NXP Semiconductors PCF1175CT/F2,112

Overview

PCF1175CT/F2,112 from NXP Semiconductors (formerly Philips) is a single-chip 4-digit duplex LCD car clock IC with integrated 4.19 MHz oscillator, programmable voltage regulator, and EEPROM-based time calibration. It drives automotive-grade LCD displays in 12- or 24-hour mode, operates from −40 to +85 °C, and supports battery-powered operation via external resistor and 47 µF capacitor.

For engineers reviewing the PCF1175CT/F2,112 datasheet, PCF1175CT/F2,112 pinout, PCF1175CT/F2,112 application, or PCF1175CT/F2,112 equivalent, key selection criteria include its 28-pin SO28 package, LCD segment/backplane drive capability (14 segment drivers + 2 backplanes), EEPROM-programmable contrast compensation, and automotive temperature range compliance.

Technical Context

The PCF1175CT/F2,112 implements a 1:2 multiplexed duplex LCD driver architecture with three-level backplane signals (BP1/BP2) generating VON(RMS) = 0.79 VDD and VOFF(RMS) = 0.35 VDD for optimal segment contrast. Its internal 4.19 MHz oscillator feeds a divider chain producing precise 1 Hz timing and colon flashing.

Time calibration is performed by inhibiting selectable numbers of 262.144 kHz pulses per second-stored in on-chip EEPROM-to compensate for crystal tolerance (±30 × 10⁻⁶). The voltage regulator adjusts output between 3–6 V across temperature (e.g., 4.0 V at 25 °C → 3–4 V at +85 °C; 5–6 V at −40 °C) to maintain LCD contrast.

Key Specifications

Pinout & Package

PCF1175CT/F2,112 is housed in a plastic small outline package (SO28), 28-lead, body width 7.5 mm (SOT136-1), with 1.27 mm pitch and JEDEC MS-013AE outline compliance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LCD car clock applications.

Compared with PCF1175CT/F2,112 (4.5 V nominal), PCF1175CT/F1,112 and PCF1175CT/F3,112 offer identical timing, drive architecture, and EEPROM programmability-but differ in factory-set baseline LCD voltage, enabling direct matching to specific display module requirements without field reprogramming.

Availability

PCF1175CT/F2,112 is available at Aetrix Electronics and suitable for automotive instrument clusters, aftermarket infotainment systems, and commercial vehicle telematics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for PCF1175CT/F2,112 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 formed from the spin-off of Philips Semiconductors in 2006, specializing in secure connectivity solutions for automotive, industrial, and IoT markets.

The PCF1175CT/F2,112 belongs to NXP's legacy automotive timing and display driver product line, designed specifically for cost-sensitive, high-reliability car clock applications with integrated LCD drive and EEPROM-based calibration.

FAQ

What is the primary function of the PCF1175CT/F2,112?

The PCF1175CT/F2,112 is a dedicated 4-digit duplex LCD car clock IC that integrates timekeeping (hours/minutes/seconds), 4.19 MHz oscillator, programmable voltage regulator, EEPROM-based time calibration, and LCD segment/backplane drivers. It delivers complete clock functionality in a single SO28 package for automotive dashboard applications without requiring external timing or display components.

How does the PCF1175CT/F2,112 handle LCD contrast across temperature?

The PCF1175CT/F2,112 uses an electrically programmable voltage regulator that automatically adjusts its output based on temperature-e.g., delivering ~4.5 V at 25 °C, ~3.5 V at +85 °C, and ~5.5 V at −40 °C. This dynamic regulation maintains consistent RMS segment voltages (VON = 0.79 VDD, VOFF = 0.35 VDD), preserving LCD contrast across the full −40 to +85 °C operating range without external compensation circuitry.

Can the PCF1175CT/F2,112 be used in both 12-hour and 24-hour display modes?

Yes, the PCF1175CT/F2,112 supports both 12-hour and 24-hour time formats. The MODE pin selects the mode: connect to VDD for 12-hour format (e.g., "1:23 AM"), connect to VSS for 24-hour format (e.g., "01:23"), or leave open-circuit to toggle mode on power-on reset. The AM/PM segment driver remains active only in 12-hour mode.

What external components are required for basic operation of the PCF1175CT/F2,112?

Basic operation of the PCF1175CT/F2,112 requires a 4.194304 MHz quartz crystal (with 50 Ω series resistor and 12 pF load capacitance), a 47 µF external capacitor (C_ext) for the internal voltage regulator, a current-limiting resistor (e.g., 6.8 kΩ for 12 V supply), and two SPST switches for time setting (S1/S2). No external trimmer, oscillator IC, or display driver is needed.

Is the PCF1175CT/F2,112 pin-compatible with other variants in the PCF1175C family?

Yes, the PCF1175CT/F2,112 is fully pin-compatible with all PCF1175CT variants (e.g., PCF1175CT/F1,112, PCF1175CT/F3,112) and shares identical SO28 (SOT136-1) packaging, pinout, and electrical interface. Differences exist only in factory-programmed EEPROM values (LCD voltage trim point), making them direct drop-in replacements for display-specific contrast optimization.