EVAL-AD7722CBZ: CMOS、16位、195 kSPS Σ-Δ 型ADC
AD7722是一款完全低功耗、16位Σ-Δ 型ADC,采用+5 V电源供电,接受以共模偏置电压为中心的0 V至+2.5 V或±1.25 V的差分输入电压。AD7722提供16位性能,输入带宽最高可达90.625 kHz,并且以195.3 kHz输出字速率提供数据。
模拟输入由模拟调制器连续采样,因而无需外部采样保持电路。调制器输出由两个串联的有限脉冲响应（FIR）数字滤波器处理。在大多数情况下,通过片内滤波可将外部抗混叠要求降至一阶。滤波器的群延迟为215.5 µs,而阶跃输入的建立时间为431 µs。采样速率、滤波器转折频率和输出字速率由外部时钟设置,该外部时钟的标称频率为12.5 MHz。
在调制器中使用单比特DAC可保证出色的线性度和直流精度。端点精度由片内校准来保证,此校准程序可使零电平与满量程误差降至最小。
转换数据通过灵活的串行端口或并行端口从输出寄存器获取,这可实现与数字信号处理器的三线式高速接口。串行接口在内部时钟（主）模式下工作,由此器件输出内部串行数据时钟和成帧脉冲。此外,可以把两个AD7722的串行数据输出端口连接起来,每个转换器在共用串行数据线上交替传输各自的转换数据。
该器件提供精确的2.5 V片内基准电压,还具有基准电压输入/输出功能,可以将内部基准电压或外部系统基准电压用作器件的基准电压源。AD7722采用44引脚PQFP封装,额定温度范围为-40°C至+85°C工业温度范围。
The AD7722 is a complete low power, 16-bit, sigma-delta ADC. The part operates from a +5 V supply and accepts a differential input voltage range of 0 V to +2.5 V or ±1.25 V centered around a common-mode bias. The AD7722 provides 16-bit performance for input bandwidths up to 90.625 kHz. The part provides data at an output word rate of 195.3 kHz.
The analog input is continuously sampled by an analog modulator eliminating the need for external sample-and-hold circuitry. The modulator output is processed by two Finite Impulse Response (FIR) digital filters in series. The on-chip filtering reduces the external antialias requirements to first order, in most cases. The group delay for the filter is 215.5 µs, while the settling time for a step input is 431 µs. The sample rate, filter corner frequency, and output word rate are set by an external clock that is nominally 12.5 MHz.
Use of a single bit DAC in the modulator guarantees excellent linearity and dc accuracy. Endpoint accuracy is ensured by on-chip calibration. This calibration procedure minimizes the zero-scale and full-scale errors.
Conversion data is provided at the output register through a flexible serial port or a parallel port. This offers 3-wire, high speed interfacing to digital signal processors. The serial interface operates in an internal clocking (master) mode, whereby an internal serial data clock and framing pulse are device outputs. Additionally, two AD7722s can be configured with the serial data outputs connected together. Each converter alternately transmits its conversion data on a shared serial data line.
The part provides an accurate on-chip 2.5 V reference. A reference input/output function is provided to allow either the internal reference or an external system reference to be used as the reference source for the part.The AD7722 is available in a 44-pin PQFP package and is specified over the industrial temperature range from –40°C to +85°C.
EVAL-AD7722CBZ 特点
- 16位Σ-Δ型ADC：
- 64 x 过采样率；
- 输出字速率最高 220 kSPS；
- 低通、线性相位数字滤波器 - 固有单调性
- 2.5 V片内基准电压
- 5 V单电源
- 高速并行或串行接口
- 16-Bit Σ-Δ ADC
- 64 x Oversampling Ratio
- Up to 220 kSPS Output Word Rate
- Low-Pass, Linear Phase Digital Filter - Inherently Monotonic
- On-Chip 2.5 V Voltage Reference
- Single-Supply 5 V
- High Speed Parallel or Serial Interface
EVAL-AD7722CBZ 功能框图
| 产品型号 | 产品状态 | 封装 | 引脚 | 温度范围 |
|---|---|---|---|---|
| AD7722ASZ | Prodn | PLASTIC QUAL FLATPACK/MQFP | 44 | 工业 |
| EVAL-AD7722CBZ | Prodn | 评估板 | - | 商业 |
EVAL-AD7722CBZ 应用技术支持与电子电路设计开发资源下载
- AD7722 数据手册DataSheet下载 . pdf
- Analog Devices, Inc.ADI 美国模拟器件公司产品订购手册 .pdf
- ADC模数转换器选型指南 . pdf
