Texas Instruments SN74ALVCH245PWR

Overview

SN74ALVCH245PWR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between 1.65-V to 3.6-V buses. It features ±24-mA output drive at 3.3 V, 3.4-ns max propagation delay, bus-hold inputs eliminating external resistors, and operates across –40°C to 85°C. It is used in voltage-level-translating I/O interfaces in FPGA-to-ASIC interconnects.

For engineers reviewing the SN74ALVCH245PWR datasheet, SN74ALVCH245PWR pinout, SN74ALVCH245PWR application, or SN74ALVCH245PWR equivalent, key selection criteria include bidirectional direction control (DIR), 3-state enable (OE), bus-hold functionality, 20-pin TSSOP package compatibility, and 1.65–3.6-V supply flexibility for mixed-voltage system interfacing.

Technical Context

The SN74ALVCH245PWR implements dual-directional 8-bit data routing controlled by DIR and OE inputs: DIR = low enables B→A transmission; DIR = high enables A→B transmission; OE = high forces all outputs into high-impedance isolation. Its bus-hold circuitry actively maintains valid logic states on undriven A/B port inputs without external biasing.

It supports mixed-voltage operation via a single VCC rail, with input thresholds scaling with VCC (e.g., VIH = 0.65×VCC at 1.65 V, 2.0 V at 3.0–3.6 V). Output drive strength and timing parameters (tpd, ten, tdis) are fully characterized across the 1.65–3.6-V range and –40°C to 85°C temperature span.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 4.4-mm width, 1.2-mm max height, 0.65-mm lead pitch, exposed pad not present, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APWR, SN74ALVCH245PWR delivers guaranteed bus-hold and consistent ±24-mA drive down to 1.65 V, simplifying design for mixed-voltage systems; versus 74AVC245TTR, it trades 1.0-ns speed gain for full pin compatibility and broader voltage margin, favoring drop-in replacement over marginal timing improvement.

Availability

SN74ALVCH245PWR is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, FPGA-to-microcontroller I/O expansion, and automotive body control modules requiring stable component supply and long-term manufacturability.

Supply support for SN74ALVCH245PWR 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The SN74ALVCH245PWR belongs to TI's ALVC/ALVCH logic family, engineered specifically for low-voltage, high-speed bidirectional bus interfacing in mixed-signal systems with stringent power and timing constraints.

FAQ

What is the recommended power-up sequence for SN74ALVCH245PWR?

TI specifies that OE must be held high (via pullup to VCC) during power-up to ensure all outputs remain in high-impedance state until system initialization completes. For SN74ALVCH245PWR, use a ≤10-kΩ pullup resistor from OE to VCC; DIR may float briefly but should be driven before enabling outputs. This prevents bus contention on powered-down downstream devices.

Does SN74ALVCH245PWR support hot-swap operation?

Yes, SN74ALVCH245PWR supports hot-swap due to its bus-hold inputs and high-impedance isolation capability. When OE is high, all A/B ports enter 3-state mode with leakage <±10 µA, and bus-hold maintains last-valid state on undriven pins. However, VCC must ramp monotonically; abrupt insertion into a live bus without current limiting may exceed absolute max ratings.

Can SN74ALVCH245PWR interface 1.8-V and 3.3-V buses simultaneously?

Yes - SN74ALVCH245PWR operates from a single 1.8-V or 3.3-V supply and accepts input voltages from 0 to VCC. When VCC = 1.8 V, it correctly interprets 3.3-V signals as high (VIH min = 1.17 V); when VCC = 3.3 V, 1.8-V signals meet VIH min = 2.0 V only if pulled up, so level translation requires external bias or use of bus-hold to retain valid state. True bidirectional translation requires VCC matching target bus voltage.

What is the thermal resistance (θJA) of the SN74ALVCH245PWR package?

The SN74ALVCH245PWR uses a TSSOP-20 (PW) package with a specified junction-to-ambient thermal resistance (θJA) of 83°C/W under standard JEDEC test conditions (1-layer 1-oz copper, 1-in² pad). Actual θJA in end equipment depends on PCB copper area, airflow, and adjacent heat sources; for continuous 24-mA output loading, junction temperature rise remains <30°C above ambient with minimal copper.

How does bus-hold functionality affect signal integrity on SN74ALVCH245PWR I/O lines?

Bus-hold in SN74ALVCH245PWR provides ±75 µA holding current at 3.0 V, actively reinforcing the last-driven logic state on A/B pins. This prevents metastability during signal transitions or open-bus conditions, eliminating ringing or oscillation caused by unterminated stubs. However, bus-hold adds ~12 pF input capacitance (Cio), slightly increasing propagation delay - verified at ≤3.4 ns in worst-case 3.3-V operation.