Texas Instruments SN74LVTH245AGQNR

Overview

SN74LVTH245AGQNR from Texas Instruments is a 3.3-V ABT octal bus transceiver with 3-state outputs, designed for bidirectional asynchronous data transfer between 3.3-V and 5-V buses. It supports mixed-mode signal operation (5-V inputs/outputs with 3.3-V V_CC), delivers 64 mA sink current per output at V_CC = 3 V, and features bus-hold circuitry eliminating external pull resistors. It is used in industrial backplane interfaces requiring hot-insertion support and level translation.

For engineers reviewing the SN74LVTH245AGQNR datasheet, SN74LVTH245AGQNR pinout, SN74LVTH245AGQNR application, or SN74LVTH245AGQNR equivalent, key selection criteria include its I_off and power-up 3-state capability for hot-swap systems, ±100 µA I_off specification, 2.7–3.6 V operating range, and VFBGA-20 (GQN) package thermal impedance of 78°C/W.

Technical Context

This device implements TTL-compatible ABT logic architecture with dual-directional data flow controlled by DIR and OE inputs. Its active bus-hold circuitry maintains valid logic levels on floating A/B port inputs without external components, and I_off protection prevents backflow current during power-down states.

The transceiver operates across a 2.7–3.6 V supply range, supports 5-V-tolerant inputs up to 5.5 V, and provides propagation delays as low as 0.7 ns (t_PLH/t_PHL) at V_CC = 3.3 V with CL = 50 pF. Output ground bounce (V_OLP) remains below 0.8 V under typical conditions.

Key Specifications

Pinout & Package

VFBGA-20 package (GQN), 3.5 mm × 4.5 mm, 0.5 mm pitch, exposed thermal pad (Pin 21), 1 mm max height. Pin 1 located at top-left corner with index area marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245A and SN74ALVC245, the SN74LVTH245AGQNR uniquely combines 5-V tolerance, bus-hold, I_off, and 2.7-V operation-making it the only option qualified for industrial hot-swap and mixed-rail backplane use without supplemental circuitry.

Availability

SN74LVTH245AGQNR is available at Aetrix Electronics and suitable for industrial backplane interfaces, embedded controller expansion buses, hot-swappable module carriers, and test equipment signal routing requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVTH245AGQNR 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 devices, with decades of experience in industrial, automotive, and communications markets.

The SN74LVTH245AGQNR belongs to TI's ABT logic family, engineered specifically for robust bidirectional bus interfacing in mixed-voltage systems where reliability, hot-swap capability, and noise immunity are critical.

FAQ

What is the maximum allowable input voltage on A/B pins of the SN74LVTH245AGQNR?

The SN74LVTH245AGQNR supports 5-V-tolerant inputs: absolute maximum VI is 7 V, and recommended operating VI is up to 5.5 V regardless of V_CC level. This allows direct connection to 5-V logic without external clamping, confirmed in the "Recommended Operating Conditions" table of the SCBS130T datasheet.

Does the SN74LVTH245AGQNR require external pullup resistors on its A/B inputs?

No. The SN74LVTH245AGQNR integrates active bus-hold circuitry on all A/B inputs, maintaining valid logic states on unused or floating lines. Using external pull resistors with this feature is explicitly discouraged in the datasheet to avoid conflict and increased power consumption.

Can the SN74LVTH245AGQNR be used in hot-swap applications?

Yes. The SN74LVTH245AGQNR includes both I_off circuitry (±100 µA leakage at V_CC = 0) and power-up 3-state functionality, which together prevent damaging current backflow and bus contention during live insertion-fully supporting hot-swap per JEDEC JESD78 and TI application guidelines.

What is the thermal pad (Pin 21) requirement for the SN74LVTH245AGQNR in the GQN package?

The exposed thermal pad (Pin 21) of the SN74LVTH245AGQNR must be soldered to a dedicated PCB thermal pad. TI specifies this as mandatory for mechanical reliability and thermal performance-failure to do so increases θ_JA beyond the rated 78°C/W and risks solder joint fatigue under thermal cycling.

How does the DIR pin control data flow direction in the SN74LVTH245AGQNR?

In the SN74LVTH245AGQNR, DIR = Low enables data transmission from B bus to A bus; DIR = High enables A-to-B transmission. The function table confirms that OE must be Low for either direction to be active, and DIR state must be stable before data edges arrive to ensure setup/hold timing compliance.