NXP Semiconductors PCF8579T/1,112

Overview

PCF8579T/1,112 from NXP Semiconductors is a low-power CMOS LCD column driver IC designed for dot matrix graphic displays with 1:8 to 1:32 multiplexing. It provides 40 column outputs, 1280-bit display RAM (32 × 40 bits), I²C-bus interface, and operates from 2.5 V to 6 V logic supply with up to 9 V LCD supply. It is optimized for use with PCF8578 row driver in automotive information systems and industrial terminals.

For engineers reviewing the PCF8579T/1,112 datasheet, PCF8579T/1,112 pinout, PCF8579T/1,112 application, or PCF8579T/1,112 equivalent, key selection criteria include multiplex rate configurability (1:8/16/24/32), hardware subaddressing (A0–A3), bank-switchable display RAM, SYNC-cascadable architecture, and bias voltage support (V3/V4) for high-contrast LCD operation.

Technical Context

The PCF8579T/1,112 implements a synchronized cascaded LCD driving architecture where it receives row timing via SYNC from the PCF8578 row driver and drives 40 columns per device. Its internal 32 × 40-bit static RAM is organized into four 40-byte banks, with auto-incremented addressing and subaddress-controlled access enabled by A0–A3 pins.

It uses an I²C-bus slave controller with dual fixed addresses (0x74/0x75) selected by SA0, supports command-based mode control (set-mode, set-start-bank, device-select), and features dedicated LCD bias inputs (V3, V4) and supply (VLCD) independent from logic VDD - enabling precise RMS voltage control across multiplex rates.

Key Specifications

Pinout & Package

PCF8579T/1,112 is supplied in a plastic very small outline package (VSO56, SOT190-1) with 56 leads, optimized for single-plane PCB routing in multi-device LCD driver stacks.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCF8579H/1 and PCF8579HT/1, the PCF8579T/1,112 offers the smallest footprint (VSO56, 12.8 × 5.8 mm) and lowest profile among variants - making it optimal for compact, cost-sensitive industrial and automotive displays where PCB area is constrained.

Availability

PCF8579T/1,112 is available at Aetrix Electronics and suitable for automotive information systems, industrial computer terminals, and point-of-sale terminals requiring stable component supply and long-term manufacturing continuity.

Supply support for PCF8579T/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 PCF8579T/1,112 belongs to NXP's legacy LCD driver product line, engineered specifically for reliable, low-power dot matrix display control in harsh environments - emphasizing robust I²C communication, flexible multiplexing, and seamless integration with PCF8578 row drivers.

FAQ

What is the primary function of the PCF8579T/1,112 in an LCD system?

The PCF8579T/1,112 serves as a dedicated LCD column driver IC that interfaces with the PCF8578 row driver to form a complete dot matrix display controller. It manages 40 column outputs, stores display data in its 1280-bit RAM, and accepts commands via I²C to configure multiplex rate, bias, display mode, and bank selection - enabling precise control of up to 32 × 40-dot LCD panels.

How does the PCF8579T/1,112 handle multiple device cascading?

The PCF8579T/1,112 supports cascading through its SYNC output pin and hardware subaddressing (A0–A3). Up to 16 devices can be daisy-chained using SYNC for timing synchronization, while A0–A3 assign each unit a unique 4-bit ID. When used with two I²C slave addresses (selected by SA0), up to 32 PCF8579T/1,112 units may share one bus - all coordinated by a single PCF8578.

What are the valid multiplex rates supported by the PCF8579T/1,112 and how are they configured?

The PCF8579T/1,112 supports four multiplex rates: 1:8, 1:16, 1:24, and 1:32. These are selected via bits M[1:0] in the set-mode command (00 = 1:32, 01 = 1:8, 10 = 1:16, 11 = 1:24). The chosen rate directly determines required bias voltage ratios (V3/V4) and display RAM scanning behavior - all documented in Tables 4 and 5 of the datasheet.

Does the PCF8579T/1,112 require external components for basic operation?

Yes - the PCF8579T/1,112 requires external pull-up resistors on SDA and SCL lines for I²C operation, plus externally generated bias voltages applied to V3 and V4 pins. It also needs separate VDD (2.5–6 V) and VLCD (up to 9 V) supplies. The TEST pin must be tied to VSS, and unused column outputs (C0–C39) should remain unconnected.

Can the PCF8579T/1,112 operate independently without the PCF8578 row driver?

No - the PCF8579T/1,112 is designed exclusively as a column driver and relies on the PCF8578 for row timing, Y-decoding, and overall display synchronization. Its SYNC input expects timing signals from the PCF8578, and its display RAM is structured to align with the PCF8578's 32-row architecture. Standalone operation is not supported.