Texas Instruments SN74AHC16540DGGR

Overview

SN74AHC16540 from Texas Instruments is a 16-bit noninverting buffer/driver with dual 3-state control (OE1/OE2) and flow-through pinout, operating from 2 V to 5.5 V. It delivers ±8 mA output drive at 5 V, supports 15 pF load propagation delays as low as 3.7 ns (tPLH/tPHL), and features distributed VCC/GND pins to suppress high-speed switching noise in wide-bus data paths.

For engineers reviewing the SN74AHC16540 datasheet, SN74AHC16540 pinout, SN74AHC16540 application, or SN74AHC16540 equivalent, key selection criteria include its dual active-low 3-state enable architecture, TSSOP-48 package thermal resistance (70°C/W), latch-up immunity (>250 mA), and compatibility with 2.5 V/3.3 V/5 V mixed-signal bus interfaces.

Technical Context

The SN74AHC16540 implements two independent 8-bit buffer sections, each with a 2-input AND gate for 3-state control-both OE1 and OE2 must be low to enable outputs. Its EPIC™ CMOS process ensures rail-to-rail input thresholds (VIH = 3.85 V @ VCC = 5.5 V; VIL = 1.65 V @ VCC = 5.5 V) and low dynamic power dissipation (Cpd = 13 pF).

Designed for wide-data-path bus interfacing, it uses flow-through architecture (input A1–A8 on left, Y1–Y8 on right; A9–A16/Y9–Y16 mirrored) to minimize PCB trace crossovers. Distributed power/ground pins reduce simultaneous switching noise, and the device meets JESD 17 latch-up and MIL-STD-883 ESD (2000 V) requirements.

Key Specifications

Pinout & Package

TSSOP-48 (DGG) package: 12.6 mm × 6.2 mm × 1.2 mm body, 0.5 mm pitch, lead-free NiPdAu finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16245ADGGR and 74ALVC164245DGGR, the SN74AHC16540 uniquely supports 2–5.5 V operation with dual independent 3-state enables and flow-through routing - making it the only option for robust, mixed-voltage, unidirectional wide-bus isolation without redesign.

Availability

SN74AHC16540 is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, test equipment data acquisition, and communications baseband processing requiring stable component supply across extended temperature ranges (–40°C to 85°C).

Supply support for SN74AHC16540 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 expertise in high-reliability interface ICs for industrial and automotive markets.

The SN74AHC16540 belongs to TI's Widebus™ family of high-speed, low-noise bus interface devices, engineered specifically for noise-sensitive wide-data-path applications in programmable logic, memory expansion, and real-time control systems.

FAQ

What is the recommended power-up sequence for SN74AHC16540 to avoid bus contention?

TI recommends tying all OE inputs (1OE1, 1OE2, 2OE1, 2OE2) to VCC through a pullup resistor (value determined by driver sink capability) to ensure outputs remain in high-impedance state during power ramp-up. This prevents unintended driving of the bus before the controller initializes. The SN74AHC16540 does not require a specific VCC sequencing order relative to other rails, as its absolute maximum ratings tolerate VCC ramp rates typical of standard DC-DC converters.

Can SN74AHC16540 operate reliably at 2.5 V VCC with 15 pF loads?

Yes - the SN74AHC16540 is fully characterized down to 2 V VCC. At 2.5 V and CL = 15 pF, typical propagation delay is 8.4 ns (tPLH/tPHL), output high voltage (VOH) is ≥2.4 V at –50 µA, and output low voltage (VOL) is ≤0.1 V at 50 µA. These values meet standard 2.5 V LVTTL interface requirements, confirming reliable operation in mixed-voltage systems without level shifters.

How does the dual OE architecture of SN74AHC16540 improve system-level bus arbitration?

The SN74AHC16540's dual active-low OE inputs per 8-bit section (1OE1/1OE2 for first byte, 2OE1/2OE2 for second) implement AND-gated enable logic: both must be low to activate outputs. This prevents partial enable due to noise glitches on one control line and enables hierarchical bus control - e.g., master OE asserts first, then slave OE - ensuring deterministic release timing and eliminating metastability during handoff.

What PCB layout practices are critical for minimizing noise with SN74AHC16540 in high-speed applications?

Use separate 0.1 µF ceramic decoupling capacitors at each VCC–GND pair (pins 7/4, 18/11, 29/22, 40/33, 44), place them within 3 mm of the pins. Route GND planes solidly beneath the device; avoid splits under signal traces. Maintain 50-Ω controlled impedance for >20 MHz signals, and stagger input/output traces to prevent crosstalk. The SN74AHC16540's distributed power/ground pins are only effective when paired with this localized decoupling strategy.

Is SN74AHC16540 compatible with 5 V TTL logic families?

Yes - the SN74AHC16540 accepts TTL-compatible input voltages (VIH ≥ 2.0 V, VIL ≤ 0.8 V at VCC = 5 V) and drives LSTTL loads (≤20 µA input current) with VOH ≥ 4.4 V and VOL ≤ 0.1 V. Its 5.5 V absolute maximum VCC rating and 2000 V HBM ESD protection make it suitable for direct interface with legacy 5 V TTL systems without external translators or current-limiting resistors.