Texas Instruments SN74ALVCH16721DGVR

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 independent clock-enable (CLKEN) and output-enable (OE) controls. It operates across 1.65 V to 3.6 V supply range, supports 150 MHz clock frequency at 3.3 V, and features ±24 mA output drive capability. It is used in high-density data-path buffering and registered bus interface applications in telecom backplanes and industrial control systems.

For engineers reviewing the SN74ALVCH16721 datasheet, SN74ALVCH16721 pinout, SN74ALVCH16721 application, or SN74ALVCH16721 equivalent, key selection criteria include its 56-pin TSSOP (DGG) package, true-edge-triggered storage with CLKEN qualification, bus-hold input retention, and guaranteed -40°C to +85°C operation without external biasing components.

Technical Context

This device implements 20 independent D-type flip-flops sharing common CLK, CLKEN, and OE signals. Each flip-flop stores data on the rising edge of CLK only when CLKEN is low; otherwise, the register holds its previous state. The 3-state outputs are controlled solely by OE - independent of clock activity - enabling concurrent data latching and bus isolation.

Bus-hold circuitry actively maintains valid logic levels on all 20 data inputs (D1–D20) when floating, eliminating need for external pullup/pulldown resistors. Input thresholds scale with VCC (VIH = 0.65×VCC min at 1.65 V; VIL = 0.35×VCC max), supporting mixed-voltage system interfacing within its 1.65–3.6 V operating window.

Key Specifications

Pinout & Package

The SN74ALVCH16721 is housed in a 56-pin Thin Shrink Small-Outline Package (TSSOP, DGG), 13.9 mm × 6.1 mm × 1.2 mm, with 0.5-mm lead pitch and exposed thermal pad (not electrically connected). Pin 1 is marked via corner chamfer and located in Quadrant 1 per JEDEC MO-153.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVCH162244DGGR and SN74LVC16374DGVR, the SN74ALVCH16721 uniquely combines true edge-triggered 20-bit storage, integrated bus-hold, and 3-state output control in a single 56-pin TSSOP - making it irreplaceable for applications requiring simultaneous data registration, bus isolation, and floating-input robustness without added passives.

Availability

SN74ALVCH16721 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLC I/O expansion, and automotive ADAS sensor hub designs requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +85°C performance.

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 communications ICs.

The SN74ALVCH16721 belongs to TI's Widebus™ family of high-speed, low-voltage logic devices engineered for dense parallel data-path applications in telecom, computing, and automation systems.

FAQ

What is the recommended power-up sequence for the 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. No specific VCC ramp rate or sequencing is required between supply rails since SN74ALVCH16721 has a single VCC domain. The SN74ALVCH16721 datasheet specifies that OE must be held high or low via solid connection - not left floating - to prevent bus contention during transients.

Does the SN74ALVCH16721 support mixed-voltage operation between inputs and outputs?

Yes - the SN74ALVCH16721 supports 1.65 V to 3.6 V VCC and features voltage-tolerant inputs: VIH and VIL thresholds scale with VCC (e.g., VIH = 0.65×VCC min at 1.65 V). Outputs swing rail-to-rail (0 V to VCC), so interfacing with lower-voltage logic requires external level-shifting or series termination. The SN74ALVCH16721 does not provide built-in level translation.

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

Each of the 20 D inputs incorporates an active feedback circuit that detects floating conditions and reinforces the last-valid logic state with ~100 µA hold current. This eliminates need for external pullup/pulldown resistors on unused or intermittently driven lines. Bus-hold is always enabled - no configuration required - and operates across full VCC and temperature range. The SN74ALVCH16721 bus-hold strength exceeds 25 µA at 1.65 V, ensuring reliable state retention even under noise.

Can CLKEN and OE be tied together for simplified control of the SN74ALVCH16721?

No - CLKEN and OE serve fundamentally different functions and must be controlled independently. CLKEN qualifies the clock edge (low = sample, high = hold), while OE controls output driver state (low = active, high = high-Z). Tying them together would prevent simultaneous data latching and bus isolation - e.g., new data could not be captured while outputs remain tri-stated. The SN74ALVCH16721 design intentionally separates these controls to enable advanced timing architectures like glitch-free bus arbitration.

What is the thermal resistance (θJA) of the 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 JESD 51 standards on a 1-inch², 2-layer board with 2 oz copper. This value assumes standard JEDEC test board layout - actual θJA in end equipment depends on PCB copper area, airflow, and nearby heat sources. The SN74ALVCH16721 maximum junction temperature remains 150°C, limiting continuous power dissipation to ~350 mW under typical ambient conditions.