Texas Instruments SN74ALVCH16820DL

Overview

SN74ALVCH16820DL from Texas Instruments is a 3.3-V, 10-bit edge-triggered D-type flip-flop with dual outputs (Q1/Q2 per bit), 3-state outputs, and integrated bus-hold circuitry on all data inputs. It operates from 1.65 V to 3.6 V, supports up to 150 MHz clock frequency, and features independent output-enable controls (1OE/2OE) for grouped output management. It is used in high-density data buffering and bus interface applications requiring level-shifted, noise-immune latching in compact TSSOP-56 packages.

For engineers reviewing the SN74ALVCH16820DL datasheet, SN74ALVCH16820DL pinout, SN74ALVCH16820DL application, or SN74ALVCH16820DL equivalent, this device serves as a low-voltage, high-speed latch for memory address/data staging, FPGA I/O expansion, and hot-swappable backplane interfaces where input floating immunity and output bus contention control are critical.

Technical Context

This device implements ten independent D-type flip-flops, each triggered on the positive edge of CLK, with true outputs Q1 and Q2 per channel. The dual-output architecture allows simultaneous access to latched data without additional fanout logic. Bus-hold circuitry actively maintains valid logic states on undriven D inputs, eliminating external pullup/pulldown resistors.

Two buffered output-enable inputs (1OE and 2OE) control two distinct groups of five outputs each, enabling selective 3-state drive on shared buses. OE does not affect internal flip-flop operation-data can be latched or retained while outputs remain high-impedance. Power-up/down sequencing is supported via OE tied to VCC through an external pullup resistor.

Key Specifications

Pinout & Package

SN74ALVCH16820DL is packaged in a 56-pin TSSOP (DL package), 13.9 mm × 6.0 mm × 1.2 mm max height, RoHS-compliant, moisture sensitivity level 1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit dual-output latch applications.

Compared with SN74ALVCH16820DL, SN74ALVCH162244DL omits clocked storage entirely, while SN74LVC16373ADL trades dual outputs and bus-hold for greater bit width and higher drive strength - making SN74ALVCH16820DL uniquely suited for noise-sensitive, space-constrained, dual-path latching.

Availability

SN74ALVCH16820DL is available at Aetrix Electronics and suitable for memory subsystems, FPGA carrier boards, hot-swap backplanes, and industrial PLC I/O modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SN74ALVCH16820DL 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 expertise in high-reliability, industry-standard interface and timing components.

The SN74ALVCH16820DL belongs to TI's Widebus™ family of advanced low-voltage logic devices, engineered specifically for high-speed, low-noise, mixed-voltage digital interfacing in computing, communications, and industrial automation systems.

FAQ

What is the function of the bus-hold circuitry in SN74ALVCH16820DL?

The bus-hold circuitry in SN74ALVCH16820DL actively maintains a valid logic state (high or low) on each D input when left un-driven or floating, eliminating the need for external pullup or pulldown resistors. This feature improves noise immunity, reduces BOM cost, and simplifies PCB layout - especially critical in high-density systems where input traces may be unterminated. SN74ALVCH16820DL's bus-hold current is specified at ±75 µA under typical conditions.

Can SN74ALVCH16820DL operate at 1.8 V, and what performance changes occur?

Yes, SN74ALVCH16820DL is fully specified for operation from 1.65 V to 3.6 V, including 1.8 V. At 1.8 V, maximum clock frequency remains 150 MHz, propagation delay increases slightly to 5.9 ns, and output drive strength reduces to ±4 mA (IOH/IOL). Input thresholds scale proportionally (VIH = 0.65 × VCC), ensuring compatibility with other 1.8-V logic families. SN74ALVCH16820DL maintains full functionality across this range without derating.

How do the dual outputs (Q1 and Q2) differ in SN74ALVCH16820DL?

In SN74ALVCH16820DL, Q1 and Q2 for each bit are electrically identical true outputs - both replicate the same latched D-input value on the rising edge of CLK. They are not complementary or time-shifted; rather, they provide redundant or parallel access points to the same stored data. This enables simultaneous connection to two independent downstream circuits (e.g., one for monitoring, one for processing) without adding fanout buffers or introducing skew.

What is the recommended power-up sequence for SN74ALVCH16820DL to ensure high-impedance outputs?

To guarantee high-impedance outputs during power-up, OE inputs (1OE and 2OE) must be held high (inactive) until VCC reaches a stable operating voltage. TI recommends tying 1OE and 2OE to VCC through a pullup resistor; the minimum resistance is determined by the current-sinking capability of the driving source - typically ≥10 kΩ suffices for most microcontroller GPIOs. This prevents unintended output activation that could cause bus contention. SN74ALVCH16820DL's internal design relies on this external bias for safe power sequencing.

Is SN74ALVCH16820DL pin-compatible with any other TI 10-bit flip-flop variants?

No - SN74ALVCH16820DL has a unique 56-pin TSSOP (DL) pinout optimized for its dual-output, dual-OE architecture and distributed power/ground layout. While other Widebus™ devices like SN74ALVCH162244DL share the same package footprint, their signal assignments, pin counts, and internal functions differ significantly. SN74ALVCH16820DL's pin mapping - including CLK, 10 D inputs, 20 Q outputs, and separate 1OE/2OE - is specific to this part and not interchangeable with other TI 10-bit latches or buffers.