TCAN1042-Q1 Datasheet, PDF (17/32 Pages) Texas Instruments – Automotive Fault Protected CAN Tranceiver

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TCAN1042-Q1, TCAN1042V-Q1, TCAN1042H-Q1
TCAN1042HV-Q1, TCAN1042G-Q1, TCAN1042GV-Q1
TCAN1042HG-Q1, TCAN1042HGV-Q1
SLLSES9 – FEBRUARY 2016
NOTE
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.
NOTE
TXD and STB are internally pulled up to V_CC. However, the internal bias may only put the
device into a known state if the terminals float. The internal bias may be inadequate for
system-level biasing. 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 separate supply for I/O level shifting (V_IO). This supply is used to set the CMOS input
thresholds of the TXD and STB pins and the RXD high level output voltage. The internal pull ups on TXD and
STB are weakly pulled up to V_IO.
Copyright © 2016, Texas Instruments Incorporated
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Product Folder Links: TCAN1042-Q1 TCAN1042V-Q1 TCAN1042H-Q1 TCAN1042HV-Q1 TCAN1042G-Q1
TCAN1042GV-Q1 TCAN1042HG-Q1 TCAN1042HGV-Q1