Tunnel-Diode Threshold Discriminator Tolerance Analysis

THE TUNNEL DIODE may be advantageously used as a threshold device in a magnetic memory sense amplifier. A signal voltage is induced in a small segment of a sense line. This induced voltage is propagated through the sense line and amplified. Finally, a current proportional to the signal voltage is compared to a threshold current to determine if the information is binary 1 or binary 0. This threshold has a nominal value and a range which depends on the tolerances of the tunnel diode parameters and the dc bias current. An analysis is made here to relate the bias current of a tunnel diode with the allowable range in the transconductance of the system that amplifies the signal voltage and switches the tunnel diode. Design equations and curves are presented relating the significant parameters.