Texas Instruments Corporation

Stephen R Tomassetti

David M Gonzalez

Christopher J Kemp

Khodor S Elnashar

Roger J Cook

Alan T Wetzel

Rich A Rochelle

Mark A Streeter

A low side line driver (10) includes a slew rate limiter (12) providing current to a pre-charge reference circuit (16). The pre-charge reference circuit (16) generates a constant voltage at the input of a pre-drive circuit (18). Upon a transition to the active state, the pre-charge reference circuit (16) is disabled and current from the slew rate limiter (12) flows to pre-drive circuit (18) which becomes enabled without undue propagation delay or high instantaneous slew rate due to the pre-charge voltage generated by the pre-charge reference circuit (16) before turn on. The pre-drive circuit (18) provides base current to an output driver (22) from a negative voltage created in a charge pump (28). At turn off, an active turn off circuit (26) produces a short output pulse causing rapid discharge of base capacitance of the output driver (22) in order to minimize turn off propagation delay.

Low side line driver

A method and apparatus for transmission line termination is provided in which a transmission line (12 and 14) is terminated by transmission gates (20 and 22) at a transmitter (24) and a receiver (26). The resistances of the transmission gates (20 and 22) are controlled by precision resistance control circuits (30 and 31), respectively. Precision resistance control circuit (30) uses a reference resistor (32) to control the resistance of the transmission gate (20).

Method and apparatus for transmission line termination

Disclosed is a bipolar-CMOS circuit which includes a NMOS transistor site (18) electrically isolated from a bipolar transistor site (16). The NMOS transistor site (18) includes a semiconductor region (24) isolated from a bipolar transistor well (26) by deep diffusion ring (32). A buried layer (13) forms a bottom of the deep diffusion isolation ring (32). A backgate voltage can be applied to the isolated semiconductor region (24) of the NMOS device, which bias may be different than that applied to the substrate (10). Optimum performance of the NMOS transistor is thus assured irrespective of the magnitude of operating voltage of the bipolar transistor.

Method for fabricating an integrated bipolar-CMOS circuit isolation for

Integrated bipolar-CMOS circuit isolation for providing different

A reference time signal generation system 10 is provided which comprises a phase lock loop circuit 12 which generates a reference voltage V.sub.m. The phase lock loop circuit 12 comprises first and second divider circuits 14 and 18 coupled to the input of a phase comparator 16. The output of the phase comparator 16 is coupled to a loop filter 20 which generates a DC representation of the phase differential of the inputs of the phase comparator 16. The output of the loop filter 20 is input into a bias generator 26. The output of the bias generator 26 is coupled to the input of a voltage controlled oscillator 28 which has its output coupled to the input of second divider circuit 18. The reference voltage signal V.sub.m is taken from the output of the bias generator 26 and is transmitted to remote timing elements 32, 34 and 36 where it may be used to create reference timing signals which will accurately track the reference clock signal input into phase lock loop circuit 12.

Time reference signal generation system

Disclosed is a proces for making a bipolar-CMOS circuit which includes a NMOS transistor site (18) electrically isolated from a bipolar transistor site (16). The NMOS transistor site (18) includes a semiconductor region (24) isolated from a bipolar transistor well (26) by deep diffusion ring (32). A buried layer (13) forms a bottom of the deep diffusion isolation ring (32). A backgate voltage can be applied to the isolated semiconductor region (24) of the NMOS device, which bias may be different than that applied to the substrate (10). Optimum performance of the NMOS transistor is thus assured irrespective of the magnitude of operating voltage of the bipolar transistor.

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Lewisville, TX, United States of America

Stephen R Tomassetti