Hello Everyone,

I am dealing with a design where the base-emitter saturation ("turn on")
voltage of a MMBT4403 matters quite a bit. (A preexisting design uses it
for temporary, fast-acting, over-current protection under the supervision
of a microcontroller)

Collector current =3D 3mA, Temperature =3D -40 to 70C

I would like to understand better in what ways the base emitter saturation
voltage can vary.
In addition I would like to know if there exists any "rules of thumb"

In the Diode's Inc datasheet page 4 [1] there is a graph titled "Figure 3
Typical Base-Emitter Turn-On Voltage vs. Collector Current"

>From this graph I can determine the "typical" base-emitter saturation
voltage Vbe(sat) with respect to temperature.

I'd like to know what factors other than temperature and collector current
affect Vbe(sat) and if there is any way to estimate their effect's on the
voltage?

I know there should be manufacturing variations from device to device.
Perhaps there exists some upper bound to how much Vbe(sat) can vary from
device to device?

[1] https://www.diodes.com/assets/Datasheets/ds30058.pdf

Thanks,
Jason White
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.