7

ATA5279/ATA5279C [DATASHEET]

9125P–RKE–05/14

3.2.1

Driver Stage

The return line stage is built by an open drain NMOS equipped with a free wheel diode. In parallel to the diode there is a pull-

up resistance to terminate the inactive antenna coils.

Figure 3-2. Principle Return Line Stage

Similar to the driver stage the components within the grey area describe the functionality in diagnosis mode.

Table 3-1.

States of Driver Outputs within Operation Modes

Mode

Operation/

Transmission Mode

Entering by SPI cmd

Shutdown Mode

Fault has detected

Idle Mode

Entering by S_CS

Power Down/Reset

Entering by NRES or

POC

Diagnosis Mode

Entering by SPI

Output

AxP

Selected driver active

others are on High

Level (VDS)

All high impedance

Selected driver stays

on VDS/2 ready for

Operation

Others are on High

Level

High impedance

High impedance

(Diagnosis current

sources

programmable)

AxN

Selected driver stays

onlowlevel

Others are on High

Level

All high impedance

Selected driver stays

onlowlevel

Others are on High

Level

High impedance

High impedance

(Diagnosis current

sources

programmable)

AxN

AxN_State

Diag Enable

VDS

Diag Enable

GND

VSHF

100kΩ