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参数资料
| 型号： | DS1553W-120 |
| 厂商： | DALLAS SEMICONDUCTOR |
| 元件分类： | Timer or RTC |
| 英文描述： | 0 TIMER(S), REAL TIME CLOCK, DMA28 |
| 封装： | 0.700 INCH, PLASTIC, MODULE, DIP-28 |
| 文件页数： | 14/19页 |
| 文件大小： | 278K |
| 代理商： | DS1553W-120 |
DS1553
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DATA RETENTION MODE
The 5-volt device is fully accessible and data can be written and read only when VCC is greater than VPF.
However, when VCC is below the power-fail point VPF (point at which write protection occurs) the
internal clock registers and SRAM are blocked from any access. When VCC falls below the battery switch
point VSO (battery supply level), device power is switched from the VCC pin to the internal backup lithium
battery. RTC operation and SRAM data are maintained from the battery until VCC is returned to nominal
levels.
The 3.3 volt device is fully accessible and data can be written and read only when VCC is greater than VPF.
When VCC falls below VPF, access to the device is inhibited. If VPF is less than VSO, the device power is
switched from VCC to the internal backup lithium battery when VCC drops below VPF. If VPF is greater
than VSO, the device power is switched from VCC to the internal backup lithium battery when VCC drops
below VSO. RTC operation and SRAM data are maintained from the battery until VCC is returned to
nominal levels.
All control, data, and address signals must be powered down when VCC is powered down.
BATTERY LONGEVITY
The DS1553 has a lithium power source that is designed to provide energy for the clock activity, and
clock and RAM data retention when the VCC supply is not present. The capability of this internal power
supply is sufficient to power the DS1553 continuously for the life of the equipment in which it is
installed. For specification purposes, the life expectancy is 10 years at 25
°C with the internal clock
oscillator running in the absence of VCC. Each DS1553 is shipped from Dallas Semiconductor with its
lithium energy source disconnected, guaranteeing full energy capacity. When VCC is first applied at a
level greater than VPF, the lithium energy source is enabled for battery backup operation. . Each DS1553
is shipped from Dallas Semiconductor with its lithium energy source disconnected, guaranteeing full
energy capacity. When VCC is first applied at a level greater than VPF, the lithium energy source is
enabled for battery backup operation. Actual life expectancy of the DS1553 will be much longer than 10
years since no internal battery energy is consumed when VCC is present.
INTERNAL BATTERY MONITOR
The DS1553 constantly monitors the battery voltage of the internal battery. The Battery Low Flag (BLF)
bit of the Flags Register (B4 of 1FF0h) is not writeable and should always be a 0 when read. If a 1 is ever
present, an exhausted lithium energy source is indicated and both the contents of the RTC and RAM are
questionable.
POWER-ON RESET
A temperature compensated comparator circuit monitors the level of VCC. When VCC falls to the power
fail trip point, the RST signal (open drain) is pulled low. When VCC returns to nominal levels, the
RST
signal continues to be pulled low for a period of 40 ms to 200 ms. The power-on reset function is
independent of the RTC oscillator and thus is operational whether or not the oscillator is enabled.
CLOCK OPERATIONS
Table 2 and the following paragraphs describe the operation of RTC, alarm, and watchdog functions.
相关PDF资料 |
PDF描述 |
|---|---|
| DS1553P-100 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
| DS1554-70 | 0 TIMER(S), REAL TIME CLOCK, PDMA32 |
| DS1554WP-120 | 0 TIMER(S), REAL TIME CLOCK |
| DS1554W-120 | 0 TIMER(S), REAL TIME CLOCK, PDMA32 |
| DS1554P-70 | 0 TIMER(S), REAL TIME CLOCK, DMA34 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1553W-120+ | 功能描述:实时时钟 64kB NV RAM Timekeeper RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| DS1553W-150 | 功能描述:实时时钟 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| DS1553W-150+ | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:64kB, Nonvolatile, Year-2000-Compliant Timekeeping RAM |
| DS1553WP-120 | 功能描述:实时时钟 64kB NV RAM Timekeeper RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| DS1553WP-120+ | 功能描述:实时时钟 64kB NV RAM Timekeeper RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
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