ATA6620 데이터 시트보기 (PDF) - Atmel Corporation

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ATA6620

LIN Bus Transceiver with Integrated Voltage Regulator

Atmel Corporation 

ATA6620

Table 4-1. Mode of Operation

Mode of

Operation

Communication

VCC

RXD

LIN

Pre-normal

OFF

5V

5V

Recessive

Normal

ON

5V

5V

Recessive

Silent

OFF

5V

5V

Recessive

Sleep

OFF

0V

0V

Recessive

4.1 Normal Mode

This is the normal transmitting and receiving mode of the LIN Interface, in accordance with LIN

specification 2.0. The VCC voltage regulator operates with a 5V output voltage, with a low toler-

ance of ±2% and a maximum output current of 50 mA.

If an undervoltage condition occurs, NRES is switched to low and the ATA6620 changes state to

Pre-normal mode. All features are available.

4.2 Silent Mode

A falling edge at EN while TXD is high switches the IC into Silent mode. The TXD Signal has to

be logic high during the Mode Select window (Figure 4-2 on page 6). For EN and TXD either two

independent outputs can be used, or two outputs from the same microcontroller port; in the sec-

ond case, the mode change is only one command.

In Silent mode the transmission path is disabled. Supply current from VBatt is typically

IVSsi = 40 µA with no load at the VCC regulator.

The overall supply current from VBatt is the result of 40 µA plus the VCC regulator output current

IVCCs.

The 5V regulator is in low tolerance mode (4.65V to 5.35V) and can source up to 50 mA. In

Silent mode the internal slave termination between pin LIN and pin VS is disabled to minimize

the power dissipation in case pin LIN is short-circuited to GND. Only a weak pull-up current (typ-

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

The Silent mode voltage is sufficient to run an external microcontroller on the ECU, for example

in Power Down mode. The undervoltage reset is VCCthS < 4.4V. If an undervoltage condition

occurs, NRES is switched to low and the ATA6620 changes state to Pre-normal mode.

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

(Tbus) results in a remote wake-up request. The device switches from Silent mode to Pre-normal

mode, then 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 4-5 on

page 8)

With EN high, ATA6620 switches directly from Silent to Normal mode.

5

4850D–AUTO–02/06

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