TH8065 Datasheet, PDF (22/40 Pages) Melexis Microelectronic Systems – Voltage Regulator with LIN Transceiver and Watchdog

TH8065
Voltage Regulator with LIN Transceiver and Watchdog
VSUP
VCC
V_RES
RESET
T>Tj T<Tj
t<t_rr
t_Res
t_rr
t_Res
t<t_rr
t_Res
t_Res
Initialisation
Thermal
shutdown
Spike VSUP
Low voltage
Current limitation
VSUP Spike VCC
active
Figure 12 - Reset behaviour
Figure 13 - Output current of reset output vs. VCC voltage
3.8.2. Watchdog
The Watchdog can be used for observation of the connected microcontroller. It has to be triggered via the
WDI input and the time is defined via the capacity connected to the CWD input. The watchdog status will be
output via the reset pin.
With rising edges on WDI the watchdog time will be reset. If the WDI input isn’t triggered the internal circuitry
generates low pulses at the RESET pin with a time t_{WD_R} and a period of t_WD-per.
The CWD capacitor provides a wide adjustment range for the watchdog time.
With every rising edge on WDI the capacitor C_WD will be charged up to the threshold V_CWDL. If there is no new
trigger pulse on WDI, the following discharging of C_WD within the time t_WDL will be done up to the lower
threshold V_CWDL.
TH8065 – Datasheet
3901008065
Page 22 of 40
May 2006
Rev 003