MPQ6411―WINDOWED WATCHDOG TIMER, AEC-Q100 QUALIFIED

PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE

MPQ6411 Rev. 1.1

www.MonolithicPower.com

13

6/16/2017

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

© 2017 MPS. All Rights Reserved.

OPERATION

Supply Voltage

VCC= 5V

10% is recommended for MPQ6411

/MPQ6411-AEC1

normal

operation;

while

VCC=

3.3V

10%

is

recommended

for

MPQ6411-33/MPQ6411-33-AEC1

normal

operation. WDO is pulled low when VCC rises

to 1V or above. After VCC rises to 90%

to reset the MCU.

TIMER

Period T (

s):



 





 

TIMER

T s

15.75 R

k

73.5



 





 

TIMER

R

k

0.063 T s

4.67

Monitor MCU Synchronization Signal

When the watchdog is in a “sync signal

monitoring state,” the following will occur:

 If the watchdog IC receives a WDI_OK

low for 10µs to 5ms), the timer will be reset,

and

the

watchdog

works

in

normal

operation.

 If the watchdog does not receive the

will generate a reset signal and go into

“sync signal monitor state” again.

Short Window Mode

If the MCU and watchdog are synchronized

correctly and MODE is low, the watchdog will

work in short window mode:

 If WDI_OK is received in a window close

signal and goes into a sync signal

monitoring state.

 If WDI_OK is received in a window open

close state. The MCU works in normal

operation in this situation.

watchdog outputs a reset signal and goes

into a sync signal monitoring state.

 If MODE is pulled high during short window

mode, the watchdog will go into long

window mode.

Long Window Mode

If the MCU and watchdog are synchronized

correctly and MODE is high, the watchdog will

operate in long window mode, and the following

will occur:

 If WDI_OK is received in a window close

signal and goes into a sync signal

monitoring state.

 If WDI_OK is received in a window open

close state. The MCU works in normal

operation in this situation.

watchdog outputs a reset signal and goes

into a sync signal monitoring state.

 If MODE is pulled low during a long window

mode, the watchdog will go into a short

window mode.

Watchdog Disable

Pull /WD_DIS low to disable the watchdog; pull

it high to enable the watchdog. /WD_DIS has a

weak internal pull-up, so the watchdog is

enabled if /WD_DIS is left open.

WDI Error

If a WDI signal remains at a low level for longer

than the maximum WDI_OK pulse width, it is

regarded as an error. When this error occurs,

WDO is pulled down until WDI returns to a high

level.