NXP Semiconductors MC145026P

Overview

MC145026P from ON Semiconductor (formerly Motorola) is a CMOS encoder IC designed for remote control systems, serially encoding nine trinary/binary address/data lines into secure dual-word transmissions. It operates from 2.5 V to 18 V, features RC oscillator (no crystal), 300 nA standby current at 25°C, and interfaces directly with RF/IR/ultrasonic modulators. Used in garage door openers, wireless security sensors, and industrial remote switches.

For engineers reviewing the MC145026P datasheet, MC145026P pinout, MC145026P application, or MC145026P equivalent, key selection criteria include its 9-bit trinary encoding capability (19,683 codes), TE-triggered transmission protocol, internal pull-up on TE, Dout serial output timing, and compatibility with ±5% external R/C components for oscillator tuning.

Technical Context

The MC145026P implements a ring counter–based sequencer with trinary input detection logic that samples A1–A5 and A6/D6–A9/D9 pins to distinguish low/high/open states using weak drive test methodology. Its internal 3-pin oscillator (RTC/CTC/RS) sets the encoder clock frequency (1 kHz–10 MHz), which directly determines data rate and timing of the dual-word transmission sequence.

Transmission is initiated by a low pulse on TE (Transmit Enable), which starts the oscillator and triggers two identical 9-digit words separated by three data periods. Each digit is encoded as pulse-width-modulated pairs: short-short (0), long-long (1), long-short (open). The Dout output delivers this waveform synchronized to the oscillator.

Key Specifications

Pinout & Package

MC145026P is supplied in a 16-pin plastic DIP (Dual In-line Package), case 648, with 0.3-inch body width and 0.1-inch lead pitch. Pin 1 is bottom-left corner when notch faces up.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar encoder applications.

Compared with SC41343P and HT12E, the MC145026P uniquely combines trinary encoding, ultra-low standby current, and integrated RC oscillator in a single 16-pin DIP - making it irreplaceable for legacy remote designs requiring 9-bit trinary security and battery longevity.

Availability

MC145026P is available at Aetrix Electronics and suitable for garage door openers, wireless security sensors, and industrial remote switches requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MC145026P 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

ON Semiconductor is a global semiconductor supplier specializing in power management, analog, and custom devices for automotive, industrial, and consumer markets.

The MC145026P belongs to Motorola's legacy CMOS encoder family, engineered specifically for low-power, secure wireless remote control systems using trinary addressing and RC-based timing.

FAQ

What is the function of the TE pin on the MC145026P?

The TE (Transmit Enable) pin on the MC145026P is an active-low input that initiates the full two-word encoding and transmission sequence. It features an internal pull-up device, allowing direct connection to a momentary switch grounded to VSS. When TE is pulled low, the internal oscillator starts and the A1–A9 inputs are sampled and serialized to Dout. The MC145026P remains in ultra-low-power standby (300 nA) while TE is high.

Can the MC145026P operate from a single 3 V battery?

Yes, the MC145026P is fully specified down to 2.5 V supply voltage, making it compatible with single 3 V lithium or alkaline cells. At 3 V, it maintains functional trinary encoding, valid Dout timing, and retains its 300 nA typical standby current - critical for multi-year battery life in remote transmitters. Electrical characteristics including VOL, VOH, and oscillator frequency are guaranteed across the 2.5–18 V range.

How does the MC145026P detect trinary (low/high/open) input states?

The MC145026P detects trinary states on A1–A9 using a weak-drive sampling method: it briefly forces each pin high, then low, and observes the resulting voltage. If only high is observed, the pin is assumed hard-wired to VDD; if only low, to VSS; if both levels are achieved, the pin is classified as open (high-impedance). This technique enables robust DIP-switch addressing without external pull resistors and is validated across the full 2.5–18 V supply range.

What external components are required for the MC145026P oscillator?

The MC145026P requires three external components for its RC oscillator: RTC and CTC set the base frequency (f ≈ 1/(2.3 × RTC × CTC′)), and RS biases the oscillator stage (RS ≈ 2 × RTC). Typical values include RTC = 10 kΩ, CTC = 1000 pF, RS = 20 kΩ for ~4 kHz operation. All components tolerate ±5% variation, and layout capacitance (Clayout) is compensated in the CTC′ calculation (CTC′ = CTC + Clayout + 12 pF).

Is the MC145026P pin-compatible with newer encoder ICs like the PT2262?

No, the MC145026P is not pin-compatible with the PT2262 or other modern encoders. Its 16-pin DIP pinout - including dedicated RS/RTC/CTC oscillator pins, nine address/data inputs distributed across Pins 1–7, 9, 10, TE on Pin 14, and Dout on Pin 15 - differs fundamentally from PT2262's 18-pin configuration and internal oscillator architecture. Replacement requires PCB redesign and firmware-level timing validation; MC145026P remains the correct choice for maintaining legacy remote control hardware.