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参数资料
| 型号： | DS1321E |
| 厂商： | Maxim Integrated |
| 文件页数： | 8/13页 |
| 文件大小： | 0K |
| 描述： | IC CTRL NV W/BATT MON 5V 20TSSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 74 |
| 控制器类型： | 非易失性 RAM |
| 电源电压： | 4.75 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 20-TSSOP（0.173"，4.40mm 宽） |
| 供应商设备封装： | 20-TSSOP |
| 包装： | 管件 |
DS1321
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BATTERY VOLTAGE MONITORING
The DS1321 automatically performs periodic battery voltage monitoring at a factory-programmed time
interval of 24 hours. Such monitoring begins within tREC after VCCI rises above VCCTP and is suspended
when power failure occurs.
After each 24-hour period (tBTCN) has elapsed, the DS1321 connects VBAT to an internal 1 M test
resistor (RINT) for one second (tBTPW). During this one second, if VBAT falls below the factory-
programmed battery voltage trip point (VBTP), the battery warning output BW is asserted. While BW is
active, battery testing will be performed with period tBTCW to detect battery removal and replacement.
Once asserted, BW remains active until the battery is physically removed and replaced by a fresh cell.
The battery is still retested after each VCC power-up, however, even if BW was active on power-down. If
the battery is found to be higher than VBTP during such testing, BW is deasserted and regular 24-hour
testing resumes. BW has an open-drain output driver.
Battery replacement following BW activation is normally done with VCCI nominal so that SRAM data is
not lost. During battery replacement, the minimum time duration between old battery detachment and
new battery attachment (tBDBA) must be met or BW will not deactivate following attachment of the new
battery. Should BW not deactivate for this reason, the new battery can be detached for tBDBA and then re-
attached to clear BW .
NOTE: The DS1321 cannot constantly monitor an attached battery because such monitoring would
drastically reduce the life of the battery. As a result, the DS1321 only tests the battery for one second out
of every 24 hours and does not monitor the battery in any way between tests. If a good battery (one that
has not been previously flagged with BW ) is removed between battery tests, the DS1321 may not
immediately sense the removal and may not activate BW until the next scheduled battery test. If a battery
is then reattached to the DS1321, the battery may not be tested until the next scheduled test.
NOTE: Battery monitoring is only a useful technique when testing can be done regularly over the entire
life of a lithium battery. Because the DS1321 only performs battery monitoring when VCC is nominal,
systems which are powered-down for excessively long periods can completely drain their lithium cells
without receiving any advanced warning. To prevent such an occurrence, systems using the DS1321
battery monitoring feature should be powered-up periodically (at least once every few months) in order to
perform battery testing. Furthermore, anytime BW is activated on the first battery test after a power-up,
data integrity should be checked via checksum or other technique.
POWER MONITORING
The DS1321 automatically detects out-of-tolerance power supply conditions and warns a processor-based
system of impending power failure. When VCCI falls below the trip point level defined by the TOL pin
(VCCTP), the VCCI comparator activates the reset signal RST . Reset occurs in the range of 4.75 to 4.5 volts
(5% tolerance) when the TOL pin is connected to GND or in the range of 4.5 to 4.25 volts (10%
tolerance) when TOL is connected to VCCO.
RST
also serves as a power-on reset during power-up. After VCCI exceeds VCCTP, RST will be held active
for 200 ms nominal (tRPU). This reset period is sufficiently long to prevent system operation during
power-on transients and to allow tREC to expire. RST has an open-drain output driver.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1321E/T&R | 制造商:Maxim Integrated Products 功能描述:NV CONTRL 5V X4 BW&RST 20-TSSOP T&R - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC CTRL NV W/BATT MON 5V 20TSSOP |
| DS1321E/T&R | 功能描述:IC CTRL NV W/BATT MON 5V 20TSSOP RoHS:否 类别:集成电路 (IC) >> 存储器 - 控制器 系列:- 标准包装:45 系列:- 控制器类型:静态 RAM（SRAM） 电源电压:4.5 V ~ 5.5 V 工作温度:0°C ~ 70°C 封装/外壳:16-SOIC（0.295"，7.50mm 宽） 供应商设备封装:16-SOIC W 包装:管件 |
| DS1321E+ | 功能描述:存储器控制器 Flexible NV Cntlr w/Lithium Battery RoHS:否 制造商:Maxim Integrated |
| DS1321E+T&R | 制造商:Maxim Integrated Products 功能描述:NONVOLATILE CNTRLR 20TSSOP - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC CTRL NV W/BATT MON 5V 20TSSOP |
| DS1321E+T&R | 功能描述:IC CTRL NV W/BATT MON 5V 20TSSOP RoHS:是 类别:集成电路 (IC) >> 存储器 - 控制器 系列:- 标准包装:45 系列:- 控制器类型:静态 RAM（SRAM） 电源电压:4.5 V ~ 5.5 V 工作温度:0°C ~ 70°C 封装/外壳:16-SOIC（0.295"，7.50mm 宽） 供应商设备封装:16-SOIC W 包装:管件 |
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