参数资料
型号: 71M6521FE-IMR/F
厂商: Maxim Integrated
文件页数: 64/107页
文件大小: 0K
描述: IC ENERGY METER 32K FLASH 68-QFN
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 2,500
系列: Single Converter Technology®
测量误差: 0.4%
电源电压: 3 V ~ 3.6 V
测量仪表类型: 单相,双相
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 64-VFQFN 裸露焊盘
供应商设备封装: 64-QFN(7.5x7.5)
包装: 带卷 (TR)
71M6521DE/DH/FE Data Sheet
Temperature Compensation and Mains Frequency Stabilization for the RTC
The flexibility provided by the MPU allows for compensation of the RTC using the substrate temperature. To achieve
this, the crystal has to be characterized over temperature and the three coefficients Y_CAL , Y_CALC , and Y_CAL_C2
have to be calculated. Provided the IC substrate temperatures tracks the crystal temperature the coefficients can be
used in the MPU firmware to trigger occasional corrections of the RTC seconds count, using the RTC_DEC_SEC or
RTC_INC_SEC registers in I/O RAM.
Example: Let us assume a crystal characterized by the measurements shown in Table 63:
Deviation from
Nominal
Temperature [°C]
+50
+25
0
-25
-50
Measured
Frequency [Hz]
32767.98
32768.28
32768.38
32768.08
32767.58
Deviation from
Nominal
Frequency [PPM]
-0.61
8.545
11.597
2.441
-12.817
Table 63: Frequency over Temperature
The values show that even at nominal temperature (the temperature at which the chip was calibrated for energy), the
deviation from the ideal crystal frequency is 11.6 PPM, resulting in about one second inaccuracy per day, i.e. more
than some standards allow. As Figure 32 shows, even a constant compensation would not bring much improvement,
since the temperature characteristics of the crystal are a mix of constant, linear, and quadratic effects.
32768.5
32768.4
32768.3
32768.2
32768.1
32768
32767.9
32767.8
32767.7
32767.6
32767.5
-50
-25
0
25
50
Figure 32: Crystal Frequency over Temperature
One method to correct the temperature characteristics of the crystal is to obtain coefficients from the curve in Figure
32 by curve-fitting the PPM deviations. A fairly close curve fit is achieved with the coefficients a = 10.89, b = 0.122,
and c = –0.00714 (see Figure 33).
f = f nom ? ? 1 +
c ?
10 6 ?
?
?
a
10 6
+ T
b
10 6
+ T 2
?
When applying the inverted coefficients, a curve (see Figure 33) will result that effectively neutralizes the original
crystal characteristics.
Page: 64 of 107
Rev 3
相关PDF资料
PDF描述
A7PPB-1506M CABLE D-SUB-AMM15B/AE15M/AMM15B
VI-BNP-EU-F2 CONVERTER MOD DC/DC 13.8V 200W
ADP194ACBZ-R7 IC POWER SWITCH HS LOGIC 4WLSCP
591D336X9016R2T15H CAP TANT 33UF 16V 10% 2824
71M6521FE-IGTR/F IC ENERGY METER 32K FLASH 64LQFP
相关代理商/技术参数
参数描述
71M6521-TGP1-68M 制造商:Maxim Integrated Products 功能描述:Programmer Accessories Gang Programmer Base w/6521 Socket Brd
71M6523-DB 功能描述:开发板和工具包 - 8051 71M6521D Demo Brd RoHS:否 制造商:Silicon Labs 产品:Development Kits 工具用于评估:C8051F960, Si7005 核心: 接口类型:USB 工作电源电压:
71M6523-IM 功能描述:计量片上系统 - SoC Residential Energy Meter IC RoHS:否 制造商:Maxim Integrated 核心:80515 MPU 处理器系列:71M6511 类型:Metering SoC 最大时钟频率:70 Hz 程序存储器大小:64 KB 数据 RAM 大小:7 KB 接口类型:UART 可编程输入/输出端数量:12 片上 ADC: 安装风格:SMD/SMT 封装 / 箱体:LQFP-64 封装:Reel
71M6523-IM/F 功能描述:计量片上系统 - SoC Residential Energy Meter IC RoHS:否 制造商:Maxim Integrated 核心:80515 MPU 处理器系列:71M6511 类型:Metering SoC 最大时钟频率:70 Hz 程序存储器大小:64 KB 数据 RAM 大小:7 KB 接口类型:UART 可编程输入/输出端数量:12 片上 ADC: 安装风格:SMD/SMT 封装 / 箱体:LQFP-64 封装:Reel
71M6523-IMR 功能描述:计量片上系统 - SoC Residential Energy Meter IC RoHS:否 制造商:Maxim Integrated 核心:80515 MPU 处理器系列:71M6511 类型:Metering SoC 最大时钟频率:70 Hz 程序存储器大小:64 KB 数据 RAM 大小:7 KB 接口类型:UART 可编程输入/输出端数量:12 片上 ADC: 安装风格:SMD/SMT 封装 / 箱体:LQFP-64 封装:Reel