Texas Instruments SN74AVCH1T45DCKR

Overview

SN74AVCH1T45 from Texas Instruments is a single-bit, dual-supply noninverting bus transceiver enabling bidirectional voltage translation between 1.2V–3.6V domains (e.g., 1.8V ↔ 3.3V), with 3-state outputs, bus-hold on data inputs, and I_off 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 considerations include dual-rail supply independence (VCCA/VCCB), DIR input referenced to VCCA, 4.6V I/O tolerance, VCC isolation behavior, and NanoFree™/SC70 package compatibility with space-constrained portable and industrial interfaces.

Technical Context

The SN74AVCH1T45 implements asynchronous bidirectional level shifting via a direction-controlled transceiver architecture: logic state at DIR (referenced to VCCA) determines signal flow-high enables A→B, low enables B→A. Both ports support independent 1.2V–3.6V supplies, enabling translation across five standard logic families without external biasing.

Its bus-hold circuitry actively maintains valid logic states on undriven A/B inputs, eliminating need for external pull resistors. VCC isolation forces outputs into high-impedance when either VCCA or VCCB is at GND, while I_off limits current backflow during partial power-down-critical for hot-swap and multi-rail system reliability.

Key Specifications

Pinout & Package

SN74AVCH1T45 is packaged in SC70-6 (DCK) with 2.00mm × 1.25mm body size, optimized for ultra-compact PCB layouts in portable electronics and wearables.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TXS0101DCKR and SN74LVC1T45DCKR, SN74AVCH1T45 uniquely delivers explicit DIR control, dual independent supplies, bus-hold, VCC isolation, and I_off-making it the only choice for robust, flexible, and space-constrained multi-voltage system interfaces.

Availability

SN74AVCH1T45 is available at Aetrix Electronics and suitable for mobile processor interfaces, FPGA I/O bridging, and PMIC communication buses requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature and voltage variations.

Supply support for SN74AVCH1T45 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.

The AVC logic family-including SN74AVCH1T45-is engineered for low-voltage, high-speed bidirectional level translation in space- and power-constrained systems where supply independence and robustness are critical.

FAQ

What voltage ranges does the SN74AVCH1T45 support on its A and B ports?

The SN74AVCH1T45 supports independent supply voltages from 1.2V to 3.6V on both VCCA and VCCB, enabling translation between any combination of 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V logic domains. Each port's I/O is referenced to its respective supply, and both tolerate up to 4.6V-ensuring interoperability with legacy or overvoltage-tolerant peripherals without damage.

How does the DIR input function in the SN74AVCH1T45, and what is its voltage reference?

The DIR input in SN74AVCH1T45 controls data direction: high enables transmission from A to B, low enables B to A. Critically, DIR is referenced to VCCA-not VCCB-so its VIH and VIL thresholds scale with the A-port supply. This ensures reliable control even when VCCA and VCCB differ significantly, and eliminates ambiguity in mixed-supply system timing budgets.

Does the SN74AVCH1T45 require external pull-up or pull-down resistors on its A and B pins?

No, the SN74AVCH1T45 integrates active bus-hold circuitry on both A and B I/O pins, which maintains valid logic states on undriven or floating inputs. TI explicitly advises against using external pull resistors with this feature. The bus-hold sustains current (±25μA to ±100μA) sufficient to override typical noise margins-reducing component count and improving signal integrity in high-density layouts.

What happens to the outputs of the SN74AVCH1T45 when one supply rail is powered down?

When either VCCA or VCCB is at GND, the SN74AVCH1T45 activates VCC isolation: all outputs enter a high-impedance (3-state) condition regardless of DIR or input states. Simultaneously, bus-hold remains active on the powered-up side. This prevents back-driving, latch-up, or unintended current paths-making SN74AVCH1T45 ideal for systems with staggered power sequencing or hot-swap capability.

Can the SN74AVCH1T45 be used in battery-powered wearable devices?

Yes-SN74AVCH1T45 is well-suited for battery-powered wearables due to its ultra-low quiescent current (10μA per supply), NanoFree™ SC70-6 package (2.00mm × 1.25mm), and support for 1.2V operation on both ports. Its I_off protection (<5μA leakage when supplies are off) and bus-hold eliminate standby power waste from floating nodes-directly extending runtime in always-on sensor hubs and BLE-connected devices.