SLLU355 October 2022 TCAN1046A-Q1 , TCAN1046AV-Q1
The TCAN1046AEVM has several bus termination options for all available buses. For the TCAN1046A half of the board (top half), the termination on the CAN bus (CANH and CANL) can be configured with the J4 and J5 (CAN1) or J7 and J9 (CAN2) jumpers. For the TCAN1046AV half of the board (bottom half), the termination on the CAN bus (CANH and CANL) can be configured with the J15 and J16 (CAN1) or J18 and J20 (CAN2) jumpers. Each jumper adds 120-Ω termination to the respective bus. When using one resistor, the EVM is used as a terminated end of a bus. For electrical measurements to represent the total loading of the bus, use both 120-Ω resistors in parallel to give the standard 60-Ω load for parametric measurement. The footprint for split termination is also available and can be populated on all 4 buses. These components are not populated out of the box. Table 2-3 summarizes how to use these termination options. If using split termination, match the resistors. Calculate the common mode filter frequency using: fC = 1 / (2πRC). Normally, the split capacitance is in the range of 4.7 nF to 100 nF. Keep in mind this is the common-mode filter frequency, not a differential filter that impacts the differential CAN signal directly.
| Termination Configuration | 120-Ω Resistors (CAN1) | 120-Ω Resistors (CAN2) | Split Termination Footprints (CAN1) | Split Termination Footprints (CAN2) | Split Termination Footprints (CAN1) | Split Termination Footprints (CAN2) | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| J5 | J9 | J4 | J7 | R2 | R6 | R15 | R11 | C2 | C9 | |
| Standard termination (120 Ω) | shorted | open | N/A | N/A | N/A | |||||
| 60-Ω load - electrical parameterics | shorted | shorted | ||||||||
| Split termination (common mode stabilization) | open | open | 60 Ω | 60 Ω | populated | |||||
| Termination Configuration | 120-Ω Resistors (CAN1) | 120-Ω Resistors (CAN2) | Split Termination Footprints (CAN1) | Split Termination Footprints (CAN2) | Split Termination Footprints (CAN1) | Split Termination Footprints (CAN2) | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| J16 | J20 | J15 | J18 | R31 | R36 | R40 | R44 | C16 | C23 | |
| Standard termination (120 Ω) | shorted | open | N/A | N/A | N/A | |||||
| 60-Ω load - electrical parameterics | shorted | shorted | ||||||||
| Split termination (common mode stabilization) | open | open | 60 Ω | 60 Ω | populated | |||||
The EVM also has footprints for various protection schemes to enhance robustness for extreme system-level EMC requirements. Table 2-5 summarizes these options.
| Configuration | Footprint Reference | Use Case | Population and Description |
|---|---|---|---|
| Series resistors or common mode choke | R1/R9 or L1 (common footprint) | Direct CAN1 transceiver to bus connection | R1 and R9 populated with 0 Ω |
| Series resistance protection, CAN1 transceiver to bus connection | R1and R9 populated with MELF resistor as necessary for harsh EMC environment | ||
| CM choke (CAN1 bus filter) | L1 populated with CM choke to filter noise as necessary for harsh EMC environment (default population) | ||
| R10/R17 or L2 (common footprint) | Direct CAN2 transceiver to bus connection | R10 and R17 populated with 0 Ω | |
| Series resistance protection, CAN2 transceiver to bus connection | R10 and R17 populated with MELF resistor as necessary for harsh EMC environment | ||
| CM choke (CAN2 bus filter) | L2 populated with CM choke to filter noise as necessary for harsh EMC environment (default population) | ||
| Bus filtering caps transient protection | C1/C3 | Bus filter | Filter noise as necessary for harsh EMC environment. Use filter caps in combination with L1 CM choke. |
| C8/C10 | Filter noise as necessary for harsh EMC environment. Use filter caps in combination with L2 CM choke. | ||
| C1/C3 or D1 | Transient and ESD protection | To add extra protection for system level transients and ESD protection, TVS diode population option via D1 footprint or varistor population via C1/C3 footprint. | |
| C8/C10 or D3 | To add extra protection for system level transients and ESD protection, TVS diode population option via D3 footprint or varistor population via C8/C10 footprint. |
| Configuration | Footprint Reference | Use Case | Population and Description |
|---|---|---|---|
| Series resistors or common mode choke | R30/R38 or L3 (common footprint) | Direct CAN1 transceiver to bus connection | R30 and R38 populated with 0 Ω |
| Series resistance protection, CAN1 transceiver to bus connection | R30and R38 populated with MELF resistor as necessary for harsh EMC environment | ||
| CM choke (CAN1 bus filter) | L3 populated with CM choke to filter noise as necessary for harsh EMC environment (default population) | ||
| R39/R46 or L4 (common footprint) | Direct CAN2 transceiver to bus connection | R39 and R46 populated with 0 Ω | |
| Series resistance protection, CAN2 transceiver to bus connection | R39 and R46 populated with MELF resistor as necessary for harsh EMC environment | ||
| CM choke (CAN2 bus filter) | L4 populated with CM choke to filter noise as necessary for harsh EMC environment (default population) | ||
| Bus filtering caps transient protection | C15/C17 | Bus filter | Filter noise as necessary for harsh EMC environment. Use filter caps in combination with L3 CM choke. |
| C22/C24 | Filter noise as necessary for harsh EMC environment. Use filter caps in combination with L4 CM choke. | ||
| C15/C17 or D4 | Transient and ESD protection | To add extra protection for system level transients and ESD protection, TVS diode population option via D4 footprint or varistor population via C15/C17 footprint. | |
| C22/C24 or D6 | To add extra protection for system level transients and ESD protection, TVS diode population option via D6 footprint or varistor population via C22/C24 footprint. |