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參數(shù)資料
| 型號(hào)： | MAX6302CPA |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類(lèi)： | 電源管理 |
| 英文描述： | +5V, Low-Power uP Supervisory Circuits with Adjustable Reset/Watchdog |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDIP8 |
| 封裝： | PLASTIC, DIP-8 |
| 文件頁(yè)數(shù)： | 8/12頁(yè) |
| 文件大?。?/td> | 102K |
| 代理商： | MAX6302CPA |
M
__________Applic ations Information
S elec ting the Reset and
Watc hdog T imeout Capac itor
The reset timeout period is adjustable to accommodate
a variety of μP applications. Adjust the reset timeout
period (t
RS
) by connecting a specific value capacitor
(C
SRT
) between SRT and ground (Figure 3). Calculate
the reset timeout capacitor as follows:
C
SRT
= t
RP
2.67
with C
SRT
in pF and t
RP
in μs. C
SRT
must be a low-leak-
age (<10nA) type capacitor. Ceramic is recommended.
The watchdog timeout period is adjustable to accom-
modate a variety of μP applications. With this feature,
the watchdog timeout can be optimized for software
execution. The programmer can determine how often
the watchdog timer should be serviced. Adjust the
watchdog timeout period (t
WD
) by connecting a specif-
ic value capacitor (C
SWT
) between SWT and ground
(Figure 3). For normal-mode operation, calculate the
watchdog timeout capacitor as follows:
C
SWT
= t
WD
2.67
where C
SWT
is in pF and t
WD
is in μs. C
SRT
must be a
low leakage (<10nA) type capacitor. Ceramic is recom-
mended.
Monitoring V oltages Other than V
CC
The Typical Operating Circuit monitors V
CC
. However,
monitoring other voltages is simple, and Figure 4 shows
a circuit that accomplishes this. Calculate V
RST
as
shown in the Reset Threshold section.
Wake-Up T imer
In some applications, it is advantageous to put a μP
into sleep mode, periodically “wake it up” to perform
checks and/or tasks, then put it back into sleep mode.
The MAX6301 family supervisors can easily accommo-
date this technique. Figure 5 illustrates an example
using the MAX6302 and an 80C51.
In Figure 5, just before the μC puts itself into sleep
mode, it pulls WDS high. The μC’s I/O pins maintain
their logic levels while in sleep mode and WDS remains
high. This places the MAX6302 in extended mode,
increasing the watchdog timeout 500 times. When the
watchdog timeout period ends, a reset is applied on
the 80C51, “waking it up” to perform tasks. While the μP
is performing tasks, the 80C51 pulls WDS low (select-
ing normal mode), and the MAX6302 monitors the μP
for hang-ups. When the μP finishes its tasks, it puts
itself back into sleep mode, drives WDS high, and
starts the cycle over again. This is a power-saving tech-
nique, since the μP is operating only part of the time
and the MAX6302 has very low quiescent current.
Adding a Manual Reset Func tion
A manual reset option can easily be implemented by
connecting a normally open momentary switch in paral-
lel with R2 (Figure 6). When the switch is closed, the
voltage on RESET IN goes to zero, initiating a reset.
When the switch is released, reset remains asserted for
the reset timeout period and then is cleared. The push-
button switch is effectively debounced by the reset
timer.
+5V, Low-Power μP S upervisory Circ uits
with Adjustable Reset/Watc hdog
8
_______________________________________________________________________________________
0.1μF
MAX6301
MAX6302
MAX6303
MAX6304
V
CC
RESET IN
R2
R1
V
IN
V
RST
= 1.22
(
R1 + R2
)
R2
V
CC
Figure 4. Monitoring a Voltage Other than V
CC
MAX6302
V
CC
RESET
WDI
WDS
V
CC
I/O
I/O
I/O
GND
80C51
V
CC
V
CC
GND
RST
* THREE-STATE LEAKAGE MUST BE <10μA.
*
Figure 5. Wake-Up Timer
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PDF描述 |
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| MAX6302CSA | +5V, Low-Power uP Supervisory Circuits with Adjustable Reset/Watchdog |
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| MAX6302ESA | SOLID TANTALUM |
| MAX6303CPA | +5V, Low-Power uP Supervisory Circuits with Adjustable Reset/Watchdog |
| MAX6303CSA | +5V, Low-Power uP Supervisory Circuits with Adjustable Reset/Watchdog |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX6302CPA+ | 功能描述:監(jiān)控電路 5V uPower Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類(lèi)型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)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 |
| MAX6302CSA | 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類(lèi)型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)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 |
| MAX6302CSA+ | 功能描述:監(jiān)控電路 5V uPower Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類(lèi)型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)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 |
| MAX6302CSA+T | 功能描述:監(jiān)控電路 5V uPower Supervisor RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類(lèi)型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)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 |
| MAX6302CSA-T | 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類(lèi)型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)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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