I have done so many amplifiers and said that I have learned it for many years. The noise of the post-amplifier noise is introduced. In the case of reasonable circuit design, the power supply and LAYOUT are mainly used.
But the preamplifier, which is the front-end, has to pay attention.
1, the choice of deviceIncluding the choice of op amp and three tube, we must try to choose low noise, including input voltage noise and bias current noise. If it is mainly applied to voltage amplification, it is biased towards voltage noise, and current amplification is current noise.
Capacitance resistors and other devices are also very particular. Capacitors should be made of CBB materials as much as possible. For resistors, it is best to use a wirewound resistor for low frequencies, which is ideal. However, if the frequency is high, a metal film must be used.
A good layout and routing, to fully consider the flow of current, try to avoid current flowing through the ground of the signal input. The general advice is to surround the sensitive student number with a copper ring that opens a small skylight. The supply current is drawn in the form of a node to an insensitive reference point. If the input signal line is long, it is also surrounded by the ground wire to the terminal.
3, a good power supplyCircuit power, the contribution of noise, can not be underestimated. In high-end applications, linear power supplies are generally used. For example, HP's programmable power supply is linear, not a switch. Its noise can be done in a few uV. A good op amp is a good suppression of the power supply, but it can't be done by it alone. If you want to improve, you have to add some additional devices. They generally suppress the low frequency very well, so it is mainly considering the suppression of high frequency interference in the power supply, if adding LC, RC, common mode filtering, etc.
4, pay attention to the electromagnetic radiation of the spaceSome sensitive devices can even be disturbed by the charge and electromagnetic of the space. The best way to deal with this is to add a shield.
Therefore, it is certain that some charge amplifiers will not be hooded and will be unstable. If the wind blows the value, the output will begin to drift.
5. Environmental impactIf some operating temperature changes are relatively large, you have to consider the ambient temperature, and some work will change dozens of degrees, then you must consider the temperature PPM value of all devices.
If it is difficult to control, then think of a way to keep warm. For example, be a constant temperature room plus a constant temperature circuit.
Anyang Kayo Amorphous Technology Co.,Ltd is located on the ancient city-Anyang. It was founded in 2011 that specializes in producing the magnetic ring of amorphous nanocrystalline and pays attention to scientific research highly,matches manufacture correspondingly and sets the design,development,production and sale in a body.Our major product is the magnetic ring of amorphous nanocrystalline and current transformer which is applied to the communication, home appliances, electric power, automobile and new energy extensively. We are highly praised by our customers for our good quality,high efficiency,excellent scheme,low cost and perfect sale service.
DC immune Compound Cores have high permeability,low coercivity and loss,excellent performance on DC immue and temperature stability that can be widely used to the leakage protection switch.
Dc Immune Compound Iron Core,Leakage Protection Iron Core,Best Compound Iron Core,Best Magnetic Ring
Anyang Kayo Amorphous Technology Co.,Ltd. , https://www.kayoamotech.com