MAX3054_14 Datasheet, PDF (14/18 Pages) Maxim Integrated Products – ±80V Fault-Protected/Tolerant CAN Transceiver

MAX3054/MAX3055/
MAX3056
±80V Fault-Protected/Tolerant CAN Transceiver
Table 1. Failure States (continued)
Failure 3—CANH Short-Circuited to Battery
MODE
Detection
Receiver
Driver
Recovery
DESCRIPTION
Sensing a permanent dominant condition on CANH for a timeout period.
Receiver switches to single ended on CANL.
CANH and RTH are both switched off (high impedance) and transmission continues on CANL after timeout.
When the short is removed, the recessive bus voltage is restored. If the differential voltage remains below the
recessive threshold level for the timeout period, reception and transmission switch back to the differential mode.
Failure 4—CANL Short-Circuited to GND
MODE
Detection
Receiver
Driver
Recovery
DESCRIPTION
Sensing a permanent dominant condition for a timeout period.
Receiver switches to single ended on CANH.
CANL and RTL are both switched off (high impedance) and transmission continues on CANH after timeout.
When the short is removed, the recessive bus voltage is restored. If the differential voltage remains below the
recessive threshold level for the timeout period, reception and transmission switch back to the differential mode.
Failure 5—CANH Short-Circuited to Ground or Below Ground (Normal Mode Only)
MODE
Detection
Receiver
Driver
Recovery
DESCRIPTION
Detection is provided, sensing the pulse-count difference between CANH and CANL (pulse count = 4).
Receiver remains in differential mode. No received data lost.
RTH remains on and CANH remains enabled.
Recovery is provided, sensing the edge-count difference between CANH and CANL after the detection of four
consecutive pulses.
Failure 6—CANL Short-Circuited to Battery (Normal Mode Only)
MODE
Detection
Receiver
Driver
Recovery
DESCRIPTION
Detected by a comparator for CANL > 7.3V after a timeout period.
Receiver switches to single ended on CANH after timeout.
RTL is switched off after timeout. CANH remains active.
Sensing CANL < 7.3V after the timeout period.
Failure 7—CANL Mutually Short-Circuited to CANH
MODE
Detection
Receiver
Driver
DESCRIPTION
Sensing a permanent dominant condition on the differential comparator (CANH - CANL > -3.2V) for the timeout
period.
Receiver switches to CANH single-ended mode after timeout.
CANL and RTL are both switched off after timeout. Transmission remains ongoing on CANH.
Recovery
When the short is removed, the recessive bus voltage is restored (RTL on if CANH - CANL < -3.2V) but CANL still
remains disabled and ERR = 0. If the differential voltage remains below the recessive threshold level (CANH - CANL
< -3.2V) for the timeout period, reception and transmission switch back to the differential mode.
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