onsemi MC74LCX16240DTRG

Overview

MC74LCX16240DTRG from onsemi is a low-voltage CMOS 16-bit inverting buffer with 5 V-tolerant inputs/outputs, operating from 2.3 V to 3.6 V supply. It features nibble-level 3-state control via four independent OE inputs, 24 mA output drive, and near-zero static ICC (10 µA), designed for memory address driving and TTL-level bus transceiver applications.

For engineers reviewing the MC74LCX16240DTRG datasheet, pinout, applications, or equivalent options, key selection criteria include 5 V tolerance under 3.3 V operation, propagation delay ≤5.4 ns at 3.3 V, 48-pin TSSOP package compatibility, and IOFF-enabled live insertion support.

Technical Context

The MC74LCX16240DTRG implements sixteen independent inverting buffers grouped into four 4-bit nibbles, each controlled by a dedicated Output Enable (OEn) input. Its 5.5 V absolute input voltage rating enables safe interfacing with legacy 5 V TTL logic while powered from 2.3–3.6 V supplies.

Each nibble operates identically and independently; OE pins may be tied together for full 16-bit control. The device guarantees high-impedance outputs when VCC = 0 V (IOFF), supports live insertion/withdrawal, and exhibits latchup immunity >500 mA per JEDEC JESD78.

Key Specifications

Pinout & Package

TSSOP-48 (Case 1201), 0.5 mm pitch, Pb-free, RoHS-compliant surface-mount package with exposed thermal pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit inverting buffer applications.

Compared with SN74LVC16240ADGGR and 74ALVC16240PW, the MC74LCX16240DTRG uniquely combines 2.3 V minimum operation, guaranteed 5 V tolerance, and sub-5.5 ns propagation at 3.3 V-making it optimal for legacy-compatible, low-voltage industrial bus designs where timing margin and voltage interoperability are critical.

Availability

MC74LCX16240DTRG is available at Aetrix Electronics and suitable for memory address buffering, backplane bus transceivers, and industrial PLC I/O expansion requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MC74LCX16240DTRG 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MC74LCX16240DTRG belongs to the LCX low-voltage CMOS logic family, engineered for mixed-voltage system interoperability, live-insertion reliability, and ultra-low static power in space-constrained embedded bus architectures.

FAQ

What is the minimum supply voltage required for reliable operation of the MC74LCX16240DTRG?

The MC74LCX16240DTRG operates reliably down to 2.3 V VCC, as specified in its Recommended Operating Conditions table. Below this voltage, parameters such as VOH, VOL, and propagation delay are not guaranteed. At 2.3 V, it delivers ±8 mA output drive and maintains VIH/VIL thresholds compatible with LVTTL logic families. This 2.3 V minimum enables use in battery-powered or brownout-prone industrial systems where other 3.3 V logic families would fail.

Can the MC74LCX16240DTRG safely interface with 5 V logic while powered at 2.5 V?

Yes, the MC74LCX16240DTRG supports 5 V-tolerant inputs and outputs when powered at 2.5 V. Its VI absolute maximum rating is +7.0 V, and the datasheet explicitly states a 5.5 V VI specification. Input clamping diodes are absent, and the internal structure prevents damage or leakage when driven by 5 V signals-even with VCC = 2.5 V. This capability eliminates external level-shifting components in mixed-voltage designs involving legacy 5 V peripherals.

How does the nibble-control architecture of the MC74LCX16240DTRG benefit system design?

The MC74LCX16240DTRG's four independent OE inputs (OE1–OE4) enable granular control over 4-bit segments-D0–D3/O0–O3, D4–D7/O4–O7, etc. This allows partial bus isolation, e.g., disabling only the upper address nibble during DMA transfers while keeping data lines active. It simplifies bus arbitration in multi-master systems and reduces ground bounce by limiting simultaneous switching to subsets of outputs, directly improving signal integrity and EMI performance compared to full 16-bit enable schemes.

What is the significance of the IOFF specification for the MC74LCX16240DTRG?

The IOFF specification guarantees that all outputs enter a high-impedance state when VCC = 0 V, regardless of input voltage levels-including up to 5.5 V. This prevents back-driving of powered circuitry during hot-plug events or power sequencing mismatches. For the MC74LCX16240DTRG, IOFF leakage is limited to 10 µA, ensuring true isolation. This feature is essential for modular systems like test equipment racks or field-replaceable units where cards may be inserted into live backplanes.

Does the MC74LCX16240DTRG require external pull-up or pull-down resistors on its OE inputs?

No, the MC74LCX16240DTRG OE inputs are TTL-compatible and do not require external biasing. They have defined VIH (≥2.0 V at VCC ≥2.7 V) and VIL (≤0.8 V) thresholds, and internal input structures ensure stable logic levels without floating conditions. However, the datasheet cautions against leaving inputs unconnected ("DO NOT FLOAT Inputs") due to potential ICC increase and noise susceptibility. For robust operation, OE inputs should be actively driven LOW to enable outputs or HIGH to disable them-either by MCU GPIOs or hardwired logic.