AD7747:内置温度传感器的24位电容数字转换器

AD7747: 内置温度传感器的24位电容数字转换器

AD7747 功能框图 AD7747是一款高分辨率、Σ-Δ电容数字转换器（CDC）,可直接与电容传感器的电容连接进行测量。该芯片还具有高分辨率（24位无失码、最高19.5位有效分辨率）、高线性度（±0.01%）和高精度（±10 fF工厂校准）等固有特性。AD7747的电容输入范围是±8 pF（可变）,而且可接受最大17 pF共模电容（不可变）,后者可以通过一个可编程片内数字电容转换器（CAPDAC）来平衡。AD7747针对一块极板接地的单端或差分输入电容传感器设计。对于浮动式（不接地）电容传感器,推荐使用AD7745或AD7746。该器件内置一个片内温度传感器,其分辨率为0.1°C,精度为±2°C；还集成片内基准电压源和片内时钟发生器,因此在电容传感器应用中无需任何额外外部元件。此款器件配有一个标准电压输入,当与差分基准电压输入结合使用时,可方便地与一个外部温度传感器（如RTD、热敏电阻或二极管等）接口。AD7747具有一个双线式I²C兼容串行接口,可采用2.7 V至5.25 V单电源供电,额定温度范围为-40°C至+125°C汽车电子温度范围,采用16引脚TSSOP封装。

The AD7747 is a high-resolution, Σ-Δ capacitance-to-digital converter (CDC). The capacitance to be measured is connected directly to the device inputs. The architecture features inherent high resolution (24-bit no missing codes, up to 19.5-bit effective resolution), high linearity (±0.01%), and high accuracy (±10 fF factory calibrated). The AD7747 capacitance input range is ±8 pF (changing), and it can accept up to 17 pF common-mode capacitance (not changing), which can be balanced by a programmable on-chip digital-to-capacitance converter (CAPDAC).The AD7747 is designed for single-ended or differential capacitive sensors with one plate connected to ground. For floating (not grounded) capacitive sensors, the AD7745 or AD7746 are recommended.The part has an on-chip temperature sensor with a resolution of 0.1°C and accuracy of ±2°C. The on-chip voltage reference and the on-chip clock generator eliminate the need for any external components in capacitive sensor applications. The part has a standard voltage input that, together with the differential reference input, allows easy interface to an external temperature sensor, such as an RTD, thermistor, or diode.The AD7747 has a 2-wire, I²C-compatible serial interface. The part can operate with a single power supply of 2.7 V to 5.25 V. It is specified over the automotive temperature range of −40°C to +125°C and is housed in a 16-lead TSSOP package.

AD7747 特点

采用单芯片解决方案的新标准
可与单一或差分接地式传感器接口
分辨率：最低20 aF（即最高19.5位 ENOB）
精度：10 fF
线性度：0.01%
共模（不可变）电容最大可达17 pF
满量程（可变）电容范围：±8 pF
更新速率：5 Hz～45 Hz
8.1 Hz更新速率时,50 Hz、60 Hz同时抑制
有源屏蔽保护传感器连接
片内温度传感器：分辨率：0.1°C,精度：±2°C
电压输入通道
内部时钟振荡器
双线式串行接口（I²C®兼容）
电源：2.7 V至5.25 V单电源工作
功耗：0.7 mA
工作温度范围：-40°C～+125°C
16引脚TSSOP封装

AD7747 技术指标

Resolution (Bits): 24bit
# Chan: 1
Sample Rate: n/a
Interface: I²C/Ser 2-Wire,Ser
Analog Input Type: Diff-Uni,SE-Uni
Ain Range: ± 8 pF (Delta C) ,(2Vref) p-p
ADC Architecture: Sigma-Delta
Pkg Type: SOP

AD7747 应用领域

压力测量
位置传感
近程传感
液位传感
流量计
杂质检测

AD7747 产品选型

产品型号	产品状态	封装	引脚	温度范围
AD7747ARUZ	Prodn	16 ld TSSOP	16	工业
AD7747ARUZ-REEL	Prodn	16 ld TSSOP	16	工业
AD7747ARUZ-REEL7	Prodn	16 ld TSSOP	16	工业
EVAL-AD7747EBZ	Prodn	EVALUATION BOARDS	-	待定