- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄376961 > DS1819 5V and 3.3V MicroMonitor PDF資料下載
參數(shù)資料
| 型號： | DS1819 |
| 英文描述： | 5V and 3.3V MicroMonitor |
| 文件頁數(shù)： | 2/8頁 |
| 文件大?。?/td> | 146K |
| 代理商： | DS1819 |
DS1814/DS1819
2 of 8
The DS1814/DS1819 ‘A’ and ‘C’ perform pushbutton reset control. They debounce the pushbutton input
and generate an active reset pulse width of 140ms minimum. The DS1814/9 ‘A’ and ‘B’ versions perform
a watchdog function. The watchdog is an internal timer that forces the reset signals to the active state if
the strobe input does not change state every 1.12 seconds. The watchdog timer function can be disabled
by leaving the watchdog strobe input disconnected.
OPERATION
Power Monitor
The DS1814 detects out-of-tolerance power supply conditions and warns a processor-based system of
impending power failure. When V
CC
falls below a preset level, a comparator outputs the signal
RST
(or
RST).
RST
(or RST) are excellent control signals for a microprocessor, as processing is stopped at the
last possible moment of valid V
CC
. On power-up,
RST
(or RST) are kept active for a minimum of 140ms
to allow the power supply and processor to stabilize.
Pushbutton Reset
The DS1814 ‘A’ and ‘C’ provide an input pin for direct connection to a pushbutton reset (see Figure 2).
The pushbutton reset input requires an active low signal. Internally, this input is debounced and timed
such that a
RST
(or RST) signal of at least 140ms minimum will be generated. The 140ms delay
commences as the pushbutton reset input is released from the low level (see Figure 3).
Watchdog Timer
The DS1814/DS1819 ‘A’ and ‘B’ versions watchdog timer function forces
RST
(and RST) signal(s)
active when the
ST
input is not clocked within the 1.12 second watchdog time-out period. Time-out of
the watchdog starts when
RST
(and RST) become(s) inactive. If a transition occurs on the
ST
input pin
prior to time-out, the watchdog timer is reset and begins to time out again. If the watchdog timer is
allowed to time out, then the reset output(s) will go active for 140ms. The watchdog can be disabled by
floating (or tri-stating) the
ST
input.
The
ST
input can be derived from many microprocessor outputs. The most typical signals used are the
microprocessor data I/O signals and control signals. When the microprocessor functions normally, these
signals would as a matter of routine cause the watchdog to be reset prior to time-out. To guarantee that
the watchdog timer does not time out, a transition must occur at or less than 1.12 seconds. A typical
circuit example is shown in Figure 4. The DS1814/19 watchdog function can be disabled at any time by
tri-starting the strobe input. A sample circuit to disable the watchdog is shown in Figure 6.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1819B | 5V and 3.3V MicroMonitor |
| DS1819C | 5V and 3.3V MicroMonitor |
| DS1815 | 3.3V EconoReset with Push-Pull Output |
| DS1815-10 | 3.3V EconoReset with Push-Pull Output |
| DS1815-15 | 3.3V EconoReset with Push-Pull Output |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1819A | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:5V and 3.3V MicroMonitor |
| DS1819AR-05 | 制造商:Maxim Integrated Products 功能描述: |
| DS1819AR-10/T&R | 制造商:Maxim Integrated Products 功能描述:UMON PBRST WD SOT23 3.3V 10% T&R - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC MICROMON 3V W/PBRST SOT-23-5 制造商:Maxim Integrated Products 功能描述:Supervisory Circuits 3.3/5V MicroMonitor |
| DS1819AR-10/T&R | 功能描述:監(jiān)控電路 3.3/5V MicroMonitor 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 安裝風格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel |
| DS1819AR-10/TR | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Power Supply Supervisor |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。