Texas Instruments SN74ALVCH16721DGGR

Overview

SN74ALVCH16721 from Texas Instruments is a 3.3-V, 20-bit edge-triggered D-type flip-flop with 3-state outputs, bus-hold inputs, and clock-enable control. It operates from 1.65 V to 3.6 V, supports up to 150 MHz clock frequency, and features ±24 mA output drive at 3 V. It is used in high-speed data latching and bus interface applications within industrial and communications systems.

For engineers reviewing the SN74ALVCH16721 datasheet, SN74ALVCH16721 pinout, SN74ALVCH16721 application, or SN74ALVCH16721 equivalent, key selection criteria include its 56-pin TSSOP (DGG) package, qualified clock storage architecture, OE-controlled 3-state outputs, and bus-hold functionality eliminating external biasing components.

Technical Context

The SN74ALVCH16721 implements 20 independent D-type flip-flops, each triggered on the positive edge of CLK when CLKEN is low. Its qualified clock storage ensures data capture only under enabled conditions, preventing spurious updates. Internal bus-hold circuitry maintains valid logic levels on unused data inputs without external resistors.

Output-enable (OE) is buffered and asynchronous - it places all 20 Q outputs simultaneously into high-impedance without affecting internal flip-flop state retention or clocked operation. The device uses TI's EPIC™ submicron CMOS process, delivering latch-up immunity >250 mA and ESD protection >2000 V (HBM).

Key Specifications

Pinout & Package

TSSOP-56 (DGG) package, 13.9 mm × 6.1 mm × 1.2 mm max height, lead-free NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVCH16721, SN74ALVCH162244DGGR omits clocked storage entirely, while SN74LVC16374DGGR provides identical latching and 3-state behavior but mandates external biasing - making SN74ALVCH16721 the only option combining registration, bus-hold, and industrial temperature range in a single 56-pin TSSOP device.

Availability

SN74ALVCH16721 is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, memory interface latching, and communications backplane buffering 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 decades of experience in high-reliability industrial and automotive IC design.

The SN74ALVCH16721 belongs to TI's Widebus™ family of advanced logic devices, engineered specifically for high-speed, low-voltage parallel data path applications in industrial automation and infrastructure equipment.

FAQ

What is the recommended power-up sequence for SN74ALVCH16721?

TI recommends tying OE to VCC through a pullup resistor during power-up or power-down to ensure outputs remain in high-impedance state until supply stabilizes. This prevents bus contention. The SN74ALVCH16721 does not require specific sequencing between VCC and control inputs, but OE must be held high before CLK or data signals become active. For robust startup, use a 10-kΩ pullup to VCC on OE.

Does SN74ALVCH16721 support mixed-voltage operation between data inputs and VCC?

Yes - the SN74ALVCH16721 accepts input voltages from 0 V to VCC (max 3.6 V), and VIH/VIL thresholds scale with VCC. At VCC = 2.5 V, VIH is 1.7 V; at VCC = 3.3 V, VIH is 2.0 V. This allows interfacing with 1.8 V or 2.5 V sources when VCC = 3.3 V, provided input voltage stays within absolute max ratings (–0.5 V to VCC + 0.5 V).

Can SN74ALVCH16721 be used without external pullup/pulldown resistors on D inputs?

Yes - the SN74ALVCH16721 integrates active bus-hold circuitry on all 20 D inputs, maintaining valid logic levels on floating or unused pins. This eliminates the need for external resistors, reducing BOM cost and PCB space. Bus-hold current is ±75 µA at VCC = 3 V, sufficient to override typical leakage but not interfere with driven signals.

What is the thermal performance of SN74ALVCH16721 in the DGG package?

The SN74ALVCH16721 in the 56-pin TSSOP (DGG) package has a junction-to-ambient thermal resistance (θJA) of 81°C/W, measured per JESD51. Under typical industrial conditions (TA = 85°C, 20% duty cycle), power dissipation remains below 100 mW. Derating is recommended above 70°C ambient; full-rated operation is guaranteed from –40°C to +85°C.

How does CLKEN differ from standard clock gating in SN74ALVCH16721?

In the SN74ALVCH16721, CLKEN is an asynchronous qualifier that blocks data capture on CLK edges when high - unlike synchronous enable signals, it does not require setup/hold timing relative to CLK. When CLKEN is low, the device behaves as a standard positive-edge D flip-flop. This allows dynamic, cycle-accurate disabling of latching without introducing additional clock domain crossings or metastability risks.