TCAN330 Datasheet, PDF (26/39 Pages) Texas Instruments – CAN Transceivers

TCAN330, TCAN332, TCAN334, TCAN337
TCAN330G, TCAN332G, TCAN334G, TCAN337G
SLLSEQ7A – DECEMBER 2015 – REVISED JANUARY 2016
11 Application and Implementation
www.ti.com
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.
11.1 Application Information
11.1.1 Bus Loading, Length and Number of Nodes
The ISO 11898 standard specifies a data rate up to 1 Mbps, maximum CAN bus cable length of 40 m, maximum
drop line (stub) length of 0.3 m and a maximum of 30 nodes. However, with careful network design, the system
may have longer cables, longer stub lengths, and many more nodes to a bus. Many CAN organizations and
standards have scaled the use of CAN for applications outside the original ISO 11898 standard. 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, CAN Kingdom, DeviceNet and NMEA200.
A high number of nodes requires a transceiver with high input impedance and wide common mode range such
as the TCAN33x CAN family. ISO 11898-2 specifies the driver differential output with a 60-Ω load (two 120- Ω
termination resistors in parallel) and the differential output must be greater than 1.5 V. The TCAN33x devices are
specified to meet the 1.5-V requirement with a 50-Ω load across a common mode range of –12 V to 12 V
through a 330-Ω coupling network. This network represents the bus loading of 120 TCAN33x transceivers based
on their minimum differential input resistance of 40 kΩ.
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 may be
lower. Bus length may also be extended beyond the original ISO 11898 standard of 40 m by careful system
design and data rate tradeoffs. For example, CANopen network design guidelines allow the network to be up to
1 km with changes in the termination resistance, cabling, number of nodes and data rate.
This flexibility in CAN network design is one of the key strengths of the various extensions and additional
standards that have been built on the original ISO 11898 CAN standard.
11.2 Typical Application
V_IN
VIN
VOUT
3-V Voltage
Regulator
(e.g. TPSxxxx)
VCC
3-V MCU
RXD
TXD
SHDN/
FAULT
S / STB
V_CC
3
5 _TCAN33x
8
7
CAN Transceiver
CANH
RXD
4
TXD
1
CANL
6
2
GND
Optional:
Terminating
Node
Figure 34. Typical 3.3-V Application
26
Submit Documentation Feedback
Copyright © 2015–2016, Texas Instruments Incorporated
Product Folder Links: TCAN330 TCAN332 TCAN334 TCAN337 TCAN330G TCAN332G TCAN334G TCAN337G