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# High Voltage Gain Cascode Circuit

IP.com Disclosure Number: IPCOM000091635D
Original Publication Date: 1968-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

IBM

## Related People

Arter, NK: AUTHOR

## Abstract

High-voltage gain can be realized for one of the series-connected semi conductors in a cascode circuit by special biasing between the node of the semiconductor and the base of the other semiconductor. The circuit has particular utility for monolithic circuits. Current I divides equally between semiconductors 11 and 13. All current for 11 would normally pass through semiconductor 12. By connecting resistor 21 between node 20 and the common junction of the base of 12 and + V2, the current through 12 equals the current through 11 less the current through 21. The current through 12 is less than thy current through 11. Therefore, resistor 23 can be made larger to increase the voltage gain without using a large supply for + V1 for either NPN or PNP transistors, differential or single-ended.

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High Voltage Gain Cascode Circuit

High-voltage gain can be realized for one of the series-connected semi conductors in a cascode circuit by special biasing between the node of the semiconductor and the base of the other semiconductor. The circuit has particular utility for monolithic circuits. Current I divides equally between semiconductors 11 and 13. All current for 11 would normally pass through semiconductor 12. By connecting resistor 21 between node 20 and the common junction of the base of 12 and + V2, the current through 12 equals the current through 11 less the current through 21.

The current through 12 is less than thy current through 11.

Therefore, resistor 23 can be made larger to increase the voltage gain without using a large supply for + V1 for either NPN or PNP transistors, differential or single-ended. The fact that this cascode circuit has high gain with low supply voltage eliminates transistor breakdowns from supply potential. Typically, + V1 is 6 volts and + V2 is 0 to 1.0 volts. The ratio of the value of resistor 23 to resistor 21, or 24 to 22, can be kept at 2 or 3 to 1 which is desirable for monolithics.

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