参数资料
型号: MAX696CPE+
厂商: Maxim Integrated Products
文件页数: 12/15页
文件大小: 0K
描述: IC MPU SUPERVISORY CIRCUIT 16DIP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 25
类型: 多压监控器
监视电压数目: 2
输出: 推挽式,推挽式
复位: 高有效/低有效
复位超时: 最小为 35 ms
电压 - 阀值: 可调节/可选择
工作温度: 0°C ~ 70°C
安装类型: 通孔
封装/外壳: 16-DIP(0.300",7.62mm)
供应商设备封装: 16-PDIP
包装: 管件
Microprocessor Supervisory Circuits
Applications Information
Adding Hysteresis to the Power-Fail
Comparator
Since the power-fail comparator circuit is noninverting,
hysteresis can be added by connecting a resistor
between the PFO output and the PFI input as shown in
Figure 7. When PFO is low, resistor R3 sinks current
from the summing junction at the PFI pin. When PFO is
high, the series combination of R3 and R4 source cur-
rent into the PFI summing junction.
Alternate Watchdog Input Drive Circuits
The watchdog feature can be enabled and disabled
under program control by driving WDI with a three-state
buffer (Figure 8). The drawback to this circuit is that a
software fault may erroneously three-state the buffer,
thereby preventing the MAX696/MAX697 from detect-
ing that the microprocessor is no longer working. In
most cases, a better method is to extend the watchdog
period rather than disabling the watchdog. See Figure
9. When the control input is high, the OSC SEL pin is
low and the watchdog timeout is set by the external
capacitor. A 0.01μF capacitor sets a watchdog timeout
delay of 100s. When the control input is low, the OSC
SEL pin is driven high, selecting the internal oscillator.
The 100ms or the 1.6s period is chosen, depending on
which diode in Figure 9 is used.
7V - 15V
7805
+5V
V CC
R1
75k ?
R4
10k ?
PFO
MAX696
MAX697
+5V
V CC
R3
PFI
GND
WATCHDOG
STROBE
EN
WDI
MAX696
MAX697
R2
13k ?
300k ?
TO μ P
{
R2
{
R2
}
V H = 9.125V
V L = 7.9V
HYSTERESIS = 1.23V
V = 1.3V
H
V L = 1.3V
R1
1+ +
R1
1+ +
R1
R3
(5V - 1.3V) R1
1.3V (R3 + R4)
}
WATCHDOG
DISABLE
GND
HYSTERESIS ≈ 5V x R1
R3
ASSUMING R4 << R3
Figure 7. Adding Hysteresis to the Power-Fail Voltage
Figure 8. Disabling the Watchdog Under Program Control
Comparator
+5V
LOW = INTERNAL
WATCHDOG TIMEOUT
HI = EXTERNAL
WATCHDOG
OSC SEL
V CC
MAX696
MAX697
TIMEOUT
OSC IN
CONNECT FOR
100ms TIMEOUT
WHEN INTERNAL
TIMEOUT IS
SELECTED
CONNECT FOR
1.6s INTERNAL
GND
TIMEOUT
Figure 9. Selecting Internal or External Watchdog Timeout
12
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相关代理商/技术参数
参数描述
MAX696CPE+ 功能描述:监控电路 MPU 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
MAX696CWE 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
MAX696CWE+ 功能描述:监控电路 MPU 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
MAX696CWE+T 功能描述:监控电路 MPU 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
MAX696CWE-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