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参数资料
| 型号： | DS1308U-33+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 4/16页 |
| 文件大小： | 0K |
| 描述： | IC RTC 56BYTE NVRAM I2C 8UMAX |
| 标准包装： | 3,000 |
| 类型： | 时钟/日历 |
| 特点： | 闰年，NVSRAM，方波输出 |
| 存储容量： | 56B |
| 时间格式： | HH:MM:SS（12/24 小时） |
| 数据格式： | YY-MM-DD-dd |
| 接口： | I²C，2 线串口 |
| 电源电压： | 3 V ~ 5.5 V |
| 电压 - 电源，电池： | 1.3 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 供应商设备封装： | 8-uMAX |
| 包装： | 带卷 (TR) |
DS1308
Low-Current I2C RTC with 56-Byte NV RAM
12
Maxim Integrated
External Synchronization
When an external clock reference is used, the input from
SQW/CLKIN is divided down to 1Hz. The 1Hz from the
divider (Ext-1Hz, see Functional Diagram) is used to
correct the 1Hz that is derived from the 32.768kHz oscil-
lator (Osc-1Hz). As Osc-1Hz drifts in relation to Ext-1Hz,
Osc-1Hz is digitally adjusted.
As shown in the Functional Diagram, the three highest
frequencies driving the SQW/CLKIN pin are derived
from the uncorrected oscillator, while the 1Hz output is
derived from the adjusted Osc-1Hz signal.
Conceptually, the circuit can be thought of as two 1Hz
signals, one derived from the internal oscillator and
the other from the external reference clock, with the
oscillator-derived 1Hz signal being locked to the 1Hz
signal derived from the external reference clock. The
edges of the 1Hz signals do not need to be aligned with
each other. While the external clock source is present
and within tolerance, the Ext-1Hz and Osc-1Hz maintain
their existing lock, regardless of their edge alignment,
with periodic correction of the Osc-1Hz signal. If the
external signal is lost and then regained sometime later,
the signals re-lock with whatever new alignment exists
The Ext-1Hz is used by the device as long as it is within
tolerance, which is about 0.8% of Osc-1Hz. While Ext-1Hz
is within tolerance, the skew between the two signals may
shift until a change of about 7.8ms accumulates, after
which Osc-1Hz signal is adjusted (Figure 5). The adjust-
ment is accomplished by digitally adjusting the 32kHz
oscillator divider chain.
Figure 4. Loss and Reacquisition of External Reference Clock
Figure 5. Drift Adjustment of Internal 1Hz to External Reference Clock
OSC-1Hz
FROM OSCILLATOR
EXT-1Hz
FROM EXTERNAL REFERENCE
SKEW
BREAK IN EXTERNAL REFERENCE SIGNAL
CURRENT LOCK
SHIFTED BACK TO CURRENT LOCK
DRIFT AFTER N CYCLES
OSC-1Hz
FROM OSCILLATOR
EXT-1Hz
FROM EXTERNAL REFERENCE
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1310 | 制造商:未知厂家 制造商全称:未知厂家 功能描述: |
| DS13-1000 | 功能描述:固态继电器-PCB安装 HIGH FREQUENCY RELAY RoHS:否 制造商:Omron Electronics 控制电压范围: 负载电压额定值:40 V 负载电流额定值:120 mA 触点形式:1 Form A (SPST-NO) 输出设备:MOSFET 封装 / 箱体:USOP-4 安装风格:SMD/SMT |
| DS13-1000S | 制造商:TE Connectivity 功能描述:High Performance Solid State Relays |
| DS13-1001 | 制造商:MA-COM 制造商全称:M/A-COM Technology Solutions, Inc. 功能描述:DS13 Series High Performance Solid State Relays For Loads Up To 2A@60Vdc |
| DS13-1002 | 功能描述:固态继电器-PCB安装 DS13 SOLID STATE D RoHS:否 制造商:Omron Electronics 控制电压范围: 负载电压额定值:40 V 负载电流额定值:120 mA 触点形式:1 Form A (SPST-NO) 输出设备:MOSFET 封装 / 箱体:USOP-4 安装风格:SMD/SMT |
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