This engineer-focused, data-driven walkthrough covers the AMELH6030S-100MT electrical limits, focusing on how DCR and Isat impact I²R loss and saturation in buck converter designs.
Background: Part Overview & Where This Inductor Fits
Physical and Electrical Footprint
The AMELH6030S-100MT is a molded power inductor with a compact surface-mount footprint. Tighter tolerance on inductance reduces the safety margin required for ripple control, while its molded construction provides excellent EMI performance.
Typical Applications
Primarily designed for synchronous buck converters, point-of-load (POL) regulators, and power filtering. Its low DCR is optimized for tight-efficiency budgets in high-density PCB layouts.
Data Deep-Dive: Key Specs — DCR, Isat, Rated DC Current
DCR & Thermal Impact
Using a typical θJA of 30°C/W, the 1.584 W loss at 6A generates approximately a 48°C rise. Always correct DCR for operating temperature as copper's resistance increases by ~0.39% per °C.
Isat vs. Rated Current
Isat (magnetic limit) and Rated Current (thermal limit) are both ~6.5A. For stability, pick an Isat 1.2–1.5× higher than your peak DC bias to prevent ripple spikes from core saturation.
DCR vs Isat: Performance Trade-offs & Thermal Derating
Efficiency vs. Headroom
Thicker copper reduces DCR but can limit the number of turns or core volume, affecting Isat. For POL designs, lower DCR is prioritized, while high-peak systems require greater Isat headroom at the cost of slight DCR penalties.
Thermal Derating Rules
Ambient temperature and PCB layout significantly dictate allowable current. Standard safety margins suggest derating continuous current by 10–30% depending on copper weight and airflow conditions.
How to Measure DCR and Isat (Practical Test Methods)
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1Four-wire (Kelvin) DCR Measurement
Eliminate lead and fixture resistance by using Kelvin probes. Apply 100–500 mA current to achieve mΩ resolution without causing significant self-heating during the test.
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2Pulsed Isat Testing
To avoid thermal skew, use pulsed current to measure inductance (L) vs. DC bias. Log the point where L drops by 20%—this is your operational saturation limit.
PCB Integration & Cooling
Maximize copper pours under the inductor and use thermal vias to transfer heat to inner planes. Align the component with prevailing airflow and avoid placement near other high-heat components like FETs or CPUs.
Mechanical Reliability
Molded packages are robust, but long-term reliability requires validating solder joints against thermal cycling. For high-vibration environments, verify the adhesive integrity of the molded body to the lead frame.
Summary
DCR & Isat: ~44 mΩ max DCR and ~6.5 A Isat define the core performance envelope.
Thermal Limit: Calculate ΔT using 30°C/W as a baseline; apply 10-30% derating for safety.
Verification: Use Kelvin sensing for DCR and pulsed bias for L-vs-I curve mapping.
Checklist: Confirm DCR, check Isat margin (1.2-1.5x), and validate board-level heat rise.
