Diodes Incorporated 74AVCH1T45FX4-7

Overview

74AVCH1T45FX4-7 from Diodes Incorporated is a single-bit, dual-supply translating transceiver with 3-state outputs and bus hold, designed for bidirectional voltage-level translation between 1.2V and 3.6V domains. It features independent VCCA and VCCB supplies, DIR-controlled directionality, I_OFF protection at 0V supply, and ±12mA drive at 3.3V - enabling robust signal isolation in portable power-managed systems like smartphones and tablets.

For engineers reviewing the 74AVCH1T45FX4-7 datasheet, 74AVCH1T45FX4-7 pinout, 74AVCH1T45FX4-7 application, or 74AVCH1T45FX4-7 equivalent, this device supports precise low-voltage domain bridging where bus hold eliminates external pull resistors, I_OFF prevents backflow during partial power-down, and sub-3ns propagation delays ensure timing-critical interconnect integrity.

Technical Context

The 74AVCH1T45FX4-7 implements a dual-rail CMOS transceiver architecture with separate VCCA (A-side reference) and VCCB (B-side reference), allowing asymmetric voltage translation (e.g., 1.8V ↔ 3.3V). Direction control is referenced to VCCA, ensuring reliable logic interpretation regardless of VCCB level.

Its bus hold circuitry integrates 10kΩ internal resistors at both A and B pins, latching the last valid logic state to prevent floating inputs. The I_OFF feature activates when either VCCA or VCCB = 0V, limiting leakage to ±1μA while maintaining up to 3.6V electrical isolation on A/B terminals.

Key Specifications

Pinout & Package

X2-DFN1409-6 package: 1.4mm × 0.9mm, 0.4mm pitch, bottom-exposed thermal pad, RoHS-compliant, lead-free, halogen-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVC1T45DBVR and TXS0101DCKR, the 74AVCH1T45FX4-7 uniquely combines bus hold, I_OFF, and DIR control in a 1.4×0.9mm DFN - making it optimal for space-constrained, power-gated, and intermittently connected applications where reliability trumps marginal BOM cost savings.

Availability

74AVCH1T45FX4-7 is available at Aetrix Electronics and suitable for smartphone baseband interfaces, IoT sensor hubs, industrial PLC I/O modules, and automotive infotainment displays requiring stable component supply across extended product lifecycles.

Supply support for 74AVCH1T45FX4-7 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

Diodes Incorporated is a global semiconductor company specializing in discrete, analog, and mixed-signal solutions for power management, signal integrity, and connectivity applications.

The 74AVCH1T45FX4-7 belongs to the AVCH family of low-voltage translators engineered for ultra-compact, battery-sensitive consumer and industrial electronics where bus hold and I_OFF reduce system-level complexity and improve power-state robustness.

FAQ

What is the maximum allowable voltage on A or B pins when VCCA or VCCB is at 0V?

The 74AVCH1T45FX4-7 supports up to 3.6V on A or B pins during I_OFF mode (when either VCCA or VCCB = 0V), per Absolute Maximum Ratings. This enables safe hot-plug operation in systems where one domain powers down while the other remains live, preventing back-current damage to upstream drivers.

Can the DIR pin be left floating in a production design?

No - although the DIR pin has bus hold, Diodes Incorporated specifies that all unused inputs must be held at VCCA or GND per Recommended Operating Conditions. Floating DIR may cause metastability during power-up or brownout, leading to undefined A/B direction and potential bus contention; tie DIR to VCCA or GND via PCB trace.

Does the X2-DFN1409-6 package require thermal vias under the exposed pad?

Yes - the datasheet specifies thermal resistance θ_JA = 450°C/W assumes FR-4 board with minimum recommended pad layout, which includes thermal vias to inner ground planes. Omitting vias degrades thermal performance by >30%, risking junction temperature exceedance above 125°C under sustained ±12mA output loading.

How does bus hold affect input capacitance compared to standard CMOS inputs?

Bus hold adds ~2.5pF to total input capacitance (CI = 2.5pF typ at 3.3V), per Electrical Characteristics. This is negligible for DC and low-speed GPIO but must be accounted for in >50MHz clock distribution paths, where added capacitance can degrade edge rate and increase jitter beyond 10ps RMS in sensitive timing loops.