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参数资料
| 型号： | DS1321E |
| 厂商： | Maxim Integrated |
| 文件页数： | 6/13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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DESCRIPTION
The DS1321 Flexible Nonvolatile Controller with Lithium Battery Monitor is a CMOS circuit which
solves the application problem of converting CMOS SRAMs into nonvolatile memory. Incoming power
is monitored for an out-of-tolerance condition. When such a condition is detected, chip enable outputs are
inhibited to accomplish write protection and the battery is switched on to supply the SRAMs with
uninterrupted power. Special circuitry uses a low-leakage CMOS process which affords precise voltage
detection at extremely low battery consumption. One DS1321 can support as many as four SRAMs
arranged in any of three memory configurations.
In addition to battery-backup support, the DS1321 performs the important function of monitoring the
remaining capacity of the lithium battery and providing a warning before the battery reaches end-of-life.
Because the open-circuit voltage of a lithium backup battery remains relatively constant over the majority
of its life, accurate battery monitoring requires loaded-battery voltage measurement. The DS1321
performs such measurement by periodically comparing the voltage of the battery as it supports an internal
resistive load with a carefully selected reference voltage. If the battery voltage falls below the reference
voltage under such conditions, the battery will soon reach end-of-life. As a result, the Battery Warning
pin is activated to signal the need for battery replacement.
MEMORY BACKUP
The DS1321 performs all the circuit functions required to provide battery-backup for as many as four
SRAMs. First, the device provides a switch to direct power from the battery or the system power supply
(VCCI). Whenever VCCI is less than the VCCTP trip point and VCCI is less than the battery voltage VBAT, the
battery is switched in to provide backup power to the SRAM. This switch has voltage drop of less than
0.2 volts.
Second, the DS1321 handles power failure detection and SRAM write-protection. VCCI is constantly
monitored, and when the supply goes out of tolerance, a precision comparator detects power failure and
inhibits the four chip enable outputs in order to write-protect the SRAMs. This is accomplished by
holding CEO1 through CEO4 to within 0.2 volts of VCCO when VCCI is out of tolerance. If any CEI is
active (low) at the time that power failure is detected, the corresponding CEO signal is kept low until the
CEI
signal is brought high again. Once the CEI signal is brought high, the CEO signal is taken high and
held high until after VCCI has returned to its nominal voltage level. If the CEI signal is not brought high
by 1.5 s after power failure is detected, the corresponding CEO is forced high at that time. This specific
scheme for delaying write protection for up to 1.5 s guarantees that any memory access in progress
when power failure occurs will complete properly. Power failure detection occurs in the range of 4.75 to
4.5 volts (5% tolerance) when the TOL pin is wired to GND or in the range of 4.5 to 4.25 volts (10%
tolerance) when TOL is connected to VCCO.
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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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