General description

The PCF85176 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 40 segments. It can be easily cascaded for larger LCD applications. The PCF85176 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).

Features and benefits

■ Single chip LCD controller and driver

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

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

■ Internal LCD bias generation with voltage-follower buffers

■ 40 segment drives:

♦ Up to 20 7-segment numeric characters

♦ Up to 10 14-segment alphanumeric characters

♦ Any graphics of up to 160 segments/elements

■ 40 x 4-bit RAM for display data storage

■ Auto-incremented display data loading across device subaddress boundaries

■ Display memory bank switching in static and duplex drive modes

■ Versatile blinking modes

■ Independent supplies possible for LCD and logic voltages

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

■ Wide logic LCD supply range:

♦ From 2.5 V for low-threshold LCDs

♦ Up to 6.5 V for guest-host LCDs and high-threshold twisted nematic LCDs

■ Low power consumption

■ 400 kHz I2C-bus interface

■ May be cascaded for large LCD applications (up to 2560 segments/elements possible)

■ No external components required

■ Manufactured in silicon gate CMOS process