TLE 7278-2G V26 Infineon Technologies, TLE 7278-2G V26 Datasheet - Page 9

• Manufacturer Part Number: TLE 7278-2G V26
• Manufacturer: Infineon Technologies

Specifications of TLE 7278-2G V26

• Packages: PG-DSO-14
• Regulator Type: single output
• Output Voltage: 2.6V
• Accuracy: 2.0 %
• Max. Output Current: 180mA
• Dropout Voltage: 250mV

5.1.2
The watchdog uses a fraction of the charge pump oscillator’s clock signal as timebase. The watchdog timebase
can be adjusted using the pins WM1 and WM2 (see
WM2 to high level. The timing values used this text refer to typ. values with WM1 and WM2 connected to GND
(fast watchdog and reset timing).
If the timebase is switched by changing the condition on the WM pins, the new timing is valid from the beginning
of the new period on. From this time on, the frequency on the WDI pin must be adapted.
Figure 5
signal at the RO pin (microcontroller reset) is kept LOW for the reset delay time T
to HIGH transition of the signal at RO the device starts the ignore window time
the Watchdog Period (time frame within a trigger at WDI must occur). From now on the timing of the signal on WDI
from the micro controller must correspond the WD-Period
based on the setting on the WM pins. A Re-Trigger of the WD-Period is done with a HIGH-to-LOW Transient at
the WDI-pin within the set
A HIGH to LOW transition of the watchdog trigger signal on pin WDI is taken as a trigger. To avoid wrong triggering
due to parasitic glitches two HIGH samples followed by two LOW samples (sample period
decoded as a valid trigger. A reset is generated (RO goes LOW) if there is no trigger pulse during the Watchdog
Period.
Figure 5
Data Sheet
Window
Trigger
WDI
V
V
I
V
Q
RO
Q
I
V
RT
shows the state diagram of the watchdog (WD) and the mode selection. After power-on, the reset output
Watchdog Operation
Watchdog Timing Diagram, Watchdog and Reset Modes
T
RD
Don’t care WDI
during IW
Ingnore
Wnd
t
1. Correct Trigger
WD,p
Reset Mode
Watchdog
WM1
WM2
Mode
.
Normal operation
t
sam
t
WD,p
t
rr
Fast
Fast
causing reset
No Trigger
L
L
T
RD
Figure
9
Slow
Slow
t
H
5). The watchdog can be turned off setting WM1 and
L
WD,p
Block Description and Electrical Characteristics
correspondent the electrical characteristics and
I
Fast
Slow
Q, WD_OFF
H
L
Current Controlled
WD-turn off
Current shut down
No Reset during
7278 Timing
I
Q, WD_ON
t
CW
RD
Slow
Off
H
H
of typ. 16 ms. With the LOW
(32 ms). Next the WD starts
Rev. 1.2, 2009-04-28
t
sam
typ. 0.5 ms) are
TLE7278-2
Power
Fail
t
rr
t
t
t
t
t
t