Altera Corporation

Ket Chiew Sia

Chiakang Sung

Khai Nguyen

Boon Jin Ang

John Henry Bui

Choong Kit Wong

Lay Hock Khoo

Foong Tek Chan

Joseph Huang

Yan Chong

Tony K Ngai

Wei Yee Koay

Teik Wah Lim

Woi Jie Hooi

Kok Siong Tee

Ee Mei Ooi

Boon Haw Ooi

Chin Ghee Ch'ng

Kin Hong Au

Xiabao Wang

Sean Woei Voon

Chai Yee Teng

A high speed IO buffer is disclosed. The high speed IO buffer includes a first P-type metal oxide semiconductor (PMOS) transistor coupled to an IO voltage source. The high speed IO buffer also includes a first N-type metal oxide semiconductor (NMOS) transistor coupled to a ground source, a second PMOS transistor coupled to the first PMOS transistor and a pad and a second NMOS transistor coupled to the first NMOS transistor and the pad. The first PMOS transistor, the first NMOS transistor, the second PMOS transistor and the second NMOS transistor are arranged in a cascoded arrangement.

High speed IO buffer

Integrated circuits with clock generation and distribution circuitry are provided. Integrated circuits may include phase-locked loops configured to generate multiple clock signals that are delayed versions of one another. The clocks signal may be distributed to various regions on an integrated circuit using serially connected clock buffer blocks. Each buffer block may include bidirectional pairs of buffer circuits coupled in parallel. Each buffer circuit may have a first input configured to receive an input clock signal, an output at which a corrected version of the input clock signal is provided (e.g., an output at which an output clock signal with desired duty cycle is provided), a second input that receives a first delayed clock signal for setting the desired duty cycle for the output clock signal, and a third input that receives a second delayed clock signal that is high at least when the first delayed clock signal rises high.

Duty cycle distortion correction circuitry

An integrated circuit system may include a first integrated circuit (IC), a second IC, and interface circuitry. The first IC is operable to output a parallel data stream at a first data rate. The second IC is operable to output a serialized data stream at a second date rate. The second data rate may be different than the first data rate. The interface circuitry may be coupled between the first integrated circuit and the second integrated circuit. The interface circuitry may be operable to convert the parallel data stream received from the first IC into a serialized data stream with the second data rate. The interface circuitry may be also operable to convert the serialized data stream received from the second IC to a parallel data stream with the first data rate.

Interface circuitry for an integrated circuit system

An integrated circuit may include a delay circuit that receives an input signal at a first logic level and produces a delayed output signal at a second logic level at an output terminal. The integrated circuit may include a preset circuit coupled to the delay circuit. The preset circuit may receive the input signal and pre-drive the delayed output signal to an intermediate logic level that lies between the first and second logic levels.

Configurable delay circuitry with compensated delay

I/O circuits and a method for transmitting different types of I/O signals are disclosed. An embodiment of the I/O circuit comprises multiple transistors with multiple switches coupled to the transistors. The switches may be used to selectively couple the transistors to a power source or to another transistor to form different transistor configurations. The transistors may be configured to form a parallel configuration or a stacked configuration. Stacking up transistors may reduce voltage swings in the transistors and subsequently reduce degradation in the transistors.

Integrated circuit with configurable I/O transistor arrangement

Methods, circuits, and systems for termination calibration are provided. Differential input buffer circuitry is used to compare a signal level at an input/output pad and a first reference signal level. Control circuitry is used to control a controllably variable impedance based on the output of the differential input buffer circuitry. Optionally, second differential input buffer circuitry is used to compare the signal level at the input/output pad to a second reference signal level. The control circuitry is used to control the controllably variable impedance based on the output of both the first and the second differential input buffer circuitry.

Methods and systems for programmable implementation of on-chip termination calibration

A circuit and methods for placing a circuit block on an integrated circuit (IC) are disclosed. An embodiment of the disclosed method includes dividing the IC into multiple regions based on pre-determined value. This pre-determined value may be a voltage drop value measured on specific regions on the IC. The performance requirement for the circuit block is determined and placed in one of the regions on the IC. In one embodiment, the placement of the circuit block is based on the performance requirement and the measured value at specific regions on the IC. The measured value may be a voltage drop value and a circuit block with a higher performance may be placed in a region with a lower voltage drop value.

Voltage drop aware circuit placement

A buffer circuit for using one buffer for multiple differential I/O standards is disclosed. The buffer circuit includes a differential input buffer. The first input of the differential input buffer may receive an input and the second input is coupled to a switch. The switch may be a one-time-programmable switch. The switch has a coupling to transmit a signal to the second input of the differential input buffer. The switch may be programmed to selectively transmit different signals to the differential input buffer. The first input terminal of the switch may receive an inverted version of the input signal and the second input terminal of the switch may receive a reference voltage. The buffer may transmit an LVDS signal or an SSTL signal or an HSTL signal. Using one differential buffer for multiple I/O standards may reduce the overall die size and may save space on the die.

Using a single buffer for multiple I/O standards

An adjustable level shifter with native and kicker transistors is provided. The level shifter provides high switching speeds, adjustable output voltage levels, and low jitter. The level shifter has first and second thick-oxide p-channel metal-oxide-semiconductor (PMOS) transistors, first and second thick-oxide native n-channel metal-oxide-semiconductor (NMOS) transistors, and first and second thin-oxide NMOS transistors. The first PMOS transistor, first native transistor, and first NMOS transistor are connected in series and the second PMOS transistor, second native transistor, and second NMOS transistor are connected in series. An input data signal and an inverted version of the input data signal drive the gates of the thin-oxide NMOS transistors. A node located between the first PMOS transistor and first native transistor is connected to an output data terminal. The kicker transistor is connected in parallel with the first PMOS transistor.

Growing community of inventors

Bayan Lepas, Malaysia

Ket Chiew Sia