The ICL8038 waveform generator is a monolithic integrated circuit capable of producing high accuracy sine, square, triangular, saw tooth and pulse waveforms with a minimum of external components. The frequency can be selected externally from 0.001Hz to more than 300kHz using either resistors or capacitors,. The ICL8038 is fabricated with advanced monolithic technology, using Schottky barrier diodes and thin film resistors, and the output is stable over a wide range of temperature and supply variations. HIGHLIGHTS
VARIABLE AUDIO OSCILLATOR, 20Hz TO 20kHz SINE WAVE OUTPUT BUFFER AMPLIFIERS WAVEFORM GENERATOR USED AS STABLE VCO IN A PHASE-LOCKED LOOP LINEAR VOLTAGE CONTROLLED OSCILLATOR
External capacitor is charged and discharged by two current sources i.e. current source 1(CS1) and current source 2(CS2) CS1 produces a current of I while CS2 produces 2I Current source 1 is always on while Current source 2 is switched on or off by the flip flop. Initial assumption that current source 2 is off.
Capacitor is charged by CS1 with a current I. The capacitor voltage thus increases linearly with time. The comparing voltage for comparator 1 is set at 2/3 of Vcc. Hence when voltage across capacitor reaches this value the flip flop is set Hence CS2 turns on Hence capacitor discharges with a current I, ie the voltage across capacitor drops linearly The comparing voltage for comparator 2 is set at 1/3 of Vcc when capacitor voltage reaches this value it triggers again clearing the flip flop ie turning off CS2 Thus resulting in a triangular wave pin no. 3
The triangular wave output is given to a triangle to sine converter circuit which gives out a sin wave and that output is at pin no.2 triangle to sine converter circuit is a non linear circuit. The output of the flip-flop is given directly to pin no.9 giving the square wave output.
Use in Phase Locked Loops Its high frequency stability makes the ICL8038 an ideal building block for a phase locked loop. In this application the remaining functional blocks, the phase detector and the amplifier, can be formed by a number of available ICs (e.g., MC4344, NE562).