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Common Base Circuit with Base Resistor and a Collector Resistor Formed in Common Isolation Region

IP.com Disclosure Number: IPCOM000049595D
Original Publication Date: 1982-Jun-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Askin, HO: AUTHOR [+2]

Abstract

A transistor connected in a common base configuration has a collector resistor formed as two series-connected resistors within a common isolation region of an integrated circuit device. The common connection point of the two resistors is connected to the base terminal to provide a reference voltage. The resistor values are adjusted to establish a switching level for the transistor.

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Common Base Circuit with Base Resistor and a Collector Resistor Formed in Common Isolation Region

A transistor connected in a common base configuration has a collector resistor formed as two series-connected resistors within a common isolation region of an integrated circuit device. The common connection point of the two resistors is connected to the base terminal to provide a reference voltage. The resistor values are adjusted to establish a switching level for the transistor.

In a common base transistor configuration, the base terminal is held at a reference voltage, an input signal is applied across an emitter resistor, and a collector resistor converts the collector current to an output voltage. When the base reference voltage is formed by a conventional resistor from the base to the supply voltage, separate isolation regions must be formed for the base resistor and the collector resistor.

Transistor 2 and associated components 3 through 6 and node 7 form a common base input circuit, and transistor 8 and resistor 9 form a conventional common emitter inverter stage. Transistor 2 turns off and transistor 8 turns on when the input voltage rises above the voltage at node 7 minus the voltage drop across the base emitter junction. A selected turn on voltage is established by the value of resistors 3, 4 and 6. Resistors 4 and 6 can be formed as a single tapped resistor within one isolation region of a semiconductor device.

As resistor 3 is increased, the voltage at...