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1. 发明专利

JP2003258635A SEMICONDUCTOR INTEGRATED CIRCUIT HAVING ANALOG CIRCUIT, DIGITAL CIRCUIT AND TEST METHOD THEREFOR 审中-公开
公开(公告)号：JP2003258635A
公开(公告)日：2003-09-12
申请号：JP2002059015
申请日：2002-03-05
申请人： HITACHI LTD , HITACHI ULSI SYS CO LTD
发明人： KAMEYAMA SADAFUMI , ISHIHARA YUKITO , KOJIMA KOJI , OKA MIKI
IPC分类号： G01R31/316 , H03M1/10
摘要： PROBLEM TO BE SOLVED: To provide a test technique capable of evaluating an analog circuit with high accuracy by use of an internal circuit in an analog-digital mixed semiconductor integrated circuit, having analog circuits including an digital-to- analog converter (DAC), an analog-to-digital converter (ADC), etc., and digital circuits including a digital control signal generator, a digital waveform generator, etc. SOLUTION: In a semiconductor integrated circuit having a PLL circuit, a digital synthesizer digital control signal generator, the DAC, and the ADC, which is configured so that the digital synthesizer digital control signal generator, the DAC and the ADC operate in synchronization with a signal generated in the PLL circuit, a current-to-voltage converter is provided between an output terminal of the DAC and an input terminal of the ADC, so that a DAC output can be input directly to the ADC, without through a filter. COPYRIGHT: (C)2003,JPO

2. 发明专利

JPH05211415A SEMICONDUCTOR DEVICE 失效
公开(公告)号：JPH05211415A
公开(公告)日：1993-08-20
申请号：JP4013092
申请日：1992-01-30
申请人： HITACHI LTD , HITACHI VLSI ENG
发明人： YOSHINAGA MAKI , KAMEYAMA SADAFUMI
IPC分类号： G11B5/02 , H03F1/26
摘要： PURPOSE:To quicken a processing by a magnetic disk or the like including plural read amplifiers and to enhance the high performance of a computer system such as a computer system including the magnetic disk. CONSTITUTION:An output section such as plural read amplifiers RA1 or the like provided on a magnetic disk, etc., is constituted of a couple of output emitter follower circuits including output transistors(TRs) 5, 6, TRs 7, 8 provided as emitter loads, and resistors R7, R8 and the base DC potential of the output TRs 5, 6 and 7, 8 is set lower when the relevant read amplifier RA1 is not selected to selectively turn off the TRs. Since a so-called tri-state output circuit is adopted for the output section of the read amplifier RA1, the read amplifier is realized, in which its output terminal is wired-OR-connected without increasing the parasitic capacitance of a coupling node.

3. 发明专利

JPH08180304A SEMICONDUCTOR INTEGRATED CIRCUIT 失效
公开(公告)号：JPH08180304A
公开(公告)日：1996-07-12
申请号：JP32534294
申请日：1994-12-27
申请人： HITACHI LTD , HITACHI VLSI ENG
发明人： HIROSE TAKESHI , NAGAYA YUJI , HASHIMOTO TAKASHI , KAMEYAMA SADAFUMI , YOSHINAGA MAKI , HATANAKA NORIAKI
IPC分类号： G11B5/09
摘要： PURPOSE: To provide a head driver circuit without reducing a write speed even when a source voltage is reduced by switching a lower step current switch transistor in the timing of faster than the switch timing of an upper step current transistor. CONSTITUTION: In the head driver circuit of this semiconductor integrated circuit, transistors Q1, Q2 constituting an upper step current switch are connected to between head terminals T1, T2 connected to an inductive head L and the source voltage VCC. Further, the transistors Q3, Q4 constituting a lower step current switch are connected to between the head terminals T1, T2 and the grounded point GND, and a constant current source 11 is connected to the common emitter of the Q3, Q4. Then, a buffer circuit constituted so that the transistors QP1, QP2 for constant current and shot key transistors QS1, QS2 are directly connected to between VCC-GND is provided in the prestage of the upper step current transistors Q1, Q2.

4. 发明专利

JPH02144871A SOCKET FOR FITTING IC 失效
公开(公告)号：JPH02144871A
公开(公告)日：1990-06-04
申请号：JP29812388
申请日：1988-11-28
申请人： HITACHI LTD , HITACHI VLSI ENG
发明人： TSUJI KOSUKE , KAMEYAMA SADAFUMI , IRIKURA SHOGO , BABA TERUYOSHI , OURAKI TAKAYUKI
IPC分类号： H01R33/76 , H05K1/18
摘要： PURPOSE:To prevent the oscillation of an IC by extracting a fitting lead to the wiring board of a socket from the contact position between an IC lead and a U-shaped contact section to be brought into contact with the IC lead. CONSTITUTION:A U-shaped contact section 10 is set to the lateral direction, and a socket lead 5 is provided on the bottom face of the movable side 10B of the contact section 10 and below the contact position between an IC lead 9 and the contact section 10. The socket lead 5 is extracted from the position in contact with the IC lead 9. An IC can be neared to the directly fitted state to a wiring board 11, and the inductance component is further decreased. When a bypass capacitor is added, its effect is exerted, and oscillation can be prevented.

5. 发明专利

JPH10269510A READ AMPLIFIER CIRCUIT AND SEMICONDUCTOR INTEGRATED CIRCUIT 失效
公开(公告)号：JPH10269510A
公开(公告)日：1998-10-09
申请号：JP7600597
申请日：1997-03-27
申请人： HITACHI LTD , HITACHI INFORMATION TECHNOLOGY , HITACHI COMMUNICATION SYSTEM , HITACHI VLSI ENG
发明人： HIROSE TAKESHI , NAGAYA YUJI , HASHIMOTO TAKASHI , YOSHINAGA MAKI , HATANAKA NORIAKI , SOGA YUJI , MORIYA ATSUSHI , MOCHIZUKI TAKEO , KAMEYAMA SADAFUMI
IPC分类号： G11B5/09 , G11B5/02 , H03F3/68
摘要： PROBLEM TO BE SOLVED: To reduce the parasitic capacitance to be connected to each emitter and the noise caused by the base resistance of the transistors for a cascade connection by plurally dividing the cascade connected transistors and connecting a few transistors for a head bias to each emitter. SOLUTION: The collectors of five transistors are connected to the emitter of an upper stage cascade connection transistor Q1. The parasitic capacitance associated with the emitter of the transistor Q1 is 5×Cb and the parasitic capacitance associated with the emitters of lower stage cascade connection transistors Q11 to Q15 becomes 5×CA. Noises generated by the base resistances of the transistors Q1 and the transistors Q11 to Q15 are equal and set to Vn. If the sizes of the transistors Q11 to Q15 and head bias transistors Qb1 to Qb10 are the same and parasitic capacitances of the emitters are CA=Cb, the noise in the read amplifier is reduced to an approximately 1/2 value and the noise reduction effect is obtained at a higher frequency band.

6. 发明专利

JPS6465906A AMPLIFIER CIRCUIT 失效
公开(公告)号：JPS6465906A
公开(公告)日：1989-03-13
申请号：JP22160087
申请日：1987-09-04
申请人： HITACHI LTD , HITACHI VLSI ENG
发明人： IRIKURA SHOGO , TSUJI KOSUKE , KAMEYAMA SADAFUMI , BABA TERUYOSHI , OURA TAKAYUKI
IPC分类号： H03F3/343 , H03F3/34
摘要： PURPOSE:To reduce the dependency upon a power source voltage variation of an output voltage without being influenced on an amplification factor by making an input transistor let a current corresponding to an input voltage flow from a coupling node with a load element, and further, letting the current corresponding to the change of the power source voltage flow from said coupling node by the action of a second current source. CONSTITUTION:The second current source BCS causes a current change corresponding to the change of the power source voltage Vcc between the coupling node ND and a second power source terminal VEE, and generates a potential difference, scarecely dependent upon the change of the power source voltage Vcc, at both ends of a load resistance RL. Then, it lets the current Ibias having a tendency to cancel the voltage difference variation of both ends of the load resistance RL according to the variation of the power source voltage Vcc flow. Namely, it the power source voltage Vcc is raised or lowered higher/lower than a reference potential, the current Ibias is increased or decreased by a portion necessitated to cancel the rise portion of the drop portion of the output voltage Vout according to the change of the power source voltage Vcc. Accordingly, the dependency upon the power source voltage variation of the output voltage is lowered without being influenced upon the amplification factor.

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