Amplification based on the noise-induced negative differential resistance in a Zener diode

Abstract

A voltage biased Zener diode always exhibit positive differential resistance, thus cannot be used as an element to provide amplification of a signal. We show how to induce negative differential resistance in the reverse bias regime of a 12V Zener diode by noise feedback. We use this to build a voltage amplifier in the audio frequency range, which we characterize by providing bandwidth, gain, power consumption, gain compression and output noise spectral density.

Figures (6)

• Figure 1: Measurement setup for the I-V characteristics of the diode. TIA represents a trans-impedance amplifier, FEMTO model DHCPA-100. Bias tees are Mini-Circuits ZFBT-6GWB+.
• Figure 2: $I(V)$ characteristics of the diode for two values of environmental resistance. The highlighted section is the negative differential resistance region.
• Figure 3: (a) Variance of the current fluctuations at $R=450$$\Omega$ integrated from 100 kHz to 200 MHz (b) Differential resistance of the diode, and normalized second derivative of its integrated noise. Both are taken at $R=450$$\Omega$.
• Figure 4: Electrical schematics of the Zener amplifier.
• Figure 5: (a) Amplifier voltage gain as a function of frequency for various input powers. Inset: gain vs. input power at 1 kHz. (b) Modulus and phase of the input impedance as a function of frequency.