NXP Semiconductors MC145027DW

Overview

MC145027DW from ON Semiconductor (formerly Motorola) is a CMOS 5-bit trinary address / 4-bit binary data decoder IC used in remote control encoder/decoder systems. It operates from 4.5 V to 18 V, supports up to 243 unique trinary addresses or 32 binary addresses, validates transmission via dual-word matching, and drives four parallel data outputs (D6–D9) with VT active-high confirmation. It interfaces directly with RF, IR, or ultrasonic demodulators in garage door openers and wireless security transceivers.

For engineers reviewing the MC145027DW datasheet, MC145027DW pinout, MC145027DW application, or MC145027DW equivalent, this page delivers verified electrical specs, decoder timing behavior, RC oscillator interface requirements, VT output logic conditions, and real-world infrared receiver design constraints - all specific to the SOG-packaged MC145027DW variant.

Technical Context

The MC145027DW implements a serial bit-synchronous decoder architecture that samples Din at a frequency derived from the encoder's RC oscillator (f_decoder ≈ f_encoder/12). It uses two external RC networks - R1/C1 for pulse-width discrimination (logic 0/1/open detection) and R2/C2 for inter-word and end-of-transmission timing - with precise decay thresholds at 1/3 VDD (EOT) and 2/3 VDD (EOW).

Address validation requires two consecutive identical 5-trit words matching local A1–A5 pins; data validation compares four received bits against the prior valid nibble before latching D6–D9 and asserting VT. Internal power-on reset forces all outputs low, and VT remains high only while valid data is continuously confirmed - dropping after four data periods of silence or any address/data mismatch.

Key Specifications

Pinout & Package

MC145027DW is housed in a 16-pin SOG (Small Outline Gull-wing) package per Case 751G, with 0.393" body width, 0.157" width, and 1.0 mm lead pitch - compatible with standard surface-mount reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar remote control decoder applications.

Compared with SC41343DW and PT2272-M4, the MC145027DW provides broader supply range (4.5–18 V), higher address density (243 vs. 16), and hardware-enforced dual-word validation - making it suitable for industrial-grade remote systems requiring robustness and scalability.

Availability

MC145027DW is available at Aetrix Electronics and suitable for garage door openers, wireless security sensors, infrared remote receivers, and industrial machine control panels requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC145027DW 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 (formerly Motorola Semiconductor) is a global supplier of high-performance silicon solutions for automotive, industrial, cloud computing, and IoT applications, with deep heritage in analog and mixed-signal IC design.

The MC145027DW belongs to Motorola's legacy CMOS encoder/decoder family designed specifically for low-power, RC-timed remote control systems - prioritizing reliability, minimal external components, and immunity to burst noise in unlicensed ISM band applications.

FAQ

What is the minimum supply voltage required for reliable operation of the MC145027DW?

The MC145027DW requires a minimum supply voltage of 4.5 V for guaranteed operation across its full temperature range (–40°C to +85°C). Below this threshold, address comparison, VT assertion timing, and output drive strength are not characterized - attempting operation at 3.3 V or lower may result in intermittent VT activation or failure to latch D6–D9 data. For sub-4.5 V systems, consider SC41343DW instead.

How does the MC145027DW distinguish between trinary "open", "low", and "high" states on its address pins?

The MC145027DW does not actively sense trinary states on its own address pins (A1–A5); those pins are static configuration inputs. Trinary encoding occurs at the *encoder* (e.g., MC145026), which internally tests each A1–A5 pin by weakly driving it high then low. Only the encoder determines "open" (high-impedance), "low", or "high" - the MC145027DW simply compares received trinary address bits against the fixed states set on its A1–A5 pins.

Can the MC145027DW decode data from an MC145026 encoder operating at 2.5 V?

No. The MC145026 encoder can operate down to 2.5 V, but the MC145027DW decoder requires a minimum of 4.5 V on VDD to function correctly. A 2.5 V MC145026 output swing (VOH ≈ 2.45 V) falls below the MC145027DW's VIH threshold (≥3.5 V at 5 V VDD), causing unreliable Din recognition. To interface, either raise the encoder supply to ≥4.5 V or use a level-shifting buffer between Dout and Din.

What happens to the VT output if the MC145027DW receives only one valid word instead of two consecutive matches?

If the MC145027DW receives only one valid address+data word - even if fully correct - VT remains low. VT asserts *only* after two consecutive identical words are received and validated. If the second word is corrupted, missing, or mismatched, VT stays deasserted. After VT goes high, it remains high until either a subsequent address/data mismatch occurs or Din remains inactive for four full data periods - at which point VT drops low automatically.

Is the MC145027DW compatible with ceramic resonator-based encoders like the MC145026 driven by a 400 kHz source?

Yes - the MC145027DW is compatible with encoders using ceramic resonators (e.g., MC145026 with MC14024 divider), provided the resulting encoder clock falls within its specified decoder frequency range (1.0–450 kHz at VDD = 15 V). At 400 kHz encoder clock, the MC145027DW expects ~33 kHz on Din (f_encoder/12), well within its 450 kHz max. Ensure R1/C1 and R2/C2 values are recalculated per the 3.95× and 77× RTC×CTC formulas to maintain timing accuracy.