AD7822: 3 V/5 V、2 MSPS、8位、1/4/8通道采样ADC

AD7822 功能框图AD7822/AD7825/AD7829 均为高速、1/4/8通道、微处理器兼容型、8位模数转换器(ADC),最大吞吐量为2 MSPS。三款器件都内置一个2.5 V(2%容差)片内基准电压源、一个采样保持放大器、一个420 ns的8位半快速型(half-flash)ADC和一个高速并行接口,可采用3 V ±10%和5 V ±10%单电源供电。

AD7822/AD7825/AD7829将转换启动与关断功能结合在一个引脚上,即CONVST引脚,这样便可实现在一次转换结束时自动关断的独特省电模式。当转换结束,即EOC(转换结束)信号变为高电平后,会对CONVST引脚上的逻辑电平进行采样。如果它在该点为逻辑低电平,则ADC关断。AD7822和AD7825还具有单独的关断引脚(参见“工作模式”部分)。利用该并行接口,可方便地与微处理器和DSP进行接口。这些器件仅使用地址解码逻辑,因此很容易实现到微处理器地址空间的映射。利用EOC脉冲,这些ADC可以分别独立工作(参见“并行接口”部分)。

AD7822和AD7825均提供三种封装:20引脚和24引脚、0.3英寸宽、塑料双列直插式封装(PDIP);20引脚和24引脚标准小形集成封装(SOIC);以及20引脚和24引脚超薄紧缩小型封装(TSSOP)。AD7829也提供三种封装:28引脚、0.6英寸宽PDIP;28引脚SOIC;以及28引脚TSSOP。

The AD7822/AD7825/AD7829 are high speed, 1-, 4-, and 8-channel, microprocessor-compatible, 8-bit analog-to-digital converters with a maximum throughput of 2 MSPS. The AD7822/AD7825/AD7829 contain an on-chip reference of 2.5 V (2% tolerance); a track-and-hold amplifier; a 420 ns, 8-bit half-flash ADC; and a high speed parallel interface. The converters can operate from a single 3 V ± 10% and 5 V ± 10% supply.

The AD7822/AD7825/AD7829 combine the convert start and power-down functions at one pin, that is, the CONVST pin. This allows a unique automatic power-down at the end of a conversion to be implemented. The logic level on the CONVST pin is sampled after the end of a conversion when an EOC (end of conversion) signal goes high. If it is logic low at that point, the ADC is powered down. The AD7822 and AD7825 also have a separate power-down pin (see the Operating Modes section).

The parallel interface is designed to allow easy interfacing to microprocessors and DSPs. Using only address decoding logic, the parts are easily mapped into the microprocessor address space. The EOC pulse allows the ADCs to be used in a stand-alone manner (see the Parallel Interface section.)The AD7822 and AD7825 are available in 20-lead and 24-lead, 0.3" wide, plastic dual in-line packages (PDIP); 20-lead and 24-lead standard small outline packages (SOIC); and 20-lead and 24-lead thin shrink small outline packages (TSSOP). The AD7829 is available in a 28-lead, 0.6" wide PDIP; a 28-lead SOIC; and a 28-lead TSSOP.

AD7822 特性
  • 8位半快速型(half-flash)ADC,转换时间为420 ns
  • 1/4/8单端模拟输入通道,并提供输入偏移调节
  • 片内采样保持
  • 提供最高10 MHz输入频率时的信噪比性能
  • 转换结束时自动关断
  • 片内基准电压源(2.5 V)
  • 工作电压范围较宽:
    3 V ± 10%和5 V ± 10%
  • 输入范围:
    0 V至2 V p-p,VDD = 3 V ± 10%
    0 V至2.5 V p-p,VDD = 5 V ±10%
  • 灵活的并行接口,利用EOC脉冲可独立工作
  • 8-bit half-flash ADC with 420 ns conversion time
  • 1, 4 and 8 Single-Ended Analog Input Channels Available with Input Offset Adjust
  • On-Chip Track-and-Hold
  • SNR Performance Given for Input Frequencies Up to 10 MHz
  • Automatic Power-Down at the End of Conversion
  • On-Chip Reference (2.5 V)
  • Wide Operating Supply Range
  • 3 V ± 10% and 5 V ± 10%
    Input Ranges:
    0 V to 2 V p-p, VDD = 3 V ± 10%
    0 V to 2.5 V p-p, VDD = 5 V ± 10%
  • Flexible Parallel Interface with EOC Pulse to Allow Stand-Alone Operation
AD7822 亮点
  1. 快速转换时间。AD7822/AD7825/AD7829的转换时间为420 ns,更快的转换时间使实时系统中的DSP处理效率最高。
  2. 模拟输入范围调节。用户可利用VMID引脚使输入范围偏移,此特性可降低单电源运算放大器的要求,并考虑系统失调。
  3. 全功率带宽(FPBW)采样保持。采样保持放大器具有出色的高频性能。AD7822/AD7825/AD7829能够转换频率最高达10 MHz的满量程输入信号,因此,这些器件非常适合子采样应用。
  4. 通道选择。无需对器件执行写入操作便可进行通道选择。
  1. Fast Conversion Time. The AD7822/AD7825/AD7829 have a conversion time of 420 ns. Faster conversion times maximize the DSP processing time in a real-time system.
  2. Analog Input Span Adjustment. The VMID pin allows the user to offset the input span. This feature can reduce the requirements of single-supply op amps and take into account any system offsets.
  3. FPBW (Full Power Bandwidth) of Track-and-Hold. The track-and-hold amplifier has an excellent high frequency performance. The AD7822/AD7825/AD7829 are capable of converting full-scale input signals up to a frequency of 10 MHz. This makes the parts ideally suited to subsampling applications.
  4. Channel Selection. Channel selection is made without the necessity of writing to the part.
AD7822 应用领域
  • 数据采集系统、DSP前端
  • 磁盘驱动器
  • 移动通信系统、子采样应用
AD7822 技术指标
  • Resolution (Bits): 8bit
  • # Chan: 1
  • Sample Rate: 2MSPS
  • Interface: Par
  • Analog Input Type: SE-Uni
  • Ain Range: 2 V p-p,2.5V p-p
  • ADC Architecture: Pipelined
  • Pkg Type: DIP,SOIC,SOP
AD7822 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 RoHS
AD7822BNZ 产品状态: 量产 20 ld PDIP 20 工业 Tube, 18 $ 4.54 $ 3.55
AD7822BR 产品状态: 量产 20 ld SOIC - Wide 20 工业 Tube, 37 $ 4.84 $ 3.79
AD7822BR-REEL 产品状态: 量产 20 ld SOIC - Wide 20 工业 Reel, 1000 - $ 3.79
AD7822BRU 产品状态: 量产 20 ld TSSOP 20 工业 Tube, 75 $ 4.84 $ 3.79
AD7822BRU-REEL 产品状态: 量产 20 ld TSSOP 20 工业 Reel, 2500 - $ 3.79
AD7822BRU-REEL7 产品状态: 量产 20 ld TSSOP 20 工业 Reel, 1000 - $ 3.79
AD7822BRUZ 产品状态: 量产 20 ld TSSOP 20 工业 Tube, 75 $ 4.41 $ 3.45
AD7822BRUZ-REEL 产品状态: 量产 20 ld TSSOP 20 工业 Reel, 2500 - $ 3.45
AD7822BRZ 产品状态: 量产 SOIC 300 MIL 20 工业 Tube, 37 $ 4.41 $ 3.45
AD7822BRZ-REEL 产品状态: 量产 20 ld SOIC - Wide 20 工业 Reel, 1000 - $ 3.45
AD7822BRZ-REEL7 产品状态: 量产 20 ld SOIC - Wide 20 工业 Reel, 400 - $ 3.45
AD7822 应用技术支持与电子电路设计开发资源下载
  1. AD7822 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