Texas Instruments SN74BCT374NSR

Overview

SN74BCT374NSR from Texas Instruments is an octal edge-triggered D-type latch with 3-state outputs, designed for bus interfacing and register buffering in 5-V TTL-compatible systems. It features a shared rising-edge clock (CLK), active-low output enable (OE), 4.5–5.5 V operation, ±64 mA output drive, and BiCMOS architecture enabling low ICCZ standby current. It is used in industrial control backplanes and memory address latching.

For engineers reviewing the SN74BCT374NSR datasheet, SN74BCT374NSR pinout, SN74BCT374NSR application, or SN74BCT374NSR equivalent, key selection criteria include 3-state bus-driving capability, 70 MHz max clock frequency, 0 ns hold time, 6.5 ns setup time, and SOP-20 package compatibility with legacy 74-series logic layouts.

Technical Context

The SN74BCT374NSR implements eight independent D-type flip-flops sharing one CLK and one OE input. Its BiCMOS design combines bipolar output transistors for high-current drive (±64 mA) with CMOS inputs for low static power and high noise immunity. All outputs switch on the rising edge of CLK and enter high-impedance when OE is high.

Internal logic decouples OE from clocked data capture: OE controls only output buffer state and does not affect latch operation, allowing data retention or new loading while outputs are disabled. Input thresholds (VIH = 2.0 V, VIL = 0.8 V) match standard TTL levels, ensuring interoperability with legacy 74LS/74F families.

Key Specifications

Pinout & Package

SOP-20 (Small Outline Package), body size 12.60 mm × 5.30 mm, surface-mount, gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal D-latch applications.

Compared with SN74ACT374NSR and SN74ALS374N, the SN74BCT374NSR uniquely balances TTL-level compatibility, 3-state bus drive strength, and moderate power - making it optimal for industrial backplane interfaces requiring robust signal integrity and legacy interoperability.

Availability

SN74BCT374NSR is available at Aetrix Electronics and suitable for industrial control backplanes, memory address latching, and programmable logic I/O expansion requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74BCT374NSR 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 for industrial, automotive, and communications markets.

The SN74BCT374NSR belongs to TI's BCT (Bipolar-CMOS-Transistor) logic family, engineered to deliver TTL-compatible performance with reduced power consumption - specifically targeting bus-oriented applications in harsh-environment control systems.

FAQ

What is the maximum clock frequency supported by the SN74BCT374NSR?

The SN74BCT374NSR supports a maximum clock frequency of 70 MHz under recommended operating conditions (VCC = 4.5–5.5 V, TA = 0°C to 70°C). This rating is validated by timing parameters including 6.5 ns setup time and 2–10.6 ns propagation delay, ensuring reliable edge-triggered operation in high-speed digital interfaces. The SN74BCT374NSR maintains this spec across its full commercial temperature range without derating.

Does the SN74BCT374NSR require external pull-up or pull-down resistors on unused inputs?

Yes - all unused inputs of the SN74BCT374NSR must be terminated to either VCC or GND to prevent floating states that cause excessive power consumption or oscillation. TI explicitly recommends 10-kΩ pull-up or pull-down resistors for intermittently used inputs, and direct connection for permanently unused pins. Leaving inputs unconnected violates the SN74BCT374NSR's recommended operating conditions and risks functional instability.

Can the SN74BCT374NSR drive a 100-pF load while meeting datasheet specifications?

No - the SN74BCT374NSR is characterized and guaranteed to meet all electrical and timing specifications only with a total capacitive load ≤50 pF. Driving 100 pF will increase propagation delay, degrade edge rates, and potentially violate setup/hold timing margins. TI's application guidance states that larger loads may be used but are not recommended; for >50 pF, consider adding a dedicated buffer or selecting a higher-drive logic family. This limit applies directly to the SN74BCT374NSR's specified performance envelope.

What is the function of the OE pin on the SN74BCT374NSR, and how does it interact with the clock?

The OE (output enable) pin on the SN74BCT374NSR is an active-low control that places all eight Q outputs in high-impedance state when high, regardless of CLK or D input activity. Crucially, OE has no effect on internal latch operation: data can be loaded or retained while outputs are disabled. This decoupling allows the SN74BCT374NSR to support bus arbitration and multi-master systems where output isolation must be independent of clocked data capture.

Is the SN74BCT374NSR pin-compatible with other 20-pin octal D-latches like the SN74LS374?

Yes - the SN74BCT374NSR uses the industry-standard 20-pin SOP (SO-20) pinout identical to SN74LS374, SN74ALS374, and SN74F374. Pin functions (CLK, OE, D0–D7, Q0–Q7, VCC, GND) and physical layout match exactly, enabling direct footprint reuse. However, voltage thresholds, drive strength, and timing differ: the SN74BCT374NSR offers higher output current (±64 mA vs. ±24 mA) and faster propagation (2–10.6 ns vs. ~15 ns), so system-level timing validation is required despite pin compatibility.