Texas Instruments 74ACT16657DLR

Overview

74ACT16657DLR from Texas Instruments is a 16-bit dual octal transceiver IC with integrated parity generator/checker circuits, 3-state outputs, TTL-compatible inputs, and flow-through pinout architecture. It operates at 4.5–5.5 V over –40°C to 85°C, delivers ±24 mA drive strength, and supports bidirectional data flow per section with independent transmit/receive control (1T/R, 2T/R), output enable (1OE, 2OE), and odd/even parity selection (1ODD/EVEN, 2ODD/EVEN). Used in high-reliability data bus systems requiring error detection.

For engineers reviewing the 74ACT16657DLR datasheet, 74ACT16657DLR pinout, 74ACT16657DLR application, or 74ACT16657DLR equivalent, key selection criteria include its dual-section parity-aware bidirectional bus interface, SSOP-56 package layout optimized for noise reduction via distributed VCC/GND, and compatibility with legacy ACT logic families in industrial backplane and memory subsystem designs.

Technical Context

The 74ACT16657DLR implements two independent octal transceiver sections-each with dedicated parity generation (transmit mode) and checking (receive mode) logic. Parity sense (odd/even) is selected per section via dedicated ODD/EVEN inputs, and parity status is reported on ERR outputs during receive operations.

Its flow-through architecture places A-side and B-side I/O pins on opposite edges of the SSOP-56 package, minimizing trace crossovers. Distributed VCC and GND pins across the perimeter reduce simultaneous switching noise, while EPIC™ 1-µm CMOS process ensures 500-mA latch-up immunity at 125°C.

Key Specifications

Pinout & Package

74ACT16657DLR uses a 56-pin Shrink Small-Outline Package (SSOP-DL) with 0.65 mm pitch and 300-mil body width. Pin 1 is located in Quadrant Q1 per tape-and-reel orientation; package includes 12 dedicated GND pins and 8 VCC pins distributed to minimize ground bounce and supply noise.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit parity-aware transceiver applications.

Compared with 74ACT16657DLR, the 74ACT16245DLR removes parity logic to reduce cost and complexity in non-critical paths, while SN74LVTH16657DGGR trades 5-V robustness and parity for speed and efficiency in modern low-voltage architectures - neither replicates the hardware-assisted error detection capability central to the 74ACT16657DLR's role.

Availability

74ACT16657DLR is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory expansion subsystems, and legacy bus bridging applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for 74ACT16657DLR 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 founded in 1930, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The 74ACT16657DLR belongs to TI's Widebus™ family of high-speed bus interface ICs, designed specifically for noise-resilient, high-density parallel data transfer in industrial control and computing infrastructure.

FAQ

What is the operating voltage range for the 74ACT16657DLR?

The 74ACT16657DLR operates over a supply voltage range of 4.5 V to 5.5 V. This range ensures compatibility with standard 5-V TTL and CMOS systems while accommodating typical rail tolerances in industrial power supplies. Operation outside this range may cause functional failure or permanent damage, as specified in the absolute maximum ratings.

How does the parity checking function work in the 74ACT16657DLR?

In receive mode, the 74ACT16657DLR evaluates the number of high bits on the B-port bus plus the 1PARITY or 2PARITY input to determine if the configured odd/even parity is satisfied. If mismatched, the corresponding 1ERR or 2ERR output goes low. This hardware-level validation occurs independently per section and requires no software intervention.

Is the 74ACT16657DLR pin-compatible with other ACT-series transceivers?

The 74ACT16657DLR uses a unique 56-pin SSOP-DL package with a flow-through pinout specific to its dual-parity transceiver architecture. It is not pin-compatible with standard octal transceivers like the 74ACT245 or 74ACT16245, which lack parity I/O and ERR signals and use different pin allocations for control functions.

What is the maximum data rate supported by the 74ACT16657DLR?

The 74ACT16657DLR supports reliable data transfer up to approximately 50 MHz in point-to-point configurations, based on its worst-case propagation delay of 14.7 ns and setup/hold timing margins. Actual achievable rate depends on PCB layout, load capacitance, and termination - TI recommends limiting trace lengths to <10 cm and using series termination for optimal signal integrity.

Does the 74ACT16657DLR require external pull-up resistors on control inputs?

No, the 74ACT16657DLR does not require external pull-ups on control inputs such as 1OE, 2OE, 1T/R, or 1ODD/EVEN. Its inputs have TTL-compatible thresholds and internal biasing sufficient for clean logic transitions. However, TI recommends tying unused inputs directly to VCC or GND to prevent floating states that could increase ICC or cause erratic behavior.