NXP Semiconductors MC145028DWR2

Overview

MC145028DWR2 from ON Semiconductor (formerly Motorola) is a 9-bit trinary address decoder IC for remote control systems, operating from 4.5 V to 18 V, supporting up to 19,683 unique addresses, featuring RC oscillator-based timing with no crystal required, and delivering valid transmission (VT) output only after two consecutive matching address words are received - used in garage door openers, wireless security sensors, and industrial remote switches.

For engineers reviewing the MC145028DWR2 datasheet, MC145028DWR2 pinout, MC145028DWR2 application, or MC145028DWR2 equivalent, key selection considerations include its 9-pin trinary address configuration, VT output logic behavior, R1/C1 and R2/C2 timing network dependencies, standby current of 50 µA at 5 V, and compatibility with RF/IR/ultrasonic demodulator front-ends.

Technical Context

The MC145028DWR2 implements a 9-bit shift register architecture that serially compares incoming encoded data against locally configured trinary (low/high/open) or binary (low/high) address inputs across pins A1–A9. It requires external R1/C1 and R2/C2 networks to decode pulse-width-modulated input on Din (Pin 9), with R1C1 set to 3.95×RTC×CTC for digit-level decision timing and R2C2 set to 77×RTC×CTC for end-of-word and end-of-transmission detection.

Its VT output (Pin 11) asserts high only after two identical 9-digit address words are consecutively received and fully matched - no data output pins are provided, distinguishing it from the MC145027. Internal power-on reset forces all outputs low, and CMOS input structure supports ±10 mA drive capability with 7.5 pF input capacitance.

Key Specifications

Pinout & Package

SOG (Small Outline Gull-wing) package, Case 751B, 16-pin, surface-mount - footprint compatible with automated reflow assembly; body dimensions 9.80 × 3.80 × 1.75 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC145027DW, MC145028DWR2 removes data outputs to maximize address space and simplify decoding logic; compared with SC41344DW, it supports higher supply voltages and lower standby current but cannot operate below 4.5 V.

Availability

MC145028DWR2 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 MC145028DWR2 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 delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and IoT applications.

The MC145028DWR2 belongs to Motorola's legacy CMOS encoder/decoder family designed specifically for cost-sensitive, low-power remote control systems using trinary addressing and RC-based timing - prioritizing reliability, minimal external components, and field-deployable robustness.

FAQ

What is the function of the R1 and C1 pins on the MC145028DWR2?

The R1 (Pin 6) and C1 (Pin 7) pins on the MC145028DWR2 form an RC timing network used to discriminate between "0", "1", and "open" pulse widths on the Din input. Per Motorola documentation, R1 × C1 must equal 3.95 × RTC × CTC to correctly resolve encoded trinary digits. This network sets the voltage decay threshold at which the internal comparator decides the logic state of each received bit - critical for reliable decoding in noisy RF or IR environments. The MC145028DWR2 will not function correctly if R1/C1 values deviate significantly from this relationship.

Does the MC145028DWR2 support binary-only addressing?

Yes, the MC145028DWR2 supports binary-only addressing by tying all nine address inputs (A1–A9) to either VDD or VSS - excluding the open (high-impedance) state. In this configuration, it provides 2⁹ = 512 unique address codes. The datasheet explicitly confirms binary operation yields 512 codes versus 19,683 in trinary mode. No internal configuration bits or external strapping is required; addressing mode is determined solely by how A1–A9 are externally terminated. The MC145028DWR2 performs identically in both modes - only the number of resolvable combinations changes.

Can the MC145028DWR2 be used with infrared (IR) demodulators?

Yes, the MC145028DWR2 is explicitly validated for infrared applications per Motorola Application Note AN1016/D. Its Din input accepts CMOS-level signals from standard IR demodulator ICs (e.g., TSOP series), and its RC timing network (R1/C1, R2/C2) is designed to interface with envelope-detected IR burst outputs. The device's 1.0–450 kHz decoder frequency range aligns with typical 30–56 kHz IR carrier systems after envelope detection. Layout guidelines emphasize shielding for A1/A2 stages and grounding best practices - all referenced in the MC145028DWR2 datasheet Figures 20 and 14.

What is the purpose of the VT output on the MC145028DWR2?

VT (Valid Transmission) on the MC145028DWR2 is a status output that goes high only after two complete, identical 9-digit address words are consecutively received and fully matched against the local A1–A9 configuration. It remains high until a mismatch occurs or no signal is detected for four data periods. VT is not a simple data latch - it embodies the core security mechanism: rejecting single-word noise bursts and enforcing dual-word validation. The MC145028DWR2 uses VT as its sole functional output; no data bits are exposed, distinguishing it from the MC145027DW.

Is the MC145028DWR2 pin-compatible with the MC145027DW?

No, the MC145028DWR2 is not pin-compatible with the MC145027DW. Although both use the same 16-pin SOG package (Case 751B), their pin functions differ significantly: MC145027DW assigns Pins 12–15 to D6–D9 data outputs, while MC145028DWR2 uses those same pins as A6–A9 address inputs. Pin 9 is Din on both, but Pin 11 is VT on both - however, the internal logic driving VT differs (address+data match vs. address-only match). Swapping them without PCB redesign will result in incorrect or nonfunctional behavior. The MC145028DWR2 and MC145027DW serve distinct system roles and require dedicated layouts.