TJA1055 データシートの表示（PDF） - NXP Semiconductors.

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TJA1055

Enhanced fault-tolerant CAN transceiver

NXP Semiconductors. 

NXP Semiconductors

TJA1055

Enhanced fault-tolerant CAN transceiver

7.2 Low power modes

The transceiver provides three low power modes which can be entered and exited via

STB and EN (see Table 5 and Figure 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. Pins RXD and ERR will signal the wake-up interrupt even

in case VCC is not present.

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 5.

Mode

Normal operating and low power modes

Pin STB Pin EN Pin ERR

LOW

HIGH

Goto-sleep LOW

command

Sleep

LOW

Standby LOW

Power-on HIGH

standby

Normal

HIGH

operating

HIGH

LOW[4]

LOW

LOW

HIGH

wake-up [2][3]

interrupt

signal[1]

VBAT

power-on

flag[5]

error flag

no error

flag

Pin RXD

LOW

HIGH

wake-up [2][3]

interrupt

signal[1]

Pin RTL

switched

to

VBAT

wake-up

interrupt

signal[1]

dominant

received

data

recessive

received

data

VBAT

VCC

[1] Wake-up interrupts are released when entering normal operating mode.

[2] For TJA1055T a diode is added in series with the high-side driver of ERR and RXD to prevent a reverse

current from ERR to VCC in the unpowered state.

[3] For TJA1055T/3, ERR and RXD are open-drain.

[4] In case the goto-sleep command was used before. When VCC drops, pin EN will become LOW, but due to

the fail-safe functionality this does not effect the internal functions.

[5] VBAT power-on flag will be reset when entering normal operating mode.

Wake-up requests are recognized by the transceiver through two possible channels:

• The bus lines for remote wake-up

• Pin WAKE for local wake-up

In order to wake-up the transceiver remotely through the bus lines, a filter mechanism is

integrated. This mechanism makes sure that noise and any present bus failure conditions

do not result into an erroneous wake-up. Because of this mechanism it is not sufficient to

simply pull the CANH or CANL bus lines to a dominant level for a certain time. To

guarantee a successful remote wake-up under all conditions, a message frame with a

dominant phase of at least the maximum specified tdom(CANH) or tdom(CANL) in it is required.

TJA1055_4

Product data sheet

Rev. 04 — 17 February 2009

© NXP B.V. 2009. All rights reserved.

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