An ECL/I2L Frequency Synthesizer for AM/FM Radio with an Alive Zone Phase Comparator

An international AM/FM radio synthesizer has been designed in a high yield standard bipolar process utilizing ECL/I2L circuitry. A novel ECL/12L interface scheme and stacked I2L is used to achieve a power dissipation of 150 milliwatts which results in generous power supply tolerances and a wide temperature range (-40 to +90°C). The synthesizer is flexibly partitioned for control by a microcontroller or microcomputer via a serial data bus. Optimum spectral purity is achieved with an alive zone phase comparator and a low leakage (< 50 nanoamp) 220 pamp quad-state charge pump which is capable of driving a 15 volt passive filter.