Motorola Corporation

Carmine Nicoletta

Hector Adrian Sanchez

Joshua Siegel

Jose M Alvarez

Michael C Alexander

Arthur R Piejko

An output buffer translates digital input signals which toggle between ground and V.sub.DDL to signals which toggle between ground and V.sub.DDH. The technology dielectric breakdown voltage limit is less than the magnitude of V.sub.DDH, such that use of a traditional output stage would subject transistors' dielectrics to voltages which exceed their dielectric breakdown limit, and would thus be damaged. Predrive circuits (40, 50) control output stage (70) transistors' (72, 78) gates, and voltage dropping circuits control output stage (70) transistors (74, 76). These control signals are generated specifically to maximize output stage transistor drive strengths, thereby minimizing output stage size. Output buffer functions when V.sub.DDL =V.sub.DDH, and its performance is V.sub.DDL independent. Temperature compensation is incorporated into the output buffer by deliberately offsetting temperature effects on output stage transistor drive strengths. Desired performance and temperature compensation are accomplished without subjecting any dielectrics to voltages which exceed the technology dielectric breakdown limit.

Digital output buffer for multiple voltage system

Output buffer (100) translates input signals from one voltage range to a second voltage range. The second voltage range may be identical to the first range or may be greater. The particular range is programmable by one of several ways. This feature makes output buffer especially suitable for use in devices which must be compatible with two voltage ranges. Output buffer uses a bias generator (110) to limit the voltage across the gate oxide of its various transistors to a level which is consistent with the first voltage range.

Method and output buffer with programmable bias to accommodate multiple

A method and apparatus for synchronizing multiple busses having different cycle times in a data processing system (10). The present invention synchronizes multiple clocks having different phase and frequencies without redundant use of phase lock loop units. An initial unit (7) receives an external system clock having an initial phase and frequency. An internal clock (112) is generated which is a phase and frequency adjusted derivation of the system clock. From this internal clock (112) a global clock (101) for use within the data processor (10) is generated. A second unit (9) receives the internal clock (112) and performs phase adjustment to provide a peripheral clock (114). The provision of the internal clock (112) detaches the dependency of peripheral clock (114) generation from the global clock (101), while maintaining a phase relationship with the global clock (101). In one embodiment, the present invention is implemented without the costly use of multiple phase lock loops.

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Austin, TX, United States of America

Carmine Nicoletta