onsemi MC74LCX652DW

Overview

MC74LCX652DW from ON Semiconductor is a low-voltage CMOS octal transceiver/registered transceiver with dual enable, operating from 2.3 V to 3.6 V supply, featuring 5 V-tolerant inputs/outputs, 24 mA balanced output drive, and real-time or registered bidirectional data transfer between A and B buses. It serves in memory address driving and TTL-level bus interfacing where voltage translation and register-controlled data staging are required.

For engineers reviewing the MC74LCX652DW datasheet, pinout, applications, or equivalent options, key selection considerations include 5 V-tolerant I/O compatibility with legacy systems, dual-clock and dual-select control for flexible data routing, isolation mode capability, and SOIC-24 package suitability for industrial bus interface designs.

Technical Context

The MC74LCX652DW implements two independent 8-bit bidirectional data paths (A↔B) with separate clock inputs (CAB, CBA), select controls (SAB, SBA), and output enables (OEAB, OEBA). Each channel supports transparent (real-time), registered (clocked), or isolated operation modes, enabling dynamic bus arbitration without external latches.

Its architecture integrates LVTTL/LVCMOS-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC ≥ 2.7 V), 3-state outputs with ±24 mA drive at 3.0–3.6 V, and IOFF protection ensuring high-impedance state when VCC = 0 V - critical for live insertion and hot-swap applications.

Key Specifications

Pinout & Package

DW suffix indicates 24-lead plastic SOIC package (Case 751E), 7.8 mm × 4.4 mm body, 1.27 mm pitch, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal registered transceiver applications.

Compared with SN74LVC8T245RHLR and 74ALVC164245PAG, the MC74LCX652DW uniquely combines 5 V-tolerant I/O, per-direction dual enable, clocked register storage, and real-time/registered output multiplexing in a compact SOIC-24 - making it optimal for memory-mapped bus bridging and controlled hot-swap interfaces where data staging and isolation are mandatory.

Availability

MC74LCX652DW is available at Aetrix Electronics and suitable for memory address driving, industrial backplane interconnect, hot-swappable module interfaces, and TTL-compatible test equipment bus applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for MC74LCX652DW 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 power management, analog, sensor, and logic solutions for automotive, industrial, and cloud infrastructure markets.

The MC74LCX652DW belongs to the LCX low-voltage CMOS logic family, designed specifically for mixed-voltage system interfacing with emphasis on 5 V tolerance, low power, and robust bus isolation in industrial control and embedded computing.

FAQ

What is the maximum clock frequency supported by the MC74LCX652DW?

The MC74LCX652DW supports a maximum clock pulse frequency of 150 MHz at VCC = 3.0–3.6 V, as specified in its AC characteristics table. This rating applies to both CAB and CBA inputs under recommended operating conditions with CL = 50 pF and RL = 500 Ω. The actual usable frequency in a given design depends on trace length, loading, and signal integrity margins - the MC74LCX652DW datasheet provides propagation delay values (1.5–9.5 ns) to aid timing closure analysis for the MC74LCX652DW.

Does the MC74LCX652DW require external pull-up or pull-down resistors on its control pins?

No, the MC74LCX652DW does not require external pull-up or pull-down resistors on OEAB, OEBA, SAB, SBA, CAB, or CBA pins under normal operation. Its inputs are TTL-compatible with defined VIH (≥2.0 V) and VIL (≤0.8 V) thresholds at VCC ≥ 2.7 V, and internal input structure ensures stable logic levels when driven directly from CMOS or LVTTL sources. However, floating control inputs are prohibited per datasheet Note * - unused pins must be tied to VCC or GND to prevent undefined states and excessive ICC.

Can the MC74LCX652DW operate with a 2.5 V supply voltage?

Yes, the MC74LCX652DW is fully specified to operate at 2.5 V supply voltage, falling within its recommended 2.3 V to 3.6 V range. At VCC = 2.5 V, DC parameters such as VOH (≥2.0 V), VOL (≤0.4 V), and output drive (±12 mA) remain compliant per the datasheet's 2.7 V–3.0 V row - and AC performance (e.g., fmax ≥100 MHz) is maintained. The MC74LCX652DW is commonly deployed in 2.5 V FPGA I/O banks and low-power microcontroller interfaces.

How does the MC74LCX652DW handle bus contention during mode transitions?

The MC74LCX652DW prevents bus contention through strict 3-state control: when either OEAB or OEBA is HIGH, the corresponding B0–B7 or A0–A7 outputs enter high-impedance state regardless of clock or select inputs. During transitions between real-time and registered modes, the output remains in its prior state until the new configuration takes effect - no glitch or momentary short occurs. The MC74LCX652DW's truth table explicitly defines isolation behavior (both OEs HIGH) and ensures no concurrent drive on opposing buses.

Is the MC74LCX652DW pin-compatible with other ON Semiconductor LCX transceivers?

The MC74LCX652DW is not pin-compatible with other LCX octal transceivers such as MC74LCX162245 or MC74LCX16245 due to differing pin assignments for clocks (CAB/CBA), selects (SAB/SBA), and dual enables (OEAB/OEBA). Its 24-pin SOIC layout is unique to the registered transceiver function set. Substituting another LCX device requires PCB redesign. Always verify pin mapping against the specific MC74LCX652DW datasheet before layout reuse.