PCF1179C is a 4-digit duplex LCD car clock produced by Philips Semiconductors.
The PCF1179C is an integrated circuit designed to drive a 4-digit duplex liquid crystal display (LCD) for hours, minutes, and seconds functions. It features an internal 4.19 MHz oscillator and an electrically programmable voltage regulator that adjusts the LCD supply voltage based on temperature to ensure good contrast.
The device supports both 12-hour and 24-hour modes and includes time calibration capabilities via an on-chip EEPROM. Time setting is accomplished using two external single-pole, single-throw switches with a debounce circuit to prevent contact bounce.
| Oscillator Frequency | 4.19 MHz |
|---|---|
| Operating Ambient Temperature | -40 to +85 °C |
| Package Type | 28-lead plastic SMD (S028) |
| Set Mode Frequency | 4 Hz |
LCD voltage programming requires setting SEL to open-circuit and applying a level of Vpp - 5 V to Vpp, followed by DATA pulses.
The device operates within an ambient temperature range of -40 to +85 °C.
When programmed to 4.5 V at 25 °C, the output voltage drops to 8 to 4 V at +85 °C.
Connecting S1 and S2 to Vss switches all LCD segments ON, but releasing them resets the display.