Patent ID: 6107873
Filing Date: 2000-08-22
Classification: G11B

Abstract:
A preamplifier comprising:(a) a first input node and a second input node across a magneto-resistive element;(b) a first amplifier, said first amplifier comprising:(i) a first transistor having a first terminal, a second terminal, and a third terminal, the second terminal of said first transistor being coupled to said first input node;(ii) a first impedance element having a first terminal and a second terminal, the first terminal of said first impedance element being coupled to the third terminal of said first transistor;(iii) a second transistor having a first terminal, a second terminal, and a third terminal, the first terminal of said second transistor being coupled to the first terminal of said first transistor;(c) a second amplifier, said second amplifier comprising:(i) a third transistor having a first terminal, a second terminal, and a third terminal, the second terminal of said third transistor being coupled to said second input node;(ii) a second impedance element having a first terminal and a second terminal, the first terminal of said second impedance element being coupled to the third terminal of said third transistor;(iii) a fourth transistor having a first terminal, a second terminal, and a third terminal, the first terminal of said fourth transistor being coupled to the first terminal of said third transistor; andwherein there is no substantial impedance between a power source and the respective third terminals of said second transistor and said fourth transistor.