Datasheet

Failure 8—CANH Short-Circuited to V
CC
Table 1. Failure States (continued)
Failure 9—CANL Short-Circuited to V
CC
(Normal Mode Only)
Table 2. Summary of the Driver Outputs and Internal Switches State During Fault
Conditions
Note: The RTH-pulldown current switch and the RTL-pullup current switch are closed in normal mode with or without fault conditions,
open in sleep mode.
MODE DESCRIPTION
Detection Sensing a permanent dominant condition on CANH for a timeout period.
Receiver Receiver switches to single ended on CANL. Data lost (permanent dominant) during timeout.
Driver
CANH and RTH are both switched off (high impedance) and transmission continues on CANL after timeout. Only a
weak pulldown current on pin RTH remains.
Recovery
When the short is removed (CANH < 1.7V) and after a timeout, CANL is forced recessive (CANL off) and CANH is
enabled (RTH on and CANH enabled). Signal can be transmitted or received in single ended on CANH and ERR
remains low. If the differential voltage remains below the recessive threshold level (CANH - CANL < -3.2V) for a
second timeout, reception and transmission switch back to the differential mode and ERR is released high.
MODE DESCRIPTION
Detection Detection is provided, sensing the pulse-count difference between CANL and CANH (pulse count = 4).
Receiver Receiver remains in differential mode. No received data lost.
Driver Driver remains in differential mode. No transmission data lost.
Recovery
Recovery is provided, sensing the pulse-count difference between CANL and CANH after the detection of four
consecutive pulses.
FAILURE NO. DESCRIPTION MODE INTERNAL SWITCHES STATE
DRIVER OUTPUTS STATE
CANH CANL
No failure — Normal RTH, RTL on Enabled Enabled
No failure — Low power RTH, I_RTL on Disabled Disabled
1 CANH wire interrupted Normal RTH, RTL on Enabled Enabled
2 CANL wire interrupted Normal RTH, RTL on Enabled Enabled
3 CANH short to BATT All RTH off Disabled Enabled
4 CANL short to GND All RTL or I_RTL off Enabled Disabled
5 CANH short to GND Normal RTH, RTL on Enabled Enabled
6 CANL short to BATT Normal RTL off, RTH on Enabled Enabled
7 CANL short to CANH All RTL or I_RTL off Enabled Disabled
8 CANH short to V
CC
All RTH off Disabled Enabled
9 CANL short to V
CC
Normal RTH, RTL on Enabled Enabled
MAX3054/MAX3055/
MAX3056
±80V Fault-Protected/Tolerant CAN Transceiver
www.maximintegrated.com
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