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參數資料
| 型號： | ADM697 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Microprocessor Supervisory Circuits(微處理器監控電路) |
| 中文描述： | 微處理器監控電路（微處理器監控電路） |
| 文件頁數： | 9/12頁 |
| 文件大?。?/td> | 359K |
| 代理商： | ADM697 |
ADM696/ADM697
REV. 0
–9–
APPLICATIONS INFORMATION
Increasing the Drive Current (ADM696)
If the continuous output current requirements at V
OUT
exceeds
100 mA or if a lower V
CC
–V
OUT
voltage differential is desired,
an external PNP pass transistor may be connected in parallel
with the internal transistor. The BATT ON output (ADM696)
can directly drive the base of the external transistor.
V
OUT
V
CC
BATTERY
+5V
INPUT
POWER
0.1μF
BATT
ON
V
BATT
PNP TRANSISTOR
ADM696
0.1μF
Figure 14. Increasing the Drive Current
Using a Rechargeable Battery for Backup (ADM696)
If a capacitor or a rechargeable battery is used for backup, then
the charging resistor should be connected to V
OUT
since this
eliminates the discharge path that would exist during power-
down if the resistor is connected to V
CC
.
V
OUT
V
CC
RECHARGABLE
BATTERY
+5V
INPUT
POWER
0.1μF
0.1μF
V
BATT
ADM696
R
I =
V
OUT
– V
BATT
R
Figure 15. Rechargeable Battery
Adding Hysteresis to the Power Fail Comparator
For increased noise immunity, hysteresis may be added to the
power fail comparator. Since the comparator circuit is nonin-
verting, hysteresis can be added simply by connecting a resistor
between the PFO output and the PFI input as shown in Fig-
ure 16. When PFO is low, resistor R3 sinks current from the
summing junction at the PFI pin. When PFO is high, the series
combination of R3 and R4 source current into the PFI summing
junction. This results in differing trip levels for the comparator.
Alternate Watchdog Input Drive Circuits
The watchdog feature can be enabled and disabled under pro-
gram control by driving WDI with a 3-state buffer (Figure 17a).
When three-stated, the WDI input will float thereby disabling
the watchdog timer.
This circuit is not entirely foolproof, and it is possible that a
software fault could erroneously 3-state the buffer. This would
then prevent the ADM69x from detecting that the microproces-
sor is no longer operating correctly. In most cases a better
ADM69x
R2
1.3V
PFO
R1
7805
R4
R3
+7V TO +15V
INPUT
POWER
+5V
PFI
V
CC
TO
μP NMI
V
H
= 1.3V
(
1+ R
)
V
L
= 1.3V
(
1+ R
)
R
2
ASSUMING R
4 < <
R
3
THEN
HYSTERESIS V
H
– V
L
= 5V
(
R
)
1
R
2
R
1
R
3
1
1
R
2
R
1
(5V – 1.3V)
1.3V (R
3 +
R
4
)
Figure 16. Adding Hysteresis to the Power Fail Comparator
method is to extend the watchdog period rather than disabling
the watchdog. This may be done under program control using
the circuit shown in Figure 17b. When the control input is high,
the OSC SEL pin is low and the watchdog timeout is set by the
external capacitor. A 0.01
μ
F capacitor sets a watchdog timeout
delay of 100 s. When the control input is low, the OSC SEL pin
is driven high, selecting the internal oscillator. The 100 ms or
the 1.6 s period is chosen, depending on which diode in Fig-
ure 17b is used. With D1 inserted, the internal timeout is set at
100 ms while with D2 inserted the timeout is set at 1.6 s.
WDI
ADM69x
WATCHDOG
STROBE
CONTROL
INPUT
Figure 17a. Programming the Watchdog Input
OSC IN
OSC SEL
ADM69x
CONTROL
INPUT*
D1
D2
*LOW = INTERNAL TIMEOUT
HIGH = EXTERNAL TIMEOUT
Figure 17b. Programming the Watchdog Input
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| ADM697AN | 功能描述:IC SUPERVISOR MPU 100MA 16DIP RoHS:否 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監視電壓數目:1 輸出:開路漏極或開路集電極 復位:高有效 復位超時:- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線 供應商設備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱:NCP301HSN18T1GOSCT |
| ADM697ANZ | 功能描述:IC SUPERVISOR MPU 16DIP RoHS:是 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 其它有關文件:STM6717 View All Specifications 標準包裝:1 系列:- 類型:多壓監控器 監視電壓數目:2 輸出:開路漏極或開路集電極 復位:低有效 復位超時:最小為 600 ms 電壓 - 閥值:1.11V，3.075V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應商設備封裝:SOT-23-5 包裝:Digi-Reel® 產品目錄頁面:1194 (CN2011-ZH PDF) 其它名稱:497-7019-6 |
| ADM697AQ | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ADM697AR | 功能描述:IC SUPERVISOR MPU 100MA 16SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 監控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監視電壓數目:1 輸出:開路漏極或開路集電極 復位:高有效 復位超時:- 電壓 - 閥值:1.8V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:6-TSOP（0.059"，1.50mm 寬）5 引線 供應商設備封裝:5-TSOP 包裝:剪切帶 (CT) 其它名稱:NCP301HSN18T1GOSCT |
| ADM697AR-REEL | 制造商:Analog Devices 功能描述:Processor Supervisor Adj 3V to 5.5V 16-Pin SOIC W T/R 制造商:Analog Devices 功能描述:PROCESSOR SUPERVISOR ADJV 1950UA 16SOIC W - Tape and Reel 制造商:Analog Devices 功能描述:Power Supply Supervisor Circuit, 16 Pin, Plastic, SOP |
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