參數(shù)資料
型號： MAX791
廠商： Maxim Integrated Products, Inc.
英文描述： Microprocessor Supervisory Circuit(微處理器監(jiān)控電路)
中文描述： 微處理器監(jiān)控電路
文件頁數(shù)： 12/20頁
文件大?。?/td> 198K
代理商： MAX791
M
Power-Fail Comparator
The power-fail comparator is an uncommitted compara-
tor that has no effect on the other functions of the IC.
Common uses include monitoring supplies other than
5V (see the Typical Operating C ircuit and the
Monitoring a Negative Voltage section) and early
power-fail detection when the unregulated power is
easily accessible (Figure 9b).
Power-Fail Input
PFI is the input to the power-fail comparator. PFI has a
guaranteed input leakage of ±25nA max over tempera-
ture. The typical comparator delay is 15μs from V
IL
to
V
OL
(power failing), and 55μs from V
IH
to V
OH
(power
being restored). If unused, connect this input to
ground.
Power-Fail Output
The Power-Fail Output (PFO) goes low when PFI goes
below 1.25V. It typically sinks 3.2mA with a saturation
voltage of 0.1V. With PFI above 1.25V, PFO is actively
pulled to V
OUT
. Connecting PFI through a voltage
divider to an unregulated supply allows PFO to gener-
ate an NMI as the unregulated power begins to fall
(Figure 9b). If the unregulated supply is inaccessible,
use LOWLINE to generate the NMI. The LOWLINE
threshold is typically 150mV above the reset threshold
(see LOWLINE Outputsection).
Mic roproc essor S upervisory Circ uit
12
______________________________________________________________________________________
Table 1. Input and Output States in
Battery-Backup Mode
* V
CC
must be below the reset threshold to enter battery-
backup mode.
Logic high. The open-circuit output
voltage is equal to V
OUT
.
–W———O
16
Logic low*
–————
15
Logic high. The open-circuit output
voltage is equal to V
OUT
.
–W——O
14
High impedance
–—IN
13
Logic high. The open-circuit output
voltage is equal to V
OUT
.
–—OUT
12
WDI is ignored, and goes high
impedance.
WDI
11
Logic low*
–—O—W——
—N—
10
–M—– is ignored.
–M—–
9
SWT is ignored.
SWT
8
The power-fail comparator remains
active in the battery-backup mode for
V
CC
≥
VBATT - 1.2V typ.
PFI
7
The power-fail comparator remains
active in the battery-backup mode for
CC
≥
VBATT - 1.2V typ. Below this
V
–——O
6
Logic high. The open-circuit output is
equal to V
OUT
.
BATT ON
5
GND—0V reference for all signals.
GND
4
Battery-switchover comparator
monitors V
CC
for active switchover.
V
CC
3
V
OUT
is connected to VBATT through
an internal PMOS switch.
V
OUT
2
Supply current is 1μA maximum.
VBATT
1
STATUS
NAME
PIN
MAX791
V
OUT
V
CC
FROM
REGULATED
SUPPLY
POWER TO
CMOS RAM
VBATT
RESET
LOWLINE
WDI
GND
4
RESET
NMI
I/OLINE
μ
P
μ
P POWER
2
0.1
μ
F
0.1
μ
F
3.0V
1
3
a)
b)
15
10
11
MAX791
V
OUT
V
CC
PFI
POWER TO
CMOS RAM
VBATT
RESET
PFO
WDI
GND
4
VOLTAGE
REGULATOR
RESET
NMI
I/OLINE
μ
P
μ
P POWER
2
0.1
μ
F
0.1
μ
F
3.0V
1
3
7
15
6
11
Figure 9. a) If the unregulated supply is inaccessible,
LOWLINE generates the NMI for the μP. b) Use PFO to gener-
ate the μP NMI if the unregulated supply is inaccessible.
相關(guān)PDF資料
PDF描述
MAX792R Microprocessor and Non-Volatile Memory Supervisory Circuits(復(fù)位門限2.61V,微處理器和非易失存儲器監(jiān)控電路)
MAX792S Microprocessor and Non-Volatile Memory Supervisory Circuits(復(fù)位門限1.91V,微處理器和非易失存儲器監(jiān)控電路)
MAX792T Microprocessor and Non-Volatile Memory Supervisory Circuits(復(fù)位門限3.06V,微處理器和非易失存儲器監(jiān)控電路)
MAX793 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits(具有監(jiān)控器、芯片使能和支持備用電池的復(fù)位器)
MAX794 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits(具有可調(diào)閾值監(jiān)控器、芯片使能和支持備用電池的復(fù)位器)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX791C/D 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
MAX791CPE 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
MAX791CPE+ 功能描述:監(jiān)控電路 MPU Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
MAX791CSE 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
MAX791CSE+ 功能描述:監(jiān)控電路 MPU Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
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