The PCF8538 is a fully featured Chip‑On‑Glass (COG) Liquid Crystal Display (LCD)driver, designed for high-contrast Vertical Alignment (VA) LCD with multiplex rates up to1:9. It generates the drive signals for a static or multiplexed LCD containing up to9 backplanes, 102 segments, and up to 918 elements. The PCF8538 features an internalcharge pump with internal capacitors for on‑chip generation of the LCD driving voltage. Toensure an optimal and stable contrast over the full temperature range, the PCF8538 offersa programmable temperature compensation of the LCD supply voltage. The PCF8538can be easily controlled by a microcontroller through either the two-line I²C‑bus or afour‑line bidirectional SPI‑bus.
Feature
- Low power consumption
- 102 segments and 9 backplanes allowing to drive:
- up to 114 7-segment numeric characters
- up to 57 14-segment alphanumeric characters
- any graphics of up to 918 elements
- 918-bit RAM for display data storage
- Two sets of backplane outputs providing higher flexibility for optimal COG layoutconfigurations
- Up to 4 chips can be cascaded to drive larger displays with an internally generated orexternally supplied VLCD
- Selectable backplane drive configuration: static, 2, 4, 6, 8, or 9 backplane multiplexing
- LCD supply voltage:
- Programmable internal charge pump for on-chip LCD voltage generation up to5 x VDD2
- External LCD voltage supply possible as well
- Selectable 400 kHz I²C‑bus or 3 MHz SPI‑bus interface
- Selectable linear temperature compensation of VLCD
- Selectable display bias configuration
- Wide range for digital and analog power supply: from 2.5 V to 5.5 V
- Wide LCD voltage range from 4.0 V for low threshold LCDs up to 12.0 V for highthreshold twisted nematic and Vertical Alignment (VA) displays
- Display memory bank switching in static, duplex, and quadruplex drive modes
- Programmable frame frequency in the range of 45 Hz to 300 Hz; factory calibratedwith a tolerance of ±3 Hz (at 80 Hz)
- Selectable inversion scheme for LCD driving waveforms: frame or n‑line inversion
- Diagnostic features for status monitoring
- Integrated temperature sensor with temperature readout
- On chip calibration of internal oscillator frequency and VLCD
- Consumer
- Medical and health care
- Measuring equipment
- Machine control systems
- Information boards
- White goods
- General-purpose display modules
