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    參數(shù)資料
    

    


    


    
型號(hào)：
MAX805REPA

    

    
廠商：
MAXIM INTEGRATED PRODUCTS INC

    

    
元件分類(lèi)：
電源管理

    

    
英文描述：
3.0V/3.3V Microprocessor Supervisory Circuits

    

    
中文描述：
1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PDIP8

    

    
封裝：
0.300 INCH, PLASTIC, DIP-8

    

    
文件頁(yè)數(shù)：
6/12頁(yè)

    

    
文件大小：
98K

    

    
代理商：
MAX805REPA


    

    

    

	
    
    
    

    
    
	
    M
    _______________Detailed Desc ription
    Reset Output
    A microprocessor’s (μP’s) reset input starts the μP in a
    known state.  When the μP is in an unknown state, it should
    be held in reset.  The MAX690A/MAX692A/MAX802L/
    MAX802M assert reset during power-up and prevent code
    execution errors during power-down or brownout condi-
    tions.
    On power-up, once V
    reaches 1V, 
    RESET
     is guaran-
    teed to be a logic low.  As V
    rises, 
    RESET
     remains
    low.  When V
    CC
    exceeds the reset threshold, an internal
    timer keeps 
    RESET
     low for a time equal to the reset
    pulse width; after this interval, 
    RESET
     goes high (Figure
    2).  If a brownout condition occurs (if V
    dips below
    the reset threshold), 
    RESET
     is triggered.  Each time
    RESET
     is triggered, it stays low for the reset pulse width
    interval.  Any time V
    goes below the reset threshold,
    the internal timer restarts the pulse.  If a brownout con-
    dition interrupts a previously initiated reset pulse, the
    reset pulse continues for another 200ms.  On power-
    down, once V
    goes below the threshold, 
    RESET
     is
    guaranteed to be logic low until V
    CC
    droops below 1V. 
    RESET
     is also triggered by a watchdog timeout.  If a
    high or low is continuously applied to the WDI pin for
    1.6sec,
     RESET
     pulses low.  As long as 
    RESET
     is assert-
    ed, the watchdog timer remains clear.  When 
    RESET
    comes high, the watchdog resumes timing and must be
    serviced within 1.6sec.  If WDI is tied high or low, a
    RESET
     pulse is triggered every 1.8sec (t
    WD
    plus t
    RS
    ).
    The MAX805L active-high RESET output is the inverse
    of the MAX690A/MAX692A/MAX802L/MAX802M 
    RESET
    output, and is guaranteed to be valid with V
    down to
    1.1V.  Some μPs, such as Intel’s 80C51, require an
    active-high reset pulse.
    Watc hdog Input
    The watchdog circuit monitors the μP’s activity.  If the
    μP does not toggle the watchdog input (WDI) within
    1.6sec, a reset pulse is triggered.  The internal 1.6sec
    timer is cleared by either a reset pulse or by open cir-
    cuiting the WDI input.  As long as reset is asserted or
    the WDI input is open circuited, the timer remains
    cleared and does not count.  As soon as reset is
    released or WDI is driven high or low, the timer starts
    counting.  It can detect pulses as short as 50ns.
    Power-Fail Comparator
    The PFI input is compared to an internal 1.25V refer-
    ence.  If PFI is less than 1.25V, 
    PFO
     goes low.  The
    power-fail comparator is intended for use as an under-
    voltage detector to signal a failing power supply; it
    Mic roproc essor S upervisory Circ uits
    6
    _______________________________________________________________________________________
    1.25V
    0.8V
    WATCHDOG
    TIMER
    PFO
    RESET
    (RESET)
    V
    OUT
    RESET
    GENERATOR
    BATTERY-SWITCHOVER
    CIRCUITRY
    1.25V
    3.5V
    V
    BATT
    V
    CC
    PFI
    WDI
    MAX690A
    MAX692A
    MAX802L
    MAX802M
    MAX805L
    (   ) ARE FOR MAX805L ONLY.
    GND
    Figure 1.  Block Diagram
    t
    RS
    +5V
    0V
    V
    CC
    0V
    +5V
    0V
    +5V
    RESET
    0V
    (RESET)
    3.0V
    3.0V
    V
    OUT
    +5V
    0V
    PFO
    V
    BATT
     = PFI = 3.0V
    I
    OUT
     = 0mA
    (    ) ARE FOR MAX805L ONLY.
    Figure 2.  Timing Diagram
    
    
    
    
    
    


    


    

    相關(guān)PDF資料
    		

    PDF描述
    		

    
    

    
MAX805LEPA
Microprocessor Supervisory Circuits

    

    
MAX805LCPA
Microprocessor Supervisory Circuits

    

    
MAX805LCSA
Microprocessor Supervisory Circuits

    

    
MAX805LESA
Microprocessor Supervisory Circuits

    

    
MAX805RCPA
Octal Buffers And Line Drivers With 3-State Outputs 20-LCCC -55 to 125

    

    

    

    


    


    

    相關(guān)代理商/技術(shù)參數(shù)
    		

    參數(shù)描述
    		

    
    

    
MAX805REPA+
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

    

    
MAX805RESA
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

    

    
MAX805RESA+
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

    

    
MAX805RESA+T
功能描述:監(jiān)控電路 3.0V/3.3V Microprocessor Supervisory Circuit with Reset Threshold of 2.625V 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

    

    
MAX805RESA-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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