TJA1020 データシートの表示（PDF） - Philips Electronics

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TJA1020

LIN transceiver

Philips Electronics 

Philips Semiconductors

LIN transceiver

Product specification

TJA1020

Table 1 Operating modes

MODE

Sleep

Standby(1)

Normal

slope

mode

Low slope

mode

NSLP TXD (OUTPUT)

RXD

INH TRANSMITTER

REMARKS

0 weak pull-down floating

floating off

no wake-up request detected

0 weak pull-down if LOW; note 3 HIGH off

remote wake-up;

strong pull-down if

local wake-up;

note 2

wake-up request detected; in

this mode the microcontroller

can read the wake-up source:

remote or local wake-up

1 weak pull-down HIGH:

HIGH normal slope notes 2, 3 and 4

recessive state

mode

LOW:

dominant state

1 weak pull-down HIGH:

HIGH low slope mode notes 2, 3 and 5

recessive state

LOW:

dominant state

Notes

1. The standby mode is entered automatically upon any local or remote wake-up event during sleep mode. Pin INH and

the 30 kΩ termination resistor at pin LIN are switched on.

2. The internal wake-up source flag (set if a local wake-up did occur and fed to pin TXD) will be reset when entering

normal slope or low slope mode (NSLP goes HIGH).

3. The wake-up interrupt (on pin RXD) is released when entering normal slope or low slope mode (NSLP goes HIGH).

4. The normal slope mode is entered during a positive edge on NSLP while pin TXD is already set HIGH. In the event

of a short-circuit to ground on pin TXD, the transmitter will be disabled.

5. The low slope mode is entered during the positive edge on NSLP while pin TXD is already pulled LOW.

Sleep mode

This mode is the most power saving mode of the TJA1020

and the default state after power-up (first battery supply).

Despite its extreme low current consumption, the TJA1020

can still be waken up remotely via pin LIN, or waken up

locally via pin NWAKE, or activated directly via pin NSLP.

Filters at the inputs of the receiver (LIN), of pin NWAKE

and of pin NSLP are preventing unwanted wake-up events

due to automotive transients or EMI. All wake-up events

have to be maintained for a certain time period (tBUS,

tNWAKE and tgotonorm).

The sleep mode is initiated by a falling edge on the pin

NSLP while TXD is already set HIGH. After a filter time

continuously driven sleep command (pin NSLP = LOW),

pin INH becomes floating.

In sleep mode the internal slave termination between

pins LIN and BAT is disabled to minimize the power

dissipation in case pin LIN is short-circuited to ground.

Only a weak pull-up between pins LIN and BAT is present.

The sleep mode can be activated independently from the

actual level on pin LIN or NWAKE. So it is guaranteed that

the lowest power consumption is achievable even in case

of a continuous dominant level on pin LIN or a continuous

LOW on pin NWAKE.

Standby mode

The standby mode is entered automatically whenever a

local or remote wake-up occurs while the TJA1020 is in its

sleep mode. These wake-up events activate pin INH and

enable the slave termination resistor at the pin LIN. As a

result of the HIGH condition on pin INH the voltage

regulator and the microcontroller can be activated.

The standby mode is signalled by a LOW level on pin RXD

which can be used as an interrupt for the microcontroller.

In the standby mode (pin NSLP is still LOW), the condition

of pin TXD (weak pull-down or strong pull-down) indicates

the wake-up source: weak pull-down for a remote wake-up

request and strong pull-down for a local wake-up request.

2004 Jan 13

5

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