TH8065KDCAA MELEXIS [Melexis Microelectronic Systems], TH8065KDCAA Datasheet - Page 21

• Manufacturer Part Number: TH8065KDCAA
• Description: Voltage Regulator with LIN Transceiver and Watchdog
• Manufacturer: MELEXIS [Melexis Microelectronic Systems]

3.8 RESET and Watchdog
The TH8065 contains a combined reset- and watchdog-unit which secures the correct initialization and
generation of the reset signal.
The RESET pin outputs the reset state and the watchdog state of the TH8065. The POR timer will be started
if V
RESET output is switched from low to high and the watchdog becomes active. The charging of the watchdog
capacity starts and dependent from the trigger pulse on the WDI input the Reset outputs the status of the
watchdog.
The watchdog is only active if V
watchdog capacity will be discharged.
3.8.1. RESET
The RESET unit combines a VCC low voltage detection unit with fixed POR timer This output is switched
from low to high if V
All conditions which cause a drop of the V
generates a reset signal. The TH8065 will be reinitialized if the V
If the voltage V
reached. For this reason short breaks of the V
The circuitry of the RESET output driver guarantees, that the reset low level during decreasing of the V
voltage will be secure kept (see Figure 13).
TH8065 – Datasheet
3901008065
SUP
is switched on and V
RESET
VSUP,
CWD
signal
VCC
POR
WDI
V
CC
RES
int.
drops below V
SUP
Start-up
V
V
CWDH
CWDL
is switched on and V
ON delay
CC
t
Res
RES
Figure 11 - Reset and Watchdog behaviour
> POR threshold (4.65V). The Watchdog is inactive. After the time t
CC
then the RESET output is switched from high to low after the time t
> V
RES
Voltage Regulator with LIN Transceiver and Watchdog
. If V
CC
CC
CC
CC
voltage will be detected from the low voltage reset unit which
>V
Page 21 of 40
voltage and uncontrolled reset generations will be inhibited.
drops below V
RES
(4.65V) after the time t
t
WDL
Watchdog
RES
CC
t
voltage rises above the low voltage limit.
WDH
the watchdog will be switched off and the
Res
.
TH8065
Power-off
t
rr
rr
has been
May 2006
Rev 003
Res
the
CC