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参数资料
| 型号： | MAX791EPE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 15/19页 |
| 文件大小： | 0K |
| 描述： | IC SUPERVISOR MPU 16-DIP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 25 |
| 类型： | 备用电池电路 |
| 监视电压数目： | 1 |
| 输出： | 推挽式，图腾柱 |
| 复位： | 低有效 |
| 复位超时： | 最小为 140 ms |
| 电压 - 阀值： | 4.65V |
| 工作温度： | -40°C ~ 85°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 Circuit
VIN
+5V
V OUT
Rp*
CE
CE
RAM 1
R1
PFI
V CC
CE IN
CE OUT
CE
CE
RAM 2
R2
R3
C1*
MAX791
CE
MAX791
CE
RAM 3
PFO
GND
GND
CE
RAM 4
TO μ P
*OPTIONAL
CE
+5V
PFO
*MAXIMUM Rp VALUE DEPENDS ON
THE NUMBER OF RAMs.
MINIMUM Rp VALUE IS 1k ?
ACTIVE-HIGH CE
LINES FROM LOGIC
0V
0V
V TRIP = 1.25
V H = 1.25 /
R1 + R2
R2
R2 || R3
R1 + R2 || R3
V L V TRIP V H
V IN
VL - 1.25 + 5 - 1.25 = 1.25
R1 R3 R2
Figure 13. Alternate CE Gating
Monitoring a Negative Voltage
The power-fail comparator can be used to monitor a
negative supply voltage using Figure 15’s circuit. When
the negative supply is valid, PFO is low. When the neg-
ative supply voltage drops, PFO goes high. This cir-
cuit’s accuracy is affected by the PFI threshold toler-
ance, the V CC voltage, and resistors R1 and R2.
Backup-Battery Replacement
The backup battery may be disconnected while V CC is
above the reset threshold. No precautions are neces-
sary to avoid spurious reset pulses.
Negative-Going V CC Transients
While issuing resets to the μP during power-up, power-
down, and brownout conditions, these supervisors are
relatively immune to short-duration negative-going V CC
transients (glitches). It is usually undesirable to reset
the μP when V CC experiences only small glitches.
Figure 16 shows maximum transient duration vs. reset
comparator overdrive, for which reset pulses are not
generated. The graph was produced using negative-
Figure 14. Adding Hysteresis to the Power-Fail Comparator
going V CC pulses, starting at 5V and ending below the
reset threshold by the magnitude indicated (reset com-
parator overdrive). The graph shows the maximum
pulse width that a negative-going V CC transient may
typically have without causing a reset pulse to be
issued. As the amplitude of the transient increases (i.e.,
goes farther below the reset threshold), the maximum
allowable pulse width decreases. Typically, a V CC tran-
sient that goes 100mV below the reset threshold and
lasts for 40μs or less will not cause a reset pulse to be
issued.
A 100nF bypass capacitor mounted close to the V CC
pin provides additional transient immunity.
Connecting a Timing Capacitor to SWT
SWT is internally connected to a ±100nA current
source. When a capacitor is connected from SWT to
ground (to select an alternative watchdog-timeout peri-
od), the current source charges and discharges the
timing capacitor to create the oscillator that controls the
watchdog-timeout period. To prevent timing errors or
oscillator start-up problems, minimize external current
leakage sources at this pin, and locate the capacitor as
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX791EPE+ | 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 |
| MAX791ESE | 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 |
| MAX791ESE+ | 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 |
| MAX791ESE+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 |
| MAX791ESE-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 |
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