Frequency Tuning of Bipolar Ring Oscillators using Complementary Inverters and Current Mirror Inverters

Abstract

Complementary bipolar devices are extensively used in analog/digital VLSI circuits. Three inverters, namely, Complementary Inverters (CI), Complementary Current Mirror Inverters (CCMI) and Diode Loaded Complementary Inverters (DLCI) which appear to be attractive for realization of ring oscillators have been simulated. Ring oscillators have been made using different combinations of high gain CI and large bandwidth CCMI. Various techniques of frequency tuning of such oscillators have been studied and the results presented. A PLL circuit has been implemented using a current controlled ring oscillator.

Indexing terms:

• Ring oscillator
• VCO
• CCO
• PLL