NXP PCF2112CT/1,118: A Comprehensive Technical Overview of the LCD Controller and Driver IC

The NXP PCF2112CT/1,118 is a highly integrated monolithic CMOS chip designed to serve as a low-power LCD controller and driver. This IC is engineered to provide a complete, compact solution for driving small, low-information-content liquid crystal displays (LCDs), commonly found in a vast array of consumer, industrial, and automotive applications. Its combination of on-chip functionality and simple microprocessor interfacing makes it a cornerstone component for embedded systems requiring a clear, reliable user interface.

At its core, the PCF2112CT/1,118 is optimized for driving 4 multiplex (MUX) LCDs, typically configured to display 2 lines of 12 characters each. It incorporates an internal character generator ROM (CGROM) that holds a standard set of alphanumeric characters and symbols, significantly reducing the workload on the host microcontroller. For custom icons or special symbols, the IC also includes a user-programmable character generator RAM (CGRAM), offering design flexibility. Communication with a host controller is streamlined through a 4-bit parallel or I²C-bus interface, allowing for easy integration into various system architectures with minimal pin count.

A key strength of this device lies in its power management capabilities. It is specifically designed for very low power consumption, a critical feature for battery-operated portable devices. The IC can be software-configured for different power-down modes, preserving energy when the display is not in active use. Furthermore, it features an integrated built-in oscillator circuit, requiring only an external resistor to set the operating frequency. This eliminates the need for an external crystal or clock source, simplifying board design and reducing the overall bill of materials (BOM) and footprint.

The driver section of the PCF2112CT/1,118 is responsible for generating the precise voltages required to control the LCD pixels. It includes internal circuitry to create the necessary LCD bias voltages (VLCD) from a single supply voltage (VDD), though an external voltage divider can be used for finer adjustment of display contrast. The output stages are designed to directly drive the segments and commons of the LCD panel, ensuring stable and flicker-free performance.

ICGOODFIND: The NXP PCF2112CT/1,118 stands out as a highly integrated and efficient solution for driving low-to-medium complexity LCDs. Its combination of an on-chip controller, character memory, versatile interface options, and minimal external component requirement makes it an exceptionally cost-effective and space-saving choice for designers. Its ultra-low power consumption profile ensures longevity in portable applications, solidifying its role as a fundamental component in creating clear and efficient human-machine interfaces (HMI).

Keywords: LCD Controller/Driver, Low Power Consumption, I²C-bus Interface, Integrated Character Generator, 4 MUX Drive