Datasheet LTC6995-1, LTC6995-2 (Analog Devices) - 18
| 制造商 | Analog Devices |
| 描述 | TimerBlox: Long Timer, Low Frequency Oscillator |
| 页数 / 页 | 28 / 18 — APPLICATIONS INFORMATION Watchdog Timers. Figure 16. Watchdog Timer. Same … |
| 修订版 | B |
| 文件格式/大小 | PDF / 1.7 Mb |
| 文件语言 | 英语 |
APPLICATIONS INFORMATION Watchdog Timers. Figure 16. Watchdog Timer. Same Circuits as Shown in Figure 15
该数据表的模型线
- LTC6995CDCB-1#TRMPBF LTC6995CDCB-1#TRPBF LTC6995CDCB-2#TRMPBF LTC6995CDCB-2#TRPBF LTC6995CS6-1#TRMPBF LTC6995CS6-1#TRPBF LTC6995CS6-2#TRMPBF LTC6995CS6-2#TRPBF LTC6995HDCB-1#TRMPBF LTC6995HDCB-1#TRPBF LTC6995HDCB-2#TRMPBF LTC6995HDCB-2#TRPBF LTC6995HS6-1#TRMPBF LTC6995HS6-1#TRPBF LTC6995HS6-1#WTRMPBF LTC6995HS6-1#WTRPBF LTC6995HS6-2#TRMPBF LTC6995HS6-2#TRPBF LTC6995HS6-2#WTRMPBF LTC6995HS6-2#WTRPBF LTC6995IDCB-1#TRMPBF LTC6995IDCB-1#TRPBF LTC6995IDCB-2#TRMPBF LTC6995IDCB-2#TRPBF LTC6995IS6-1#TRMPBF LTC6995IS6-1#TRPBF LTC6995IS6-1#WTRMPBF LTC6995IS6-1#WTRPBF LTC6995IS6-2#TRMPBF LTC6995IS6-2#TRPBF LTC6995IS6-2#WTRMPBF LTC6995IS6-2#WTRPBF LTC6995MPS6-1#TRMPBF LTC6995MPS6-1#TRPBF LTC6995MPS6-2#TRMPBF LTC6995MPS6-2#TRPBF
文件文字版本
link to page 17 link to page 18 link to page 18 LTC6995-1/LTC6995-2
APPLICATIONS INFORMATION Watchdog Timers
returns to issuing watchdog pulses. Figure 16 shows the Using the same circuits as shown in Figure 15 with pe- timing for this application. riodic pulsing of the reset input can create an effective Watchdog timers are used to detect if a system operating watchdog timer. A watchdog pulse is required from a software is diverted from the designed program sequence system within each timing interval. The watchdog timeout for any reason. It is always a possibility that the software interval can be programmed from 500µs to 4.8 hours. If a could get stuck in a way that keeps the watchdog pulse in pulse is missed the output goes high to indicate that the the state that holds the timer in the reset so it can never system software may be caught in an infinite loop. This time out. In this condition the watchdog timer is ineffective high level can be used to initiate software diagnostic or and will never force corrective action. To help to prevent restart procedures. The LTC6995 internal clock stops and this a second one shot can be used to reset the watchdog the output remains high until the software recovers and timer as shown in Figure 17. V+ MISSED PULSE RST (LTC6995-1) WATCHDOG PULSES RST (LTC6995-2) OUTPUT SERVICE WATCHDOG TIMER RESTARTS TIMEOUT RESUME 699512 F16
Figure 16. Watchdog Timer. Same Circuits as Shown in Figure 15
100µs ONE SHOT 50ms WATCHDOG TIMER SYSTEM POSITIVE OUT RST OUT OUTPUT WATCHDOG PULSE TRG LTC6993-1 LTC6995-1 GND V+ V+ GND V+ V+ R R1 0.1µF SET 604k 976k SET DIV SET DIV RSET R2 619k 102k RISING EDGE TRIGGERED FALLING EDGE TRIGGERED POSITIVE OUTPUT PULSE POL = 0 DIVCODE = 1 DIVCODE = 1 699512 F17
Figure 17. Extra-Reliable Watchdog Timer. Allows Timeout if System Watchdog Pulse Gets Stuck in the Timer Reset State. Both Timer Devices Can Share the Same DIVCODE Setting
Rev. B 18 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts
APPLICATIONS INFORMATION Watchdog Timers
returns to issuing watchdog pulses. Figure 16 shows the Using the same circuits as shown in Figure 15 with pe- timing for this application. riodic pulsing of the reset input can create an effective Watchdog timers are used to detect if a system operating watchdog timer. A watchdog pulse is required from a software is diverted from the designed program sequence system within each timing interval. The watchdog timeout for any reason. It is always a possibility that the software interval can be programmed from 500µs to 4.8 hours. If a could get stuck in a way that keeps the watchdog pulse in pulse is missed the output goes high to indicate that the the state that holds the timer in the reset so it can never system software may be caught in an infinite loop. This time out. In this condition the watchdog timer is ineffective high level can be used to initiate software diagnostic or and will never force corrective action. To help to prevent restart procedures. The LTC6995 internal clock stops and this a second one shot can be used to reset the watchdog the output remains high until the software recovers and timer as shown in Figure 17. V+ MISSED PULSE RST (LTC6995-1) WATCHDOG PULSES RST (LTC6995-2) OUTPUT SERVICE WATCHDOG TIMER RESTARTS TIMEOUT RESUME 699512 F16
Figure 16. Watchdog Timer. Same Circuits as Shown in Figure 15
100µs ONE SHOT 50ms WATCHDOG TIMER SYSTEM POSITIVE OUT RST OUT OUTPUT WATCHDOG PULSE TRG LTC6993-1 LTC6995-1 GND V+ V+ GND V+ V+ R R1 0.1µF SET 604k 976k SET DIV SET DIV RSET R2 619k 102k RISING EDGE TRIGGERED FALLING EDGE TRIGGERED POSITIVE OUTPUT PULSE POL = 0 DIVCODE = 1 DIVCODE = 1 699512 F17
Figure 17. Extra-Reliable Watchdog Timer. Allows Timeout if System Watchdog Pulse Gets Stuck in the Timer Reset State. Both Timer Devices Can Share the Same DIVCODE Setting
Rev. B 18 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts