Texas Instruments SN74HCT374NS

Overview

SN74HCT374NS from Texas Instruments is an octal D-type positive-edge-triggered flip-flop with 3-state non-inverting outputs, 13 ns typical propagation delay (VCC = 5 V), 48 MHz maximum clock frequency, and TTL-compatible input thresholds. It serves as a bus-oriented 8-bit register in digital control systems requiring synchronized data latching and tri-state bus driving.

For engineers reviewing the SN74HCT374NS datasheet, SN74HCT374NS pinout, SN74HCT374NS application, or SN74HCT374NS equivalent, key selection criteria include edge-triggered register timing, 3-state output enable behavior, TTL-level input compatibility, and SO-20 package constraints for PCB layout and thermal management.

Technical Context

The SN74HCT374NS implements eight independent D-type latches triggered on the LOW-to-HIGH clock transition, with set-up time of 12 ns and hold time of 5 ns at VCC = 4.5 V. Its 3-state output buffer is controlled by a single active-low OE input, decoupled from register operation.

It belongs to the 74HCT logic family, ensuring TTL-compatible input voltage thresholds (VIH = 2.0 V min, VIL = 0.8 V max) while delivering CMOS-level output drive strength and low static current. The device operates across −40 °C to +85 °C with supply range 4.5 V to 5.5 V.

Key Specifications

Pinout & Package

SN74HCT374NS is housed in a 20-pin plastic small-outline (SO-20) package with 0.600-inch body width and 0.050-inch lead pitch, compliant with JEDEC MS-013AC and Philips "Package Outlines" specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT374NS, 74HCT374D offers identical functionality in a smaller SO-16 package but demands PCB redesign, while SN74ACT374N delivers superior speed and drive at higher cost and power - making SN74HCT374NS optimal for cost-sensitive, timing-moderate 5 V bus interfaces.

Availability

SN74HCT374NS is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, microcontroller parallel bus interface, and digital test equipment data capture requiring stable component supply and long-term lifecycle support.

Supply support for SN74HCT374NS 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 U.S.-based semiconductor company specializing in analog, embedded processing, and logic ICs, with leadership in industrial, automotive, and communications markets.

The SN74HCT374NS belongs to TI's 74HCT logic family, engineered for seamless interoperability between TTL and CMOS systems in industrial control, instrumentation, and legacy-compatible digital design.

FAQ

What is the operating voltage range for SN74HCT374NS?

The SN74HCT374NS operates over a supply voltage range of 4.5 V to 5.5 V. This range ensures compatibility with standard 5 V TTL systems while maintaining noise margins and stable 3-state output behavior. Operation outside this range may result in undefined logic states or excessive ICC. Always use a local 0.1 µF ceramic capacitor between VCC and GND pins for reliable performance in the SN74HCT374NS.

Does SN74HCT374NS support hot swapping on a shared bus?

SN74HCT374NS supports controlled bus sharing via its active-low OE input, but does not inherently support hot swapping without external protection. When OE is HIGH, outputs enter high-impedance state, isolating the device from the bus - however, VCC and GND must remain powered during insertion/removal to avoid latch-up. For true hot-swap capability, additional circuitry such as current-limiting resistors or dedicated hot-swap controllers is required alongside the SN74HCT374NS.

How does the clock edge sensitivity of SN74HCT374NS affect timing design?

The SN74HCT374NS is strictly positive-edge-triggered: it samples all D inputs only on the LOW-to-HIGH transition of CP. This requires meeting 12 ns setup and 5 ns hold times relative to that edge under worst-case conditions. Violating these windows risks metastability or incorrect latching. Designers must ensure clean, monotonic clock edges and account for skew between CP and D signals - especially critical in the SN74HCT374NS when used in high-speed data acquisition paths.

Can SN74HCT374NS drive standard TTL loads directly?

Yes, SN74HCT374NS can drive up to 10 LSTTL loads per output, thanks to its ±6 mA output drive capability at VCC = 4.5 V and TTL-compatible input thresholds. Its VOH and VOL levels meet LSTTL specifications across temperature and voltage ranges, enabling direct connection without level shifters. This makes the SN74HCT374NS particularly suitable for bridging legacy TTL subsystems with modern CMOS logic in mixed-technology designs.

What is the function of the OE pin during clock activity in SN74HCT374NS?

In SN74HCT374NS, the OE (output enable) pin operates independently of the clock (CP) and register state. While CP transitions continue to update internal flip-flop values regardless of OE status, the Q outputs reflect those values only when OE is LOW. When OE is HIGH, all Q outputs go high-impedance - but stored data remains intact. This decoupling allows dynamic bus arbitration without disrupting ongoing register updates in the SN74HCT374NS.