tja1054 NXP Semiconductors, tja1054 Datasheet - Page 8

• Manufacturer Part Number: tja1054
• Description: Fault-tolerant Can Transceiver
• Manufacturer: NXP Semiconductors

Philips Semiconductors
3. A local or remote wake-up event will be signalled at the transceiver pins RXD and NERR if V
4. In case the goto-sleep command was used before. When V
5. V
Wake-up requests are recognized by the transceiver
through two possible channels:
In order to wake-up the transceiver remotely through the
bus lines, a filter mechanism is integrated. This
mechanism makes sure that noise and any present bus
failure conditions do not result into an erroneous wake-up.
Because of this mechanism it is not sufficient to simply pull
the CANH or CANL bus lines to a dominant level for a
certain time. To guarantee a successful remote wake-up
under all conditions, a message frame with a dominant
phase of at least the maximum specified t
it is required.
A local wake-up through pin WAKE is detected by a rising
or falling edge with a consecutive level with the maximum
specified t
On a wake-up request the transceiver will set the output on
pin INH to HIGH which can be used to activate the external
supply voltage regulator.
If V
ERR or RXD outputs, so the external microcontroller can
activate the transceiver (switch to normal operating mode)
via pins STB and EN.
To prevent a false remote wake-up due to transients or
RF fields, the wake-up voltage levels have to be
maintained for a certain period of time. In the low power
modes the failure detection circuit remains partly active to
prevent an increased power consumption in the event of
failures 3, 3a, 4 and 7.
To prevent a false local wake-up during an open wire at
pin WAKE, this pin has a weak pull-up current source
towards V
is recommended to connect a not used pin WAKE to pin
BAT. INH is set to floating only if the goto-sleep command
is entered successfully. To enter a successful goto-sleep
command under all conditions, this command must be
kept stable for the maximum specified t
2004 Mar 23
The bus lines for remote wake-up
Pin WAKE for local wake-up.
Fault-tolerant CAN transceiver
CC
fail-safe functionality this does not effect the internal functions.
BAT
is provided the wake-up request can be read on the
power-on flag will be reset when entering normal operating mode.
BAT
WAKE
. However, in order to prevent EMC issues, it
.
h(sleep)
CANH
.
or t
CANL
in
8
Pin INH will be set to a HIGH level again by the following
events only:
To provide fail-safe functionality, the signals on pins STB
and EN will internally be set to LOW when V
certain threshold voltage (V
Power-on
After power-on (V
will become HIGH and an internal power-on flag will be set.
This flag can be read in the power-on standby mode
through pin ERR (STB = 1; EN = 0) and will be reset by
entering the normal operating mode.
Protections
A current limiting circuit protects the transmitter output
stages against short-circuit to positive and negative
battery voltage.
If the junction temperature exceeds the typical value of
165 C, the transmitter output stages are disabled.
Because the transmitter is responsible for the major part of
the power dissipation, this will result in a reduced power
dissipation and hence a lower chip temperature. All other
parts of the device will continue to operate.
The pins CANH and CANL are protected against electrical
transients which may occur in an automotive environment.
CC
V
Rising or falling edge on pin WAKE
A message frame with a dominant phase of at least the
maximum specified t
pin STB is at a LOW level
Pin STB goes to a HIGH level with V
BAT
drops, pin EN will become LOW, but due to the
power-on (cold start)
BAT
switched on) the signal on pin INH
CANH
CC(stb)
or t
CANL
).
BAT
, while pin EN or
Product specification
CC
= 5.3 V to 27 V.
TJA1054
active.
CC
is below a