Typical Applications & Form-Factor Implications
Point: This family is optimized for compact DC-DC converter power stages where board area and height are constrained.
Evidence: Published datasheet values indicate a flat-wire molded SMD form-factor intended for high current density.
Explanation: Designers pick such parts for lower DC Resistance (DCR) and smaller footprint versus larger wound parts, but must balance thermal dissipation, PCB copper area, and proximity to hot components.
Datasheet Baseline: Declared Parameters to Expect
Point: Before specifying any inductor, confirm the key published specs.
Evidence: Typical datasheet entries list inductance and tolerance, DCR, saturation current (Isat), rated/Irms current, temperature rise, and frequency behavior.
Explanation: Flag missing or ambiguous entries for supplier clarification; unspecified thermal-rise or frequency curves are common red flags that require lab verification before production builds.
Measured Specs vs. Published Specs
DC Resistance & Inductance
Measured DCR and inductance can deviate from published specs. Using a four-wire DCR meter and LCR at defined test frequencies, we isolate lead resistance. A 10–20% higher DCR increases conduction losses significantly.
Saturation vs. Rated Current
Treat Isat as the short-term nonlinear limit and Irms as the continuous thermal limit. Derating ensures converters run well below the lower of these boundaries to preserve reliability.
Thermal & Frequency Performance
Thermal Rise Under Load
Thermal rise determines long-term reliability. Our tests at controlled ambient and defined airflow show temperature delta per watt loss. Acceptable targets are typically constrained by surrounding components and insulation limits.
Impedance & Frequency Losses
A frequency sweep highlights the inductive region, core loss rise, and Self-Resonant Frequency (SRF). Use the impedance plot to size the inductor for switching frequency and to anticipate skin effect losses.
Reproducible Test Protocols
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1
Standardized Equipment
Four-wire DCR measurement, LCR settings for small-signal level, and steady-state thermal thermocouples.
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2
Data Processing & Uncertainty
Compute mean, standard deviation, and expanded uncertainty for each metric to prevent overconfidence in nominal differences.
Design Limits & Selection Checklist
Safe Operating Area (SOA)
Apply a 20–30% margin from published current limits for continuous operation. Increase margin where airflow or copper area is limited to preserve performance.
Layout & Cooling Tips
Provide ample copper for heat spread and keep inductors away from concentrated heat sources. Use a simple pass/fail flow: DCR → Isat/Irms → Thermal Rise.
Summary
Key Summary Highlights
- Verify: Cross-check inductance under DC bias and published DCR to capture real loss impacts.
- Derate: Apply 20–30% margin for continuous operation, especially with limited airflow.
- Test: Prioritize board-level thermal tests with realistic copper pours and airflow.
