ATA6626C(2014) データシートの表示（PDF） - Atmel Corporation

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ATA6626C
(Rev.:2014)

LIN Bus Transceiver with 3.3V (5V) Regulator and Watchdog

Atmel Corporation 

5. Wake-up Scenarios from Silent or Sleep Mode

5.1 Remote Wake-up via Dominant Bus State

A voltage less than the LIN Pre_Wake detection VLINL at the LIN pin activates the internal LIN receiver.

A falling edge at the LIN pin followed by a dominant bus level VBUSdom maintained for a certain time period (> tBUS) and a

rising edge at pin LIN result in a remote wake-up request. The device switches from Silent or Sleep Mode to Fail-safe Mode.

The VCC voltage regulator is/remains activated, the INH pin is switched to high, and the remote wake-up request is

indicated by a low level at the RXD pin to generate an interrupt for the microcontroller. A low level at the LIN pin in the

Normal Mode starts the bus wake-up filtering time, and if the IC is switched to Silent or Sleep Mode, it will receive a wake-up

after a positive edge at the LIN pin.

5.2 Local Wake-up via Pin WAKE

A falling edge at the WAKE pin followed by a low level maintained for a certain time period (> tWAKE) results in a local wake-

up request. The device switches to Fail-safe Mode. The local wake-up request is indicated by a low level at the RXD pin to

generate an interrupt in the microcontroller and a strong pull down at TXD. When the Wake pin is low, it is possible to switch

to Silent or Sleep Mode via pin EN. In this case, the wake-up signal has to be switched to high > 10µs before the negative

edge at WAKE starts a new local wake-up request.

5.3 Local Wake-up via Pin KL_15

A positive edge at pin KL_15 followed by a high voltage level for a certain time period (> tKL_15) results in a local wake-up

request. The device switches into the Fail-safe Mode. The extra long wake-up time ensures that no transients at KL_15

create a wake up. The local wake-up request is indicated by a low level at the RXD pin to generate an interrupt for the

microcontroller and a strong pull down at TXD. During high-level voltage at pin KL_15, it is possible to switch to Silent or

Sleep Mode via pin EN. In this case, the wake-up signal has to be switched to low > 250µs before the positive edge at KL_15

starts a new local wake-up request. With external RC combination, the time is even longer.

5.4 Wake-up Source Recognition

The device can distinguish between a local wake-up request (Wake or KL_15 pins) and a remote wake-up request

(dominant LIN bus state). The wake-up source can be read on the TXD pin in Fail-safe Mode. A high level indicates a remote

wake-up request (weak pull up at the TXD pin); a low level indicates a local wake-up request (strong pull down at the TXD

pin). The wake-up request flag (signalled on the RXD pin), as well as the wake-up source flag (signalled on the TXD pin), is

immediately reset if the microcontroller sets the EN pin to high (see Figure 4-2 on page 8 and Figure 4-3 on page 9) and the

IC is in Normal Mode. The last wake-up source flag is stored and signalled in Fail-safe Mode at the TXD pin.

5.5 Fail-safe Features

● During a short-circuit at LIN to VBattery, the output limits the output current to IBUS_lim. Due to the power dissipation, the

chip temperature exceeds TLINoff, and the LIN output is switched off. The chip cools down and after a hysteresis of

Thys, switches the output on again. RXD stays on high because LIN is high. During LIN overtemperature switch-off,

the VCC regulator works independently.

● During a short-circuit from LIN to GND the IC can be switched into Sleep or Silent Mode. If the short-circuit

disappears, the IC starts with a remote wake-up.

● The reverse current is very low < 2µA at the LIN pin during loss of VBatt. This is optimal behavior for bus systems

where some slave nodes are supplied from battery or ignition.

● During a short circuit at VCC, the output limits the output current to IVCClim. Because of undervoltage, NRES switches

to low and sends a reset to the microcontroller. The IC switches into Fail-safe Mode. If the chip temperature exceeds

the value TVCCoff, the VCC output switches off. The chip cools down and after a hysteresis of Thys, switches the output

on again. Because of the Fail-safe Mode, the VCC voltage will switch on again although EN is switched off from the

microcontroller. The microcontroller can start with its normal operation.

● EN pin provides a pull-down resistor to force the transceiver into recessive mode if EN is disconnected.

● RXD pin is set floating if VBatt is disconnected.

● TXD pin provides a pull-up resistor to force the transceiver into recessive mode if TXD is disconnected.

12 ATA6622C/ATA6624C/ATA6626C [DATASHEET]

4986O–AUTO–10/14

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