A Schottky transistor is an electronic component that is a combination of a bipolar transistor and a Schottky diode .
Content
Device
A Schottky transistor is obtained by connecting a Schottky diode between the base and the collector of a bipolar transistor, and to create an npn Schottky transistor, a Schottky diode is connected to the base by an anode to the base, and a cathode to the collector, and a Schottky transistor is connected to the bipolar p-pin and anode to the collector.
The Schottky diode, due to its properties, has a lower voltage between the anode and cathode in the open state compared to a silicon diode (0.2-0.3 V vs. 0.5-0.7 V) and its inclusion between the base and the collector of the bipolar transistor prevents entering saturation in the open state - in fact, here the Schottky diode provides negative feedback (OOS): the stronger the transistor opens, the more the collector potential decreases relative to the ground and relative to the base, while the current flowing through the diode Ш increases drainage, diverting the base current to the ground and fixing the base-collector voltage at the level of 0.2-0.3 V, in the open state, the Schottky transistor is in the intermediate region between the active mode and saturation, thereby preventing double injection and accumulation of charges, eliminating the delay in time associated with the resorption of excess media when switching from open to closed state. In addition, the Schottky diode itself has a high speed when switching from open to closed state, since it does not have carrier accumulation processes and all processes are not associated with diffusion, but are caused only by drift in the electric field. In the closed state of the transistor, the voltage of the anode-cathode of the diode shifts the latter in the opposite direction and does not affect the operation of the transistor.
Application
The Schottky transistor is used in the Schottky transistor-logic chip (TTLS) , while the speed of the TTLS is much higher than the usual TTL with a multi-emitter transistor.
Designation on schemes
The Schottky transistor on electrical circuit diagrams has an independent symbol, which is usually used instead of a combination of the notation of a bipolar transistor and a Schottky diode.