AD7991 4通道、12-Bit ADC,带I^2C兼容接口,采用8引脚SOT-23封装

AD7991/AD7995/AD7999是具有I^2C(R)兼容接口的12/10/8位、低功耗、逐次逼近型ADC。这些器件均采用2.7 V至5.5 V单电源供电,转换时间为1微秒（us）。采样保持放大器使这些器件均能够处理频率高达14 MHz的输入信号,而多路复用器可用于4通道采样。

AD7991/AD7995/AD7999均提供与I^2C接口兼容的双线式串行接口。AD7991和AD7995有两个版本,每个版本均具有独立的I^2C地址,因此可以将两个相同的器件连接到同一I^2C总线。这两个版本均支持标准、快速及高速I^2C接口模式。AD7999只有一个版本。

AD7991/AD7995/AD7999通常保持在关断状态,仅在执行转换操作时上电。转换过程受命令模式控制,在命令模式中,每次I^2C读操作都会启动一次转换,且通过I^2C总线传回结果。

当四个通道都用作模拟输入时,基准电压从VDD获得,由此可以实现最宽的动态输入范围。因此,ADC的模拟输入范围是0 V至VDD。也可以使用外部基准电压,通过VIN3/VREF引脚接入

12-/10-/8-bit ADC with fast conversion time: 1 μs typical
4 analog input channels/3 analog input channels with reference input
Specified for VDD of 2.7 V to 5.5 V
Sequencer operation
Temperature Range: -40 °C to 125 °C
I2C (R)-compatible serial interface supports standard, fast, and High-speed modes
2 versions allow 2 I2C addresses(See Table 8 of data sheet for address and part number selection)
Low power consumption Shutdown mode: 1 μA max
8-lead SOT-23 package

Recommended Input Buffer Amplifiers for the AD7991
- For low distortion, low noise, dual supplies, we recommend the AD8599.
- For precision, low noise, single supply, we recommend the AD8605 family of operational amplifiers.
- For single supply, high speed, low power, we suggest the AD8031 or the dual AD8032.
- For precision, high speed, low cost, we recommend the quad AD8604.
Recommended External References - 2.5V for the AD7991
- For applications requiring best accuracy, low noise, low drift, we recommend the ADR421 or AD780.
- For low noise, high output current applications, we recommend the ADR431.
- For wide supply applications, we recommend the ADR03 or AD780.
- For cost sensitive applications, we suggest the AD1582, ADR381 or ADR391.
- For the reference buffer amplifier, we recommend the AD8605.
- For applications requiring 2.048V to 4.096V, we recommend the REF191 reference family.
Recommended Digital Isolators for the AD7991
- For dual I2C isolators, we recommend the ADuM1250, ADuM1251, ADuM2250 or the ADuM2251.
Recommended Power Solutions
- For selecting voltage regulator products, use ADIsimPower.
- For selecting supervisor products, use the Supervisor Parametric Search.