Is there a pin-compatible replacement for BAS40LT1G?

Yes, parts like BAS20LT1G and MMBD1501A are pin-compatible in the SOT-23 package. The key difference is electrical; they are standard switching diodes, not Schottky diodes, which affects forward voltage and performance in low-loss applications.

What risks should I check before replacing BAS40LT1G?

The main risk is the higher forward voltage (Vf) of non-Schottky substitutes, which increases power loss and heat. Also, ensure the voltage and current ratings of any replacement provide sufficient margin for your circuit's operating conditions.

BAS40LT1G Alternatives, Datasheet & Cross Reference | onsemi

BAS40LT1G is a 40V, 120mA Schottky diode in a SOT-23 package, valued for high-speed, low-loss applications. When seeking alternatives, prioritize parts with a similarly low forward voltage and fast switching characteristics to maintain circuit efficiency.

AI replacement insight

Electrical riskmedium

Higher forward voltage in substitutes can increase power loss and heat, affecting circuit performance.

Package risklow

All viable candidates use the same SOT-23 package, ensuring mechanical compatibility.

Can it be replaced directly?

No direct drop-in Schottky replacement was found in this batch. BAS20LT1G is a strong functional alternative that requires review of its forward voltage characteristics for your specific application.

Best replacement path

The best path is to use a fast switching diode with comparable forward voltage, like onsemi's BAS20LT1G, after careful review. Alternatively, source another true 40V+ SOT-23 Schottky diode.

Main risk

Increased power dissipation and reduced efficiency due to the higher forward voltage of non-Schottky alternatives.

Recommended alternatives

A SOT-23 switching diode from the same manufacturer with higher ratings and comparable forward voltage.

View details

Alternative comparison matrix

Feature / factor	BAS40LT1G	BAS20LT1G	BAS21LT1G	MMBD1501A	Compatibility / risk
Package	SOT-23 (TO-236)	SOT-23 (TO-236)	SOT-23 (TO-236)	SOT-23	SOT-23 (TO-236) — Package matches, ensuring form and fit compatibility.; BAS21LT1G: Package matches, ensuring form and fit compatibility.; MMBD1501A: Package matches, ensuring form and fit compatibility.
Voltage	40V	200V	250V	200V	200V / 250V — Candidate has a significantly higher voltage rating.; BAS21LT1G: Candidate has a significantly higher voltage rating.; MMBD1501A: Candidate has a higher voltage rating.
Current	120mA	200mA	200mA	200mA	200mA — Candidate has a higher current rating.; BAS21LT1G: Candidate has a higher current rating.; MMBD1501A: Candidate has a higher current rating.
Forward Voltage	1.0V @ 40mA	1.0V @ 100mA	1.25V @ 200mA	1.3V @ 200mA	1.0V @ 100mA / 1.25V @ 200mA / 1.3V @ 200mA — Forward voltage is comparable, but check the curve for your operating point.; BAS21LT1G: Forward voltage is higher than the target Schottky diode.; MMBD1501A: Forward voltage is higher than the target Schottky diode.
Diode Type	Schottky	Fast Switching	-	-	Fast Switching — Candidate is a fast switching diode, not a Schottky. Review for low-loss applications.

Application & sourcing insights

Questions & answers

onsemi's BAS20LT1G is a strong candidate. It matches the SOT-23 package and offers higher voltage/current ratings with a very similar forward voltage. However, it is a fast switching diode, not a Schottky, so engineering review is advised.