BAV99 and BAS16 – Smart Diodes
Two-terminal diodes are among the best-known components in electrical engineering: electronics 101 cannot be passed without them – BAV99 and BAS16. Combining multiple diodes reduces part count and assembly cost.
Candidate number one is the BAS16: a classic diode with 100V of reverse voltage capability and a decently fast switching time of about 4nS. It I s interesting mainly due to the VV and VY families, whose configuration is shown in the image:
With the BAS16, it takes three to tango
This arrangement makes the parts ideally suited to attenuators: if a series of similar elements must be protected from reverse voltages, a BAS16VV reduces the number of components the pick and place machine must touch.
Sadly, the BAS16 family is extremely wide: in addition to the three diode parts, single diodes can also be had (albeit in the larger SOT23 form factor). Keep an eye when ordering, as mess-ups lead to production delays.
Tango to Two
Classic four diode bridges usually come as four diodes or a dedicated rectifier pack. Vishay’s BAV99 combines two diodes in series and provides an additional middle tap output as shown in figure two.
The middle tap makes good use of SOT23 housing’s three pins
Obviously, two BAV99s make for a great rectifier – a job hampered by their relatively low reverse voltage resistance which is in the area of 70V. Another interesting application involves separating “areas of concern” – if a process computer pulls an attenuator down, adding a diode chain provides a small additional buffer for other recipients.
Nexperia’s version of the BAV99 is even more advanced – as shown in figure three, they even offer a housing with two of these diode assemblies combined.
The BAV99S contains four diodes
Should we tango?
From an economic point of view, simplifying boards almost always makes sense. When deciding for and against these diodes, do not limit yourself to price and space factor-based models.