One Chip Digital FM/AM Frequency and Clock Indicator Using Improved In2 Technology

A one-chip digital frequency and clock indicator (T1400) has been developed using improved I2L technology which enables the integration of ECL and LED driver circuits on the same chip. The LSI is suitable for use in FM/AM radio receivers and displays time of days or FM/AM tuning frequencies on a four digit LED display. An ECL prescaler circuit for FM input frequency and seven segment drivers with large current drain are co-integrated on this chip, and an application system can be constructed simply with a few external components. The 6.4 MHz reference frequency is divided by the I2L circuit. The FM input frequency as high as 120 MHz is prescaled by the ECL circuit. The application system consists of only this chip, a quartz crystal and LED display elements.