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參數資料
| 型號： | ADM8697 |
| 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 |
| 文件大小： | 172K |
| 代理商： | ADM8697 |
ADM8696/ADM8697
REV. 0
–9–
APPLICAT IONS INFORMAT ION
Increasing the Drive Current (ADM8696)
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. T he BAT T ON output (ADM8696)
can directly drive the base of the external transistor.
BATTERY
+5V
INPUT
POWER
0.1
μ
F
PNP
TRANSISTOR
0.1
μ
F
V
OUT
V
CC
BATT
ON
V
BATT
ADM8696
Figure 14. Increasing the Drive Current
Using a Rechargeable Battery for Backup (ADM8696)
If a capacitor or a rechargeable battery is used for backup, the
charging resistor should be connected to V
OUT
since this elimi-
nates 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
0.1
μ
F
0.1
μ
F
V
BATT
ADM8696
R
R
V
OUT
– V
BATT
I =
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 by connecting a resistor be-
tween 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. T his results in differing trip levels for the comparator.
Alternate Watchdog Input Drive Circuits
T he watchdog feature can be enabled and disabled under pro-
gram control by driving WDI with a three-state buffer (Figure
17a). When three-stated, the WDI input will float, thereby dis-
abling the watchdog timer.
T his circuit is not entirely foolproof and it is possible a software
fault could erroneously three-state the buffer. T his would pre-
vent the ADM869x from detecting that the microprocessor is no
longer operating correctly. In most cases, a better method is to
ADM869x
R2
1.3V
R1
PFO
7805
R4
R3
+7V TO +15V
INPUT
POWER
+5V
PFI
V
CC
TO
μ
P NMI
V
H
= 1.3V
(
1+ R
)
V
L
= 1.3V
(
1+ R
)
2
ASSUMING R
4 < <
R
3
THEN
HYSTERESIS V
H
– V
L
= 5V
(
R
)
1
R
2
R
1
R
3
R
1
1
R
2
R
1
(5V – 1.3V)
1.3V (R
3 +
R
4
)
Figure 16. Adding Hysteresis to the Power Fail Comparator
extend the watchdog period rather than disabling the watchdog.
T his 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. T he 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
ADM869x
WATCHDOG
STROBE
CONTROL
INPUT
Figure 17a. Programming the Watchdog Input
OSC IN
OSC SEL
ADM869x
CONTROL
INPUT*
D1
D2
*LOW = INTERNAL TIMEOUT
HIGH = EXTERNAL TIMEOUT
Figure 17b. Programming the Watchdog Input
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相關代理商/技術參數 |
參數描述 |
|---|---|
| ADM8697AN | 功能描述:IC SUPERVSR MPU ADJ/RESET 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 |
| ADM8697ANZ | 功能描述:IC SUPERVSR MPU ADJ/RESET 16DIP RoHS:是 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 |
| ADM8697ARU | 制造商:AD 制造商全稱:Analog Devices 功能描述:Microprocessor Supervisory Circuits |
| ADM8697ARU-REEL | 功能描述:Supervisor Push-Pull, Push-Pull 1 Channel 16-TSSOP 制造商:analog devices inc. 系列:- 包裝:帶卷（TR） 零件狀態:上次購買時間 類型:備用電池電路 受監控電壓數:1 輸出:推挽式，推挽式 復位:高有效/低有效 復位超時:最小為 35 ms 電壓 - 閾值:1.3V 工作溫度:-40°C ~ 85°C（TA） 安裝類型:表面貼裝 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應商器件封裝:16-TSSOP 標準包裝:1 |
| ADM8697ARW | 功能描述:IC SUPERVSR MPU ADJ/RESET 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 |
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