AD7879:  用于触摸屏的低成本控制器

AD7879 功能框图AD7879是一款12-bit逐次逼近型ADC,具有同步串行接口以及用于驱动4线电阻触摸屏的低导通电阻开关。AD7879工作电源电压极低,采用1.6 V~3.6V单电源供电,吞吐率为105 kSPS。这款器件具有待机模式,待机功耗不足5 µA。为了降低来自LCD以及其它噪声源的噪声,AD7879内置预处理模块。预处理功能包括中值滤波器及均值滤波器。这两项技术的结合提供了更鲁棒的解决方案,既能滤除信号中的杂散噪声,又能只保留有用的数据。两个滤波器的尺寸都可以设置。用户可设置的其它转换控制包括可变采集时间及第一转换延迟。每次转换可利用多达16个均值。AD7879采用自动转换序列器与定时器,可以工作在从模式或待机模式。AD7879拥有可编程引脚,可以用作到ADC的辅助输入、电池监控器或通用接口。可编程中断输出有三种工作模式:作为当新数据可用时的通用中断,INT;作为超过限定范围的指示中断信号;或作为屏幕被触摸时的落笔中断, PENIRQ。AD7879可提供温度与触觉压力测量。AD7879采用1.6mm x 2mm 12引脚WLCSP封装以及4mm x 4mm 16引脚LFCSP封装,具有SPI(AD7879)或II²C(AD7879-1)接口。

The AD7879/AD7889 are 12-bit successive approximation analog-to-digital converters (SAR ADCs) with a synchronous serial interface and low on-resistance switches for driving 4-wire resistive touch screens. The AD7879/AD7889 work with a very low power supply–a single 1.6 V to 3.6 V supply–and feature throughput rates of 105 kSPS. The devices include a shutdown mode that reduces current consumption to less than 6 μA.To reduce the effects of noise from LCDs and other sources, the AD7879/AD7889 contain a preprocessing block. The prepro-cessing function consists of a median filter and an averaging filter. The combination of these two filters provides a more robust solution, discarding the spurious noise in the signal and keeping only the data of interest. The size of both filters is programmable. Other user-programmable conversion controls include variable acquisition time and first conversion delay; up to 16 averages can be taken per conversion. The AD7879/AD7889 can run in slave mode or standalone (master) mode, using an automatic conversion sequencer and timer.

The AD7879/AD7889 have a programmable pin that can operate as an auxiliary input to the ADC, as a battery monitor, or as a GPIO. In addition, a programmable interrupt output can operate in three modes: as a general-purpose interrupt to signal when new data is available (DAV), as an interrupt to indicate when limits are exceeded (INT), or as a pen-down interrupt when the screen is touched (PENIRQ). The AD7879/AD7889 offer temp-erature measurement and touch-pressure measurement.The AD7879 is available in a 12-ball, 1.6 mm × 2 mm WLCSP and in a 16-lead, 4 mm × 4 mm LFCSP. The AD7889 is available in a backside-coated version of the WLCSP. Both parts support an SPI interface (AD7879/AD7889) or an I²C® interface (AD7879-1/AD7889-1).

AD7879 特性
  • 4-wire touch screen interface
  • 1.6V to 3.6V operation
  • Median and averaging filter to reduce noise
  • Automatic conversion sequencer and timer
  • WLCSP package with backside coating
  • User-programmable conversion parameters
  • Auxiliary analog input /Battery Monitor (0.5 V to 5 V)
  • 1 Optional GPIO
  • See data sheet for additional features.
  • 4线触摸屏接口
  • 电源电压:1.6V~3.6V
  • 中值滤波器与均值滤波器,用于降低噪声
  • 自动转换序列器与定时器
  • 用户可编程的转换参数
  • 辅助模拟输入/电池监控器(0.5 V~5 V)
  • 1个可选的通用接口(GPIO )
  • 中断输出(INT,PENIRQ)
AD7879 技术指标
  • Resolution (Bits): 12bit
  • # Chan: 6
  • Sample Rate: 105kSPS
  • Interface: I²C/Ser 2-Wire,Ser,SPI
  • Analog Input Type: SE-Uni
  • Ain Range: Uni Vdd
  • ADC Architecture: SAR
  • Pkg Type: CSP,WLCSP
AD7879 应用领域
  • Personal digital assistants
  • Smart hand-held devices
  • Touch screen monitors
  • Point-of-sales terminals
  • Medical devices
  • Cell phones
  • 个人数字助理
  • 智能手持式设备
  • 触摸屏监控器
  • POS终端机
  • 医疗设备
  • 蜂窝电话
AD7879 芯片订购指南
产品型号 封装 引脚 温度范围 包装和数量 报价*(100-499) 报价*1000 pcs
AD7879-1ACPZ-500R7 产品状态: 量产 16 ld LFCSP (4x4mm, 2.35mm exposed pad) 16 工业 Reel, 500 - $ 1.69
AD7879-1ACPZ-RL 产品状态: 量产 16 ld LFCSP (4x4mm, 2.35mm exposed pad) 16 工业 Reel, 5000 - $ 1.69
AD7879-1WACPZ-RL 产品状态: 量产 LFCSP:LEADFRM CHIP SCALE 16 工业 Reel, 5000 - $ 1.69
AD7879-1WACPZ-RL7 产品状态: 量产 LFCSP:LEADFRM CHIP SCALE 16 工业 Reel, 1500 - $ 1.69
AD7879-1WARUZ-RL 产品状态: 量产   16 工业 Reel, 2500 - $ 1.69
AD7879-1WARUZ-RL7 产品状态: 量产   16 工业 Reel, 1000 - $ 1.69
AD7879ACPZ-RL 产品状态: 量产 16 ld LFCSP (4x4mm, 2.35mm exposed pad) 16 工业 Reel, 5000 - $ 1.69
AD7879WACPZ-R5 产品状态: 量产 LFCSP:LEADFRM CHIP SCALE 16 工业 Reel, 500 - $ 1.80
AD7879WACPZ-RL 产品状态: 量产 LFCSP:LEADFRM CHIP SCALE 16 工业 Reel, 5000 - $ 1.80
AD7879WARUZ-RL 产品状态: 量产 TSSOP 4.4 MM 16 工业 Reel, 2500 - $ 1.69
AD7879WARUZ-RL7 产品状态: 量产   16 工业 Reel, 1000 - $ 1.69
AD7879 应用技术支持与电子电路设计开发资源下载
  1. AD7879 数据手册DataSheet下载 .pdf
  2. Analog Devices, Inc.ADI 美国模拟器件公司产品订购手册 .pdf
  3. ADC模数转换器选型指南 .pdf