ATA6663_14 datasheet(8/19 Pages) ATMEL

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ATA6663/ATA6664 [DATASHEET]

9146I–AUTO–10/14

Figure 2-5. Wake-up from Wake-up Switch

2.14

Wake-up Source Recognition

The device can distinguish between a local wake-up request (pin WAKE) and a remote wake-up request (LIN bus). The

wake-up source can be read at pin TXD in fail-safe mode. If an external pull-up resistor (typically 5k

Ω) has been added on

pin TXD to the power supply of the microcontroller, a high level indicates a remote wake-up request (weak pull-down at pin

TXD), a low level indicates a local wake-up request (strong pull-down at pin TXD). The wake-up request flag (indicated at pin

RXD) as well as the wake-up source flag (indicated at pin TXD) are reset immediately if the microcontroller sets pin EN to

high (see Figure 2-2 on page 5 and Figure 2-5 on page 8).

2.15

Fail-safe Features

●

During a short-circuit at LIN to VBAT, the output limits the output current to IBUS_LIM. Due to the power dissipation, the

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

it switches the output on again.

●

During a short-circuit from LIN to GND the IC can be switched to sleep mode, and even in this case the current

consumption is lower than 45µA. When the short-circuit has elapsed, the IC starts with a remote wake-up.

●

If the Atmel® ATA6663/ATA6664 is in sleep mode and a floating condition occurs on the bus, the IC switches back to

sleep mode automatically. The current consumption is lower than 45µA in this case.

●

The reverse current is < 2µA at pin LIN during loss of VBAT. This is the best behavior for bus systems where some

slave nodes are supplied from battery or ignition.

●

Pin EN provides a pull-down resistor to force the transceiver into sleep mode if EN is disconnected

●

Pin RXD is set floating if VBAT is disconnected

●

Pin TXD provides a pull-down resistor to provide a static low if TXD is disconnected

●

After switching the IC into Normal Mode the TXD pin must be pulled to high longer than 10µs in order to activate the

LIN driver. This feature prevents the bus from being driven into dominant state when the IC is switched into Normal

Mode and TXD is low.

●

The INH output transistor is protected by temperature monitoring

Microcontroller start-up

delay time

Wake filtering time

tWAKE

Off state

Node in sleep state

High or floating

TXD weak pull-down resistor

Low or floating

State change

TXD strong pull-down

Node in

operation

Weak

pull-down

EN High

High

Low

On state

High

Regulator wake-up time delay

Wake pin

INH

TXD

RXD

Voltage

regulator

ATA6663 Datasheet(PDF) 8 Page - ATMEL Corporation

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