TCAN1042-Q1_17 Datasheet, PDF (24/40 Pages) Texas Instruments – Automotive Fault Protected CAN Transceiver with CAN FD

TCAN1042-Q1, TCAN1042V-Q1, TCAN1042H-Q1
TCAN1042HV-Q1, TCAN1042G-Q1, TCAN1042GV-Q1
TCAN1042HG-Q1, TCAN1042HGV-Q1
SLLSES9B – FEBRUARY 2016 – REVISED MAY 2017
10 Application and Implementation
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NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
10.1 Application Information
These CAN transceivers are typically used in applications with a host microprocessor or FPGA that includes the
data link layer portion of the CAN protocol. Below are typical application configurations for both 5 V and 3.3 V
microprocessor applications. The bus termination is shown for illustrative purposes.
10.2 Typical Applications
Node 1
MCU or DSP
CAN
Controller
CAN
Transceiver
Node 2
MCU or DSP
CAN
Controller
CAN
Transceiver
Node 3
MCU or DSP
CAN
Controller
CAN
Transceiver
Node n
(with termination)
MCU or DSP
CAN
Controller
CAN
Transceiver
RTERM
RTERM
Figure 16. Typical CAN Bus Application
10.2.1 Design Requirements
10.2.1.1 Bus Loading, Length and Number of Nodes
The ISO 11898-2 Standard specifies a maximum bus length of 40 m and maximum stub length of 0.3 m.
However, with careful design, users can have longer cables, longer stub lengths, and many more nodes to a bus.
A large number of nodes requires transceivers with high input impedance such as the TCAN1042 family of
transceivers.
Many CAN organizations and standards have scaled the use of CAN for applications outside the original ISO
11898-2. They have made system-level trade-offs for data rate, cable length, and parasitic loading of the bus.
Examples of some of these specifications are ARINC825, CANopen, DeviceNet and NMEA2000.
The TCAN1042 family is specified to meet the 1.5 V requirement with a 50Ω load, incorporating the worst case
including parallel transceivers. The differential input resistance of the TCAN1042 family is a minimum of 30 kΩ. If
100 TCAN1042 family transceivers are in parallel on a bus, this is equivalent to a 300Ω differential load worst
case. That transceiver load of 300 Ω in parallel with the 60Ω gives an equivalent loading of 50 Ω. Therefore, the
TCAN1042 family theoretically supports up to 100 transceivers on a single bus segment. However, for CAN
network design margin must be given for signal loss across the system and cabling, parasitic loadings, network
imbalances, ground offsets and signal integrity thus a practical maximum number of nodes is typically much
lower. Bus length may also be extended beyond the original ISO 11898 standard of 40 m by careful system
design and datarate tradeoffs. For example CANopen network design guidelines allow the network to be up to 1
km with changes in the termination resistance, cabling, less than 64 nodes and significantly lowered data rate.
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Product Folder Links: TCAN1042-Q1 TCAN1042V-Q1 TCAN1042H-Q1 TCAN1042HV-Q1 TCAN1042G-Q1
TCAN1042GV-Q1 TCAN1042HG-Q1 TCAN1042HGV-Q1