Texas Instruments SN74AHCT16540DGVR

Overview

SN74AHCT16540 from Texas Instruments is a 16-bit noninverting buffer/driver with dual 3-state control inputs (OE1, OE2), TTL-compatible inputs, and CMOS outputs operating at 4.5–5.5 V. It features flow-through pinout, distributed V_CC/GND for noise suppression, and is rated for –40°C to 85°C. Used in wide-data-path bus interfacing between FPGAs and memory subsystems.

For engineers reviewing the SN74AHCT16540 datasheet, SN74AHCT16540 pinout, SN74AHCT16540 application, or SN74AHCT16540 equivalent, key selection criteria include 3-state timing (t_PZH/t_PHZ ≤ 12 ns @ 50 pF), ±8 mA drive strength, latch-up immunity (>250 mA), ESD robustness (>2 kV HBM), and TSSOP-48 package compatibility with high-density PCB layouts.

Technical Context

This device implements two independent 8-bit noninverting buffers, each controlled by a 2-input AND gate with active-low OE1/OE2 inputs-ensuring high-impedance output if either enable is high. The EPIC™ process enables TTL-level input compatibility while maintaining CMOS output swing and low static current.

Its flow-through architecture places inputs on one side and outputs on the opposite side of the 48-pin TSSOP package, minimizing trace crossovers. Distributed power/ground pins reduce simultaneous switching noise, and the design exceeds JESD 17 latch-up and MIL-STD-883 ESD specifications.

Key Specifications

Pinout & Package

SN74AHCT16540 is packaged in a 48-pin Thin Shrink Small-Outline Package (TSSOP-DGG), 12.5 mm × 6.1 mm × 1.2 mm, with 0.5 mm pitch and exposed thermal pad (not electrically connected). Pin 1 identifier located at top-left corner per JEDEC MO-153.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit 3-state buffer applications.

Compared with SN74AHCT16540, SN74AHCT16244DGVR offers finer enable control but lacks flow-through layout and dual-OE synchronization, while 74LVTH16244DGGR trades TTL compatibility and 5 V operation for lower voltage and faster timing - making SN74AHCT16540 the optimal choice for industrial 5 V bus isolation requiring robust noise immunity and byte-synchronized gating.

Availability

SN74AHCT16540 is available at Aetrix Electronics and suitable for memory subsystems, FPGA interconnects, industrial backplanes, and automated test equipment requiring stable component supply and long-term industrial lifecycle support.

Supply support for SN74AHCT16540 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with decades of heritage in industrial-grade interface ICs.

The SN74AHCT16540 belongs to TI's Widebus™ family of high-speed bus interface devices, engineered specifically for noise-resilient, high-density data path buffering in industrial and communications infrastructure.

FAQ

What is the recommended power-up sequence for SN74AHCT16540 to avoid bus contention?

TI recommends tying OE1 and OE2 to V_CC through a pullup resistor (value determined by driver sink capability) during power-up to ensure outputs remain in high-impedance state until system initialization completes. This prevents undefined states on shared buses. The SN74AHCT16540 datasheet specifies this practice to guarantee safe power sequencing without requiring external reset circuitry.

Does SN74AHCT16540 support hot-swap insertion in live backplanes?

Yes - SN74AHCT16540 features latch-up immunity exceeding 250 mA per JESD 17 and ESD protection >2000 V HBM, enabling robust operation during hot-plug events. Its distributed V_CC/GND pins and flow-through layout further reduce transient coupling. However, OE must be held inactive (high) until power stabilizes, as specified in the SN74AHCT16540 application guidance.

Can SN74AHCT16540 drive 50-pF loads at 20 MHz reliably?

Yes - SN74AHCT16540 guarantees t_PLH/t_PHL ≤ 9.5 ns and t_PZH/t_PHZ ≤ 12 ns into 50-pF loads at V_CC = 5 V, supporting clean signal edges up to ~20 MHz. Its ±8 mA drive strength and low output capacitance (C_O = 3 pF) ensure minimal rise/fall time degradation, making SN74AHCT16540 suitable for high-speed parallel bus applications.

What is the function of the dual OE inputs (OE1 and OE2) on SN74AHCT16540?

Each 8-bit section (1Y1–1Y8 and 2Y1–2Y8) has two active-low OE inputs wired as an AND gate: both OE1 and OE2 must be low for outputs to drive; if either is high, all eight outputs go high-impedance. This dual-control architecture allows fail-safe bus isolation - e.g., one OE tied to system reset, the other to local controller - ensuring SN74AHCT16540 remains safely disabled under fault conditions.

Is SN74AHCT16540 pin-compatible with older 74ACT or 74F series 16-bit buffers?

No - SN74AHCT16540 uses a proprietary flow-through pinout optimized for PCB layout (inputs left, outputs right), differing from legacy 74ACT16540 or 74F540 packages. While functionally equivalent, mechanical compatibility requires board redesign. The SN74AHCT16540 datasheet confirms its DGG/DL/DGV footprints are unique to the AHCT family and not drop-in replacements for earlier families.