Texas Instruments SN74ALVCH374DWR

Overview

SN74ALVCH374DWR from Texas Instruments is an octal positive-edge-triggered D-type flip-flop with 3-state outputs, designed for 1.65 V to 3.6 V operation. It features ±24-mA output drive at 3.3 V, 3.6 ns max propagation delay, bus-hold inputs eliminating external resistors, and operates across –40°C to 85°C. It serves as a buffer register or bidirectional bus driver in low-voltage digital systems.

For engineers reviewing the SN74ALVCH374DWR datasheet, SN74ALVCH374DWR pinout, SN74ALVCH374DWR application, or SN74ALVCH374DWR equivalent, key selection criteria include its 20-pin TSSOP package, 3-state output control via OE, edge-triggered data latching on CLK rising edge, and compatibility with mixed-voltage I/O interfaces in industrial and embedded control logic.

Technical Context

This device implements eight independent D-type latches synchronized to the rising edge of CLK, with each Q output reflecting the corresponding D input state after clock transition. Internal bus-hold circuitry actively maintains valid logic levels on unused D inputs without external biasing.

The buffered OE input controls all eight outputs simultaneously, placing them in high-impedance (Z) state without affecting internal latch operation-enabling concurrent data retention or update while outputs are disabled. Output drive strength scales with VCC, delivering ±24 mA at 3.3 V and maintaining rail-to-rail VOH/VOL performance across the full 1.65–3.6 V supply range.

Key Specifications

Pinout & Package

SN74ALVCH374DWR is housed in a 20-pin TSSOP (PW) package, 6.5 mm × 4.4 mm footprint, 1.2 mm max height, with 0.65 mm lead pitch and exposed pad not present. Pin 1 is located at top-left corner with index area marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal D-type flip-flop with 3-state output applications.

Compared with SN74ALVCH374DWR, SN74LVC374APW offers identical pinout but reduced flexibility in mixed-voltage or unterminated systems, while 74AVC374PW trades bus-hold robustness for marginal speed gain-making SN74ALVCH374DWR optimal for industrial I/O where input stability and supply tolerance are critical.

Availability

SN74ALVCH374DWR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, low-voltage memory interface buffering, and embedded display data latching requiring stable component supply and long-term manufacturability.

Supply support for SN74ALVCH374DWR 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 SN74ALVCH374DWR belongs to TI's ALVC/ALVCH advanced low-voltage CMOS logic family, engineered for low-noise, high-speed, mixed-supply digital interfacing in space-constrained industrial and communications equipment.

FAQ

What is the recommended power-up sequence for SN74ALVCH374DWR to ensure predictable output states?

TI recommends tying OE to VCC through a pullup resistor (minimum value determined by driver sink capability) during power-up and power-down to guarantee outputs enter high-impedance state before internal logic stabilizes. This prevents bus contention. The SN74ALVCH374DWR does not require specific VCC ramp rate or sequencing with other rails, as its operating range (1.65–3.6 V) accommodates standard linear or switching regulator startup profiles. Always verify OE voltage exceeds VIH(min) before CLK activation.

Does SN74ALVCH374DWR support hot insertion or live bus swapping?

SN74ALVCH374DWR is not rated for hot insertion per JEDEC standards. Its absolute maximum ratings specify VI and VO limits of –0.5 V to VCC + 0.5 V, and it lacks powered-off protection circuitry. While the 3-state outputs and bus-hold inputs improve robustness during partial power conditions, TI documentation does not validate safe operation during live insertion into an energized bus. For such applications, dedicated hot-swap buffers or isolation logic should be used upstream of SN74ALVCH374DWR.

How does the bus-hold circuitry in SN74ALVCH374DWR interact with externally applied pullup resistors?

Texas Instruments explicitly advises against using external pullup or pulldown resistors with SN74ALVCH374DWR's bus-hold inputs, as they conflict electrically and may cause excessive current draw or metastability. The bus-hold circuit actively maintains the last-valid logic state with ~100 µA hysteresis current-sufficient to override noise without external bias. Adding resistors defeats this function and risks violating II(hold) specifications. If stronger hold strength is needed, select a variant with higher bus-hold current or use a dedicated bus-hold IC.

Can SN74ALVCH374DWR operate reliably at 1.65 V supply while driving 50-pF loads at 100 MHz?

Yes-SN74ALVCH374DWR is fully characterized down to 1.65 V. At that voltage, its fmax is 100 MHz (per timing table), and tpd is 6.4 ns (VCC = 1.8 V) - extrapolating conservatively, 1.65 V operation meets 100 MHz timing with margin when driving ≤50-pF loads. Output drive remains functional (IOL/IOH ≥ ±4 mA), though VOL/VOH margins shrink slightly. Ensure CL ≤ 50 pF and maintain clean power delivery with local 100-nF decoupling near VCC/GND pins to sustain signal integrity.

Is SN74ALVCH374DWR pin-compatible with older 74-series variants like SN74ALS374 or SN74AS374?

No-SN74ALVCH374DWR uses a 20-pin TSSOP (PW) package with standardized pinout per TI's ALVCH family, whereas SN74ALS374 and SN74AS374 are typically offered in 20-pin SOIC (DW) or PDIP (N) packages with identical pin numbering but incompatible electrical characteristics. While pin assignments (e.g., CLK on pin 20, OE on pin 1) match across these families, the SN74ALVCH374DWR is not a drop-in replacement due to differences in supply range (ALS/AS require 5 V), drive strength, and timing. Migration requires schematic and layout review.