AD7849是一款14/16位串行输入乘法DAC。该DAC架构可确保拥有出色的微分线性性能;在额定温度范围内,A级产品可保证14位单调性,所有其它等级产品可保证16位单调性。在上电与关断期间(当电源电压变化不定时),V
OUT引脚通过一个低阻抗路径箝位在0 V。为避免此时A3的输出短路变为0 V,传输门G1也会打开。这种状况会一直持续到电源稳定下来并向DAC寄存器写入一个有效字,此时G2打开,G1闭合。通过复位输入(RST IN)控制输入,也可以从外部对两个传输门进行控制。例如,如果RST IN输入采用电池监控器芯片驱动,则在关断或掉电时,RST IN输入将变为低电平以开启G1并闭合G2。要重新使能输出,必须重新加载DAC,使RST IN变为高电平。相反地,用户也可以利用片内电压检测器输出(RST OUT)来控制系统的其它部分。
The AD7849 features a versatile serial interface structure that can be controlled via three lines for easy optical isolator applications.
SDOUTs are the outputs of on-chip shift registers that can be daisy-chained to program devices in multi-channel systems. This function is controlled by the DCEN (daisy-chaining) input.
The BIN/COMP pin sets the DAC encoding method. When BIN/COMP is set to 0, the encoding method is standard binary; When set to 1, the encoding method is binary complement. This allows the user to reset the DAC to 0 V in both unipolar and bipolar output ranges.
The device is available in 20-pin DIP and 20-pin SOIC packages.