TJA1054A View Datasheet(PDF) - Philips Electronics
Part Name
Description
MFG CO.
TJA1054A Datasheet PDF : 25 Pages
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Philips Semiconductors
Fault-tolerant CAN transceiver
Product specification
TJA1054A
Failure 6 is detected if the CANL bus line exceeds its
comparator threshold for a certain period of time. This
delay is needed to avoid false triggering by external RF
fields. After detection of failure 6, the reception is switched
to the single-wire mode through CANH; the CANL driver is
switched off and the RTL bias changes to the pull-up
current source.
Recovery from failures 3, 3a and 6 is detected
automatically after reading a consecutive recessive level
by corresponding comparators for a certain period of time.
Failures 4 and 7 initially result in a permanent dominant
level on pin RXD. After a time-out the CANL driver is
switched off and the RTL bias changes to the pull-up
current source. Reception continues by switching to the
single-wire mode via pins CANH or CANL. When
failures 4 or 7 are removed, the recessive bus levels are
restored. If the differential voltage remains below the
recessive threshold level for a certain period of time,
reception and transmission switch back to the differential
mode.
If any of the wiring failure occurs, the output signal on
pin ERR will be set to LOW. On error recovery, the output
signal on pin ERR will be set to HIGH again. In case of an
interrupted open bus wire, this failure will be detected and
signalled only if there is an open wire between the
transmitting and receiving node(s). Thus, during open wire
failures, pin ERR typically toggles.
During all single-wire transmissions, EMC performance
(both immunity and emission) is worse than in the
differential mode. The integrated receiver filters suppress
any HF noise induced into the bus wires. The cut-off
frequency of these filters is a compromise between
propagation delay and HF suppression. In single-wire
mode, LF noise cannot be distinguished from the required
signal.
Low power modes
The transceiver provides three low power modes which
can be entered and exited via STB and EN (see Table 2
and Fig.3).
The sleep mode is the mode with the lowest power
consumption. Pin INH is switched to HIGH-impedance for
deactivation of the external voltage regulator. Pin CANL is
biased to the battery voltage via pin RTL. If the supply
voltage is provided, pins RXD and ERR will signal the
wake-up interrupt.
The standby mode operates in the same way as the sleep
mode but with a HIGH level on pin INH.
The power-on standby mode is the same as the standby
mode, however, in this mode the battery power-on flag is
shown on pin ERR instead of the wake-up interrupt signal.
The output on pin RXD will show the wake-up interrupt.
This mode is only for reading out the power-on flag.
Table 2 Normal operating and low power modes
MODE
PIN
STB
PIN EN
PIN ERR
LOW
HIGH
PIN RXD
LOW
HIGH
Goto-sleep
command
Sleep
Standby
Power-on
standby
LOW
LOW
LOW
HIGH
Normal
HIGH
operating
HIGH
LOW(4)
LOW
LOW
HIGH
wake-up
interrupt signal;
notes 1 2 and 3
VBAT power-on
flag;
notes 1 and 5
error flag
no error flag
wake-up
interrupt signal;
notes 1 2 and 3
wake-up
interrupt signal;
notes 1 2 and 3
dominant
recessive
received data received data
Notes
1. If the supply voltage VCC is present.
2. Wake-up interrupts are released when entering normal operating mode.
PIN RTL
SWITCHED
TO
VBAT
VBAT
VCC
2004 Mar 23
7
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