Is there a pin-compatible replacement for SMAJ18CA?

SMAJ16CA shares the same SMA package and pinout. However, its lower standoff voltage (16V vs 18V) means it is not a direct drop-in and requires engineering review to ensure it doesn't clamp during normal operation.

What risks should I check before replacing SMAJ18CA?

Key risks include package footprint mismatch (e.g., SMA vs SMB), incorrect standoff voltage which can cause false clamping (too low) or inadequate protection (too high), and different power/current handling capabilities. Always verify the candidate's datasheet.

SMAJ18CA Alternatives, Datasheet & Cross Reference | BOURNS

SMAJ18CA is a popular 400W, 18V bidirectional TVS diode in an SMA package. Finding alternatives involves balancing standoff voltage, power rating, and physical package compatibility.

AI replacement insight

Package riskmedium

Some candidates have different footprints (e.g., SMB vs SMA).

Electrical riskhigh

Standoff voltage is critical for TVS diodes and varies between candidates.

Can it be replaced directly?

No direct drop-in replacement was identified. SMAJ16CA is pin-compatible but has a lower voltage rating, requiring review.

Best replacement path

Consider SMBJ20CA for an electrical upgrade if the larger SMB package is acceptable, or SMAJ16CA for a form-factor match with a voltage downgrade risk.

Main risk

The primary risk is mismatch in standoff voltage, which can either interfere with circuit operation or fail to provide adequate protection.

Recommended alternatives

A form-fit alternative in an SMA package, but with a lower 16V standoff voltage that requires careful review.

View details

Alternative comparison matrix

Feature / factor	SMAJ18CA	SMAJ16CA	SMBJ20CA	Compatibility / risk
Package	DO-214AC (SMA)	DO-214AC (SMA)	DO-214AA (SMB)	DO-214AC (SMA) / DO-214AA (SMB) — Same package and footprint.; SMBJ20CA: Larger package requires layout change.
Polarity Or Type	Bidirectional	Bidirectional	Bidirectional	Bidirectional — Polarity matches.; SMBJ20CA: Polarity matches.
Voltage V	18.0V	16.0V	20.0V	16.0V / 20.0V — Lower standoff voltage is a risk.; SMBJ20CA: Slightly higher standoff voltage is often acceptable.
Power W	400.0W	400.0W	600.0W	400.0W / 600.0W — Power rating is identical.; SMBJ20CA: Higher power rating provides more robustness.
Current A	13.7A	15.4A	18.52A	15.4A / 18.52A — Higher peak current capability.; SMBJ20CA: Higher peak current capability.

Application & sourcing insights

Questions & answers

SMBJ20CA offers higher power (600W) and a slightly higher standoff voltage (20V), but requires verifying the larger SMB package footprint. For the same package, SMAJ16CA is an option but has a lower 16V standoff voltage, which needs careful circuit review.