Texas Instruments SN74ALVCHR16245GR

Overview

SN74ALVCHR16245GR from Texas Instruments is a 16-bit dual-octal noninverting bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between 1.65-V to 3.6-V buses. It features ±12-mA drive strength at 3.3 V, 4.2-ns max propagation delay, integrated 26-Ω series output resistors, and bus-hold circuitry eliminating external pullup/pulldown resistors. It is used in high-speed board-level interconnects such as memory expansion interfaces and FPGA-to-ASIC data bridges.

For engineers reviewing the SN74ALVCHR16245GR datasheet, SN74ALVCHR16245GR pinout, SN74ALVCHR16245GR application, or SN74ALVCHR16245GR equivalent, key selection considerations include voltage compatibility (1.65–3.6 V), 3-state isolation timing (ten = 5.6 ns, tdis = 5.5 ns at 3.3 V), dual-directional control per 8-bit section, bus-hold input retention, and TSSOP-48 package thermal performance (θJA = 70°C/W).

Technical Context

This device implements two independent 8-bit transceiver sections, each with dedicated DIR (direction) and OE (output-enable) controls. Logic-level DIR selects data flow direction-low enables B→A transmission, high enables A→B-while OE asserts high-impedance state on all outputs when high.

All 16 I/Os feature integrated 26-Ω series termination and bus-hold circuitry that maintains valid logic states on undriven inputs without external components. The design supports mixed-voltage system interfacing across 1.65–3.6 V supply range, with VIH/VIL thresholds scaled to VCC and guaranteed operation from –40°C to 85°C.

Key Specifications

Pinout & Package

TSSOP-48 (DGG) package: 12.6 mm × 6.2 mm × 1.2 mm body, 0.5-mm lead pitch, gull-wing leads, RoHS-compliant NiPdAu finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVCHR16245GR, SN74LVC16245ADGGR offers higher drive but requires more external components, while SN74AVC16245DGGR extends voltage range downward but removes bus-hold and series resistors-making SN74ALVCHR16245GR optimal for robust, component-minimized 1.65–3.6-V interconnects.

Availability

SN74ALVCHR16245GR is available at Aetrix Electronics and suitable for industrial backplane interconnects, FPGA-to-peripheral bridging, memory expansion subsystems, and automated test equipment requiring stable component supply across extended temperature and mixed-voltage conditions.

Supply support for SN74ALVCHR16245GR 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 decades of experience in high-reliability logic and interface solutions.

The SN74ALVCHR16245GR belongs to TI's Widebus™ family-designed specifically for high-speed, low-voltage, space-constrained board-level data routing where integration, noise immunity, and voltage flexibility are critical.

FAQ

What is the recommended power-up sequence for SN74ALVCHR16245GR to avoid bus contention?

TI specifies that OE should be tied to VCC through a pullup resistor during power-up to ensure all outputs remain in high-impedance state until system control logic initializes. For SN74ALVCHR16245GR, minimum pullup value is determined by driver sink capability; a 10-kΩ resistor is typical. This prevents unintended data leakage or bus conflicts before DIR and OE signals are asserted by the host controller.

Does SN74ALVCHR16245GR support hot-swap operation in live backplane systems?

SN74ALVCHR16245GR supports hot-swap operation due to its bus-hold circuitry, which maintains valid logic levels on undriven inputs, and its robust latch-up immunity (>250 mA per JESD17). However, TI recommends using series current-limiting resistors on VCC/GND pins and ensuring OE is held inactive (high) during insertion to guarantee full 3-state isolation before signal engagement.

Can SN74ALVCHR16245GR be used as a unidirectional buffer instead of a transceiver?

Yes-SN74ALVCHR16245GR can operate as two independent 8-bit unidirectional buffers. Fix DIR low and use only A→B data flow, or fix DIR high for B→A flow, while controlling OE to manage enable/disable. Each octet functions autonomously, so one section may be configured for A→B while the other remains disabled or used differently-no hardware modification required.

What is the impact of the integrated 26-Ω series resistors on signal integrity at 100 MHz?

The 26-Ω series resistors in SN74ALVCHR16245GR dampen ringing and reduce edge overshoot on PCB traces up to ~10 cm in length at 100 MHz. Measured data shows <5% overshoot into 50-pF loads at 3.3 V, eliminating need for external RC networks. This improves timing margin and EMI performance without sacrificing propagation delay (4.2 ns max at 3.3 V).

How does bus-hold functionality interact with externally pulled inputs on SN74ALVCHR16245GR?

Texas Instruments explicitly warns against using external pullup or pulldown resistors with SN74ALVCHR16245GR's bus-hold circuitry. Doing so creates contention: bus-hold draws ±45 µA to retain state, while external resistors force opposing DC bias. This increases static current, degrades noise margin, and may cause input threshold instability. Bus-hold alone suffices for floating-input retention.