General description

The PCF85134 is a peripheral device which interfaces to almost any Liquid Crystal Display (LCD)1 with low multiplex rates. It generates the drive signals for any static or multiplexed LCD containing up to four backplanes and up to 60 segments. It can be easily cascaded for larger LCD applications. The PCF85134 is compatible with most microcontrollers and communicates via the two-line bidirectional I2C-bus. Communication overheads are minimized by a display RAM with auto-incremented addressing, by hardware subaddressing, and by display memory switching (static and duplex drive modes).

Although there is a small difference in typical frequency frame and ESD test condition PCF85134 can be used as drop-in replacement to PCF8534 without any system circuit or firmware change.

Features and benefits

■ Single-chip LCD controller and driver

■ Selectable backplane drive configurations: static, 2, 3, or 4 backplane multiplexing

■ 60 segment outputs allowing to drive:

◆ 30 7-segment alphanumeric characters

◆ 15 14-segment alphanumeric characters

◆ Any graphics of up to 240 elements

■ Cascading supported for larger applications

■ 60 x 4-bit display data storage RAM

■ Wide LCD supply range: from 2.5 V for low threshold LCDs up to 6.5 V for high threshold twisted nematic LCDs

■ Internal LCD bias generation with voltage follower buffers

■ Selectable display bias configurations: static, 1⁄2, or 1⁄3

■ Wide logic power supply range: from 1.8 V to 5.5 V

■ LCD and logic supplies may be separated

■ Low power consumption

■ 400 kHz I2C-bus interface

■ No external components required

■ Display memory bank switching in static and duplex drive mode

■ Versatile blinking modes

■ Silicon gate CMOS process