Datasheet

TJA1021 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 7 — 25 March 2011 5 of 25
NXP Semiconductors
TJA1021
LIN 2.1/SAE J2602 transceiver
7. Functional description
The TJA1021 is the interface between the LIN master/slave protocol controller and the
physical bus in a Local Interconnect Network (LIN). The TJA1021 is LIN 2.1/SAE J2602
compliant and provides optimum ElectroMagnetic Compatibility (EMC) performance due
to wave shaping of the LIN output.
The TJA1021T/20 and TJA1021TK/20 are optimized for the maximum specified LIN
transmission speed of 20 kBd; theTJA1021T/10 and TJA1021TK/10 are optimized for the
LIN transmission speed of 10.4 kBd as specified by the SAE J2602.
7.1 Operating modes
The TJA1021 supports modes for normal operation (Normal mode), power-up (Power-on
mode) and very-low-power operation (Sleep mode). An intermediate wake-up mode
between Sleep and Normal modes is also supported (Standby mode). Figure 3
shows the
state diagram.
TERM.: slave termination resistor, connected between pins LIN and V
BAT
.
Fig 3. State diagram
001aae073
t
(SLP_N = 1)
> t
gotonorm
t
(SLP_N = 1)
> t
gotonorm
t
(SLP_N = 1)
> t
gotonorm
t
(SLP_N = 0)
> t
gotosleep
t
(WAKE_N = 0; after 1→0)
> t
WAKE_N
or t
(LIN = 0→1; after LIN = 0)
> t
BUS
switching on V
BAT
Normal
INH: high
TERM. = 30 kΩ
RXD: receive data output
TXD: transmit data input
Transmitter: on
Standby
INH: high
TERM. = 30 kΩ
RXD: low
TXD: wake source output
Transmitter: off
Sleep
INH: floating
TERM. = high ohmic
RXD: floating
TXD: weak pull-down
Transmitter: off
Power-on
INH: high
TERM. = 30 kΩ
RXD: floating
TXD: weak pull-down
Transmitter: off