ass7_w2011

ass7_w2011 - ECE 100 Lab 7 Design of a Mixed-Mode...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 100 Lab 7 Design of a Mixed-Mode Oscillators Winter 2011 The Wein-Bridge oscillator is a very good low-frequency sinusoidal oscillator. However there are many applications where higher frequencies are needed and often, for example for digital clocks, a pure sinusoidal waveform is not needed. In this lab we will test two widely used oscillators which are partly digital and partly analog (or mixed-mode) circuits. We will also use an opamp, the LM301A, in which the internal compensation pins are accessible to improve its performance as a Schmitt trigger. 1. The Ring Oscillator: The ring oscillator is simply a ring of N digital inverters each output connected to another input. To oscillate N must be an odd number N 3. It is often used as a test circuit on VLSI chips where N might be several 100s. The period of the oscillation depends on the delay time of the inverter T D as P = 2 N T D . If the HL and LH delay times are different one uses the average delay in this expression. We will use an antique CMOS chip, the CD4069, which contains 6 inverters. (a) Measure the time delay of the CD4069 in both HL and LH transitions (defined by the output transition) at a supply voltage V DD of 5v. To do this properly the device under test (DUT) should be between two identical inverters (a driver and a load). This way the delay time is typical of the inverter as operating in a larger digital circuit. The delay time is measured as the interval between the time the DUT input crosses V
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 09/24/2011.

Page1 / 2

ass7_w2011 - ECE 100 Lab 7 Design of a Mixed-Mode...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online