參數資料
型號: ADM805L
廠商: Analog Devices, Inc.
英文描述: Microprocessor Supervisory Circuits
中文描述: 微處理器監(jiān)控電路
文件頁數: 7/8頁
文件大?。?/td> 327K
代理商: ADM805L
ADM690A/ADM692A/ADM802L/M/ADM805L/M
–7–
REV. 0
If the watchdog timer is not needed, the WDI input should be
left floating.
The Power Fail Input, PFI, monitors the input power supply via
a resistive divider network. The voltage on the PFI input is
compared with a precision 1.25 V internal reference. If the input
voltage drops below 1.25 V, a power fail output (
PFO
) signal is
generated. This warns of an impending power failure and may
be used to interrupt the processor so that the system may be
shut down in an orderly fashion. The resistors in the sensing
network are ratioed to give the desired power fail threshold
voltage V
T
.
V
T
=
(1.25
R
1/
R
2)
+
1.25
V
R
1/
R
2 = (
V
T
/1.25) – 1
Alternate Watchdog Input Drive Circuits
The watchdog feature can be enabled and disabled under
program control by driving WDI with a 3-state buffer. When
three-stated, the WDI input will float thereby disabling the
watchdog timer.
High Capacity Backup Capacitors
High capacity (0.1
μ
F or greater) capacitors may be used as a
backup power source. A typical application is shown in Fig-
ure 12.
V
CC
V
OUT
RESET
RESET
*
GND
V
BATT
+5V
+
0.1F
TO STATIC RAM
TO μP
*
FOR ADM805L/ADM805M ONLY
Figure 12. High Capacity Capacitor
Operation Without a Backup Supply
If a backup power source is not used, V
BATT
should be con-
nected to GND and V
OUT
should be connected to V
CC
.
Replacing the Backup Battery
The backup battery may be replaced without any danger of
spurious resetting when V
CC
is present. Since V
CC
is above the
reset threshold, a reset will not occur even if V
BATT
is floating
while a replacement battery is being inserted. This differs from
older generation products where leakage currents flowing out
V
BATT
could cause spurious resetting during battery replacement.
m
Ps With Bidirectional
RESET
In order to prevent contention for microprocessors with a
bidirectional reset line, a current limiting resistor should be
inserted between the ADM69xA/ADM80xx
RESET
output pin
and the
μ
P reset pin. This will limit the current to a safe level if
there are conflicting output reset levels. A suitable resistor value
is 4.7 k
. If the reset output is required for other uses, then it
should be buffered as shown in Figure 13.
RESET
μP
V
CC
GND
+5V
RESET
GND
ADM690A
ADM692A
ADM802L
ADM802M
BUFFERED
RESET
Figure 13. Bidirectional Reset
相關PDF資料
PDF描述
ADM805LAN Microprocessor Supervisory Circuits
ADM805M Microprocessor Supervisory Circuits
ADM805MAN Microprocessor Supervisory Circuits
ADM805MARN Microprocessor Supervisory Circuits
ADM690AAN Microprocessor Supervisory Circuits
相關代理商/技術參數
參數描述
ADM805LAN 功能描述:IC SUPERVISOR 4.65V WD 8DIP RoHS:否 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監(jiān)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
ADM805LANZ 功能描述:IC SUPERVISOR MPU 4.65V WD 8DIP RoHS:是 類別:集成電路 (IC) >> PMIC - 監(jiān)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(jiān)控器 監(jiān)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
ADM805LARN 功能描述:IC SUPERVISOR 4.65V WD 8SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 監(jiān)控器 系列:- 標準包裝:1 系列:- 類型:簡單復位/加電復位 監(jiān)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
ADM805LARN-REEL 制造商:Analog Devices 功能描述:Processor Supervisor 4.65V 4.65V 8-Pin SOIC N T/R
ADM805LARNZ 功能描述:IC SUPERVISOR MPU 4.65V WD 8SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 監(jiān)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(jiān)控器 監(jiān)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