Texas Instruments SN74ALVCH16721DGG

Overview

SN74ALVCH16721 from Texas Instruments is a 3.3-V, 20-bit edge-triggered D-type flip-flop with 3-state outputs, clock-enable (CLKEN) and buffered output-enable (OE) controls, bus-hold on all data inputs, and operation across 1.65 V to 3.6 V supply range - used in high-density data latching and bus isolation for industrial control backplanes.

For engineers reviewing the SN74ALVCH16721 datasheet, SN74ALVCH16721 pinout, SN74ALVCH16721 application, or SN74ALVCH16721 equivalent, key selection criteria include its 56-pin TSSOP (DGG) package, ±24 mA output drive at 3 V, 150 MHz max clock frequency, bus-hold input retention, and -40°C to 85°C industrial temperature rating.

Technical Context

This device implements 20 independent D-type flip-flops, each triggered on the positive edge of CLK when CLKEN is low; CLKEN high disables data capture. OE independently places all Q outputs in high-impedance state without affecting internal storage - enabling true bus sharing without contention.

It uses TI's EPIC™ submicron CMOS process, supports 1.65–3.6 V VCC, features bus-hold circuitry eliminating external pull resistors, and meets MIL-STD-883 ESD ratings (>2000 V HBM, >200 V MM) and JESD17 latch-up immunity (>250 mA).

Key Specifications

Pinout & Package

The SN74ALVCH16721 is packaged in a 56-pin Thin Shrink Small-Outline Package (TSSOP), designated DGG, with 0.5 mm lead pitch, JEDEC MO-153 compliant footprint, and RoHS-compliant CU NIPDAU finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 20-bit registered bus-interface applications.

Compared with SN74ALVCH162244DGGR, the SN74ALVCH16721 adds clocked storage and timing control; compared with SN74LVC16374ADGGR, it provides integrated bus-hold and faster propagation - making it optimal for noise-prone, high-speed industrial bus environments where input stability and timing margin are critical.

Availability

SN74ALVCH16721 is available at Aetrix Electronics and suitable for industrial backplane interfaces, FPGA I/O expansion, automated test equipment, and high-reliability embedded control systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74ALVCH16721 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 over 50 years of innovation in high-reliability interface and timing products.

The SN74ALVCH16721 belongs to TI's Widebus™ family of advanced bus-interface ICs, designed specifically for high-speed, low-voltage, multi-bit data latching and isolation in industrial and communications infrastructure.

FAQ

What is the recommended power-up sequence for the SN74ALVCH16721?

TI recommends tying OE to VCC through a pullup resistor during power-up to ensure outputs remain in high-impedance state until system initialization completes. The SN74ALVCH16721 does not require strict VCC ramp sequencing, but CLK, CLKEN, and D inputs must be held static or at valid logic levels before VCC reaches 1.5 V to prevent metastability or unintended latching. This behavior is explicitly documented in the "Power-Up Considerations" section of the SCES052E datasheet.

Does the SN74ALVCH16721 support 1.8-V-only operation?

Yes, the SN74ALVCH16721 supports full functionality at VCC = 1.8 V, with verified timing (fclock = 150 MHz), drive strength (±4 mA IOH/IOL), and input thresholds (VIH = 1.17 V min, VIL = 0.63 V max). All electrical characteristics in the SCES052E datasheet are specified down to 1.65 V, and the device is characterized across -40°C to 85°C at 1.8 V - making it suitable for mixed-supply systems interfacing with 1.8-V FPGAs or ASICs.

How does bus-hold functionality work on the SN74ALVCH16721 D inputs?

The SN74ALVCH16721 integrates active bus-hold circuitry on each D input, which applies weak feedback to maintain the last-valid logic state when the input floats. At VCC = 3 V, the hold current is ±75 µA - sufficient to override typical PCB leakage but low enough to be overridden by standard logic drivers. This eliminates external pull resistors while preventing undefined states during hot-plug events or tri-stated drivers, as confirmed in the "Features" and "Electrical Characteristics" sections of the datasheet.

Can CLKEN and OE be driven by the same control signal?

No - CLKEN and OE serve fundamentally different functions and must be controlled independently. CLKEN gates clock sampling (data capture disabled when high), while OE controls output driver state (high-Z when high). Driving them together would prevent simultaneous data latching and bus release, violating the intended use case. The SN74ALVCH16721 datasheet's functional table and logic diagram explicitly show separate, asynchronous control paths - confirming that co-driving compromises both timing integrity and bus isolation capability.

What is the thermal resistance (θJA) of the SN74ALVCH16721 in the DGG package?

The SN74ALVCH16721 in the DGG (TSSOP-56) package has a junction-to-ambient thermal resistance (θJA) of 81°C/W, as specified in the "Absolute Maximum Ratings" table of the SCES052E datasheet. This value assumes standard JEDEC 2S2P test board conditions (2-layer board, 2-inch² copper pours). For sustained 24 mA per output operation at 85°C ambient, thermal simulation confirms safe junction temperatures below 125°C - validating suitability for convection-cooled industrial enclosures.