Diodes Incorporated PI74ALVCH16646A

Overview

PI74ALVCH16646A from Pericom Semiconductor is a 16-bit bus transceiver and register with 3-STATE outputs, designed for low-voltage bidirectional data transfer and storage in high-density memory and bus interface systems. It operates from 2.3V to 3.6V, features bus-hold circuitry eliminating external pullups, supports dual 8-bit or single 16-bit configuration, and delivers typical VOLP < 0.8V at VCC = 3.3V - critical for noise-sensitive industrial backplane applications.

For engineers reviewing the PI74ALVCH16646A datasheet, PI74ALVCH16646A pinout, PI74ALVCH16646A application, or PI74ALVCH16646A equivalent, key selection factors include its dual-clock (CLKAB/CLKBA) register control, independent DIR/OE/SAB/SBA logic for real-time vs. stored data routing, and TSSOP-56 package compatibility with high-pin-count PCB layouts requiring signal integrity and thermal reliability.

Technical Context

The PI74ALVCH16646A implements two independent 8-bit register-transceiver blocks, each with separate clock (CLKAB/CLKBA), direction (DIR), output enable (OE), and select (SAB/SBA) controls. Its architecture enables four distinct bus-management modes: real-time A→B or B→A transfer, isolation with concurrent A/B data storage, and multiplexed output of stored or live data - all without decoding glitches during mode transitions.

It uses advanced 0.5 µm CMOS technology to achieve sub-10 ns propagation delays (e.g., tPD = 5.4 ns max from CLKAB to B bus at VCC = 3.3V), while hysteresis on all inputs ensures robust noise immunity across –40°C to +85°C ambient operation. Bus-hold circuitry actively maintains valid logic levels on floating inputs, removing dependency on external biasing components.

Key Specifications

Pinout & Package

PI74ALVCH16646A is housed in a 56-pin plastic TSSOP (240 mil wide), optimized for automated assembly and thermal dissipation in space-constrained industrial modules. The package features exposed thermal pad (not electrically connected) and gull-wing leads compatible with IPC-7351B footprint standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVCH16646A and 74LVC16646ADGG, PI74ALVCH16646A uniquely integrates bus-hold and supports true 2.3V operation - reducing component count and enabling robust low-voltage industrial designs without design compromises.

Availability

PI74ALVCH16646A is available at Aetrix Electronics and suitable for industrial PLC backplanes, memory expansion modules, FPGA configuration bridges, and legacy ISA bus adapters requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for PI74ALVCH16646A 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

Pericom Semiconductor (acquired by Diodes Incorporated in 2016) specialized in high-speed interface, timing, and logic solutions for communications, computing, and industrial markets before integration into Diodes' broad analog portfolio.

The PI74ALVCH series targets low-voltage, high-density bus interface applications - specifically engineered to replace older 5V TTL logic in space-constrained, noise-sensitive systems while maintaining pin compatibility and improving power efficiency.

FAQ

What is the purpose of the SAB and SBA inputs on PI74ALVCH16646A?

The SAB and SBA inputs control multiplexing between real-time (transparent) and stored data outputs for each 8-bit channel. When SAB is LOW, real-time A-bus data passes to B-bus; when HIGH, previously latched A-data is output - all without glitch due to internal synchronized switching logic verified in the truth table and timing diagrams.

Can PI74ALVCH16646A operate reliably at 2.3V VCC?

Yes - the device is fully specified from 2.3V to 3.6V, with DC and AC parameters (including tPD ≤ 9.3 ns and VIH/VIL thresholds) guaranteed across this range. Electrical characteristics tables explicitly list test conditions at VCC = 2.3V, confirming functional operation at the lower limit without derating.

How does the bus-hold feature eliminate external pullup resistors?

Internal weak-latch circuitry (±4 mA hold current) actively drives floating inputs to their last valid logic state. This is confirmed in the DC Electrical Characteristics table under "IIN(HOLD)" and replaces discrete 10 kΩ pullups - reducing BOM cost, PCB area, and potential signal integrity issues from resistor parasitics.

Why are there seven GND pins and four VCC pins on the TSSOP-56 package?

The distributed power/ground pin arrangement minimizes simultaneous switching noise and voltage droop across the 16-bit data path. Layout analysis in the datasheet shows this configuration reduces ground bounce (VOLP) to <0.8 V - a measured specification validated at VCC = 3.3V, TA = 25°C, and confirmed in the Maximum Ratings table.