Texas Instruments 74AVCH20T245ZQLR

Overview

74AVCH20T245ZQLR from Texas Instruments is a 20-bit dual-supply noninverting bus transceiver with independent A- and B-side rails (VCCA/VCCB), enabling bidirectional voltage translation between 1.2 V, 1.5 V, 1.8 V, 2.5 V, and 3.3 V logic domains. It features bus-hold on all data inputs, Ioff partial-power-down protection, and VCC isolation. Used in FPGA-to-ASIC interconnects, memory interface bridging, and mixed-voltage SoC subsystem communication.

For engineers reviewing the 74AVCH20T245ZQLR datasheet, 74AVCH20T245ZQLR pinout, 74AVCH20T245ZQLR application, or 74AVCH20T245ZQLR equivalent, key selection criteria include its 4.6-V I/O tolerance, 100–380 Mbps data rate scalability across supply combinations, dual-rail configurability, and VFBGA ZQL package compatibility with high-density PCB layouts.

Technical Context

This device implements two independent 10-bit transceiver sections (1A↔1B and 2A↔2B), each controlled by dedicated DIR and OE signals referenced to VCCA. Direction control is asynchronous and level-sensitive, supporting real-time bidirectional data flow without clocking.

The architecture integrates bus-hold circuitry on all 20 data inputs (A1–A10, B1–B10), eliminating external pull resistors, and employs Ioff logic to disable outputs during power-down, preventing backdrive current when either VCCA or VCCB is at GND - enforced by the VCC isolation feature.

Key Specifications

Pinout & Package

VFBGA package (ZQL): 56-pin, 3.5 mm × 4.5 mm, 0.5 mm pitch, Pb-free, moisture sensitivity level 1 (260°C peak reflow). Exposed die pad enhances thermal performance (θJA = 42°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVCH20T245VR and SN74AVCH16T245DGGR, the 74AVCH20T245ZQLR delivers identical signal integrity and voltage translation capability in the smallest footprint - critical for space-constrained automotive and portable industrial modules requiring 20-bit parallel interfaces.

Availability

74AVCH20T245ZQLR is available at Aetrix Electronics and suitable for high-density FPGA interconnects, automotive sensor hubs, and industrial PLC backplanes requiring stable component supply and long-term lifecycle support.

Supply support for 74AVCH20T245ZQLR 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 high-reliability electronic components.

The AVCH-series bus transceivers are designed for mixed-voltage system integration in industrial automation, automotive electronics, and communications infrastructure - prioritizing low-power operation, robust ESD immunity, and seamless voltage-domain bridging.

FAQ

What is the maximum allowable voltage on the I/O pins of the 74AVCH20T245ZQLR?

The 74AVCH20T245ZQLR supports up to 4.6 V on all A- and B-side I/O pins regardless of VCCA or VCCB voltage - enabling safe interfacing with higher-voltage peripherals without external clamping. This rating applies in both active and high-impedance states, as confirmed in the Absolute Maximum Ratings table of SCES567F.

Does the 74AVCH20T245ZQLR support partial power-down operation?

Yes, the 74AVCH20T245ZQLR fully supports partial power-down via its Ioff feature: when either VCCA or VCCB is at GND, all outputs enter high-impedance state and Ioff leakage remains below ±1 µA across temperature - preventing damaging back-current flow during asymmetric power sequencing.

How does bus-hold functionality work on the 74AVCH20T245ZQLR, and can it coexist with external pull resistors?

The 74AVCH20T245ZQLR integrates active bus-hold circuitry on all 20 data inputs, sourcing or sinking current (IBHH/IBHL) to maintain valid logic levels on undriven lines. TI explicitly advises against using external pull resistors with this feature, as they may conflict with internal hold strength and degrade noise margin or increase power consumption.

What is the pin-compatible alternative to the 74AVCH20T245ZQLR in a surface-mount package suitable for manual assembly?

The SN74AVCH20T245VR in TVSOP (DGV) package is functionally identical to the 74AVCH20T245ZQLR and shares the same 56-pin pinout and electrical behavior. Its larger pitch (0.5 mm) and exposed leads make it significantly more suitable for prototyping, rework, and low-volume manual soldering than the VFBGA ZQL variant.

What are the recommended power supply decoupling practices for the 74AVCH20T245ZQLR in high-speed operation?

TI recommends placing a 0.1 µF ceramic capacitor between each VCCA/VCCB pin and the nearest GND pin, plus a bulk 4.7 µF capacitor per supply rail near the device. Decoupling capacitors must be placed within 3 mm of their respective pins, and VCCA/VCCB traces should be short and wide to minimize inductance - critical for maintaining signal integrity at >260 Mbps data rates.