STMicro diac provides 0.505s rise time

The SMDB3 diac from STMicroelectronics provides a rise time of 0.505s that leads to the transfer of more energy during the start-up phase of the power oscillator in lighting applications such as fluorescent lamp ballast or in electronic transformers.

The SOT-23 device is also used as a trigger diode with a fixed voltage reference that can also be used with triacs as simplified gate-control circuits.

The SMDB3 has a maximum breakover current of 1055A and leakage current of 15A. Maximum repetitive peak on-state current for the device is 1A (120Hz).

When tested with a 22nF capacitor connected in parallel, the device produces a breakover voltage of 32V. The device's dynamic breakover voltage is 10V (min.), while the breakover voltage asymmetry is 3V (max.).