1. Name the loaded terminal relationship
A wiper-current question begins with the terminals carrying the intended load. Analog Devices AN-1291 describes the maximum-current boundaries at a given resistance setting, including voltage applied across any two of terminals A, B and W. The setting and terminal relationship therefore belong to the electrical question itself. Naming only the end-to-end resistance leaves out which part of the device is being loaded and which terminal-voltage relationship must be considered.
Separate the selected nominal resistance option from the setting at which the application expects current to flow. These descriptions answer different questions: one identifies a product option, while the other identifies the loading situation under review. Two uses of the same resistance option need not present the same terminal relationship. A current statement detached from that relationship can obscure the condition to which the manufacturer's discussion actually applies.
The useful starting description is consequently a defined load path at a defined setting, with the associated terminal voltages identified as application requirements. This does not require a universal connection diagram. It makes the subsequent voltage, dissipation and switch-current reviews refer to the same electrical situation rather than to different interpretations of the phrase wiper current.
2. Preserve the independent current constraints
AN-1291 names three boundaries: maximum applied voltage between terminals, package power dissipation and the current-handling capability of internal switches. Preserve all three. The voltage constraint concerns an electrical stress between the identified terminals. The package-dissipation constraint concerns the permitted power burden. The internal-switch constraint concerns the current path through the switching structure. Although they meet in one loading situation, they are not three interchangeable ways of stating a single resistance value.
Satisfying a terminal-voltage condition therefore does not, by itself, establish that the package-dissipation condition has also been satisfied. Likewise, a current below a quoted switch limit does not supply the missing terminal-voltage assessment. The manufacturer's explanation requires the boundaries to remain individually visible. Collapsing them into one maximum-current label would remove the reason that the exact setting and load were needed at the outset.
A technical comparison should show which evidence addresses each boundary under the same proposed use. If the evidence discusses different conditions, it cannot be combined silently into one accepted operating claim. This is a constraint comparison, without a current calculation or a substitute resistance recommendation.
3. Distinguish continuous from pulsed loading
The maximum-current discussion in AN-1291 distinguishes pulsed and continuous contexts and directs the reader to the exact device datasheet. Preserve that distinction when interpreting a candidate. A pulsed rating describes a qualified loading context; it should not be copied into a field intended to describe uninterrupted current. Removing the context changes what the number is being asked to establish, even if the underlying component reference remains unchanged.
The same caution applies to the role of the rating table. The application note places its maximum-current discussion in the absolute-maximum context. An absolute maximum is not an operating target or a recommended design point. It cannot independently establish that the proposed use is within the device's operating requirements. The intended operating condition needs its own exact-device assessment alongside the separate stress boundaries.
Keep the application's loading description explicit enough to distinguish continuous use from a pulsed requirement. This guide supplies no duty-factor equation, pulse conversion or allowable-current value. Its contribution is to preserve the rating category so that evidence for one loading context is not used to approve another.
4. Ask for exact-device loading evidence
Ask the device reviewer to identify the exact datasheet statements that cover the intended terminal relationship and setting. Which applied terminal-voltage conditions apply? Which package-dissipation condition covers the proposed loading? Which internal-switch current limitation is relevant to that path? These are separate technical evidence questions. A single page reference labelled maximum current is incomplete if it does not establish how all three constraints relate to the same use.
Then ask whether the cited current statement covers continuous loading or the particular pulsed context being considered. Keep the operating requirement distinguishable from any absolute-maximum stress statement. Where the exact device uses different qualifications from the application-note example, its own qualifications must govern the comparison. The example explains why the distinctions matter; it does not transfer an example rating to every digital potentiometer.
The resulting assessment should connect each limit to a stated loading condition, with unresolved electrical questions clearly identified. It should not replace that analysis with a general purchasing checklist. A defensible current requirement explains the applicable boundaries and rating context without claiming a universal safe current, supplying a buffer circuit or deriving permission from nominal resistance alone.
Sources and further reading
Analog Devices AN-1291 saved text characters 9527–11050 were reread on 16 October 2026 for the three current constraints and pulsed-versus-continuous context. Numerical examples, equations, other application sections and the whole document were not used; no allowable current or operating approval is supplied.