TPS3813J25, TPS3813L30, TPS3813K33, TPS3813I50

PROCESSOR SUPERVISORY CIRCUITS WITH WINDOW-WATCHDOG

SLVS331A – DECEMBER 2000 – REVISED APRIL 2001

4

POST OFFICE BOX 655303

detailed description

implemented window-watchdog settings

There are two different ways to set up the watchdog window. The first way is to use the implemented timing which

There is a total of four different timings available with these settings. They are listed in the table below.

SELECTED OPERATION MODE

WINDOW

FRAME

LOWER WINDOW

FRAME

Max = 0.3 s

Max = 9.46 ms

WDR = 0 V

Typ = 0.25 s

Typ = 7.86 ms

WDT=0V

Min = 0.2 s

Min = 6.27 ms

WDT = 0 V

Max = 0.3 s

Max = 2.43 ms

WDR = VDD

Typ = 0.25 s

Typ = 2 ms

Min = 0.2 s

Min = 1.58 ms

Max = 3 s

Max = 93.8 ms

WDR = 0 V

Typ = 2.5 s

Typ = 78.2 ms

WDT=VDD

Min = 2 s

Min = 62.5 ms

WDT = VDD

Max = 3 s

Max = 23.5 ms

WDR = VDD

Typ = 2.5 s

Typ = 19.6 ms

Min = 2 s

Min = 15.6 ms

To visualize the values named in the table, a timing diagram was prepared. It is used to describe the upper and

Within these values, the watchdog timer should be retriggered to avoid a timeout condition or a boundary

violation in the event of a trigger pulse in the lower boundary. The values in the table above are typical and worst

case conditions. They are valid over the whole temperature range of –40

°C to 85°C.

In the shaded area of Figure 1, it cannot be predicted if the device will detect a violation or not and release a

areas.

Window Frame to Reset the WDI

tboundary, min

tboundary, max

tboundary, typ

Detection of

Rising Edge

WDI

t

twindow, min

twindow, typ

twindow, max

Figure 1. Upper and Lower Boundary Visualization