Texas Instruments SN74LVTH245AZQNR

Overview

SN74LVTH245AZQNR 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 output drive at V_CC = 3.3 V, and features bus-hold circuitry eliminating external pullup/pulldown resistors - used in industrial backplane interfaces and legacy system voltage translation.

For engineers reviewing the SN74LVTH245AZQNR datasheet, SN74LVTH245AZQNR pinout, SN74LVTH245AZQNR application, or SN74LVTH245AZQNR equivalent, key selection criteria include its I_off-enabled hot-insertion support, 2.7–3.6 V supply range, 3.5 ns typical propagation delay (t_PLH/t_PHL), latch-up immunity >500 mA, and VQFN-20 (RGY) package thermal performance (θ_JA = 37°C/W).

Technical Context

This device implements an ABT (Advanced BiCMOS Technology) architecture enabling TTL-compatible input thresholds (V_IL = 0.8 V, V_IH = 2 V) while operating from a 3.3-V supply. Its dual-bus transceiver topology uses DIR to control direction (A→B or B→A) and OE to enable/disable all eight channels simultaneously into high-impedance state.

The integrated bus-hold circuitry provides ±750 μA dynamic hold current (V_CC = 3.6 V), preventing floating inputs without external resistors. Power-up 3-state and I_off protection ensure safe hot insertion: outputs remain high-Z during power ramp (Δt/ΔV_CC ≤ 200 μs/V), and reverse current is blocked when V_CC = 0 V.

Key Specifications

Pinout & Package

VQFN-20 (RGY) package: 3.5 mm × 4.5 mm, 0.5 mm pitch, exposed thermal pad (Pin 21), 1 mm max height. RoHS-compliant, NIPDAU lead finish, MSL Level-2 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245A and SN74AVC245, the SN74LVTH245AZQNR uniquely combines 5-V-tolerant I/O, integrated bus-hold, I_off-based hot-swap safety, and industrial temperature rating - making it the only option among the three qualified for mixed-voltage, field-replaceable, and legacy-interfacing applications.

Availability

SN74LVTH245AZQNR is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system voltage translation, hot-swappable module communication, and embedded test equipment bus isolation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVTH245AZQNR 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 connectivity technologies, with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74LVTH245A family belongs to TI's ABT logic portfolio, engineered specifically for robust mixed-voltage system integration - targeting industrial control, test equipment, and legacy-to-modern interface bridging where reliability, hot-swap capability, and 5-V compatibility are mandatory.

FAQ

What is the recommended power supply decoupling for SN74LVTH245AZQNR?

Place a 0.1 μF ceramic capacitor and a 4.7 μF tantalum capacitor between V_CC (Pin 12) and GND (Pin 10), located within 5 mm of the SN74LVTH245AZQNR package. This minimizes supply noise and ensures stable operation during high-current switching events, especially critical given the device's 64 mA output drive capability and low ground bounce specification (V_OLP < 0.8 V).

Does SN74LVTH245AZQNR support true 5-V input tolerance?

Yes, SN74LVTH245AZQNR supports input voltages up to 5.5 V independent of V_CC, verified per absolute maximum ratings (VI = −0.5 V to 7 V) and electrical characteristics (II ≤ 20 μA at VI = 5.5 V). This allows direct connection to 5-V logic outputs without external clamping or level-shifting circuitry - a core feature enabling mixed-mode system integration.

How does the bus-hold function behave on unused SN74LVTH245AZQNR inputs?

Bus-hold circuitry on SN74LVTH245AZQNR actively maintains unused A/B port inputs at their last-valid logic state using ±750 μA dynamic hold current (V_CC = 3.6 V). This eliminates floating inputs and removes the need for external pullup/pulldown resistors - confirmed in the datasheet's "Electrical Characteristics" table under II(hold) parameter, reducing BOM cost and layout overhead.

Can SN74LVTH245AZQNR be used in hot-swap applications?

Yes, SN74LVTH245AZQNR is explicitly designed for hot-insertion via two complementary features: I_off circuitry blocks reverse current when V_CC = 0 V (±100 μA max), and power-up 3-state forces outputs into high-impedance during supply ramp (Δt/ΔV_CC ≤ 200 μs/V). These are documented in the "Features" and "Recommended Operating Conditions" sections of the official datasheet.

What is the thermal pad (Pin 21) connection requirement for SN74LVTH245AZQNR?

The exposed thermal pad (Pin 21) of SN74LVTH245AZQNR must be soldered to a PCB copper pour tied to GND. This is mandatory for achieving the specified θ_JA = 37°C/W and ensuring mechanical reliability. The datasheet's "Package Outline" and "Example Board Layout" documents confirm this requirement and provide land pattern dimensions (3.05 mm × 4.3 mm) and solder paste coverage guidance (78% of pad area).