NXP Semiconductors PCF8578T/1,112

Overview

PCF8578T/1,112 from NXP Semiconductors is a low-power CMOS LCD row/column driver IC designed for dot matrix graphic displays at 1:8, 1:16, 1:24 or 1:32 multiplex rates. It provides 40 outputs-24 programmable for configurable row/column ratios (32/8, 24/16, 16/24, 8/32)-and integrates 1280-bit display RAM, on-chip oscillator (R_ext-controlled), and I²C-bus interface. It serves as a stand-alone controller in small systems or as master driver synchronized with up to 32 PCF8579s in large displays (up to 40960 dots), e.g., automotive information panels.

For engineers reviewing the PCF8578T/1,112 datasheet, PCF8578T/1,112 pinout, PCF8578T/1,112 application, or PCF8578T/1,112 equivalent, key selection considerations include its VSO56 package compatibility, 2.5–6 V logic supply range, 9 V max LCD supply, selectable bias configuration (5 or 6 levels), and mixed-mode vs. row-mode operation flexibility.

Technical Context

The PCF8578T/1,112 implements a dual-role display controller architecture: in mixed mode, it drives both rows and columns using R0–R7 (fixed rows), C32–C39 (fixed columns), and R8/C8–R31/C31 (programmable 24 outputs); in row mode, it functions exclusively as a row driver with up to 32 outputs while generating CLK and SYNC signals for cascaded PCF8579s. Its timing generator derives frame synchronization from an internal oscillator whose frequency is set by an external resistor on OSC–VSS.

Communication occurs via I²C-bus with two fixed 7-bit slave addresses (0111100 and 0111101), selected by SA0, and supports auto-incremented RAM addressing with bank switching across four 40-byte display memory banks. The device includes Power-On Reset that initializes display blanking, 1:32 multiplex rate, and X/Y address 0,0 pointer.

Key Specifications

Pinout & Package

PCF8578T/1,112 is supplied in a plastic very small outline package (VSO56, SOT190-1) with 56 leads, optimized for compact PCB layout and single-plane wiring in multi-device LCD systems.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LCD row/column driver applications.

Compared with PCF8578T/1,112, the PCF8578H/1 offers improved thermal management in LQFP64 form, while PCF8578HT/1 delivers identical performance in a lower-profile TQFP64 variant-both retain full functional and timing compatibility but differ solely in mechanical implementation.

Availability

PCF8578T/1,112 is available at Aetrix Electronics and suitable for automotive information systems, point-of-sale terminals, and industrial computer terminals requiring stable component supply and long-lifecycle support.

Supply support for PCF8578T/1,112 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor company specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The PCF8578T/1,112 belongs to NXP's legacy LCD controller and driver product line, engineered specifically for cost-sensitive, low-power dot matrix graphic display systems requiring minimal MCU intervention and scalable multi-chip architectures.

FAQ

What is the primary function of the PCF8578T/1,112 in an LCD system?

The PCF8578T/1,112 functions as a dedicated LCD row and column driver IC that generates timing, bias voltages, and segment/column waveforms for dot matrix graphic displays. It operates in either mixed mode (driving both rows and columns) or row mode (synchronizing up to 32 PCF8579 column drivers), reducing host MCU load through integrated display RAM and auto-incremented addressing. Its design targets systems needing reliable, low-power display control without external timing components.

How does the PCF8578T/1,112 handle display memory and data loading?

The PCF8578T/1,112 contains a 1280-bit (32 × 40-bit) static RAM organized into four 40-byte banks. Data is loaded via I²C-bus using RAM-access commands and a programmable data pointer that auto-increments across hardware subaddress boundaries. In mixed mode, the subaddress is fixed at 0000, enabling seamless streaming of display data without manual address management-critical for smooth scrolling or dynamic content updates in the PCF8578T/1,112.

Can the PCF8578T/1,112 be used without an external microcontroller?

Yes-the PCF8578T/1,112 can operate as a stand-alone LCD controller in small systems. It includes an on-chip oscillator (requiring only one external resistor), Power-On Reset, and internal timing generator, allowing it to drive displays autonomously once configured. However, initial setup (mode selection, start bank, RAM loading) requires I²C communication from a host; after initialization, it maintains display refresh independently. This capability makes the PCF8578T/1,112 suitable for ultra-low-cost or resource-constrained applications.

What are the key differences between PCF8578T/1,112 and PCF8578H/1?

The PCF8578T/1,112 and PCF8578H/1 share identical electrical specifications, pin functions, and command sets. Their sole difference is packaging: PCF8578T/1,112 uses a 56-lead VSO56 (SOT190-1) package, while PCF8578H/1 uses a 64-lead LQFP64 (SOT314-2). The VSO56 offers smaller footprint and height; the LQFP64 provides better thermal dissipation and solder joint reliability. Both are drop-in replacements electrically, but PCB layout must match the respective package.

How does the PCF8578T/1,112 generate LCD bias voltages for different multiplex rates?

The PCF8578T/1,112 does not generate bias voltages internally-it accepts externally supplied V2, V3, V4, and V5 bias inputs (Pins 10–13) derived from a resistor divider network referenced to VLCD. The optimal voltage ratios (e.g., V2/Voper = 0.739 for 1:8, 0.800 for 1:16) are defined in the datasheet and depend strictly on the selected multiplex rate. Designers must configure the external bias circuit accordingly; the PCF8578T/1,112 uses these inputs to shape correct row/column waveforms and ensure maximum display contrast.