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参数资料
| 型号： | TC1232COETR |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PDSO16 |
| 封装： | SOIC-16 |
| 文件页数： | 20/20页 |
| 文件大小： | 262K |
| 代理商： | TC1232COETR |
2005 Microchip Technology Inc.
Preliminary
DS21370C-page 9
TC1232
4.3
Watchdog Timer
When the ST input is not stimulated for a preset time
period, the watchdog timer function forces RST and
RST signals to the active state. The preset time period
is determined by the TD inputs to be 150 ms with TD
connected to ground, 600 ms with TD floating or
1200 ms with TD connected to VCC (typ.). The
watchdog timer starts timing-out from the set time
period as soon as RST and RST are inactive. If a high-
to-low 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, the RST and RST signals are driven to the active
state for 250 ms, minimum (Figure 4-7).
The software routine that strobes ST is critical. The
code must be in a section of software that is executed
frequently enough so the time between toggles is less
than the watchdog time-out period. One common
technique controls the microprocessor I/O line from two
sections of the program. The software might set the I/O
line high while operating in the Foreground mode and
set it low while in the Background or Interrupt modes. If
both modes do not execute correctly, the watchdog
timer issues reset pulses.
tTD is the maximum elapsed time between ST high-to-
low transitions (ST is activated by falling edges only),
which will keep the watchdog timer from forcing the
reset outputs active for a time of tRST. tTD is a function
of the voltage at the TD pin, as tabulated below:
TABLE 4-1:
WATCHDOG TIMER
PERIODS
Figure 4-7 shows a block diagram for using the
TC1232 with a PICmicro MCU and the Watchdog
input.
FIGURE 4-7:
Watchdog Timer.
Figure 4-8 shows the expected reset output pin wave-
forms depending on the period of the ST pin falling
edge and the state of the TD input pin.
FIGURE 4-8:
Strobe Input.
4.4
Supply Monitor Noise Sensitivity
The TC1232 is optimized for fast response to negative-
going changes in VDD. Systems with an inordinate
amount of electrical noise on VDD (such as systems
using relays) may require a 0.01 F or 0.1 F bypass
capacitor to reduce detection sensitivity. This capacitor
should be installed as close to the TC1232 as possible
to keep the capacitor lead length short.
Condition
tTD
Min
Typ
Max
TD pin = 0V
62.5 ms
150 ms
250 ms
TD pin = Open
250 ms
600 ms
1000 ms
TD pin = VCC
500 ms
1200 ms
2000 ms
VCC
TOL GND
RST
ST
RESET
+5V
TC1232
TD
0.1
10 k
Ω
I/O
PICmicro
3-Terminal
Regulator
+5V
F
MCU
(example:
MCP1700)
tST
ST
tTD
RST (when tTD ≤ tTD (min))
“H”
RST
(when tTD(min) ≤ tTD ≤ tTD(max))
(when tTD ≥ tTD(max))
RST
RST (when tTD ≤ tTD(min))
“L”
RST
(when tTD(min) ≤ tTD ≤ tTD(max))
(when tTD ≥ tTD(max))
RST
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TC1232CPA | 功能描述:监控电路 Microprocessor Montr RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel |
| TC1232CPA | 制造商:Microchip Technology Inc 功能描述:MICROPROCESSOR MONITOR 1232 DIP8 |
| TC1232EOA | 功能描述:监控电路 Microprocessor Montr RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel |
| TC1232EOA | 制造商:Microchip Technology Inc 功能描述:MICROPROCESSOR MONITOR SMD 1232 |
| TC1232EOA713 | 功能描述:监控电路 Microprocessor Montr RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel |
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