RTT trim method
AssigneeMicron Technology, Inc.
InventorRyo Fujimaki
Life of this patent
Estimating the term…
Abstract
Systems and methods are provided for trimming RTTs in a memory device. The effective termination resistance (RTT) of the ODT may be adjusted by adjusting one or more driver units having predefined values (e.g., 240Ω). Because PVT characteristics may impact the driver unit values, resistances of the driver units may be fluctuated away from the predefined values (e.g., 240Ω). ZQ calibration signals may be used to calibrate the resistances of the driver units to the predefined values (e.g., 240Ω) to trim the RTTs. Separate ZQ calibration signals may be generated for different circuits (e.g., a circuit associated with DQ pad, a circuit associated with CA pad).
Claims20
An apparatus, comprising:
- a first external pin communicatively coupled to a first circuit;
- a second external pin communicatively coupled to a second circuit different from the first circuit;
- and
- a calibration circuit comprising a logic circuit that is configured to modify ZQ codes, wherein the calibration circuit is configured to:
- generate a first calibration signal comprising a first ZQ code for calibrating a first termination resistance of the first circuit;
- and
- generate a second calibration signal comprising a second ZQ code, wherein the second ZQ code is generated via the logic circuit by using the first ZQ code, and wherein the second calibration signal is for calibrating a second termination resistance of the second circuit.
A method, comprising:
- generating, via a calibration circuit comprising a logic circuit that is configured to modify ZQ codes, a first calibration signal comprising a first ZQ code for calibrating a first termination resistance of a first circuit communicatively coupled to a first external pin;
- and
- generating a second calibration signal comprising a second ZQ code, wherein the second ZQ code is generated via the logic circuit by using the first ZQ code, and wherein the second calibration signal is for calibrating a second termination resistance of a second circuit communicatively coupled to a second external pin, wherein the second circuit is different from the first circuit.
An apparatus, comprising:
- a first external pin;
- a second external pin;
- a first circuit coupled to the first external pin, the first circuit including a pull-up driver and a pull-down driver;
- a termination driver coupled between the second external pin and a voltage node;
- and
- a ZQ circuit comprising a logic circuit that is configured to modify ZQ codes, wherein the ZQ circuit is configured to generate a first calibration signal comprising a first ZQ code for calibrating a first termination resistance of the pull-up driver of the first circuit, a second calibration signal comprising a second ZQ code for calibrating a second termination resistance of the pull-down driver of the first circuit and a third calibration signal comprising a third ZQ code for calibrating a third termination resistance of the termination driver, the third ZQ code being generated via the logic circuit based on one of the first ZQ code and the second ZQ code.
Dependencies are inferred from the claim text.