Bourns has expanded its SRN3010BTA series of semi‑shielded power inductors with a new 33 µH variant aimed at compact automotive and industrial power designs.
The new power inductor combines AEC‑Q200 qualification, a 1 mm maximum height and soldered lead‑wire construction to support higher reliability where board space and long‑term robustness are critical.
Key features and benefits
The SRN3010BTA series targets compact DC‑DC converter and power supply stages where a low‑profile, semi‑shielded inductor is required rather than a full molded or open construction. The newly added model is SRN3010BTA‑330M with the following headline parameters according to the manufacturer datasheet:
- Inductance: 33 µH nominal
- Package size: 3 mm × 3 mm footprint, 0.9 mm max height (1 mm max profile specified for the series)
- Semi‑shielded construction
- Heating current Irms=0.60 AI_{\text{rms}} = 0.60 \,\text{A} (temperature rise defined per datasheet)
- Saturation current Isat=0.45 AI_{\text{sat}} = 0.45 \,\text{A}
- Operating temperature range: −55 °C to +125 °C
- AEC‑Q200 compliant automotive grade
- RoHS compliant and halogen free as defined by the manufacturer
Semi‑shielded inductors typically use a composite magnetic material around the winding, which reduces radiated EMI compared with open inductors while still offering cost and height advantages versus fully molded shielded types. In this case, the 1 mm profile is especially attractive for slim automotive ECUs, infotainment modules and low‑profile consumer/industrial boards where z‑height is a primary constraint.
The series also utilizes soldered lead‑wire construction for the internal connection between the coil and terminations, which helps improve mechanical robustness and long‑term reliability under automotive vibration and thermal cycling. For engineers designing for elevated temperature and long operating life, this construction detail can be an important differentiator versus low‑cost alternatives.
Typical applications
Bourns positions the SRN3010BTA series for a range of automotive and general‑purpose low‑power DC‑DC conversion tasks. The 33 µH value in particular is suitable where relatively higher inductance is required at modest currents, for example in pre‑regulation or noise‑sensitive stages.
Typical use cases include:
- Automotive systems and ECUs in body electronics and infotainment
- Advanced driver assist system boards where board area and height are limited
- Automotive lighting modules, including LED drivers with compact step‑down converters
- Low‑power DC‑DC converters in consumer devices that must meet automotive‑grade reliability in harsh environments
- Point‑of‑load regulators and auxiliary rails in industrial and telecom equipment with tight z‑height limits
- Noise‑sensitive rails where semi‑shielding helps reduce coupling into adjacent traces or RF sections
In many of these applications, the 33 µH inductance can be used in conjunction with relatively low switching frequencies to reduce ripple current, at the expense of lower saturation current compared with lower‑value inductors. This makes the SRN3010BTA‑330M a candidate for control rails, bias supplies and other non‑primary, low‑power rails in automotive electronics.
Design‑in notes for engineers
When designing in the SRN3010BTA‑330M, several practical points should be checked at the schematic and layout stages:
- Verify that the peak inductor current in your converter topology stays below the 0.45 A saturation current with adequate margin, considering worst‑case input voltage, load and switching frequency.
- Confirm that the RMS inductor current remains within the 0.60 A heating current rating for your chosen ripple current and operating temperature rise.
- Ensure that the −55 °C to +125 °C operating range aligns with the target ambient and hot‑spot temperature in the end application, including self‑heating.
- Pay attention to PCB copper area around the inductor pads to aid heat dissipation and help keep the component within its thermal budget.
- In layouts sensitive to EMI, place the semi‑shielded inductor so that its remaining stray field does not interfere with nearby high‑impedance or RF nodes; semi‑shielding reduces but does not eliminate coupling.
- Where mechanical shock and vibration are concerns (automotive ECUs, under‑hood modules), follow the manufacturer’s recommended land pattern and consider additional board‑level reinforcement strategies as needed.
For power stage optimization, designers can use the series’ available inductance options to trade off ripple current versus transient response and dynamic performance of the DC‑DC converter. The 33 µH value is typically more suited for lower current rails or higher input‑to‑output voltage ratios where a higher inductance helps keep ripple within specification.
Source
This article is based on the official Bourns product extension release for the SRN3010BTA semi‑shielded power inductor series, specifically the announcement of the SRN3010BTA‑330M 33 µH model, complemented by general design considerations for automotive‑grade power inductors according to the manufacturer’s documentation.