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| 型号： | MAX690ACSA |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 8/12页 |
| 文件大小： | 0K |
| 描述： | IC MPU SUPERVISORY CIRCUIT 8SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 100 |
| 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： | 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 |
Microprocessor Supervisory Circuits
+5V
V IN
+5V
V CC
MAX692A
MAX802M
V OUT
TO STATIC RAM
R 1
PFI
V CC
MAX690
MAX692A
+
V BATT
RESET
TO μ P
R 2
C1*
R 3
MAX802L
MAX802M
MAX805L
100k
0.1F
GND
PFO
GND
TO μ P
*OPTIONAL
+5V
Figure 5. Using a SuperCap? as a Backup Power Source with
the MAX692A/MAX802M and a +5V ±10% Supply
PFO
0V
When V BATT connects to V OUT , backup mode is activat-
ed and the internal circuitry is powered from the battery
0V
V L
V TRIP
V IN
V H
VTRIP = 1.25/ ? ?
? R2 || R3 ?
? R1 + R2 || R3 ?
VL ? 1.25 5 ? 1.25 1.25
(Table 1). When V CC is just below V BATT , the current
drawn from V BATT is typically 30μA. When V CC drops to
more than 1V below V BATT , the internal switchover com-
parator shuts off and the supply current falls to less
than 1μA.
__________Applications Information
Using a SuperCap? as a Backup
Power Source
SuperCaps are capacitors with extremely high capaci-
tance values, on the order of 0.1F. Figure 4 shows a
SuperCap used as a backup power source. Do not allow
the SuperCap’s voltage to exceed the maximum reset
threshold by more than 0.6V. In Figure 4’s circuit, the
SuperCap rapidly charges to within a diode drop of V CC .
However, after a long time, the diode leakage current will
pull the SuperCap voltage up to V CC . When using a
SuperCap with the MAX690A/MAX802L/MAX805L, V CC
may not exceed 4.75V + 0.6V = 5.35V.
Use the SuperCap circuit of Figure 5 with a MAX692A
or MAX802M and a ±10% supply. This circuit
ensures that the SuperCap only charges to V CC -
? R2 ?
? R2 + R2 ?
VIH = 1.25/
+ =
R1 R3 R2
Figure 6. Adding Hysteresis to the Power-Fail Comparator
Allowable Backup Power-Source
Batteries
Lithium batteries work very well as backup batteries due to
very low self-discharge rates and high energy density.
Single lithium batteries with open-circuit voltages of 3.0V to
3.6V are ideal. Any battery with an open-circuit voltage
less than the minimum reset threshold plus 0.3V can be
connected directly to the V BATT input of the
MAX690A/MAX692A/MAX802L/MAX802M/MAX805L with
Table 2. Allowable Backup-Battery Voltages
(see Using a SuperCap as a Backup Power Source
section for use with a SuperCap)
0.5V. At the maximum V CC of 5.5V, the SuperCap
charges up to 5.0V, only 0.5V above the maximum
reset threshold—well within the requisite 0.6V.
?SuperCap is a trademark of Baknor Industries.
PART NO.
MAX690A/
MAX802L/MAX805L
MAX692A/
MAX802M
MAXIMUM BACKUP-BATTERY
VOLTAGE (V)
4.80
4.55
8
_______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX690ACSA+ | 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 |
| MAX690ACSA+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 |
| MAX690ACSA-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 |
| MAX690AEJA | 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 |
| MAX690AEPA | 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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