Because “16-bit” is a converter resolution, while board-level performance is limited by the signal chain: acquisition settling, reference integrity, return-path coupling, and timing cleanliness.

• Settling margin: the driver and input network may not settle within the ACQ window at the chosen sample rate.
• Reference modulation: VREF noise or dynamic loading can directly move codes.
• Coupling and returns: ground bounce and digital coupling can inject errors into input/VREF pins.
• Timing integrity: clock coupling and edge uncertainty can degrade repeatability.

Practical rule: treat mid-speed 16-bit as a system requirement, not a chip-only specification.

Inadequate settling typically appears as code-dependent error, distortion, or strong performance changes when sample rate or source impedance changes.

• FFT symptoms: THD/SFDR worsens disproportionately versus noise floor.
• Rate sensitivity: ENOB improves significantly when sampling slower (more ACQ time).
• Source impedance sensitivity: adding series resistance or a weak source worsens linearity.

Fast checks: reduce sample rate, reduce source impedance, and compare results. If performance tracks these changes strongly, settling is a top suspect.

It depends on whether the application is DC/transfer-function limited or dynamic/noise limited.

• Measurement of absolute values: INL, gain/offset error, and drift often dominate accuracy.
• Dynamic capture: ENOB/SNR and THD/SFDR matter more when signals are band-limited and frequency content is important.

For fair comparisons, ensure ENOB/SNR/THD are compared only under matching input frequency, sampling rate, and input amplitude conditions.

Channel interaction is usually caused by shared impedance and sampling transients rather than the ADC core itself.

• Shared return paths: ground bounce couples one channel’s transient into others.
• Shared reference impedance: VREF droop or noise appears on multiple channels simultaneously.
• Input network coupling: inadequate isolation/RC lets kickback propagate.
• Digital activity coupling: interface switching couples into analog routing.

Mitigation priorities: control return paths, isolate input networks, and keep reference decoupling local and low-inductance.

A fast triage uses controlled changes to reveal which dependency dominates.

• Change sample rate: if noise/distortion changes strongly with rate, settling and sampling transients are suspects.
• Reduce digital activity: if the noise floor drops, coupling/returns are suspects.
• Improve VREF decoupling/buffering: if codes stabilize, reference integrity is a key limiter.

The goal is to identify the strongest dependency first, then focus optimization on that block.

Simultaneous sampling fits phase-consistent capture and multi-signal correlation; muxed fits sensor polling and cost-driven channel expansion.

• Control and correlation: simultaneous sampling avoids phase skew across channels.
• Many slow sensors: muxed solutions reduce hardware but demand better settling after each switch.

If muxed, budget extra acquisition time and isolate inputs to prevent memory and cross-coupling artifacts.

The key trade is between routing simplicity and throughput headroom.

• SPI: fewer pins and simpler routing, usually enough for many mid-speed use cases.
• LVDS/parallel: higher throughput and deterministic capture, but higher routing and coupling management effort.

Choose the simplest interface that meets throughput with margin, then spend effort on settling, reference, and layout integrity.

Control systems typically value deterministic latency more than absolute minimum latency.

• A fixed, repeatable sample-to-code delay simplifies loop tuning and validation.
• Averaging or filtering improves noise but adds group delay and should be used only when the loop can tolerate it.

Set latency limits from loop bandwidth and stability margin, then select the ADC class and data path accordingly.

Internal references can simplify BOM and routing, while external references can improve system control and noise management in demanding designs.

• Prefer internal when requirements are moderate and board noise is well-controlled.
• Prefer external when tighter noise, thermal stability, or multi-channel consistency is required.

In both cases, VREF decoupling and return paths must be treated as critical analog routing.

The minimum requirement is a driver that can settle fast and remain stable while driving the sampling network and any input RC isolation.

• Low effective source impedance across the acquisition window.
• Stability with the ADC input capacitance and added RC/filter components.
• Linearity headroom at the required input amplitude and bandwidth.

A stable, well-settling driver often matters more than small differences in the ADC’s headline SNR.

Use a clock route that is short, well-referenced, and isolated from sensitive input and reference nodes.

• Keep clock loops small and avoid running parallel to analog inputs or VREF traces.
• Maintain a continuous return reference and avoid splits that force return detours.
• Control edge coupling by keeping aggressor digital lines away from the ADC input and reference regions.

In the mid-speed 16-bit tier, reducing coupling and preserving clean returns often yields larger gains than pursuing extreme clock sources.

Early validation should isolate the analog chain and establish repeatable conditions before complex software features are added.

• DC linearity sweep: step or ramp input and check monotonic behavior and transfer consistency.
• Sine FFT: measure SNR/ENOB and THD with stated fin/fs/amplitude and stable input source impedance.
• Rate and impedance sensitivity: change sampling rate and input network and observe performance deltas.
• Channel interaction test: toggle one channel’s stimulus and observe others for coupling signatures.

Record conditions (fin, fs, amplitude, input network, VREF mode, digital activity) so results can be compared across builds.