Is there a pin-compatible replacement for FNR4018S6R8MT?

YNR4018-4R7M is pin-compatible in its 4.0x4.0mm package, but it is not electrically equivalent. It has lower inductance (4.7µH vs 6.8µH) and lower current ratings, which constitutes a downgrade risk.

What risks should I check before replacing FNR4018S6R8MT?

Key risks include package size mismatch, changes in inductance affecting circuit stability and ripple, and lower current ratings (Isat, Irms) causing saturation or overheating under load.

FNR4018S6R8MT Alternatives, Datasheet & Cross Reference | Shenzhen CJiang Technology Co., Ltd.

FNR4018S6R8MT is a 6.8µH power inductor in a 4.0x4.0mm package. While no direct drop-in replacements were found, several alternatives with different packages or electrical parameters exist that may be suitable after engineering review.

AI replacement insight

Electrical riskhigh

Inductance and current mismatches require circuit re-evaluation.

Package riskmedium

One candidate has a different footprint, requiring a PCB redesign.

Can it be replaced directly?

No direct, electrically equivalent drop-in replacement for FNR4018S6R8MT has been identified. All candidates require engineering validation.

Best replacement path

YNR4018-4R7M is the closest form-fit candidate but requires careful review due to lower inductance and current ratings.

Main risk

The primary risks are circuit instability from mismatched inductance and potential failure from lower current handling capabilities.

Recommended alternatives

Functional alternative with a larger footprint, different inductance, and lower saturation current. Requires circuit and layout review.

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Alternative comparison matrix

Feature / factor	FNR4018S6R8MT	FNR5020S100MT	YNR4018-4R7M	Compatibility / risk
Package	4018 (4.0mm x 4.0mm)	5020 (5.0mm x 5.0mm)	4018 (4.0mm x 4.0mm)	5020 (5.0mm x 5.0mm) / 4018 (4.0mm x 4.0mm) — Larger footprint, requires layout change.; YNR4018-4R7M: Package size matches.
Inductance	6.8µH	10µH	4.7µH	10µH / 4.7µH — Higher inductance will alter circuit behavior.; YNR4018-4R7M: Lower inductance will increase ripple current.
Current	1.45A	1.7A	1.2A	1.7A / 1.2A — Higher heat rating current (Irms).; YNR4018-4R7M: Lower heat rating current (Irms).
Resistance	143mΩ	-	90mΩ	90mΩ — Lower DCR improves efficiency.

Application & sourcing insights

Questions & answers

YNR4018-4R7M has the same package but lower inductance and current ratings, requiring circuit analysis. FNR5020S100MT has different inductance and a larger package, requiring a board redesign.