SMD WNR4018 Power Inductors 1µH–330µH

SMD WNR4018 Power Inductors — 1µH–330µH, Shielded, DC-DC Converter & SMPS

WNR4018 series shielded SMD power inductors in 4.0×4.0×1.8mm package, available in inductance values from 1µH to 330µH. The shielded construction minimises electromagnetic interference (EMI) radiation and provides stable inductance under DC bias current. Low DC resistance (DCR) and high saturation current rating make the WNR4018 suitable for high-efficiency DC-DC converter output filter inductors, SMPS choke inductors, and power supply EMI filter applications.

Technical Specifications

Parameter	Value
Series	WNR4018
Package Size	4.0 × 4.0 × 1.8mm (SMD)
Inductance Range	1µH – 330µH
Tolerance	±20% (M grade)
Construction	Shielded (ferrite core)
DCR	Low (see datasheet per value)
Saturation Current (I_sat)	High (see datasheet per value)
Operating Temperature	−40°C to +85°C
Rated Temperature Rise	40°C at rated current
Certification	RoHS

Inductance Value Selection Guide

Inductance	Typical Application
1–4.7µH	High-frequency DC-DC converter output filter (1–3MHz switching)
10–47µH	Standard DC-DC converter output filter (200kHz–1MHz switching)
100–330µH	Low-frequency SMPS choke, EMI filter, power line filter

Typical Applications

• DC-DC Converter Output Filter: Output inductor in buck (step-down) and boost (step-up) DC-DC converter circuits for Arduino, ESP32, and embedded system power supplies
• SMPS Choke: Series choke inductor in switch-mode power supply output filter for ripple current reduction
• EMI Filter: Common-mode and differential-mode EMI filter inductor for power supply input and output filtering
• Battery Charger: Output filter inductor in Li-ion and LiPo battery charger circuits for ripple current reduction
• LED Driver: Output filter inductor in constant-current LED driver circuits for LED strip and LED panel power supplies

FAQ

Q: What is the difference between shielded and unshielded power inductors?
A: Shielded inductors (like the WNR4018) have a closed ferrite core that contains the magnetic field, minimising EMI radiation to adjacent components. Unshielded inductors radiate more EMI but are typically smaller and cheaper. Shielded inductors are preferred in noise-sensitive applications and where components are closely spaced.

Q: How do I select the correct inductance value for my DC-DC converter?
A: For a buck converter: L = (V_in − V_out) × V_out / (V_in × f_sw × ΔI_L), where ΔI_L is the desired ripple current (typically 20–40% of I_out) and f_sw is the switching frequency. Refer to the DC-DC converter IC datasheet for the recommended inductance calculation.

Package Contents

• SMD WNR4018 power inductor (inductance value as selected)

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