Can a power supply be used for a high speed ADC?

Can a power supply be used for a high speed ADC?

Designing clean power supplies for high speed ADCs can be challenging with so many power options that are available to the designer today. This is especially important when utilizing efficient switching power supplies rather than traditional LDOs.

What should be considered when designing an ADC?

Thus, when designing with ADCs, it is crucial that designers consider the noise contributions from an often forgotten source—the system power supply. ADC are sensitive devices and each input, that is, analog, clock, and power should be treated equally to achieve the best performance as specified in the data sheet.

Is the DC accuracy of the supply rail specified?

While the DC accuracy of the supply rail is specified for the ADC12DJ5200RF, there is no specification on supply voltage noise and supply voltage ripple. Any supply ripple or noise appears attenuated on the output spectrum of the ADC. This attenuation can be

How is phase noise affected by an ADC?

On the ADC12DJ5200 evaluation module, an RF PLL is used as a frequency synthesizer for clocking the ADC. Similar to high speed ADCs, higher frequencies command larger supply currents. At the same time, higher frequencies require lower clock jitter and therefore lower phase noise. Phase noise is directly impacted by the

How much switching power does the adr445 reference have?

The switching frequency power at the ADR445 reference’s power pin is about –70 dBFS with an AD7616 ±10 V input range, which means 6.325 mV p-p or –64 dBFS at an AD7175-2 ±5 V input range. Figure 8. 3.3 V VADJ_FMC switching ripple captured by EVAL-AD7616SDZ GUI FFT.

How to calculate the AC signal for an ADC?

To make things simple define the amount of ac signal riding on the supply as a value related to the converter’s input full-scale. For example, if the ADC’s full-scale is 2 V p-p, then use 200 mV p-p or −20 dB.

How are clock, clock, and ADC treated?

ADC are sensitive devices and each input, that is, analog, clock, and power should be treated equally to achieve the best performance as specified in the data sheet. Noise sources are abundant and can come in many forms and be emitted or radiated affecting the performance.

Is it necessary to separate analog and digital power supplies?

Such separation involves separation of both ground returns and power rails—which can be inconvenient in a mixed-signal system. Nevertheless, if a high-accuracy mixed-signal system is to deliver full performance, it is essential to have separate analog and digital grounds and separate power supplies.

What happens when a DC power supply is reading 12.56v?

If you get a reading of “-12.56V” then your probes are attached in reverse. If this happens and you are positive you connected your probes correctly, double check the polarity on your power supply’s label and make sure the circuit you will be powering with this unit is designed to handle this polarity. Figure 6.

How to choose voltage reference for precision ADC?

Additionally, the initial output voltage accuracy of VREF should be low, in the range of 0.5% or less for precision ADC applications. The voltage reference should have noise value specifications lower than the ADC.

How is the reference device related to the ADC?

The voltage reference is external to the ADC, and along with an amplifier to drive the reference, contributes to the overall system noise. Figure 1: Both the voltage reference device and the amplifier (reference buffer) can contribute to overall system noise for the ADC. (Source: e2e.ti.com)