Texas Instruments SN74AVCH1T45YEPR

Overview

SN74AVCH1T45 from Texas Instruments is a single-bit, dual-supply noninverting bus transceiver enabling bidirectional voltage translation between 1.2V–3.6V domains. It features independent VCCA and VCCB rails, bus-hold on both I/O ports, Ioff partial-power-down support, and 4.6V I/O tolerance. It serves in low-voltage interconnects between SoC I/O and peripheral ICs in space-constrained portable electronics.

For engineers reviewing the SN74AVCH1T45 datasheet, SN74AVCH1T45 pinout, SN74AVCH1T45 application, or SN74AVCH1T45 equivalent, key selection criteria include its configurable dual-rail operation, 3-state output control via DIR referenced to VCCA, propagation delays as low as 0.2 ns (typ.) at 3.3V→3.3V, bus-hold current thresholds, and NanoFree™/SC70/SOT-23 package compatibility with high-density PCB layouts.

Technical Context

The SN74AVCH1T45 implements a fully configurable dual-rail architecture where A-port logic levels track VCCA (1.2V–3.6V) and B-port levels track VCCB (1.2V–3.6V), enabling asynchronous bidirectional translation across five standard voltage nodes. The DIR input is strictly referenced to VCCA, decoupling direction control from B-side supply conditions.

Its bus-hold circuitry actively sustains undriven inputs at valid logic states without external resistors-IBHL ≥25 µA (low) and IBHH ≤–25 µA (high) at 1.2V-and Ioff leakage remains ≤±5 µA when either supply is at 0 V, ensuring robust isolation during partial power-down sequences.

Key Specifications

Pinout & Package

SN74AVCH1T45 is offered in three miniature packages: DCK (SC70-6, 2.00 mm × 1.25 mm), DBV (SOT-23-6, 2.90 mm × 1.60 mm), and YZP (DSBGA-6, 1.50 mm × 0.90 mm). All variants share identical pin functionality and 6-pin configuration.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage translation applications.

Compared with TXB0101DGSR and SN74LVC1T45DBVR, SN74AVCH1T45 uniquely delivers explicit DIR control, true dual-rail independence, bus-hold, Ioff, and VCC isolation-making it the only option among the three suitable for robust, mixed-voltage, hot-pluggable embedded interfaces.

Availability

SN74AVCH1T45 is available at Aetrix Electronics and suitable for mobile processor interfacing, low-power sensor hub design, and industrial PLC I/O modules requiring stable component supply across extended product lifecycles.

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 specializing in analog, embedded processing, and connectivity technologies, with over 90 years of innovation in high-reliability electronic components.

The SN74AVCH1T45 belongs to TI's AVC logic family, engineered specifically for ultra-low-voltage, high-speed bidirectional translation in space-constrained portable and industrial systems demanding robust power sequencing and ESD resilience.

FAQ

What voltage ranges can SN74AVCH1T45 translate between?

SN74AVCH1T45 supports translation between any two voltage domains from 1.2 V to 3.6 V on its A and B ports independently-enabling interoperability among 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V logic families. Both VCCA and VCCB must be within this range, and the device maintains specified performance across all combinations, including 1.2V ↔ 3.3V and 1.8V ↔ 2.5V. The SN74AVCH1T45 does not support translation outside this window.

How does the DIR pin function in SN74AVCH1T45, and what supply references it?

The DIR pin in SN74AVCH1T45 controls data direction: logic high enables transmission from A to B, and logic low enables transmission from B to A. Critically, DIR is referenced exclusively to VCCA-not VCCB-so its VIH and VIL thresholds scale with the A-side supply voltage. This ensures reliable direction control even when VCCB differs significantly from VCCA, a key distinction from single-supply translators. The SN74AVCH1T45 datasheet specifies DIR thresholds as VCCA × 0.65 (VIH min) and VCCA × 0.35 (VIL max) for VCCA = 1.2V–1.95V.

Does SN74AVCH1T45 require external pull-up or pull-down resistors on its I/O pins?

No, SN74AVCH1T45 does not require external pull-up or pull-down resistors due to its integrated bus-hold circuitry on both A and B ports. This feature actively maintains undriven or floating inputs at valid logic states using sustaining currents (e.g., ±25 µA minimum at 1.2V), eliminating risk of metastability and reducing BOM count. TI explicitly advises against adding external resistors when bus-hold is enabled, as they may interfere with the internal hold strength. The SN74AVCH1T45 bus-hold behavior is active whenever its associated supply (VCCA or VCCB) is powered.

What protection features does SN74AVCH1T45 provide during partial power-down?

SN74AVCH1T45 provides three coordinated partial-power-down protections: (1) Ioff circuitry disables outputs and limits leakage to ±5 µA when either VCCA or VCCB is at 0 V; (2) VCC isolation forces outputs into high-impedance state if either supply is grounded, preventing bus contention; and (3) bus-hold remains active on the powered side only, preserving signal integrity. These features allow safe hot-insertion and staggered power sequencing in modular systems. All are inherent to the SN74AVCH1T45 silicon design and require no external circuitry.

Which packages are available for SN74AVCH1T45, and how do their thermal characteristics differ?

SN74AVCH1T45 is available in three packages: DBV (SOT-23-6, 2.90 mm × 1.60 mm), DCK (SC70-6, 2.00 mm × 1.25 mm), and YZP (DSBGA-6, 1.50 mm × 0.90 mm). Thermally, the YZP package offers the lowest junction-to-board resistance (RθJB = 51 °C/W), followed by DBV (93.3 °C/W) and DCK (94.4 °C/W). The YZP variant also achieves the lowest junction-to-ambient rating (RθJA = 130 °C/W) due to its die-as-package construction, making it optimal for thermally constrained portable designs. All packages maintain identical electrical specifications for the SN74AVCH1T45.