TCAN1042-Q1_17 Datasheet, PDF (19/40 Pages) Texas Instruments – Automotive Fault Protected CAN Transceiver with CAN FD

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TCAN1042-Q1, TCAN1042V-Q1, TCAN1042H-Q1
TCAN1042HV-Q1, TCAN1042G-Q1, TCAN1042GV-Q1
TCAN1042HG-Q1, TCAN1042HGV-Q1
SLLSES9B – FEBRUARY 2016 – REVISED MAY 2017
• TXD dominant time out (fault case limiting)
These ensure a minimum recessive amount of time on the bus even if the data field contains a high percentage
of dominant bits. The short circuit current of the bus depends on the ratio of recessive to dominant bits and their
respective short circuit currents. The average short circuit current may be calculated with the following formula:
I_OS(AVG) = %Transmit × [(%REC_Bits × I_{OS(SS)_REC}) + (%DOM_Bits × I_{OS(SS)_DOM})] + [%Receive × I_{OS(SS)_REC}]
(1)
Where:
• I_OS(AVG) is the average short circuit current
• %Transmit is the percentage the node is transmitting CAN messages
• %Receive is the percentage the node is receiving CAN messages
• %REC_Bits is the percentage of recessive bits in the transmitted CAN messages
• %DOM_Bits is the percentage of dominant bits in the transmitted CAN messages
• I_{OS(SS)_REC} is the recessive steady state short circuit current
• I_{OS(SS)_DOM} is the dominant steady state short circuit current
NOTE
Consider the short circuit current and possible fault cases of the network when sizing the
power ratings of the termination resistance and other network components.
9.3.7 Digital Inputs and Outputs
9.3.7.1 5-V V_CC Only Devices (Devices without the "V" Suffix):
The 5-V V_CC only devices are supplied by a single 5-V rail. The digital inputs have TTL input thresholds and are
therefore 5 V and 3.3 V compatible. The RXD outputs on these devices are driven to the V_CC rail for logic high
output. Additionally, the TXD and STB pins are internally pulled up to V_CC. The internal bias of the mode pins
may only place the device into a known state if the terminals float, they may not be adequate for system-level
biasing during transients or noisy enviroments.
NOTE
TXD pull up strength and CAN bit timing require special consideration when these devices
are used with CAN controllers with an open-drain TXD output. An adequate external pull
up resistor must be used to ensure that the CAN controller output of the micrcontroller
maintains adequate bit timing to the TXD input.
9.3.7.2 5 V V_CC with V_IO I/O Level Shifting (Devices with the "V" Suffix):
These devices use a 5 V V_CC power supply for the CAN driver and high speed receiver blocks. These
transceivers have a second power supply for I/O level-shifting (V_IO). This supply is used to set the CMOS input
thresholds of the TXD and pins and the RXD high level output voltage. Additionally, the internal pull ups on TXD
and STB are pulled up to V_IO.
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Product Folder Links: TCAN1042-Q1 TCAN1042V-Q1 TCAN1042H-Q1 TCAN1042HV-Q1 TCAN1042G-Q1
TCAN1042GV-Q1 TCAN1042HG-Q1 TCAN1042HGV-Q1