Rainbow Electronics ATA6630 - Manual (Page 9)

9
9117C–AUTO–10/09
ATA6628/ATA6630 [Preliminary]
4.1 Normal Mode
This is the normal transmitting and receiving mode. The voltage regulator is active and can
source up to 50 mA. The undervoltage detection is activated. The watchdog needs a trigger sig-
nal from NTRIG to avoid resets at NRES. If NRES is switched to low, the IC changes its state to
Fail-safe Mode.
4.2 Silent Mode
A falling edge at EN when TXD is high switches the IC into Silent Mode. The TXD Signal has to
be logic high during the Mode Select window (see
Figure 4-2 on page 9 ). The transmission path
is disabled in Silent Mode. The INH output is switched off and the voltage divider is enabled. The
overall supply current from V
Batt
is a combination of the I
VSsi
= 40 µA plus the VCC regulator out-
put current I
VCC
.
The 3.3V/5V regulator with 2% tolerance can source up to 50 mA. The internal slave termination
between the LIN pin and the VS pin is disabled in Silent Mode to minimize the current consump-
tion in the event that the LIN pin is short-circuited to GND. Only a weak pull-up current (typically
10 µA) between the LIN pin and the VS pin is present. Silent Mode can be activated indepen-
dently from the actual level on the LIN, WAKE, or KL_15 pins. If an undervoltage condition
occurs, NRES is switched to low, and the IC changes its state to Fail-safe Mode.
A voltage less than the LIN Pre_Wake detection VLINL at the LIN pin activates the internal LIN
receiver and starts the wake-up detection timer.
Figure 4-2. Switch to Silent Mode
Del a y time s ilent mode
t
d
_ s ilent = m a xim u m 20 µs
Mode s elect window
LIN s witche s directly to rece ss ive mode
t
d
= 3 .2 µs
LIN
VCC
NRE S
TXD
EN
Normal Mode
S ilent Mode