Achieving the lowest noise in a signal chain is vital as industry trends push the boundaries of resolution and precision. And when pushing these boundaries, it’s important to consider not just the noise of signal-chain components such as analog-to-digital converters (ADCs) and amplifiers, but also power products such as switching and low-dropout regulators (LDOs). Advances in silicon technologies have reduced the trade-offs when attempting to achieve low noise and high precision in power topologies.

Recent trends in 24-bit delta-sigma ADCs have increased sampling speeds and lowered power consumption. New low-noise power supplies and low-noise voltage references can take advantage of these trends and help ADCs achieve high-resolution measurements in low-power applications.

To achieve the lowest noise, let’s review the sources of noise in the signal chain and power architecture. Figure 1 shows a typical signal-chain application centered around an ADC that requires an external voltage reference, clock and signal-conditioning circuit. Every component in Figure 1 contributes to system noise and requires optimization.

Figure 1 Common signal-chain power architecture.