Texas Instruments 74AVCH8T245RHLRG4

Overview

74AVCH8T245RHLRG4 from Texas Instruments is an 8-bit dual-supply noninverting bus transceiver with configurable level-shifting between 1.2V–3.6V rails, 3-state outputs, bus-hold circuitry, and VCC isolation. It enables bidirectional voltage translation between A-port (VCCA-referenced) and B-port (VCCB-referenced), supporting up to 320Mbps data rate at ≥1.8V supplies. Used in mixed-voltage SoC interconnects, FPGA I/O bridging, and industrial controller backplanes.

For engineers reviewing the 74AVCH8T245RHLRG4 datasheet, 74AVCH8T245RHLRG4 pinout, 74AVCH8T245RHLRG4 application, or 74AVCH8T245RHLRG4 equivalent, key selection criteria include dual-rail supply flexibility (VCCA/VCCB = 1.2–3.6V), 4.6-V I/O tolerance, Ioff partial-power-down support, bus-hold elimination of external resistors, and VQFN-24 (RHL) thermal performance (RθJB = 15.7°C/W).

Technical Context

The 74AVCH8T245RHLRG4 implements asynchronous bidirectional data flow controlled by DIR (direction) and OE (output enable), both referenced to VCCA. Its dual-rail architecture isolates A-port logic levels from B-port levels, enabling translation across 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V domains without level-shifter ICs.

VCC isolation ensures high-impedance outputs when either VCCA or VCCB is at GND, while active bus-hold on all I/O pins maintains valid logic states during undriven conditions. Ioff protection limits current backflow during partial power-down, and ESD ratings meet ±8000V HBM, ±200V MM, ±1000V CDM.

Key Specifications

Pinout & Package

74AVCH8T245RHLRG4 uses a 24-pin VQFN package (RHL) with 0.5-mm pitch, 5.5 mm × 3.5 mm footprint, and exposed thermal pad. Pin 1 is VCCA; pins 11–13 are GND; pins 23–24 are VCCB; DIR (pin 2) and OE (pin 22) reference VCCA; A1–A8 (pins 3–10) are VCCA-referenced I/Os; B1–B8 (pins 14–21) are VCCB-referenced I/Os.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC8T245RHLR and TXB0108RGER, the 74AVCH8T245RHLRG4 uniquely delivers true dual-rail independence, VCC isolation for robust power sequencing, and 320Mbps throughput - making it the only option for high-speed, mixed-voltage, fail-safe industrial and medical backplane designs.

Availability

74AVCH8T245RHLRG4 is available at Aetrix Electronics and suitable for industrial PLC backplanes, FPGA-to-MCU interfaces, and automotive infotainment gateways requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for 74AVCH8T245RHLRG4 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 solutions, with over 90 years of innovation in high-reliability electronics.

The SN74AVCH8T245 product line targets mixed-voltage system interconnects in industrial automation, medical devices, and automotive electronics, delivering robust level translation with integrated power management features.

FAQ

What voltage ranges does the 74AVCH8T245RHLRG4 support on its A and B ports?

The 74AVCH8T245RHLRG4 supports independent supply voltages from 1.2V to 3.6V on both VCCA (A port) and VCCB (B port). This enables translation between any combination of 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V logic domains. The 74AVCH8T245RHLRG4's I/O pins are rated for 4.6V tolerance regardless of supply setting, allowing safe interfacing with higher-voltage peripherals without external protection.

How does the VCC isolation feature function in the 74AVCH8T245RHLRG4?

VCC isolation in the 74AVCH8T245RHLRG4 forces all outputs into high-impedance state when either VCCA or VCCB is at GND, preventing backdrive current flow. This protects downstream components during staggered power-up or fault conditions. The bus-hold circuitry remains active on the powered side, maintaining valid logic states on undriven inputs - a critical capability for automotive and industrial systems with complex power sequencing requirements.

Can the 74AVCH8T245RHLRG4 replace single-supply transceivers like the SN74LVC8T245 in existing designs?

The 74AVCH8T245RHLRG4 is not a drop-in replacement for SN74LVC8T245 due to fundamental architectural differences: it requires two independent supplies (VCCA/VCCB) and references DIR/OE to VCCA. However, it can replace SN74LVC8T245 in new designs needing mixed-voltage operation, VCC isolation, or Ioff support - provided PCB layout accommodates separate VCCA/VCCB routing and decoupling.

What is the maximum data rate achievable with the 74AVCH8T245RHLRG4, and under what conditions?

The 74AVCH8T245RHLRG4 achieves up to 320Mbps when both VCCA and VCCB are ≥1.8V. At lower supplies (e.g., VCCA ≤1.8V or VCCB ≤1.8V), the maximum rate drops to 170Mbps. These rates assume proper signal integrity: controlled-impedance traces, matched load capacitance ≤15pF, and clean power delivery. The 74AVCH8T245RHLRG4's typical propagation delay of 2.5ns (A→B, 1.8V/1.8V) directly enables these high-speed timings.

Does the 74AVCH8T245RHLRG4 require external pullup or pulldown resistors on its data lines?

No - the 74AVCH8T245RHLRG4 integrates active bus-hold circuitry on all A1–A8 and B1–B8 pins, eliminating the need for external pullup or pulldown resistors. This feature maintains valid logic states on undriven or floating inputs, reducing BOM cost and PCB area. Texas Instruments explicitly advises against adding external resistors when bus-hold is enabled, as they may interfere with the internal sustaining current thresholds.