Texas Instruments SN74ALVCH16973DL

Overview

SN74ALVCH16973DL from Texas Instruments is an 8-bit bus transceiver with transparent D-type latch and four independent noninverting buffers, operating from 1.65 V to 3.6 V. It supports asynchronous bidirectional A↔B data transfer, latched Q-bus address buffering, and isolated Y-buffer outputs. Used in demultiplexed address/data bus architectures for microprocessor-based systems.

For engineers reviewing the SN74ALVCH16973DL datasheet, SN74ALVCH16973DL pinout, SN74ALVCH16973DL application, or SN74ALVCH16973DL equivalent, key selection criteria include latch-enable timing (t_su/t_h = 0.9 ns), bus-hold input stabilization, dual-output-enable isolation (TOE/LOE), and DL-package thermal impedance (63°C/W).

Technical Context

The SN74ALVCH16973DL integrates three functional blocks: an 8-bit bidirectional transceiver (A/B ports) controlled by DIR and TOE, a transparent 8-bit D-latch (A→Q path) enabled by LE and output-controlled by LOE, and four independent D→Y buffers unaffected by control signals. All I/Os feature active bus-hold circuitry eliminating external bias resistors.

Logic operation follows strict level-sensitive timing: LE high enables transparent Q-output tracking of A inputs; LE low latches current A values. TOE high isolates A/B buses; LOE high places Q outputs in high-impedance state without affecting internal latch state. Bus-hold sustaining currents (IBHL/IBHH) are specified per supply voltage (e.g., ±75 µA at 3 V).

Key Specifications

Pinout & Package

SN74ALVCH16973DL uses a 48-pin SSOP (Shrink Small Outline Package) with 0.5 mm pitch, 12.4–12.6 mm length, 6.0–6.2 mm width, and 1.2 mm max height. Pin 1 identifier located at top-left corner with beveled edge marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus transceiver and latch applications.

Compared with SN74ALVCH16973DL, SN74ALVCH162245DGGR offers simpler transceiver-only operation but adds design complexity for latching, while SN74ALVCH16373DL provides identical latch timing and footprint but forces external bus isolation-neither matches the integrated functionality of SN74ALVCH16973DL in address/data demultiplexing.

Availability

SN74ALVCH16973DL is available at Aetrix Electronics and suitable for microprocessor address latching, memory bus isolation, configurable logic subsystems, and legacy bus signal conditioning requiring stable component supply and long-term industrial availability.

Supply support for SN74ALVCH16973DL 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 interface and bus technologies.

The SN74ALVCH16973DL belongs to TI's Widebus™ family, designed specifically for high-density, low-voltage bus interface applications requiring combined transceiver, latch, and buffer functionality in compact packages.

FAQ

What is the recommended power-up sequence for SN74ALVCH16973DL to ensure high-impedance outputs?

TI recommends tying LOE and TOE to VCC through pullup resistors during power-up/down to guarantee high-impedance states. Minimum resistor values depend on driver sink capability; typical 10 kΩ resistors suffice for most 3.3 V systems. This prevents bus contention before control logic initializes. The SN74ALVCH16973DL internal circuitry does not auto-tri-state on power ramp, making external pullups essential for robust startup behavior.

Does SN74ALVCH16973DL support hot-insertion or live insertion into a powered backplane?

No, SN74ALVCH16973DL is not rated for hot-insertion. Its absolute maximum ratings specify VI ≤ VCC + 0.5 V on I/O ports, and exceeding this-even briefly during plug-in-can damage bus-hold circuitry. TI documentation requires all control inputs (LE, DIR, TOE, LOE) to be held at VCC or GND before power application. For live-insertion applications, consider purpose-built hot-swap buffers instead of SN74ALVCH16973DL.

How does bus-hold functionality behave when SN74ALVCH16973DL operates at 1.65 V VCC?

At 1.65 V, SN74ALVCH16973DL bus-hold sustains ±25 µA (IBHL/IBHH) at VILmax/VILmin thresholds, sufficient to hold logic states against typical PCB leakage (<1 µA). Hold strength scales linearly with VCC, so 1.65 V operation retains reliable undriven input stabilization-verified in TI's SCES435B characterization. No external components are needed, and bus-hold remains active regardless of TOE/LOE/DIR/LE states.

Can SN74ALVCH16973DL's Q outputs drive standard TTL loads?

Yes, SN74ALVCH16973DL Q outputs meet TTL voltage thresholds: VOH ≥ 2.0 V and VOL ≤ 0.8 V at VCC = 3.0–3.6 V with IOL = 24 mA, satisfying TTL input requirements (VIH ≥ 2.0 V, VIL ≤ 0.8 V). At lower VCC (1.65–1.95 V), VOH drops to VCC − 0.2 V, which may not meet legacy TTL specs-use only with LVTTL or ALVTTL receivers in those cases. The SN74ALVCH16973DL datasheet confirms compatibility with 3.3 V LVTTL and 2.5 V/1.8 V CMOS interfaces.

What is the maximum clock frequency supported by SN74ALVCH16973DL's latch function?

SN74ALVCH16973DL has no internal clock; its latch is level-sensitive and transparent while LE is high. Maximum effective "latch rate" depends on external LE pulse width (tw ≥ 2 ns) and data setup/hold (tsu/th ≥ 0.9 ns). With clean 3.3 V LE edges, it reliably captures data at >200 MHz LE toggle rates-confirmed by TI's timing diagrams showing tpd = 2.8 ns and minimal skew. System-level speed is limited by PCB routing, not SN74ALVCH16973DL internal architecture.