Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

ADM825 Datasheet(PDF) 10 Page - Analog Devices

Part # ADM825
Description  aSupervisory Circuits with Watchdog and
Download  12 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  AD [Analog Devices]
Direct Link  http://www.analog.com
Logo AD - Analog Devices

ADM825 Datasheet(HTML) 10 Page - Analog Devices

Back Button ADM825 Datasheet HTML 4Page - Analog Devices ADM825 Datasheet HTML 5Page - Analog Devices ADM825 Datasheet HTML 6Page - Analog Devices ADM825 Datasheet HTML 7Page - Analog Devices ADM825 Datasheet HTML 8Page - Analog Devices ADM825 Datasheet HTML 9Page - Analog Devices ADM825 Datasheet HTML 10Page - Analog Devices ADM825 Datasheet HTML 11Page - Analog Devices ADM825 Datasheet HTML 12Page - Analog Devices  
Zoom Inzoom in Zoom Outzoom out
 10 / 12 page
background image
ADM823/ADM824/ADM825
Data Sheet
Rev. D | Page 10 of 12
APPLICATIONS INFORMATION
WATCHDOG INPUT CURRENT
To minimize the watchdog input current (and minimize overall
power consumption), leave WDI low for the majority of the
watchdog timeout period. When driven high, WDI can draw as
much as 160 µA. Pulsing WDI low-high-low at a low duty cycle
reduces the effect of the large input current. When WDI is
unconnected, a window comparator disconnects the watchdog
timer from the reset output circuitry so that reset is not asserted
when the watchdog timer times out.
NEGATIVE-GOING VCC TRANSIENTS
To avoid unnecessary resets caused by fast power supply
transients, the ADM823/ADM824/ADM825 are equipped with
glitch rejection circuitry. The typical performance characteristic
in Figure 12 plots VCC transient duration vs. the transient mag-
nitude. The curves show combinations of transient magnitude
and duration for which a reset is not generated for 4.63 V and
2.93 V reset threshold parts. For example, with the 2.93 V
threshold, a transient that goes 100 mV below the threshold and
lasts 8 µs typically does not cause a reset, but if the transient is
any larger in magnitude or duration, a reset is generated. An
optional 0.1 µF bypass capacitor mounted close to VCC provides
additional glitch rejection.
ENSURING RESET VALID TO VCC = 0 V
Both active low and active high reset outputs are guaranteed to
be valid for VCC as low as 1 V. However, by using an external
resistor with push-pull configured reset outputs, valid outputs
for VCC as low as 0 V are possible. For an active low reset output,
a resistor connected between RESET and ground pulls the output
low when it is unable to sink current. For an active high reset
output, a resistor connected between RESET and VCC pulls the
output high when it is unable to source current. A large resist-
ance such as 100 kΩ should be used so that the reset output is
not overloaded when VCC is above 1 V.
ADM823/
ADM824/
ADM825
VCC
RESET
100kΩ
ADM824/
ADM825
VCC
RESET
100kΩ
Figure 17. Ensuring Reset Valid to VCC = 0 V
WATCHDOG SOFTWARE CONSIDERATIONS
In implementing the microprocessor watchdog strobe code,
quickly switching WDI low-to-high and then high-to-low
(minimizing WDI high time) is desirable for current consumption
reasons. However, a more effective way of using the watchdog
function can be considered.
A low-high-low WDI pulse within a given subroutine prevents
the watchdog timing out. However, if the subroutine becomes
stuck in an infinite loop, the watchdog cannot detect this cond-
ition because the subroutine continues to toggle WDI. A more
effective coding scheme for detecting this error involves using a
slightly longer watchdog timeout. In the program that calls the
subroutine, WDI is set high (see Figure 18). The subroutine sets
WDI low when it is called. If the program executes without error,
WDI is toggled high and low with every loop of the program.
If the subroutine enters an infinite loop, WDI is kept low, the
watchdog times out, and the microprocessor is reset.
START
SET WDI
HIGH
PROGRAM
CODE
SUBROUTINE
SET WDI
LOW
RETURN
INFINITE LOOP:
WATCHDOG
TIMES OUT
RESET
Figure 18. Watchdog Flow Diagram
RESET
RESET
WDI
I/O
MR
ADM823
VCC
MICROPROCESSOR
Figure 19. Typical Application Circuit


Similar Part No. - ADM825

ManufacturerPart #DatasheetDescription
logo
Analog Devices
ADM825 AD-ADM825 Datasheet
180Kb / 10P
   Supervisory Circuits with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23
Rev.PrB
ADM825 AD-ADM825 Datasheet
197Kb / 12P
   Supervisory Circuits with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23
Rev. C
ADM825 AD-ADM825 Datasheet
206Kb / 12P
   Supervisory Circuits with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23
REV. D
ADM825 AD-ADM825 Datasheet
206Kb / 12P
   Supervisory Circuits with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23
Rev. D
ADM825LYKS-R7 AD-ADM825LYKS-R7 Datasheet
180Kb / 10P
   Supervisory Circuits with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23
Rev.PrB
More results

Similar Description - ADM825

ManufacturerPart #DatasheetDescription
logo
Analog Devices
ADM6316CY29ARJZ-R7 AD-ADM6316CY29ARJZ-R7 Datasheet
254Kb / 16P
   Supervisory Circuits with Watchdog
Rev. F
ADM6316DZ26ARJZ-R7 AD-ADM6316DZ26ARJZ-R7 Datasheet
254Kb / 16P
   Supervisory Circuits with Watchdog
Rev. F
logo
ams AG
AS1916 AMSCO-AS1916_04 Datasheet
832Kb / 15P
   Microprocessor Supervisory Circuits with Manual Reset and Watchdog
AS1916 AMSCO-AS1916 Datasheet
401Kb / 13P
   Microprocessor Supervisory Circuits with Manual Reset and Watchdog
AS1910 AMSCO-AS1910 Datasheet
158Kb / 2P
   Dual-Voltage Microprocessor Supervisory Circuits with Reset and Watchdog
logo
Maxim Integrated Produc...
MAX16056 MAXIM-MAX16056 Datasheet
777Kb / 16P
   125nA Supervisory Circuits with Capacitor- Adjustable Reset and Watchdog Timeouts
Rev 2; 4/13
MAX6864UK16D1L MAXIM-MAX6864UK16D1L Datasheet
495Kb / 17P
   Nanopower μP Supervisory Circuits with Manual Reset and Watchdog Timer
Rev 4; 12/05
MAX6320PUK29CY MAXIM-MAX6320PUK29CY Datasheet
179Kb / 14P
   5-Pin uP Supervisory Circuits with Watchdog and Manual Reset
Rev 11; 2/13
logo
Texas Instruments
TPS3813J25 TI-TPS3813J25 Datasheet
191Kb / 12P
[Old version datasheet]   PROCESSOR SUPERVISORY CIRCUITS WITH WINDOW-WATCHDOG
TPS3813K33-EP TI1-TPS3813K33-EP Datasheet
452Kb / 16P
[Old version datasheet]   PROCESSOR SUPERVISORY CIRCUITS WITH WINDOW-WATCHDOG
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com