5G mmWave power supply testing is part of the active-array, beamformer and RF power-amplifier test setup. The supply must keep the DUT rail within its specified range while the array changes transmit state, beam direction or data load. Voltage drop, current bursts and supply noise can affect the repeatability of EVM and beamforming measurements.
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What the DC supply powers in a mmWave test
A 5G mmWave evaluation setup may power an active phased-array antenna, beamformer IC, RF power amplifier, converter board, control board and auxiliary circuits. These parts may use separate analog, digital, bias and control rails.
The DC supply does not generate the mmWave signal. It provides the controlled rails that allow the RF measurement system to evaluate the DUT under repeatable voltage and current conditions. The required supply depends on the array documentation, evaluation board and test fixture.
Why voltage drop affects array validation
High-current array rails can lose voltage across force leads, connectors, relays and feedthroughs. The loss increases with current and can change as beam steering or transmission activity changes. The voltage displayed at the supply terminals may therefore differ from the voltage at the evaluation board.
That difference can change the operating point of a beamformer or power amplifier. A test may then show a change in EVM, output power or beamforming behavior that comes from the DC rail rather than from the RF design.
| Test condition | DC supply consideration |
|---|---|
| Active-array transmission | Continuous rail current and thermal power. |
| Beam steering | Changing current and load-side voltage stability. |
| RF power-amplifier evaluation | Bias voltage, current limit and output protection. |
| OTA chamber test | Lead length, feedthrough, filtering and measurement repeatability. |
Current bursts and transient response
Beam steering, data transmission and amplifier activity can create burst or pulsed current demand. The supply and fixture need enough current capacity and output headroom for the operating condition described by the DUT documentation.
Transient response matters when the rail changes quickly. A voltage droop or overshoot during a current step can disturb the DUT operating point and create inconsistent RF results. Compare the model’s transient specifications, current-limit behavior and recovery information under the stated load conditions. Do not infer fast transient performance from the display or maximum current rating alone.
Local bypass capacitors on the evaluation board can support fast local demand, but their value, placement and permitted operating range belong to the board design. The external power supply still needs to provide the required average and burst current without entering an unwanted protection state.
Remote SENSE for long leads
Remote SENSE uses separate feedback leads connected at the DUT to measure the load-side voltage. It can compensate the specified steady-state drop in the force leads on a supported programmable DC power supply.
For a mmWave fixture, the useful specifications are the sense-terminal arrangement, compensation range, output headroom, open-sense behavior and permitted lead routing. The force pair carries current; the sense pair measures voltage. Polarity and the local/remote configuration must follow the exact model wiring diagram.
Remote SENSE addresses DC load voltage at the DUT. It does not replace correct cable ratings, connector design, local decoupling or RF shielding.
OTA chambers, filtering and decoupling
OTA tests place the DUT and antenna inside a controlled RF environment. The DC supply may remain outside the chamber, with power routed through cables, filters and feedthroughs. Every added element changes resistance, inductance and possible noise coupling.
DC power lines should be planned separately from RF signal paths. Filtering and decoupling should follow the chamber, fixture and DUT requirements. A power supply with a quiet published output is useful, but the complete path—including cables, feedthroughs, filters and board capacitors—determines the voltage and noise seen by the array.
The test record should identify the supply settings, DUT-side voltage measurement point, cable arrangement and chamber configuration. This makes an RF result easier to reproduce across setups.
When multiple output matters
Some mmWave evaluation boards use separate analog, digital or auxiliary rails. Multiple output is relevant only when the board documentation requires those rails to be powered and adjusted independently. If the fixture has one externally powered rail, a single programmable supply may be sufficient.
Power supply options for the test setup
For a low-voltage, high-current array or amplifier fixture, compare the eTM-30200C 30V/200A programmable DC power supply. It is a relevant example when the DUT rail and fixture require high current with programmable control and Remote SENSE options.
If the evaluation board documentation specifies independent analog, digital or auxiliary rails, the Multiple Output DC Power Supply category is relevant. For the single-rail and high-current cases covered here, the Programmable DC Power Supply category is the direct starting point.
5G mmWave supply specifications
| Specification | What it affects |
|---|---|
| Rail voltage | DUT operating point and permitted test margin. |
| Continuous and burst current | Array transmission, beam steering and amplifier activity. |
| Transient behavior | Rail droop, overshoot and recovery during load changes. |
| Remote SENSE | Load-side voltage regulation across the force-lead path. |
| Output channels | Independent analog, digital, bias and auxiliary rails. |
| Control and protection | Repeatable test states, output enable and fault response. |
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