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Voltage Regulator Selection Calculator

Compare actual regulator operating envelopes and check LDO dropout, current and board thermal estimates; retain unresolved compatibility conditions.

Use this result well

Inputs that matter
LDO and board conditions, Minimum input voltage (V), Maximum input voltage (V), Output voltage (V), and 16 more
Output to expect
LDO dropout and thermal estimate, Regulator candidate operating envelope
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details

How it works

LDO dropout and thermal estimate

Check an actual LDO’s input range, dropout and output current, then estimate steady-state heating using thermal resistance justified for the actual board and airflow. A datasheet test-board number alone cannot qualify the layout.

Pd = (Vin,max − Vout) × Iout + Vin,max × Iq; Tj,estimate = Tamb + Pd × thermal resistance.

Regulator candidate operating envelope

Screen reviewed regulator candidates against the full source voltage range and output requirement. Each candidate’s guaranteed output range and current allowance must apply over that entire input and thermal range. Topology, stability and transient suitability remain explicit.

Candidate fits when its documented input and output ranges contain the requirements, its current allowance is sufficient and application compatibility is confirmed.

Updated: September 2026

Example Scenarios

Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.

→ Numerical limits fit; thermal evidence needs review

Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.

→ 0 candidate(s) fit · 1 need compatibility review

FAQ

Check an actual LDO’s input range, dropout and output current, then estimate steady-state heating using thermal resistance justified for the actual board and airflow. A datasheet test-board number alone cannot qualify the layout. Screen reviewed regulator candidates against the full source voltage range and output requirement. Each candidate’s guaranteed output range and current allowance must apply over that entire input and thermal range. Topology, stability and transient suitability remain explicit.

Use the exact equipment data, measurement point, operating conditions and units described in the selected mode. Record source documents, dates and unresolved conditions in Sources and assumptions. Built-in examples illustrate arithmetic; they are not manufacturer ratings or approved designs.

Use Save planning case for an explicit local history entry. Copy MD keeps current inputs and notes; Download CSV exports the result breakdown. Export portable copies before clearing storage and save a separate case after changing equipment, conditions or measurements.

About Voltage Regulator Selection Calculator

Check an actual LDO’s input range, dropout and output current, then estimate steady-state heating using thermal resistance justified for the actual board and airflow. A datasheet test-board number alone cannot qualify the layout. Screen reviewed regulator candidates against the full source voltage range and output requirement. Each candidate’s guaranteed output range and current allowance must apply over that entire input and thermal range. Topology, stability and transient suitability remain explicit.