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Best Alternatives to ETA3521FSG

Package: SOT563ETAPMIC - Voltage Regulators - DC DC Switching RegulatorsOutput Current: 4 AInput Voltage Range: 2.5 V to 6.0 VOutput Voltage Range: 0.6 V to VINSwitching Frequency: 2 MHzEfficiency: Up to 95%

ETA3521FSG is a 4A sync buck converter in a SOT563 package. While no drop-in replacement is confirmed, several alternatives exist that require careful review of electrical parameters and pinout.

AI replacement insight

Electrical riskmedium

Control loop and minor voltage range differences require review.

Package riskhigh

While package matches, pinout is unverified and is a critical risk.

Can it be replaced directly?

Direct replacement for ETA3521FSG should use only Datasheet verified or Strong match candidates; many approved options still require engineering review.

Best replacement path

TPS62A06DRLR from Texas Instruments is a strong candidate with higher current capability (6A) and similar package and electricals, but requires pinout verification.

Main risk

The main risks are pinout incompatibility and differences in control loop behavior, which can affect stability and transient response.

Recommended alternatives

2
TPS62A06DRLR package
TPS62A06DRLR

TI

Needs validationmedium risk

Strong alternative with higher current, similar package and electricals; pinout verification is required.

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Alternative comparison matrix

Feature / factorETA3521FSGTPS62A06DRLRETA1654FSGAlt 3Compatibility / risk
PackageSOT563SOT563SOT563SOT563 — Package matches.; ETA1654FSG: Package matches.
Voltage2.5V - 6.0V2.5V - 5.5V4.5V - 18V2.5V - 5.5V / 4.5V - 18V — Very similar input range, slightly lower max.; ETA1654FSG: Higher min input voltage (4.5V vs 2.5V).
Current4A6A4.0A6A / 4.0A — Higher output current capability.; ETA1654FSG: Output current matches.
Switching Frequency2 MHz2.2 MHz600 kHz2.2 MHz / 600 kHz — Frequency is very close.; ETA1654FSG: Significantly lower frequency, affects externals.

Application & sourcing insights

Questions & answers

Verified drop-in options for ETA3521FSG are limited in the current batch. Review candidates marked Strong match or Datasheet verified, and validate package, pinout, and electrical limits before committing a BOM change.