PDF《典型应用》

概述 MAX31856可以对任何类型热电偶的信号进行冷端补偿和 数字转换,输出数据以摄氏度为单位.

转换器温度分辨率 达0.0078125°C,允许读取最高+1800°C、最低-210°C?(取 决于热电偶类型)的温度读数,热电偶电压测量精度达 ±0.15%.热电偶输入端提供±45V过压保护. 查找表(LUT)储存不同类型热电偶(K、J、N、R、S、T、E 和B)的线性修正数据.器件包括50Hz和60Hz电网频率滤 波,也是热电偶故障检测频率.SPI兼容接口允许选择热 电偶类型并设置转换和故障检测过程. 典型应用 温度控制器 工业恒温箱、高温炉及环境舱 工业设备 特点和优点 提供高精度热电偶温度读数 ? 包括8种热电偶的自动线性补偿 ? ±0.15%?(最大值,-20°C至+85°C)热电偶满幅和线 性误差 ? 19位、0.0078125°C热电偶温度分辨率 内置冷端补偿,将系统元件数量降至最少 ? ±0.7°C?(最大值,-20°C至+85°C)冷端补偿精度 ±45V输入保护,确保可靠的系统性能 简化系统故障管理和诊断 ? 检测热电偶开路 ? 高温和低温故障检测 50Hz/60Hz噪声抑制滤波器,提高系统性能 14引脚TSSOP封装 定购信息在数据资料的最后给出. T- T+ 0.01?F 0.1?F 0.01?F AVDD 0.1?F 3.3V DNC DRDY BIAS AGND MAX31856 DGND FAULT SDI SDO SCK CS DVDD 0.1?F 3.3V TO MICROCONTROLLER 典型应用电路 备有评估板本文是英文数据资料的译文,文中可能存在翻译上的不准确或错误.如需进一步确认,请在您的设计中参考英文资料. 有关价格、供货及订购信息,请联络Maxim亚洲销售中心:10800

852 1249 (北中国区),10800

152 1249 (南中国区), 或访问Maxim的中文网站:www.maximintegrated.com/cn. 19-7534;

Rev 0;

2/15 AVDD, DVDD.0.3V to +4.0V T+, T-, Bias.45V T+, T-, Bias.20mA All Other Pins.0.3V to (VDVDD + 0.3V) Continuous Power Dissipation (TA = +70°C) TSSOP (derate 9.1mW/°C above +70°C)727.3mW ESD Protection (All pins, Human Body Model). 2000V Operating Temperature Range. 55°C to +125°C Junction Temperature.150°C Storage Temperature Range 65°C to +150°C Lead Temperature (soldering, 10s)300°C Soldering Temperature (reflow) . See IPC/JEDEC J-STD-020A Specification TSSOP Junction-to-Ambient Thermal Resistance (θJA)110°C/W Junction-to-Case Thermal Resistance (θJC)30°C/W (Note 1) (3.0V ≤ VDD ≤ 3.6V, TA = -55°C to +125°C, unless otherwise noted.)(Notes 2, 3, and 4) Recommended DC Operating Conditions Electrical Characteristics (TA = -55°C to +125°C, unless otherwise noted.)(Notes

2 and 4) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Power-Supply Voltage VAVDD, VDVDD 3.0 3.3 3.6 V AVDD-DVDD -100 +100 mV Cable Resistance RCABLE Per lead

40 k? Input Logic

0 VIL 0.8 V Input Logic

1 VIH 2.1 V PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Current IDD Standby 5.25

10 ?A Active conversion 1.2

2 mA Thermocouple Temperature Resolution

19 Bits 0.0078125 °C Cold-Junction Temperature Data Resolution 0.015625 °C Thermocouple Input Bias Current ITCBIAS TA = +25°C -10 +10 nA TA = -40°C to +85°C -10 +65 TA = -55°C to +105°C -20 +110 TA = -55°C to +125°C -20 +400 ??

2 www.maximintegrated.com/cn Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Absolute Maximum Ratings Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Package Thermal Characteristics (3.0V ≤ VDD ≤ 3.6V, TA = -55°C to +125°C, unless otherwise noted.)(Notes 2, 3, and 4) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Thermocouple Input Differential Bias Current (Note 4) ITCIDBIAS TA = +25°C ±0.2 nA TA = -40°C to +85°C -4 +4 TA = -55°C to +105°C -5.5 +5.5 TA = -55°C to +125°C -10 +10 Input-Referred Noise VN AV =