Rainbow Electronics ATA6631 - Manual (Page 6)

6
9165A–AUTO–11/09
ATA6629/ATA6631
4.1 Normal Mode
This is the normal transmitting and receiving mode of the LIN Interface, in accordance with LIN
specification 2.x. The V
CC
voltage regulator operates with a 3.3V/5V output voltage, with a low
tolerance of ±2% and a maximum output current of 50 mA.
If an undervoltage condition occurs, NRES is switched to low and the IC changes its state to
Fail-safe Mode.
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 4-3 on page 7 ). The transmission path is
disabled in Silent Mode. The overall supply current from V
Batt
is a combination of the
I
VSsi
= 40 µA plus the V
CC
regulator output current I
VCCs
.
Figure 4-2. Switch to Silent Mode
The 3.3V/5V regulator with 2% tolerance can source up to 50 mA. In Silent Mode the internal
slave termination between pin LIN and pin VS is disabled to minimize the current consumption in
case pin LIN is short-circuited to GND. Only a weak pull-up current (typically 10 µA) between pin
LIN and pin VS is present. The Silent Mode can be activated independently from the current
level on pin LIN.
If an undervoltage condition occurs, NRES is switched to low and the ATA6629/ATA6631
changes its state to Fail-safe Mode.
Del a y time s ilent mode
t
d
_ s ilent = m a xim u m 20 µs
Mode select window
LIN switches directly to recessive mode
t
d
= 3.2 µs
LIN
VCC
NRES
TXD
EN
Normal Mode Silent Mode