The World's Fastest ADC - EEs Talk Tech #13

Building ADCs and specs that might surprise you! Click to subscribe! ► http://bit.ly/Scopes_Sub ◄

electrical engineering podcast: https://eestalktech.com

More links: How to pick an oscilloscope bandwidth - app note: http://literature.cdn.keysight.com/litweb/pdf/5989-5733EN.pdf

Bandwidth and measurement accuracy - app note: http://literature.cdn.keysight.com/litweb/pdf/5991-0662EN.pdf

Evaluating Oscilloscope Vertical Noise Characteristics - app note: http://literature.cdn.keysight.com/litweb/pdf/5989-3020EN.pdf

Making an ASIC - blog: https://community.keysight.com/community/keysight-blogs/oscilloscopes/blog/2017/05/15/creating-an-asic-our-quest-to-make-the-best-cheap-oscilloscope

How to get an Oscilloscope Bandwidth of over 16 GHz - App Note http://literature.cdn.keysight.com/litweb/pdf/5990-6515EN.pdf

Intro: Mike is an ASIC planner on the ASIC Design Team What is an ADC? Analog vs. Digital ASICs?

Three camps of ASICs:

1. Signal conditioning
2. Signal processing (digital)
3. In the middle is a convertor, either digital to analog (DAC) or analog to digital (ADC)

1:50 Signal conditioning ASICs can be very simple or very complicated e.g. Stripline filters are simple, oscilloscope front ends aren't

2:45 Converter vs. an analog chip with some digital functionality A converter has both digital and analog and a digital interface, like an I2C or SPI interface. It is digital in, analog out.

4:25 How do you get what's happening into the analog world into a digital interface, and how fast can you do it?

4:35 Mike did a basic ADC design in school Ladder converter, or "thermometer code" is the most basic of ADC architectures.

6:00 Slow ADC can use single ended CMOS, faster might use parallel LVDS, now it's almost always SERDES for highest performance chips

6:35 The world's fastest ADC?

6:55 Why do we design ADCs? We usually don't make what we can buy off the shelf. Nyquist rate determines sample rate, for example a 10 GHz signal needs to be sampled at 20 - 25 gigasamples

8:45 Then there's vertical resolution, number of bits. ADCs generally have two main specs, speed (sample rate) and vertical resolution.

9:00 The ability to measure time very accurately is often most important, but people often miss the noise side of things.

9:45 Normally, we oversimplify into just two specs. But, there's more than that. For example, bandwidth, frequency flatness, noise, and SFDR

10:20 It's much easier to add bits to an ADC design than it is to decrease the noise.

10:42 Noise floor and SFDR and SNR measure how good an analog to digital converter really is. SFDR means "spurious free dynamic range" and SNR is "signal to noise ratio"

11:00 Third tier things you need to worry about are error codes, especially for instrumentation. For some folding architect ... https://www.youtube.com/watch?v=2NLzJBhdlv4