6.2
Watchdog
VW
TLE4263-2ES
Application Information
VD
VDU
VDWL
VRO
t
No positive
VW edge
tWI,tr
TWI,p
t
tWD,L
tWD,L
VRO,l
Ti mi n g Di a g ra m_ Wa tch d o g .vsd
t
Figure 5 Timing of the Watchdog Function Reset
Watchdog Timing
The period of the watchdog pulses has to be smaller than the minimum watchdog trigger time which is set by the
external reset delay capacitor CD. Use the following formula for dimensioning CD:
CD
=
T-----W----I--,-t-r--,-n---e--w--
TWI,tr
×
100
nF
(2)
with
• CD: capacitance of the delay capacitor to be chosen
• TWI,tr,new: desired watchdog trigger time
• TWI,tr: watchdog trigger time specified in this data sheet
Data Sheet
19
Rev. 1.0, 2008-04-21