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参数资料
| 型号： | DS1744-70+ |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | XO, clock |
| 英文描述： | Y2K-Compliant, Nonvolatile Timekeeping RAMs |
| 中文描述： | 0 TIMER(S), REAL TIME CLOCK, PDIP28 |
| 封装： | ROHS COMPLIANT, EDIP-28 |
| 文件页数： | 12/16页 |
| 文件大小： | 176K |
| 代理商： | DS1744-70+ |
DS1744/DS1744P Y2K-Compliant, Nonvolatile Timekeeping RAMs
5 of 16
Table 1. Truth Table
VCC
CE
OE
WE
MODE
DQ
POWER
VIH
X
Deselect
High-Z
Standby
VIL
X
VIL
Write
Data In
Active
VIL
VIH
Read
Data Out
Active
VCC > VPF
VIL
VIH
Read
High-Z
Active
VSO < VCC < VPF
X
Deselect
High-Z
CMOS Standby
VCC < VSO < VPF
X
Deselect
High-Z
Data-Retention Mode
SETTING THE CLOCK
As shown in Table 2, bit 7 of the century register is the write bit. Setting the write bit to a 1, like the read
bit, halts updates to the DS1744 registers. The user can then load them with the correct day, date, and time
data in 24-hour BCD format. Resetting the write bit to a 0 then transfers those values to the actual clock
counters and allows normal operation to resume.
STOPPING AND STARTING THE CLOCK OSCILLATOR
The clock oscillator can be stopped at any time. To increase the shelf life, the oscillator can be turned off
to minimize current drain from the battery. The OSC bit is the MSB (bit 7) of the seconds registers (Table
2). Setting it to a 1 stops the oscillator.
FREQUENCY TEST BIT
As shown in Table 2, bit 6 of the day byte is the frequency test bit. When the frequency test bit is set to
logic 1 and the oscillator is running, the LSB of the seconds register toggles at 512Hz. When the seconds
register is being read, the DQ0 line toggles at the 512Hz frequency as long as conditions for access remain
valid (i.e., CE low, OE low, WE high, and address for seconds register remain valid and stable).
CLOCK ACCURACY (DIP MODULE)
The DS1744 is guaranteed to keep time accuracy to within
1 minute per month at +25C. The RTC is
calibrated at the factory by Maxim using nonvolatile tuning elements, and does not require additional
calibration. For this reason, methods of field clock calibration are not available and not necessary. Clock
accuracy is also affected by the electrical environment; caution should be taken to place the RTC in the
lowest-level EMI section of the PC board layout. For additional information, refer to Application Note 58:
Crystal Considerations with Dallas Real-Time Clocks.
CLOCK ACCURACY (PowerCap MODULE)
The DS1744 and DS9034PCX are individually tested for accuracy. Once mounted together, the module
typically keeps time accuracy to within
1.53 minutes per month (35ppm) at +25°C. Clock accuracy is
also affected by the electrical environment and caution should be taken to place the RTC in the lowest-
level EMI section of the PC board layout. For additional information, refer to Application Note 58:
Crystal Considerations with Dallas Real-Time Clocks.
相关PDF资料 |
PDF描述 |
|---|---|
| DS1744-70IND+ | Y2K-Compliant, Nonvolatile Timekeeping RAMs |
| DS1744P-70IND+ | Y2K-Compliant, Nonvolatile Timekeeping RAMs |
| DS1744W-120+ | Y2K-Compliant, Nonvolatile Timekeeping RAMs |
| DS1744W-120IND+ | Y2K-Compliant, Nonvolatile Timekeeping RAMs |
| DS1744WP-120+ | Y2K-Compliant, Nonvolatile Timekeeping RAMs |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1744-70+ | 功能描述:实时时钟 Timekeeping NV RAM 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 |
| DS1744-70IND | 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 |
| DS1744-70IND/C01 | 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 |
| DS1744-70IND+ | 功能描述:实时时钟 Timekeeping NV RAM 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 |
| DS1744P | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:Y2K-Compliant, Nonvolatile Timekeeping RAMs |
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