| 摘要 |
A method of operating an electronic device having an output driver with on die termination legs ODT, and non-ODT legs, includes the step of selectively tri-stating tuning transistors (ZQ trim devices) in the legs as a function of the operational state of the output driver. The tri-stating step is performed such that when a leg is not being utilized, the tuning transistors in the unused leg are placed in a tri-state. For example, during an ODT mode of the output driver, the tuning transistors in the non-ODT legs are tri-stated. During a READ mode of the output driver, the tuning transistors in the ODT legs are tri-stated. During a HiZ mode of the output driver, the tuning transistors in both legs are tri-stated. Tri-stating the tuning transistors in the unused output driver legs can reduce DQ pin capacitance by a total of approximately (Cgd+Cgs+Cgb). A circuit for performing the method includes tri-state components in electrical communication with the tuning transistors, and logic units configured to control the tri-state components. An electronic device includes the output driver having the tri-state components in electrical communication with the logic units.
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