公开(公告)号：JP2000285403A

公开(公告)日：2000-10-13

申请号：JP2000068582

申请日：2000-03-13

Applicant: IBM

Inventor： KLAASSEN KLAAS BEREND ,  JACOBUS CORNELIS L

IPC: G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/39 ,  H03F1/42 ,  H03F3/45 ,  H03H11/28

Abstract: PROBLEM TO BE SOLVED: To enlarge a channel bandwidth without deteriorating a signal-to-noise ratio performance by forming an input impedance of a read back amplifier of a combination of impedances related to a gain stage and an active terminal, and making the impedance almost equal to a characteristic impedance of a mutual connection part. SOLUTION: In a current detection read back amplifier constitution 300, an MR element Rmr present at a head 301 is connected to a current detection read back amplifier 302 via a mutual connection part 303. A characteristic impedance of the mutual connection part 303 satisfies Z0=R0, and an input impedance Zin is raised to a level of 2O-RO by positive feedback. When an input impedance of the read back amplifier is electronically raised to agree with the characteristic impedance of the mutual connection part 303, a signal-to-noise ratio performance of the channel does not change. A total bandwidth of a channel front end is determined only by an electronics bandwidth.