tja1054a NXP Semiconductors, tja1054a Datasheet - Page 8

• Manufacturer Part Number: tja1054a
• Description: Fault-tolerant Can Transceiver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TJA1054A_4
Product data sheet
7.3 Power-on
7.4 Protections
A local wake-up through pin WAKE is detected by a rising or falling edge with a
consecutive level exceeding 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
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
any EMC immunity issues, it is recommended to connect a not used pin WAKE to pin
BAT. Pin 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
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
After power-on (V
power-on flag will be set. This flag can be read in the power-on standby mode through
pin ERR (STB = HIGH; EN = LOW) and will be reset by entering the normal operating
mode.
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
t
Pin STB goes to a HIGH level with V
(CANL)
BAT
is provided the wake-up request can be read on the ERR or RXD outputs, so the
power-on (cold start)
, while pin EN or pin STB is at a LOW level
CC
is below a certain threshold voltage (V
BAT
switched on) the signal on pin INH will become HIGH and an internal
Rev. 04 — 2 January 2007
BAT
h(sleep)
. However, in order to protect the transceiver against
.
CC
active
WAKE
CC(stb)
Fault-tolerant CAN transceiver
.
).
TJA1054A
© NXP B.V. 2007. All rights reserved.
(CANH)
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