- 您现在的位置：买卖IC网 > PDF目录13324 > MAX802SCSA+ (Maxim Integrated Products)IC SUPERVISOR MPU 8-SOIC PDF资料下载
参数资料
| 型号： | MAX802SCSA+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 8/12页 |
| 文件大小： | 0K |
| 描述： | IC SUPERVISOR MPU 8-SOIC |
| 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： | 2.925V |
| 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 |
3.0V/3.3V Microprocessor Supervisory Circuits
Manual Reset
A logic – — – on M R asserts reset. Reset remains — – asserted
–
– — — — — –
Backup-Battery Switchover
In the event of a brownout or power failure, it may be
necessary to preserve the contents of RAM. With a
backup battery installed at VBATT, the devices auto-
matically switch RAM to backup power when V CC
falls.
This family of μP supervisors (designed for 3.3V and 3V
systems) doesn’t always connect VBATT to V OUT when
VBATT is greater than V CC . VBATT connects to V OUT
(through a 140 Ω switch) when V CC is below V SW and
VBATT is greater than V CC , or when V CC falls below
1.75V (typ) regardless of the VBATT voltage. This is
done to allow the backup battery (e.g., a 3.6V lithium
cell) to have a higher voltage than V CC .
Switchover at V SW (2.40V) ensures that battery-backup
mode is entered before V OUT gets too close to the 2.0V
minimum required to reliably retain data in CMOS RAM.
Switchover at higher V CC voltages would decrease
backup-battery life. When V CC recovers, switchover is
deferred until V CC rises above the reset threshold
(V RST ) to ensure a stable supply. V OUT is connected to
V CC through a 3 Ω PMOS power switch.
– — –
low
while M R is low, and for t WP (200ms) after M R returns
– — –
high. This input has an internal 70μA pull-up current, so
it can be left open if it is not used. M R can be driven with
TTL or CMOS logic levels, or with open-drain/collector
– —
outputs. – Connect a normally open momentary switch
from M R to GND to create a manual-reset function;
external debounce circuitry is not required.
Table 1. Input and Output Status in
Battery-Backup Mode
__________Applications Information
These μP supervisory circuits are not short-circuit
protected. Shorting V OUT to ground—excluding power-
up transients such as charging a decoupling
capacitor—destroys the device. Decouple both V CC
and VBATT pins to ground by placing 0.1μF capacitors
as close to the device as possible.
Using a SuperCap
as a Backup Power Source
SuperCaps ? are capacitors with extremely high
capacitance values (e.g., order of 0.47F) for their size.
Figure 3 shows two ways to use a SuperCap as a
backup power source. The SuperCap may be
connected through a diode to the 3V input (Figure 3a)
or, if a 5V supply is also available, the SuperCap may
be charged up to the 5V supply (Figure 3b) allowing a
longer backup period. Since VBATT can exceed V CC
while V CC is above the reset threshold, there are no
special precautions when using these μP supervisors
with a SuperCap.
Operation without a Backup
Power Source
These μP supervisors were designed for battery-
backed applications. If a backup battery is not used,
connect both VBATT and V OUT to V CC , or use a
different μP supervisor such as the MAX706T/S/R or
MAX708T/S/R.
Replacing the Backup Battery
The backup power source can be removed while V CC
remains valid, if VBATT is decoupled with a 0.1μF
capacitor to ground, without danger of triggering
RESET/ R E S E T . As long as V CC stays above V SW ,
battery-backup mode cannot be entered.
Adding Hysteresis
– — — –
PIN NAME
V OUT
V CC
PFI
– — — –
P F O
WDI
– — –
M R
– — — — — –
R E S E T
RESET
VBATT
STATUS
Connected to VBATT through an internal
140 Ω switch
Disconnected from V OUT
The power-fail comparator is disabled when
V CC < V SW
Logic low when V CC < V SW or PFI < V PFT
The watchdog timer is disabled
Disabled
Low logic
High impedance
Connected to V OUT
to the Power-Fail Comparator
The power-fail comparator has a typical input
hysteresis of 10mV. This is sufficient for most applica-
tions where a power-supply line is being monitored
through an external voltage divider (see the Monitoring
an Additional Power Supply section).
If additional noise margin is desired, connect a resistor
between P F O and PFI as shown in Figure 4a. Select
the ratio of R1 and R2 such that PFI sees 1.237V (V PFT )
when V IN falls to its trip point (V TRIP ). R3 adds the
hysteresis and will typically be more than 10 times the
value of R1 or R2. The hysteresis window extends both
above (V H ) and below (V L ) the original trip point (V TRIP ).
SuperCap is a trademark of Baknor Industries.
8
_______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| RCM18DTMT-S273 | CONN EDGECARD 36POS R/A .156 SLD |
| ECC50DREN-S13 | CONN EDGECARD 100POS .100 EXTEND |
| ACC08DRTN-S13 | CONN EDGECARD 16POS .100 EXTEND |
| ECC50DREH-S13 | CONN EDGECARD 100POS .100 EXTEND |
| SCEP134S-6R4 | INDUCTOR SMD 6.40UH 8.00A 100KHZ |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX802SCSA+ | 功能描述:监控电路 3/3.3V 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 |
| MAX802SCSA+T | 功能描述:监控电路 3/3.3V 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 |
| MAX802SCSA-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 |
| MAX802SEPA | 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 |
| MAX802SEPA+ | 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 |
发布紧急采购，3分钟左右您将得到回复。