Hitachi, Ltd.

Takashi Muto

Yuji Ushio

Hiroki Yamashita

Keiichi Higeta

Toshiro Takahashi

Goichi Ono

Takayuki Muranaka

Isao Kimura

Tomofumi Hokari

Yasuhiro Fujimura

Junji Baba

Keiki Watanabe

Hideki Koba

Kazuhito Nagashima

Hiroaki Kurahashi

A transmitter circuit in which a driver circuit includes MOS transistors for bias voltage application, in which a driving current flows, cascode-connected to MOS transistors for differential signal input controlled by a voltage value of transmitted data signals, controlled by a voltage value of a bias voltage, and driver circuits include MOS transistors for bias voltage application, in which a driving current flows, cascode-connected to MOS transistors for differential signal input that is controlled by a voltage value of signals obtained by the transmitted data signals, connected to a load portion, and controlled by a voltage value of a bias voltage.

Transmitter circuit

Power consumption is increased in an interface circuit having a signal processing function for waveform shaping due to influence of a circuit added for waveform shaping. Also, since a plurality of boards are connected to a backplane in a system, they are not exchanged in accordance with distances while there are boards being far or near are mixed, but a common board is used. Thus, it is necessary to prepare a configuration of an interface circuit meeting the longest transfer distance. An interface circuit disabling a part of or all of operations of a waveform shaping circuit is provided. Accordingly, in accordance with transfer distances, switching of operation ranges of waveform shaping circuit inside the interface circuit is possible, and operation ranges of the waveform shaping circuit can be limited, and power consumption of the interface circuit, an LSI including the interface circuit, and a server device can be reduced.

Interface circuit, LSI, server device, and method of training the interface circuit

A differential amplifier stage under a band design whereby a data signal at a maximum transfer rate among received waveforms is subjected to attenuation upon passing through a transmission line is not amplified, and a signal at a transfer rate half the maximum transfer rate is amplified. If it is determined that a signal whose amplitude is larger in value than a high reference voltage, the signal is determined as a signal '' while if smaller in value than a low reference voltage, the signal is determined as a signal ''. If the first amplitude detector detects that the amplitude of the signal is smaller in value than the high reference voltage, and the second amplitude detector detects that the amplitude of the signal is larger in value than the low reference voltage, the present signal is determined as an inverting signal of an immediately preceding signal.

Receiving apparatus and method for signal detection

In a data transfer device which cancells an offset of a differential amplifier for amplifying a received signal and an offset caused by characteristics of a differential transmission line and selects optimum conditions such as pre-emphasis amount of an output pre-emphasis circuit, a first chip (transmission side LSI=transfer engine) and a second chip (reception side LSI=multiplexing engine) are connected to each other through differential transmission lineand a SerDes (serializer)and a SerDes (deserializer)are used to make signal transmission, so that optimum setting conditions of an offset amount of an offset cancellation circuit included in an input buffer amplifier and a pre-emphasis amount of pre-emphasis circuit included in an output buffer are decided in training using a training PRBS generatorand a training PRBS comparator

Data transfer device of serializer/deserializer system

In an output circuit having a de-emphasis for use in high-speed serial transmission, a circuit for suppressing a fluctuation of a common mode potential which occurs in output amplitude is provided. A positive pole and a negative pole of an output circuit in a serial transmission device for differential transmission having de-emphasis are connected to the respective outputs of a differential circuit that differentially receives outputs of a detector device for a pattern of data to be transmitted, and a detector device for an inverted pattern of the data to be transmitted. When a specific pattern of data to be transmitted and its reverted pattern appear, a current of the output circuit is compensated by the connected differential circuit, thereby enabling a common mode noise to be prevented.

Serial output circuit, semiconductor device, and serial transmission method

In order to transfer data at high speed over a long distance, a current mode logic output circuit (CML) having a large number of taps, high accuracy, and a wide switchable range of the amount of pre-emphasis is needed. However, when the amount of emphasis is set by adding unit source-coupled pair circuits, a problem will arise that the output capacitance of the current mode logic output circuit would increase, thus hampering high-speed transmission. An output circuit of the invention is constructed from unit source-coupled pair circuits, which are obtained by dividing a current mode logic output circuit (CML) into m groups, terminal resistors, and a data selector. The amount of emphasis of each tap is determined by the ratio of the number of unit source-coupled pair circuits, which have been obtained by dividing the CML into m groups, allocated to each tap. Thus, the amount of emphasis can be set to be any arbitrary amount without a change in the output amplitude of 1. As a result, the transmission speed can be increased and the transmission distance can be extended.

Semiconductor integrated circuit device

Disclosed herewith is a semiconductor integrated circuit provided with a differential input circuit that can transmit data signals fast to an internal circuit free from distortion of their waveforms without increasing the subject chip in size. The differential input circuit is provided with a pair of first differential input transistors used to amplify mainly the low frequency components of those input signals and having gate terminals connected to a pair of input terminals that receive inputs of differential signals respectively, as well as a pair of second differential input transistors used mainly to amplify high frequency components of those input signals and having control terminals connected to a pair of input terminals that receive inputs of differential signals respectively through capacitance elements. The pairs of first and second differential transistors are connected to each other through a differential connection point (common source).

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Hamura, Japan

Takashi Muto