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| 型号： | MAX6304CSA |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 6/12页 |
| 文件大小： | 0K |
| 描述： | IC CIRCUIT SUPERVISORY LP 8-SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 100 |
| 类型： | 简单复位/加电复位 |
| 监视电压数目： | 1 |
| 输出： | 推挽式，图腾柱 |
| 复位： | 高有效 |
| 复位超时： | 最小为 2.8 ms |
| 电压 - 阀值： | 可调节/可选择 |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC |
| 包装： | 管件 |
+5V, Low-Power μP Supervisory Circuits
with Adjustable Reset/Watchdog
Detailed Description
Reset Function/Output
The reset output is typically connected to the reset input
of a μP. A μP’s reset input starts or restarts the μP in a
known state. The MAX6301–MAX6304 μP supervisory
R1
V IN
circuits provide the reset logic to prevent code-execution
errors during power-up, power-down, and brownout
RESET IN
V CC
( )
conditions (see the Typical Operating Circuit).
For the MAX6301/MAX6303, RESET changes from high
to low whenever the monitored voltage (V IN ) drops
below the reset threshold voltage (V RST ). RESET
remains low as long as V IN is below V RST . Once V IN
exceeds V RST , RESET remains low for the reset timeout
period, then goes high. When a reset is asserted due to
R2
MAX6301
MAX6302
MAX6303
MAX6304
0.1μF
V RST = 1.22 R1 + R2
R2
a watchdog timeout condition, RESET stays low for the
( )
R1 = R2 × ?
? 1 ? ?
reset timeout period. Any time reset asserts, the watch-
dog timer clears. At the end of the reset timeout period,
RESET goes high and the watchdog timer is restarted
from zero. If the watchdog timeout period is exceeded
again, then RESET goes low again. This cycle contin-
ues unless WDI receives a transition.
On power-up, once V CC reaches 1V, RESET is guaran-
teed to be a logic-low. For information about applica-
tions where V CC is less than 1V, see the Ensuring a
Valid RESET /RESET Output Down to V CC = 0V (MAX6303/
MAX6304) section. As V CC rises, RESET remains low.
When V IN rises above V RST , the reset timer starts and
RESET remains low. When the reset timeout period
ends, RESET goes high.
On power-down, once V IN goes below V RST , RESET
goes low and is guaranteed to be low until V CC drops
below 1V. For information about applications where
V CC is less than 1V, see the Ensuring a Valid
RESET /RESET Output Down to V CC = 0V (MAX6303/
MAX6304) section.
The MAX6302/MAX6304 active-high RESET output is
the inverse of the MAX6301/MAX6303 active-low
RESET output, and is guaranteed valid for V CC > 1.31V.
Reset Threshold
These supervisors monitor the voltage on RESET IN.
The MAX6301 –MAX6304 have an adjustable reset
threshold voltage (V RST ) set with an external resistor
voltage-divider (Figure 1). Use the following formula to
calculate V RST (the point at which the monitored voltage
triggers a reset):
Figure 1. Calculating the Reset Threshold Voltage (V RST )
and R2 can have very high values to minimize current
consumption. Set R2 to some conveniently high value
(1M ? , for example) and calculate R1 based on the desired
reset threshold voltage, using the following formula:
? V RST ?
? V TH ?
Watchdog Timer
The watchdog circuit monitors the μP’s activity. If the μP
does not toggle the watchdog input (WDI) within t WD
(user selected), reset asserts. The internal watchdog
timer is cleared by reset, by a transition at WDI (which
can detect pulses as short as 30ns), or by a transition
at WDS. The watchdog timer remains cleared while
reset is asserted; as soon as reset is released, the timer
starts counting (Figure 2).
The MAX6301–MAX6304 feature two modes of watchdog
timer operation: normal mode and extended mode. In
normal mode (WDS = GND), the watchdog timeout
period is determined by the value of the capacitor con-
nected between SWT and ground (see the Selecting
the Reset and Watchdog Timeout Capacitor section). In
extended mode (WDS = V CC ), the watchdog timeout
period is multiplied by 500. For example, in the extended
mode, a 1μF capacitor gives a watchdog timeout period
of 22 minutes (see the Extended-Mode Watchdog
Timeout Period vs. C SWT graph in the Typical
Operating Characteristics).
V RST =
V TH × ( R1 + R2 )
R2
( V )
In extended mode, the watchdog function can be
disabled by leaving WDI unconnected or by three-stating
the driver connected to WDI. In this mode, the watchdog
where V RST is the desired reset threshold voltage and
V TH is the reset input threshold (1.22V). Resistors R1
input is internally driven low during the watchdog timeout
period, then momentarily pulses high, resetting the
6
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX6304CSA+ | 功能描述:监控电路 5V uPower Supervisor 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 |
| MAX6304CSA+T | 功能描述:监控电路 5V uPower Supervisor 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 |
| MAX6304CSA-T | 功能描述:监控电路 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 |
| MAX6304CUA | 功能描述:监控电路 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 |
| MAX6304CUA+ | 功能描述:监控电路 5V uPower Supervisor 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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