Diodes Incorporated PI74ALVCH16823A

Overview

PI74ALVCH16823A from Pericom Semiconductor is an 18-bit bus-interface D-type flip-flop with independent 3-state outputs, designed for 2.3V–3.6V V_CC operation. It supports dual 9-bit or single 18-bit register configurations, features active-low Clock Enable (CLKEN) and Clear (CLR), buffered Output Enable (OE), and integrated bus-hold circuitry on all data inputs. It is used in high-capacitance bus buffering, I/O port expansion, and bidirectional data path control in industrial embedded systems.

For engineers reviewing the PI74ALVCH16823A datasheet, PI74ALVCH16823A pinout, PI74ALVCH16823A application, or PI74ALVCH16823A equivalent, key selection criteria include 3-state drive strength (±24 mA), bus-hold retention during tri-state, low ground bounce (<0.8 V), and TSSOP-56 packaging compatibility with high-density PCB layouts.

Technical Context

This device implements two independent 9-bit edge-triggered D-type flip-flop banks, each with synchronous clock enable and asynchronous clear. The CLKEN input disables clock propagation to internal latches without affecting output state, enabling transparent data hold during clock gating.

All 18 Q outputs are individually controlled by a shared OE input, placing them simultaneously in high-impedance mode without disrupting internal register contents. Bus-hold circuitry actively maintains last-valid logic level on unused D inputs, eliminating external pullup resistors in floating-bus scenarios.

Key Specifications

Pinout & Package

PI74ALVCH16823A is housed in a 56-pin plastic TSSOP (240 mil wide), JEDEC MO-153 compliant, with 0.5 mm pitch and exposed thermal pad. Package dimensions: 14.0 mm × 6.1 mm × 1.2 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus-interface flip-flop applications.

Compared with SN74ALVCH16823 and 74LVC16374, PI74ALVCH16823A uniquely combines bus-hold, industrial temperature rating, and guaranteed 2.3 V minimum V_CC-making it optimal for ruggedized industrial I/O and legacy bus interfacing where signal integrity and component count reduction are critical.

Availability

PI74ALVCH16823A is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, memory interface buffering, and communications backplane interface requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature extremes.

Supply support for PI74ALVCH16823A 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 (now part of Diodes Incorporated) specialized in high-speed interface and signal-integrity solutions for computing, communications, and industrial markets before its 2016 acquisition.

PI74ALVCH16823A belongs to Pericom's ALVCH advanced low-voltage CMOS logic family, engineered for low-noise, high-drive parallel bus interfacing in industrial and telecom infrastructure where signal fidelity and power efficiency are co-prioritized.

FAQ

What is the purpose of the CLKEN input on PI74ALVCH16823A?

The CLKEN (Clock Enable) input is an active-low control that gates the clock signal to the internal D-type latches. When CLKEN is LOW, the device operates normally-capturing D-input data on the rising edge of CLK. When CLKEN is HIGH, clock propagation is blocked, freezing the current Q-output state regardless of further CLK transitions. This enables precise timing control without requiring external clock gating logic or risking metastability.

Does PI74ALVCH16823A require external pullup resistors on its data inputs?

No. PI74ALVCH16823A integrates active bus-hold circuitry on all 18 D inputs, which automatically maintains the last valid logic level when inputs float. This eliminates the need for external pullup or pulldown resistors in applications with unterminated or hot-swappable bus segments, reducing component count and improving reliability in industrial I/O designs.

Can PI74ALVCH16823A operate reliably at 2.5 V V_CC?

Yes. PI74ALVCH16823A is fully specified for operation from 2.3 V to 3.6 V, including 2.5 V. All key parameters-including propagation delay (max 5.4 ns), output drive (±24 mA), and bus-hold current (±4 mA)-are guaranteed across this full range at –40°C to +85°C. This makes it compatible with mixed-voltage systems integrating 2.5 V FPGAs or ASICs.

How does the OE (Output Enable) function interact with internal register state?

The OE input controls only the output drivers-not the internal latches. When OE is asserted (LOW), the 18 Q outputs enter high-impedance mode, electrically isolating the device from the bus. Internally, the flip-flops continue to retain their stored data and respond to CLK and D inputs normally. New data can be loaded or existing data held during tri-state operation, enabling non-intrusive bus arbitration and multi-master sharing.