About high speed and high precision

[wanneng]

I am a beginner with the ciecuit design,and I am comfused with some concept,A op amp with high speed ans high precision,is the high speed means that it has the wide bandwidth and high SR,is the high precision means that it has the low noise,and with a datasheet ,how i can know if it is a high speed or high precision op amp.

 

[lollobrigido]

Yes, high speed means high SR and bandwidth. high precision means high linearity.

Lollo

 

[Wenye]

Yes, high speed means high SR, wide-bandwithd.

But, high precision means no low noise. High precision means low input and output offset.

 

[sutapanaki]

No doubt that high-speed means high BW and SR. To me however, high precision also means high gain of the amplifier. All opamps work in a feedback configuration and high gain is needed to define the low frequency gain of the configuration more precisly. How low frequency is this - well it depends on where is the frequency limiting the BW. Higher the gain and higher the BW will certainly cause problems with stability. So, in a way high precision trades-off with high BW.

 

[flatulent]

precision

The precision could be about settling time. If a pole and zero are close together in frequency it will not affect the small signal sine wave frequency response, but it will make the settling time very long.

 

[wanneng]

thanks,I see,and I am a beginner ,can someone give me some advice with the circuit designing.

 

[flatulent]

circuit requirements

You need to list the circuit requirements, such as:

Gain
frequency where gain is reduced by x dB.
output amplitude swing
load impeance
source impedance
distortion

 

[wanneng]

Thanks,Can you give me some advice about the circuit design procidure,and the diffirence between the circuit design software of Pspice and ewb

 

[sutapanaki]

Flatulent is right about the effect of pole-zero doublets on the settling time - this is yet another point of consideration.
Wanneg, are you going to design on PCB level ot IC level? This in a way will define what software you gonna use.

 

[wanneng]

Thanks ,We gonna design on pcb,we gonna to take part in the competition about the circuit design in the nation wild,
and I am preparing for it,can you give me some good books and some good experience about circuit design.

 

[sutapanaki]

Well, I work in the IC design area and can't be very helpful in the pcb design what concerns the software.
About books - I guess there are a lot of them around. There was one ebook which I saw in the forum called "Opamps for everyone" which is by TI. Also look for application notes by National, Analog Devices, TI. There are a lot of practical things that you can find there. There are as well seminars on Practical analog design by Analog Devices which in electronic for can also be found in the forum, and on the website of ADI too.

 

[wanneng]

Thanks,I am also interested in the ic design,and I have the book "opamps for everyone ",and I think it is a very good book,and I am looking for the book of "the art of electronics",but it is difficult to find it (ebook),can tell me some ebook download web.

wanneng