在集成电路中，通常采用T型解码网络实现数字量往模拟的转换，再利用运算放大器完成模拟电流变为模拟电压的转换。所以，要把一个数字量变为模拟电压，实际上需要两个环节，先把数字量变为模拟电流，这是由D/A转换器完成的；再将模拟电流变成模拟电压，这是由运算放大器完成的。有时D/A转换器芯片只包含前一个环节，有些D/A转换器则包含两个环节，用前一种芯片时，需要外接运算放大器才能得到模拟电压。-In integrated circuits, the usual T-decode digital networks to analog conversion, and then complete the simulation of the use of op-amp current into the analog voltage conversion. Therefore, it is necessary to become a digital simulation of voltage, in fact, need two links, first into a digital simulation of currents, this is determined by D/A converters completed　then simulate current into the analog voltage, this is determined by computing completed amplifier. Sometimes D/A converter chip contains only a part before, some D/A converter includes two aspects, before a chip, the need for external op-amp voltage can be simulated.