tja1042 NXP Semiconductors, tja1042 Datasheet - Page 5

• Manufacturer Part Number: tja1042
• Description: High-speed Can Transceiver With Standby Mode
• Manufacturer: NXP Semiconductors

NXP Semiconductors
6. Functional description
TJA1042_1
Product data sheet
6.1.1 Normal mode
6.1.2 Standby mode
6.1 Operating modes
The TJA1042 is a HS-CAN stand-alone transceiver with Standby mode. It combines the
functionality of the PCA82C250, PCA82C251 and TJA1040 transceivers with improved
EMC and ESD handling capability and quiescent current performance. Improved slope
control and high DC handling capability on the bus pins provide additional application
flexibility.
The TJA1042 is available in two versions, distinguished only by the function of pin 5:
The TJA1042 supports two operating modes, Normal and Standby, which are selectable
via pin STB. See
conditions.
Table 3.
A LOW level on pin STB selects Normal mode. In this mode, the transceiver can transmit
and receive data via the bus lines CANH and CANL (see
The differential receiver converts the analog data on the bus lines into digital data which is
output to pin RXD. The slope of the output signals on the bus lines is controlled and
optimized in a way that guarantees the lowest possible EME.
A HIGH level on pin STB selects Standby mode. In Standby mode, the transceiver is not
able to transmit or correctly receive data via the bus lines. The transmitter and
Normal-mode receiver blocks are switched off to reduce supply current, and only a
low-power differential receiver monitors the bus lines for activity. The wake-up filter on the
output of the low-power receiver does not latch bus dominant states, but ensures that only
bus dominant and bus recessive states that persist longer than t
pin RXD.
In Standby mode, the bus lines are biased to ground to minimize the system supply
current. The low-power receiver is supplied by
activity even if
a wake-up request, a transition to Normal mode will not be triggered until STB is forced
LOW.
Mode
Normal
Standby
•
•
The version with a SPLIT output is 100 % backwards compatible with the TJA1040,
and also covers existing PCA82C250 and PCA82C251 applications
The version with a V
voltages down to 3 V
Operating modes
V
IO
Table 3
is the only supply voltage available. When pin RXD goes LOW to signal
Pin STB
LOW
HIGH
Rev. 01 — 9 March 2009
IO
for a description of the operating modes under normal supply
pin allows for direct interfacing to microcontrollers with supply
High-speed CAN transceiver with Standby mode
Pin RXD
LOW
bus dominant
wake-up request
detected
V
IO
, and is capable of detecting CAN bus
Figure 1
fltr(wake)bus
for the block diagram).
HIGH
bus recessive
no wake-up request
detected
© NXP B.V. 2009. All rights reserved.
TJA1042
are reflected on
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