Texas Instruments 74AVCH4T245PWTE4

Overview

74AVCH4T245PWTE4 from Texas Instruments is a 4-bit dual-supply bus transceiver enabling bidirectional voltage translation between 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V domains. It features independent VCCA (1.2–3.6V) and VCCB (1.2–3.6V) rails, 4.6V I/O tolerance, bus-hold on all data inputs, and Ioff for partial power-down operation. It is used in low-voltage interconnects between SoCs and peripherals in portable electronics.

For engineers reviewing the 74AVCH4T245PWTE4 datasheet, 74AVCH4T245PWTE4 pinout, 74AVCH4T245PWTE4 application, or 74AVCH4T245PWTE4 equivalent, key selection criteria include configurable dual-rail level-shifting capability, 380Mbps max data rate (1.8V→3.3V), 16-pin TSSOP package, bus-hold functionality eliminating external resistors, and guaranteed operation down to 1.2V on both ports.

Technical Context

The 74AVCH4T245PWTE4 implements a fully asynchronous, direction-controlled bidirectional translation architecture with two independent 2-bit sections. Each section uses DIR to select data flow direction (A→B or B→A) and OE to enable/disable outputs into high-impedance state. Control inputs (1DIR, 2DIR, 1OE, 2OE) are referenced to VCCA, while A-port I/Os track VCCA and B-port I/Os track VCCB.

VCC isolation ensures both ports enter high-impedance mode if either VCCA or VCCB falls below ~0.4V. Bus-hold circuitry actively maintains valid logic states on undriven A/B data inputs without external resistors, and Ioff blocks current backflow during partial power-down, meeting JESD78 Class II latch-up requirements.

Key Specifications

Pinout & Package

Packaged in a 16-pin TSSOP (PW), the 74AVCH4T245PWTE4 measures 5mm × 6.4mm with standard 0.65mm lead pitch and exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC4T245PWR and TXS0104EPWR, the 74AVCH4T245PWTE4 uniquely supports true dual-rail independence, 4.6V tolerance, and guaranteed Ioff behavior-making it the only choice for mixed-voltage systems requiring robust power sequencing and high-speed bidirectional communication.

Availability

74AVCH4T245PWTE4 is available at Aetrix Electronics and suitable for mobile SoC interfacing, industrial sensor hubs, enterprise SSD controllers, and telecom baseband interfaces requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for 74AVCH4T245PWTE4 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 company delivering analog and embedded processing solutions for industrial, automotive, personal electronics, and communications markets.

The SN74AVCH4T245 product line targets low-voltage, high-speed bidirectional level translation in space-constrained, multi-rail systems-designed specifically for seamless interoperability between next-generation processors, memory, and peripherals operating at 1.2V–3.3V.

FAQ

What voltage ranges does the 74AVCH4T245PWTE4 support on its VCCA and VCCB supplies?

The 74AVCH4T245PWTE4 supports independent supply voltages from 1.2V to 3.6V on both VCCA and VCCB. This enables translation between any combination of 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V logic domains. Operation is guaranteed down to 1.2V on either rail, and the device remains functional even when VCCA and VCCB differ by up to 2.4V. The 74AVCH4T245PWTE4 datasheet specifies absolute maximum ratings up to 4.6V on I/O pins, but supply rails must remain within the 1.2–3.6V operating range.

How does the bus-hold feature on the 74AVCH4T245PWTE4 eliminate the need for external pull-up or pull-down resistors?

The 74AVCH4T245PWTE4 integrates active bus-hold circuitry on all eight data I/O pins (1A1–2A2, 1B1–2B2). This circuitry applies a weak sustaining current (±25µA to ±100µA depending on VCC) to hold undriven inputs at their last valid logic state-either HIGH or LOW-without external components. Because the bus-hold strength is calibrated to override noise but not interfere with active drivers, TI explicitly advises against adding pull-up or pull-down resistors, which would conflict with and degrade the function. This reduces BOM cost and PCB real estate versus discrete resistor solutions.

Can the 74AVCH4T245PWTE4 be used in partial-power-down applications, and how does Ioff protect the system?

Yes, the 74AVCH4T245PWTE4 supports partial-power-down via its Ioff feature. When either VCCA or VCCB is at 0V (or near ground), the Ioff circuitry disables all I/O output drivers, limiting leakage current to ±0.1µA maximum. This prevents damaging reverse current from flowing back into a powered-down supply rail through the transceiver's I/O paths. The 74AVCH4T245PWTE4 meets JESD78 Class II latch-up immunity, ensuring reliability during uncontrolled power sequencing-critical in battery-backed or hot-swap subsystems where supplies may ramp independently.

What is the maximum data rate supported by the 74AVCH4T245PWTE4, and under what conditions is it achieved?

The 74AVCH4T245PWTE4 supports up to 380Mbps, but only when translating from 1.8V to 3.3V with VCCA = 1.8V and VCCB = 3.3V. Data rates decrease with lower supply voltages: 200Mbps for <1.8V→3.3V or translation to 2.5V/1.8V, 150Mbps to 1.5V, and 100Mbps to 1.2V. These values are measured under specified load conditions (CL = 15pF, RL = 2kΩ) and reflect guaranteed min/max switching characteristics-not typical-only performance. The 74AVCH4T245PWTE4 achieves these speeds using optimized internal driver strength and low propagation delay (as low as 2.6ns in 1.8V→2.5V mode).

Does the 74AVCH4T245PWTE4 provide protection against supply sequencing faults, and how does VCC isolation work?

Yes, the 74AVCH4T245PWTE4 includes VCC isolation: if either VCCA or VCCB falls below approximately 0.4V (e.g., during power-up/down or fault), both A-port and B-port outputs automatically enter high-impedance state. This prevents invalid logic levels or contention from propagating across the transceiver when one side is unpowered. Unlike basic high-Z enable, this behavior is automatic and supply-driven-not dependent on OE or DIR states. It ensures system-level robustness in applications with independent power domains, such as modular telecom equipment or multi-board industrial controllers where supply ramps are unsynchronized.