NXP Semiconductors MC145026DR2

Overview

MC145026DR2 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 an internal RC oscillator (1 kHz–10 MHz), consumes ≤300 nA standby current at 25°C, and interfaces directly with RF/IR/ultrasonic modulators in garage door openers and wireless security transmitters.

For engineers reviewing the MC145026DR2 datasheet, MC145026DR2 pinout, MC145026DR2 application, or MC145026DR2 equivalent, key selection criteria include its 9-bit trinary encoding capability (19,683 codes), TE-triggered transmission protocol, DIP-16 package compatibility, and voltage-flexible operation down to 2.5 V - critical for battery-powered remote designs requiring low quiescent power and robust noise immunity.

Technical Context

The MC145026DR2 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 pull-up/pull-down test currents (≤1 mA at 15 V). Its internal 3-pin oscillator (RS/RTC/CTC) generates the timing reference without requiring a crystal.

Transmission is initiated by a low-going TE signal, triggering two identical serial words sent via Dout with inter-word silence of three data periods. Each trinary digit encodes as pulse-width-modulated waveforms: short-short (0), long-long (1), or long-short (open), ensuring deterministic decoding under noisy channel conditions.

Key Specifications

Pinout & Package

MC145026DR2 is housed in a 16-pin plastic DIP (Dual In-line Package), case 648, with 0.3-inch body width and 0.1-inch lead pitch - compatible with standard through-hole PCB assembly and socketing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SC41343 and MC145026P, the MC145026DR2 offers full 2.5–18 V operation and ultra-low standby current ideal for long-life battery remotes, while maintaining pin compatibility with both alternatives for flexible sourcing and design reuse.

Availability

MC145026DR2 is available at Aetrix Electronics and suitable for garage door openers, wireless security systems, and industrial remote controls requiring stable component supply across extended product lifecycles.

Supply support for MC145026DR2 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 manufacturer specializing in energy-efficient electronics, with legacy roots in Motorola's semiconductor division.

The MC145026DR2 belongs to the MC145000 series of CMOS encoder/decoder ICs, engineered specifically for low-power, cost-sensitive remote control applications requiring robust encoding security and minimal external components.

FAQ

What is the minimum supply voltage required for reliable operation of the MC145026DR2?

The MC145026DR2 is guaranteed to operate down to 2.5 V, with full functionality including trinary input detection, oscillator startup, and valid Dout signaling. At 2.5 V, VOL remains ≤0.05 V and VOH ≥2.45 V, ensuring interoperability with downstream CMOS logic. Operation below 2.5 V is not characterized and may result in incomplete encoding or oscillator failure.

How does the MC145026DR2 detect trinary (low/high/open) states on its address pins?

The MC145026DR2 applies weak test currents - up to 1 mA at 15 V - to each address pin (A1–A5, A6/D6–A9/D9) to determine logic state. If only high results, the pin is assumed hard-wired to VDD; if only low, it is hard-wired to VSS; if both levels are achievable, the pin is classified as open (high-impedance). This enables true 3-state encoding without external trinary switches.

Can the MC145026DR2 be used with an external clock source instead of the internal RC oscillator?

Yes - the MC145026DR2 supports external clock injection via the RS pin. When an external signal is applied to RS, the RTC and CTC pins must be left unconnected. The internal oscillator is disabled, and the encoder synchronizes to the external clock frequency, allowing precise timing control or integration with system clocks in synchronized multi-device networks.

What is the purpose of the dual-word transmission feature in the MC145026DR2?

The MC145026DR2 transmits each encoded word twice per TE assertion to enhance reliability in noisy RF/IR channels. This redundancy allows decoders like MC145027/MC145028 to require consecutive matching words before asserting VT, effectively rejecting single-packet corruption caused by interference, dropouts, or reflections - a critical feature for safety-critical remote commands.

Does the MC145026DR2 require external passive components to function, and if so, what are their roles?

Yes - the MC145026DR2 requires three external components: RS, RTC, and CTC form the RC oscillator network setting the encoding clock frequency (f ≈ 1/(2.3 × RTC × CTC′)). RS must be ≥2×RTC to minimize current error. These components define timing accuracy and data rate; typical values yield 4–9 kHz for IR applications, with ±5% tolerance fully supported.