The key techniques for designing the circuit of high - stable row operation amplifier are described as below:
I. Grounding technology
During the design of the operation amplifier circuit, there will be two ground lines: signal ground and power supply. In the processing of these two ground lines, there are many methods, but it still need to be noted: the signal is connected to the main circuit, such as signal amplifying circuit, feedback network, etc. Power supply is common. In circuit design, the line is mainly the loop of the ground wire of various components, so as to reduce interference and ensure the stability of the operational amplifier!
2. Power filtering
In order to prevent the change of supply current causes the op-amp input profile feedback path, then it need to filter of power supply, breaking the feedback path. It is recommended to use 0.01 uf - 0.1 uf capacitance to bypass the power supply, which had better use low ESR and low ESL patch type ceramic capacitors. In circuit layout must be in the lead length is as short as possible. At this time, the location for the feedback network element is also close to a reverse input pin in order to minimize the stray capacitance, ensuring the high stability of the operational amplifier circuit.
3. The zero analysis of the circuit
In the design of the operation amplifier
circuit, we often use the design of amplification, filter, comparator and schmidt trigger, etc. However, in our design process, we need to control the essence of the stability of the operational amplifier: transfer function.