Texas Instruments SN74AVCH1T45DCKT

Overview

SN74AVCH1T45 from Texas Instruments is a single-bit dual-supply noninverting bus transceiver enabling bidirectional voltage translation between 1.2V–3.6V rails (e.g., 1.8V ↔ 3.3V), with bus-hold on both I/O ports, VCC isolation, and Ioff partial-power-down support. It operates across –40°C to 85°C and delivers up to 500Mbps data rate in 1.8V-to-3.3V translation.

For engineers reviewing the SN74AVCH1T45 datasheet, SN74AVCH1T45 pinout, SN74AVCH1T45 application, or SN74AVCH1T45 equivalent, key selection criteria include dual-rail supply flexibility (VCCA/VCCB = 1.2–3.6V), 4.6V I/O tolerance, DIR input referenced to VCCA, 3-state output control, and NanoFree™/SC70-6 package compatibility with space-constrained portable electronics designs.

Technical Context

The SN74AVCH1T45 implements a fully configurable dual-rail architecture where A-port signals track VCCA (1.2V–3.6V) and B-port signals track VCCB (1.2V–3.6V), enabling asynchronous bidirectional translation without external level-shifting components. The DIR input-referenced solely to VCCA-controls data direction: high enables A→B, low enables B→A.

VCC isolation forces outputs into high-impedance when either VCCA or VCCB is at GND, while Ioff circuitry limits power-off leakage to ±5μA per port. Bus-hold eliminates external pull resistors by sustaining undriven inputs at valid logic levels using programmable sustaining currents (e.g., ±100μA at 3.3V).

Key Specifications

Pinout & Package

SN74AVCH1T45DCKT uses the SC70-6 (DCK) package: 2.00mm × 1.25mm body, 0.65mm pitch, 6-pin surface-mount configuration optimized for ultra-compact PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TXB0101DGSR and SN74LVC1T45DCKR, SN74AVCH1T45DCKT uniquely combines explicit DIR control, full dual-rail flexibility (1.2V–3.6V per rail), integrated bus-hold, and VCC isolation - making it the only option for high-speed, low-power, mixed-voltage bidirectional interfaces requiring guaranteed timing and power-domain independence.

Availability

SN74AVCH1T45DCKT is available at Aetrix Electronics and suitable for mobile processor I/O bridging, FPGA-to-ASIC voltage interface, and low-power wearable sensor hub applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature.

Supply support for SN74AVCH1T45DCKT 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

SN74AVCH1T45 belongs to TI's AVC logic family, engineered specifically for low-voltage, high-speed bidirectional level translation in space- and power-constrained portable and IoT systems.

FAQ

What voltage ranges does the SN74AVCH1T45DCKT support on its VCCA and VCCB supplies?

The SN74AVCH1T45DCKT supports independent supply voltages from 1.2V to 3.6V on both VCCA and VCCB pins. This allows translation between any combination of standard low-voltage nodes - including 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V - without external components. Operation outside this range violates absolute maximum ratings and may damage the SN74AVCH1T45DCKT.

How does the DIR input function in the SN74AVCH1T45DCKT, and what is its voltage reference?

The DIR input on the SN74AVCH1T45DCKT controls data direction: a high-level signal enables transmission from A to B, while a low-level signal enables transmission from B to A. Critically, DIR is referenced exclusively to VCCA - not VCCB - meaning its VIH and VIL thresholds scale with the A-side supply voltage. This design ensures reliable control even when VCCA and VCCB differ significantly, as confirmed in the SN74AVCH1T45DCKT datasheet Section 6.3.

Does the SN74AVCH1T45DCKT require external pull-up or pull-down resistors on its A and B ports?

No, the SN74AVCH1T45DCKT does not require external pull-up or pull-down resistors because it integrates active bus-hold circuitry on both A and B I/O ports. This feature maintains undriven inputs at valid logic states using programmable sustaining currents (e.g., ±100μA at 3.3V). TI explicitly advises against adding external resistors when bus-hold is enabled, as stated in the SN74AVCH1T45DCKT datasheet Section 4.

What happens to the outputs of the SN74AVCH1T45DCKT if either VCCA or VCCB is disconnected or at ground?

When either VCCA or VCCB is at GND, the SN74AVCH1T45DCKT activates its VCC isolation feature, forcing both A and B outputs into a high-impedance (3-state) condition. This prevents signal contention and back-current flow between powered and unpowered domains. The bus-hold circuitry remains active on the powered side, preserving valid logic states on undriven inputs - a behavior verified in the SN74AVCH1T45DCKT functional description (Section 4).

What is the maximum data rate supported by the SN74AVCH1T45DCKT, and under what conditions is it achieved?

The SN74AVCH1T45DCKT achieves a maximum data rate of 500Mbps under 1.8V-to-3.3V translation conditions, as specified in the official datasheet Features section. This rate assumes proper signal integrity layout, 15pF load capacitance, and operation within recommended voltage and temperature ranges. Lower rates apply for other combinations - e.g., 240Mbps for 1.2V translation - due to reduced drive strength and increased propagation delay.