Texas Instruments 74ALVCHR16245LRG4

Overview

74ALVCHR16245LRG4 from Texas Instruments is a 16-bit dual-octal noninverting bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between voltage-level-compatible buses operating from 1.65 V to 3.6 V. It features ±12-mA drive strength at 3.3 V, 4.2-ns max propagation delay, integrated 26-Ω series output resistors, and active bus-hold circuitry-enabling robust signal integrity in high-speed industrial backplanes and memory interface subsystems.

For engineers reviewing the 74ALVCHR16245LRG4 datasheet, 74ALVCHR16245LRG4 pinout, 74ALVCHR16245LRG4 application, or 74ALVCHR16245LRG4 equivalent, key selection considerations include its dual-directional control per octet (1DIR/2DIR), independent 3-state enable (1OE/2OE), bus-hold input retention, and compatibility with mixed-voltage 1.8-V/2.5-V/3.3-V system interconnects.

Technical Context

This device implements two independent 8-bit transceiver sections, each with separate direction (DIR) and output-enable (OE) controls, allowing simultaneous A→B and B→A data flow when configured asymmetrically. Its logic diagram confirms true noninverting signal path with no internal inversion or latching.

All I/O pins support hot-swap–capable 3-state operation with guaranteed high-impedance isolation during power-up/down when OE is pulled up. Bus-hold circuitry maintains valid logic states on undriven inputs without external resistors, and integrated 26-Ω series termination eliminates need for discrete source-series resistors on PCB traces.

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.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVCH16245GR, the 74ALVCHR16245LRG4 offers identical performance but with enhanced traceability via G4 suffix indicating green/RoHS-compliant packaging; versus 74LVC16245APAG, it delivers superior signal integrity out-of-box via integrated termination and bus-hold, reducing validation effort in high-reliability systems.

Availability

74ALVCHR16245LRG4 is available at Aetrix Electronics and suitable for industrial backplane interconnect, memory interface buffering, communications line card design, and automated test equipment requiring stable component supply across extended temperature and mixed-voltage environments.

Supply support for 74ALVCHR16245LRG4 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 logic solutions, with decades of expertise in high-speed interface ICs and industrial-grade reliability.

The 74ALVCHR16245LRG4 belongs to TI's Widebus™ family-engineered specifically for low-skew, high-drive parallel bus applications in industrial automation, telecom infrastructure, and test instrumentation where signal integrity and voltage flexibility are critical.

FAQ

What is the maximum operating frequency supported by the 74ALVCHR16245LRG4?

The 74ALVCHR16245LRG4 does not specify a maximum clock frequency, but its 4.2-ns maximum propagation delay at 3.3 V implies reliable operation up to approximately 238 MHz in point-to-point configurations with proper termination. Actual usable frequency depends on trace length, loading, and system-level timing margins-not an intrinsic clock limit of the 74ALVCHR16245LRG4 itself.

Does the 74ALVCHR16245LRG4 require external pull-up resistors on OE pins?

Yes-TI recommends tying OE pins to VCC through a pull-up resistor to ensure high-impedance state during power-up or power-down. The minimum resistor value depends on the driver's current-sinking capability; for typical microcontroller GPIOs, 4.7-kΩ to 10-kΩ is appropriate. This requirement applies directly to the 74ALVCHR16245LRG4 to prevent bus contention at power transition.

Can the 74ALVCHR16245LRG4 be used in a 1.8-V only system without level shifters?

Yes-the 74ALVCHR16245LRG4 operates natively from 1.65 V to 3.6 V, so it functions correctly with 1.8-V VCC, 1.8-V input signals, and 1.8-V output loads. No external level shifting is needed, making the 74ALVCHR16245LRG4 ideal for single-supply 1.8-V systems such as portable instrumentation or low-power FPGA interfaces.

How does bus-hold functionality work on the 74ALVCHR16245LRG4, and when should it be disabled?

The 74ALVCHR16245LRG4 includes active bus-hold circuitry on all data inputs that maintains the last-valid logic state when inputs float. TI explicitly advises against using external pullup/pulldown resistors with this feature. Bus-hold cannot be disabled-it is inherent to the silicon-and is beneficial in hot-swap, test fixture, and unterminated stub scenarios where the 74ALVCHR16245LRG4 prevents metastability.

Is the 74ALVCHR16245LRG4 pin-compatible with older ALVC or LVT variants?

No-the 74ALVCHR16245LRG4 shares the same TSSOP-48 (DGG) footprint and pinout as SN74ALVCH16245GR and SN74ALVCHR16245LR, but is not pin-compatible with legacy ALVC16245 or LVT16245 devices due to differences in power pin placement (e.g., VCC/GND distribution) and internal bus-hold implementation. Always verify pin mapping before substituting the 74ALVCHR16245LRG4 into existing layouts.