Datasheet

Data Sheet 10 Rev. 2.1, 2007-08-09
TLE6254-3G
If either of the supply voltages drops below the specified limits, the transceiver is
automatically switched to V
BAT
stand-by mode or power down mode respectively.
Bus Failure Management
The TLE6254-3G detects the bus failures as described in Table 3, and automatically
switches to a dedicated CANH or CANL single wire mode to maintain data transmission
if necessary. Therefore, the device is equipped with one differential receiver and 4 single
ended receivers, two for each bus line. To avoid false triggering by external RF
influences the single wire modes are only activated after a certain delay time. As soon
as the bus failure disappears the transceiver switches back to differential mode after
another time delay. Bus failures are indicated in the normal operation mode by setting
the NERR output low.
The differential receiver threshold is typ. -3.1 V. This ensures correct reception in the
normal operation mode as well as in the failure cases 1, 2 and 4 with a noise margin as
high as possible. For these failures, further failure management is not necessary.
Detection of the failure cases 1, 2, 3a and 4 is only possible when the bus is dominant.
Nevertheless, they are reported on the NERR output until transmission of the next CAN
word on the bus begins.
Table 2 Truth Table of the CAN Transceiver
NSTB ENT Mode INH NERR RxD RTL
00
V
BAT
stand-by
mode
1)
1) Wake-up interrupts are released when entering normal operation mode.
V
BAT
active LOW wake-up interrupt if
V
CC
is present
switched
to V
BAT
0 0 sleep mode
2)
2) If go to sleep command was used before, ENT may turn LOW as V
CC
drops, without affecting internal
functions.
floating switched
to V
BAT
0 1 go to sleep
command
becomes
floating
switched
to V
BAT
1 0 Receive-only
mode
V
BAT
active LOW
V
BAT
power-on
flag
3)
3) V
BAT
power-on flag will be reseted when entering normal operation mode.
HIGH = recessive
receive data;
LOW = dominant
receive data
switched
to V
CC
1 1 normal mode V
BAT
active LOW
bus error flag
HIGH = recessive
receive data;
LOW = dominant
receive data
switched
to V
CC