition exists when the C/Q driver’s load
current exceeds the current limit. In SPI mode, both the
current limit and blanking time may be configured.
In pin-mode, the IRQ/OC output asserts low when a short
circuit fault occurs on C/Q or DO. In SPI mode, the
C/QFault and C/QFaultInt bits are set and IRQ/OC asserts.
When a short-circuit event occurs on C/Q, the driver can
either be set to continue supplying the selected current
until the device enters thermal shutdown or to enter
autoretry mode when an overcurrent event occurs. In
autoretry mode the driver is automattically disabled after
the current blanking time and is then re-enabled.
C/Q Receiver Output (RX)
RX is the output of the C/Q receiver. RX is the inverse logic
of the C/Q input.
In pin-control mode, the C/Q receiver is always on.
In SPI mode, the receiver can be disabled by setting the
Rx_Dis bit in the CQConfig register. RX is high impedance
when Rx_Dis is set. Note that the CQLvl bit in the Status
register is invalid when the Rx_Dis bit is set.
When operating in multiplexed mode, SDO/RX/THSH is the
output of the C/Q receiver. In this mode, SDO/RX/THSH is
high impedance when CS/PP is high and Rx_Dis bit is set.
C/Q Receiver Threshold
The IO-Link standard defines device operation with a
sensor supply between 18V and 30V. Industrial sensors,
however, commonly operate with supply voltages as low as
9V. The MAX14827A C/Q receiver supports operation with
lower supply voltages by scaling the receiver thresholds
when V24 is less than 18V (V₂₄ < 18V).
DO Driver
In pin-mode, the DO driver is always enabled. DO is the
logic inverse of the LO input.
In SPI mode, the DO driver can be enabled/disabled,
configured, and controlled in the DIOConfig register.
DO Current Limit
The DO driver is optimized for driving large capacitive
loads and dynamic impedances like incandescent lamps.
In pin-control mode, the driver current limit is selectable
by setting the CLK/TXEN/200MA input high or low. Set
CLK/TXEN/200MA low for 100mA maximum load current.
Set CLK/TXEN/200MA high for a 200mA maximum load
current.
In SPI operation, the maximum driver current limit is
selectable as 50mA, 100mA, 200mA, or 250mA by setting
the CL1 and CL0 bits in the CURRLIM register.
DO Fault Detection
The MAX14827A senses a fault condition on the DO output
when it detects a short circuit for longer than the blanking
time. A short condition exists when the DO driver’s load
current exceeds the current limit. In SPI mode, both the
current limit and blanking time may be configured.
In pin-mode, the IRQ/OC output asserts low when a short
circuit fault occurs on C/Q or DO. In SPI mode, the DoFault
and DoFaultInt bits are set and IRQ/OC asserts.
When a short-circuit event occurs on DO, the driver can
either be set to continue supplying the selected current
until the device enters thermal shutdown or to enter
autoretry mode when an overcurrent event occurs. In
autoretry mode the driver is automattically disabled after
the current blanking time and is then re-enabled.
DO and C/Q Tracking
In SPI mode, the DO driver can be configured to track the
C/Q driver. Set the CQDOPar bit in the CQConfig register
to enable this functionality. When the DO driver is set to
track C/Q, both C/Q and DO switch as a function of the TX
and TXEN inputs or CQ_Q bit.
In pin-mode, or when CQDOPar is 0, C/Q and DO operate
independently.
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