Texas Instruments SN74ALVCH16821DGG

Overview

SN74ALVCH16821DGG from Texas Instruments is a 3.3-V, 20-bit bus-interface D-type flip-flop with 3-state outputs, designed for 1.65-V to 3.6-V V_CC operation. It functions as two independent 10-bit edge-triggered flip-flops or one unified 20-bit register, featuring bus-hold on all data inputs and buffered output-enable control. It is used in high-density memory address/data bus latching and bidirectional bus isolation in industrial control backplanes.

For engineers reviewing the SN74ALVCH16821DGG datasheet, SN74ALVCH16821DGG pinout, SN74ALVCH16821DGG application, or SN74ALVCH16821DGG equivalent, key selection criteria include its 3.3-V compatible I/O, ±24-mA drive strength at 3.0 V, bus-hold circuitry eliminating external resistors, and operation across –40°C to 85°C industrial temperature range.

Technical Context

This device implements dual 10-bit positive-edge-triggered D-type flip-flops with independent clock (1CLK/2CLK) and output-enable (1OE/2OE) controls. Each 10-bit section drives true Q outputs synchronized to its respective clock edge, while OE asserts high-impedance state without affecting internal latch retention or data capture timing.

It uses TI's EPIC™ submicron CMOS process, delivering ESD protection >2000 V (HBM), latch-up immunity >250 mA (JESD 17), and bus-hold circuitry that maintains valid logic levels on floating inputs-enabling robust operation in unterminated or hot-swap bus environments.

Key Specifications

Pinout & Package

SN74ALVCH16821DGG is housed in a 56-pin Thin Shrink Small-Outline (DGG) package per JEDEC MO-153, measuring 13.9 mm × 7.9 mm × 1.2 mm (max height), with 0.5-mm lead pitch and gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVCH16821DGG, SN74ALVCH162244DGG provides no storage and cannot synchronize data, while SN74LVC16373ADGGR offers functionally similar latching but requires level-sensitive enable timing and board-level rework due to incompatible pin mapping.

Availability

SN74ALVCH16821DGG is available at Aetrix Electronics and suitable for industrial control systems, programmable logic controllers, and FPGA-based embedded instrumentation requiring stable component supply and long-term manufacturability.

Supply support for SN74ALVCH16821DGG 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 for industrial, automotive, and communications markets.

The SN74ALVCH16821DGG belongs to TI's Widebus™ family of advanced bus-interface devices, engineered for high-speed, low-voltage, noise-immune data transfer in dense digital systems.

FAQ

What is the maximum clock frequency supported by the SN74ALVCH16821DGG?

The SN74ALVCH16821DGG supports a maximum clock frequency of 150 MHz across its full operating voltage range (1.65 V to 3.6 V). This specification is validated under recommended conditions with CL = 50 pF and applies to both 10-bit sections independently. Timing parameters such as t_su (4.4 ns min at 1.8 V) and t_pd (4.5 ns max at 3.3 V) ensure reliable operation at this rate in properly terminated systems.

Does the SN74ALVCH16821DGG require external pullup resistors on its data inputs?

No, the SN74ALVCH16821DGG does not require external pullup or pulldown resistors on any of its 20 data inputs. It integrates active bus-hold circuitry on all D inputs, which maintains a valid logic level (±75 µA hold current at 3.0 V) when inputs are floating or unterminated. This eliminates BOM items and layout overhead while improving noise immunity in high-impedance bus environments.

Can the SN74ALVCH16821DGG operate at 1.8 V V_CC?

Yes, the SN74ALVCH16821DGG is fully specified to operate at 1.8 V V_CC, within its 1.65-V to 3.6-V supply range. At 1.8 V, it delivers 150-MHz maximum clock frequency, 3.3-ns minimum clock pulse width, and maintains bus-hold functionality with ±25 µA hold current. All DC and AC specifications-including VIH/VIL thresholds and output drive-are guaranteed across this extended low-voltage range.

How does the output-enable (OE) function interact with internal flip-flop state in the SN74ALVCH16821DGG?

In the SN74ALVCH16821DGG, the OE input affects only the output drivers-not the internal flip-flop storage elements. When OE is asserted (low), outputs enter high-impedance state while retained data remains intact in both 10-bit sections. New data can be clocked in via CLK while outputs are disabled, and previously latched values persist until overwritten-enabling seamless bus arbitration and glitch-free state retention during system reconfiguration.

What package type is used for the SN74ALVCH16821DGG, and what are its key mechanical dimensions?

The SN74ALVCH16821DGG uses a 56-pin Thin Shrink Small-Outline (DGG) package compliant with JEDEC MO-153. Its body measures 13.9 mm × 7.9 mm, with 0.5-mm lead pitch and maximum height of 1.2 mm. The package features gull-wing leads, exposed thermal pad (not electrically connected), and is optimized for automated surface-mount assembly and thermal performance in compact industrial modules.