An output transistor of a TTL device with a means for discharging carriers.

摘要

In the device a p<-> diffusion region 3 is formed between p-type base 6 and p<+> isolation diffusion 5. There is a junction between collector region 4 and p<-> diffusion region 3. When the potential of collector region 4 is less than that of p<-> region 3, region 3 provides a path for discharge of carriers from base 6 to isolation diffusion 5 to speed up switching. When the potential of collector region 4 is higher than that of p<-> region 3, the depletion layer at the junction pinches off the path and isolates the base 6 from the isolation diffusion 5.
<??>The p<-> region 3 may be replaced by an extension of the base region 6 up to the isolation diffusion 5.
<??>An n<+> region, shorted to collector region 4, may be formed over p<-> diffusion region 3 to provide another junction for pinch off of the path.
<??>The path may alternatively provide for carrier discharge to p-type substrate 1.