| 摘要 |
PURPOSE:To obtain a monolithic IC by connecting diodes of forward and reverse direction, the collector of a write use differential transistor, and the base of a read-out use differential transistor which has adjusted a density of an impurity of a base diffusion area, to both ends of a magnetic head coil. CONSTITUTION:Diodes (D) 13, 14 provided in series in the forward and reverse directions are connected to both ends of a magnetic head coil 1 having an intermediate terminal. Transistors (TR) 11, 12 for executing a switching for supplying a write current are connected between both the ends of the coil and a constant-current supply source. The base of differential TR, 9, 10 for reproducing a read-out current is connected to both the ends of the coil 1. A density of an impurity of a base diffusion area of the TRs 9, 10 and a P type diffusion area of the Ds 13, 14 is changed, and a breakdown voltage of the base and the emitter of the TRs 9, 10 is formed higher than a breakdown voltage of the Ds 13, 14. In this way, a magnetic recording and reproducing circuit is constituted of one monolithic IC and can be formed on the same substrate. Also, a characteristic of a write and read-out circuit can be improved. |
