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Monolithic Reference Voltage Source Using Ion Implanted Resistors

IP.com Disclosure Number: IPCOM000085049D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Lebesnerais, G: AUTHOR

Abstract

With ion implantation technology, the feasibility of 10-bit digital-to-analog converters (DAC's) has been demonstrated. However, a major problem is to guarantee performances over the entire operating temperature range. For example, a 10-bit DAC in the temperature range 25-75 degrees C should not drift more than 10 ppm/ degrees C to guarantee a 1/2 LSB (least significant bit) accuracy.

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Monolithic Reference Voltage Source Using Ion Implanted Resistors

With ion implantation technology, the feasibility of 10-bit digital-to-analog converters (DAC's) has been demonstrated. However, a major problem is to guarantee performances over the entire operating temperature range. For example, a 10-bit DAC in the temperature range 25-75 degrees C should not drift more than 10 ppm/ degrees C to guarantee a 1/2 LSB (least significant bit) accuracy.

It is therefore necessary to develop a high-performance voltage regulator, the output voltage of which being independent of the temperature. A band-gap reference voltage regulator will be hereafter described to meet this requirement. This type of reference voltage regulator is preferred, because its performance depends only on device matching and resistor ratios. With respect to the circuit shown, the following relations apply:

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where I(1), I(2) are the currents in transistors pairs T2, T3 and T4, T5, respectively, I is the collector-base saturation current and kT/9 which is a constant at room temperature of about 26 mV.

(Image Omitted)

It is obvious from the above expression that circuit performance depends on the resistor ratio R4/R3 theoretically independent of the temperature, and device matching of transistor pairs T2,T3 and T4, T5 to assure that the current ratio I1/I2 is also independent of the temperature.

Lastly this expression also depends on the temperature coefficients of transistors T6 and...