- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄385550 > MAX791 (Maxim Integrated Products, Inc.) Microprocessor Supervisory Circuit(微處理器監(jiān)控電路) PDF資料下載
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)： | 16/20頁 |
| 文件大?。?/td> | 198K |
| 代理商： | MAX791 |
M
Monitoring a Negative V oltage
The power-fail comparator can be used to monitor a
negative supply voltage using Figure 15’s circuit. When
the negative supply is valid, PFO is low. When the neg-
ative supply voltage drops, PFO goes high. This cir-
cuit’s accuracy is affected by the PFI threshold toler-
ance, the V
CC
voltage, and resistors R1 and R2.
Bac kup-Battery Replac ement
The backup battery may be disconnected while V
CC
is
above the reset threshold. No precautions are neces-
sary to avoid spurious reset pulses.
Negative-Going V
CC
T ransients
While issuing resets to the μP during power-up, power-
down, and brownout conditions, these supervisors are
relatively immune to short-duration negative-going V
CC
transients (glitches). It is usually undesirable to reset
the μP when V
CC
experiences only small glitches.
Figure 16 shows maximum transient duration vs. reset
comparator overdrive, for which reset pulses are not
generated. The graph was produced using negative-
going V
CC
pulses, starting at 5V and ending below the
reset threshold by the magnitude indicated (reset com-
parator overdrive). The graph shows the maximum
pulse width that a negative-going V
CC
transient may
typically have without causing a reset pulse to be
issued. As the amplitude of the transient increases (i.e.,
goes farther below the reset threshold), the maximum
allowable pulse width decreases. Typically, a V
CC
tran-
sient that goes 100mV below the reset threshold and
lasts for 40μs or less will not cause a reset pulse to be
issued.
A 100nF bypass capacitor mounted close to the V
CC
pin provides additional transient immunity.
Connec ting a T iming Capac itor to S WT
SWT is internally connected to a ±100nA current
source. When a capacitor is connected from SWT to
ground (to select an alternative watchdog timeout peri-
od), the current source charges and discharges the
timing capacitor to create the oscillator that controls the
watchdog timeout period. To prevent timing errors or
oscillator start-up problems, minimize external current
leakage sources at this pin, and locate the capacitor as
close to SWT as possible. The sum of PC board leak-
age + SWT capacitor leakage must be small compared
to ±100nA.
Mic roproc essor S upervisory Circ uit
16
______________________________________________________________________________________
100
0
10
1000
10,000
40
20
80
60
M
RESET COMPARATOR OVERDRIVE (mV)
(Reset Threshold Voltage - V
CC
)
M
μ
s
100
V
CC
= +5V
T
A
= +25°C
0.1
μ
F CAPACITOR
FROM V
OUT
TOGND
Figure 16. Maximum Transient Duration without Causing a
Reset Pulse vs. Reset Comparator Overdrive
MAX791
V
CC
GND
PFI
R2
R1
+5V
PFO
PFO
+5V
0V
NOTE
: V
TRIP
IS NEGATIVE
0V
V
TRIP
V-
TRIP
5 - 1.25 = 1.25 - V
V-
Figure 15. Monitoring a Negative Voltage
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 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。