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      參數(shù)資料
      型號: MAX6301CSA
      廠商: MAXIM INTEGRATED PRODUCTS INC
      元件分類: 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, PDSO8
      封裝: 0.150 INCH, MS-012AA, SOIC-8
      文件頁數(shù): 8/12頁
      文件大小: 102K
      代理商: MAX6301CSA
      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
      相關(guān)PDF資料
      PDF描述
      MAX6301EPA +5V, Low-Power uP Supervisory Circuits with Adjustable Reset/Watchdog
      MAX6301ESA +5V, Low-Power uP Supervisory Circuits with Adjustable Reset/Watchdog
      MAX6304ESA +5V, Low-Power uP Supervisory Circuits with Adjustable Reset/Watchdog
      MAX6303 +5V, Low-Power uP Supervisory Circuits with Adjustable Reset/Watchdog
      MAX6304 +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
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      MAX6301CUA 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
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