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4887D–AUTO–12/06

ATA6621

In Silent Mode, the 5V regulator is in low tolerance mode (4.65V to 5.35V) and can source up to

50 mA. The internal slave termination between pin LIN and pin VS is disabled to minimize the

power dissipation in case pin LIN is shorted to GND. Only a weak pull-up current (typically

10 µA) between pin LIN and pin VS is present.

The Silent Mode voltage tolerance is sufficient to run the internal timers of the microcontroller.

The undervoltage reset is now V

switched to low and the ATA6621 changes state to Pre Normal Mode.

A falling edge at pin LIN followed by a dominant bus level maintained for a certain time period

(T

Mode. The internal LIN slave termination resistor is switched on. The remote wake-up request is

indicated by a low level at pin RXD to interrupt the microcontroller. (Figure 3-5 on page 10)

With EN high, you can switch directly from Silent Mode to Normal Mode.

Figure 3-2.

Switch to Silent Mode

Delay time Silent Mode

Mode Select window

LIN switches directly to recessive mode

LIN

VCC

NRES

TXD

EN

Silent Mode