4-digit duplex LCD car clock

Designed to drive a 4-digit duplex liquid crystal display (LCD), PCF1175C is a single chip, 4.19 MHz CMOS car clock circuit providing hours, minutes and seconds functions.

The chip contains a time calibration and voltage regulator that are electrically programmable via an on-chip EEPROM. It has also two external single-pole, single-throw switches that accomplish all time setting functions. The circuit is battery-operated via an internal voltage regulator and an external resistor.

Programming Diagram

Programming Diagram

Why Used

  • Internal voltage regulator is electrically programmable for various LCD voltages
  • Time calibration is electrically programmable (no trimming capacitor required)
  • LCD voltage adjusts with temperature for good contrast
  • 4.19 MHz oscillator
  • 12-hour or 24-hour mode
  • Operating ambient temperature: -40 to +85 °C
  • 28-lead plastic SMD (SO28)
  • 1 Hz set mode

Where Used

  • Car radio
  • car audio systems

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