Avalanche transistor

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An avalanche transistor , even avalanche transistor called, is a special type of a bipolar transistor , specifically for an operation above the breakdown voltage in the region of the avalanche breakthrough ( English breakdown Avalanche was) developed. The essential property of the transistor in this operating mode is a negative differential resistance . The first publication on the avalanche transistor dates back to 1955 and was made by JJ Ebers and SL Miller at Bell Laboratories .

Due to this special operating point, the transistor achieves relatively large currents, several 10 A for some types  , and switching times of less than 1 ns compared to conventional bipolar transistors  . A special subtype of the avalanche transistor is the Controlled Avalanche Transit Time Triode (CATT), which is used in amplifiers in the microwave range.

In contrast to a normal bipolar transistor, while the current flow is limited at the same time, it is possible to manufacture avalanche transistors that can also be operated in the area of ​​the 2nd breakdown without permanently damaging or destroying them. This operating mode can be used to further increase the switchable voltage and the switchable currents without negatively affecting the switching time. RJ Baker published a paper on this in 1991 with a few examples.

application

The transistors are used in fast pulse generators with high output voltages and output currents with rise and fall times below 1 ns. The Controlled Avalanche Transit Time Triode (CATT) subspecies is used to amplify microwaves . Another possibility is to use it as a multivibrator .

Examples

Examples of this type of transistor are the NPN avalanche transistors with the type designations FMMT413 , FMMT415 , FMMT417 and ZTX415 from Diodes Incorporated .

Individual evidence

  1. ^ SL Miller, JJ Ebers: Alloyed Junction Avalanche Transistors . tape 34 . Bell System Technical Journal, 1955, pp. 883-902 ( online ).
  2. ↑ RJ Baker: High voltage pulse generation using current mode second breakdown in a bipolar junction transistor . In: Review of Scientific Instruments . tape 62 , no. 4 , April 1, 1991, pp. 1031-1036 , doi : 10.1063 / 1.1142054 ( PDF [accessed March 24, 2014]).