Rambus Inc.

Makarand Ajit Shirasgaonkar

Pravin Kumar Venkatesan

Kashinath Ullhas Prabhu

Liji Gopalakrishnan

Wayne D Dettloff

A method of operation of a flash integrated circuit (IC) memory device is described. The flash IC memory device has an array of memory cells and an interface to receive control, address and data signals using an internal reference voltage. The method includes, at boot-up, initializing the internal reference voltage to a default voltage. At boot-up, the interface is operable to receive, using the internal reference voltage, signals having a first voltage swing at a first signaling frequency. The method includes receiving a first command that specifies calibration of the interface during a calibration mode. The calibration mode is used to calibrate the interface to operate at a second signaling frequency and receive signals having a second voltage swing. The second voltage swing is smaller than the first voltage swing and the second signaling frequency is higher than the first signaling frequency.

Flash memory device having a calibration mode

A single-ended receiver is coupled to an input-output (I/O) pin of a command and address (CA) bus. The receiver is configurable with dual-mode I/O support to operate the CA bus in a low-swing mode and a high-swing mode. The receiver is configurable to receive a first command on the I/O pin while in the high-swing mode, initiate calibration of the slave device to operate in the low-swing mode in response to the first command, switch the slave device to operate in the low-swing mode while the CA bus remains active, and to receive a second command on the I/O pin while in the low-swing mode.

Calibration protocol for command and address bus voltage reference in low-swing single-ended signaling

A transmitter is coupled to a command and address (CA) bus. The transmitter is configurable with dual-mode support to send commands over the CA bus in a first swing mode and a second swing mode. The transmitter is configurable to send a first command over the CA bus via the pins while in the first swing mode, initiate calibration of the master device to send commands over the CA bus in the second swing mode, and to send a second command over the CA bus via the pins while in the second swing mode.

A single-ended receiver includes an internal voltage generation circuit to set a first internal reference voltage (Vref). A model voltage generation circuit is configurable to receive an external reference voltage to be calibrated during an initial calibration. The model voltage generation circuit is configurable to track an offset value for voltage-temperature (VT) drift and the offset value is applied to the internal voltage generation circuit to calibrate the internal Vref during a periodic calibration of the single-ended receiver.

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Bengaluru, India

Makarand Ajit Shirasgaonkar