Description
GL6840A are monolithic integrated circuits designed to replace the mechanical bell in telephone sets, in connection with an electro acoustical converter. The device can drive either directly a piezo ceramic converter(buzzer) or a small loudspeaker. In this case a transformer is needed. The two tone frequencies generated are switched by an internal oscillator in a fast sequence and made audible across output amplifiers in the transducer, both tone frequencies and switching frequency can be externally adjusted.

Features
• Low current consumption, in order to allow the parallel operation of 4 devices
• Integrated rectifier bridge with zener diodes to protect against overvoltages
• Little external circuitry
• Tone and switching frequencies adjustable by external components
• Integrated voltage and current hysteresis
• Bridge output configuration