Texas Instruments SNJ54BCT374W

Overview

SNJ54BCT374W from Texas Instruments is a military-grade octal edge-triggered D-type latch with 3-state outputs, operating across –55°C to 125°C at 4.5 V–5.5 V supply. It features eight independent D inputs, shared rising-edge clock (CLK), active-low output enable (OE), and biCMOS output drivers capable of 48 mA low-level sink current. It serves as a bus-interface register in radiation-tolerant avionics data acquisition systems.

For engineers reviewing the SNJ54BCT374W datasheet, SNJ54BCT374W pinout, SNJ54BCT374W application, or SNJ54BCT374W equivalent, key selection criteria include its CFP-20 package thermal performance (R_θJA = 73.4°C/W), guaranteed 70 MHz clock frequency over full military temperature range, 3-state output isolation capability, and compatibility with TTL/CMOS logic families in high-reliability control plane designs.

Technical Context

This device implements eight synchronous D-type latches sharing one clock input and one active-low output-enable signal. Each latch captures data on the rising edge of CLK and holds it until the next clock transition, while OE independently controls all eight outputs' high-impedance state without affecting internal storage.

The biCMOS output stage combines bipolar pull-down and CMOS pull-up transistors, delivering strong drive strength (48 mA sink, –2 mA source) with reduced quiescent current (I_CCZ ≤ 8 mA) compared to standard TTL. Input thresholds follow TTL-compatible levels (V_IL ≤ 0.8 V, V_VIH ≥ 2.0 V), ensuring interoperability with legacy 5-V logic systems.

Key Specifications

Pinout & Package

SNJ54BCT374W is housed in a 20-pin Ceramic Flatpack (CFP) package measuring 13.72 mm × 6.92 mm, designed for hermetic sealing and high thermal conductivity in harsh-environment PCB assemblies.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SNJ54ACT374W and SNJ54LS374J, SNJ54BCT374W uniquely balances military-grade temperature resilience, 70 MHz speed, and biCMOS efficiency-making it optimal for new avionics and defense electronics where reliability, speed, and power coexist as non-negotiable constraints.

Availability

SNJ54BCT374W is available at Aetrix Electronics and suitable for avionics data acquisition, secure communication interface, industrial PLC backplane, and spacecraft telemetry buffer applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SNJ54BCT374W 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, aerospace, and communications markets.

SNJ54BCT374W belongs to TI's military-grade BiCMOS logic family, engineered specifically for high-reliability digital interfacing in extreme environments where signal integrity, timing precision, and operational longevity are mission-critical.

FAQ

What is the maximum clock frequency supported by SNJ54BCT374W across its full operating temperature range?

SNJ54BCT374W supports a guaranteed maximum clock frequency of 70 MHz from –55°C to 125°C, as specified in Section 6.6 of the official datasheet. This rating applies under recommended operating conditions (V_CC = 4.5 V to 5.5 V, C_L = 50 pF) and reflects worst-case timing across the entire military temperature range-not just at 25°C. The SNJ54BCT374W achieves this performance through its biCMOS architecture, which minimizes propagation delay variation with temperature.

Does SNJ54BCT374W require external pull-up or pull-down resistors on unused inputs?

Yes, all unused inputs of SNJ54BCT374W must be terminated to either V_CC or GND to prevent floating states that could cause excessive power consumption or oscillation. The datasheet explicitly mandates this in Section 6.3 and Figure 11-1. While 10-kΩ resistors are commonly used, direct connections are acceptable for permanently unused inputs. Leaving inputs unconnected violates the device's recommended operating conditions and risks functional instability in SNJ54BCT374W-based systems.

How does the 3-state output functionality of SNJ54BCT374W behave during power-up or brown-out conditions?

During power-up or brown-out, SNJ54BCT374W outputs enter a high-impedance state only when OE is actively driven high; they do not auto-tri-state. The device has no internal power-on reset circuitry, so outputs may briefly glitch or float until V_CC stabilizes and OE is asserted. To ensure safe bus initialization, system design must coordinate OE assertion with power supply sequencing-typically delaying OE activation until V_CC exceeds 4.5 V and remains stable for ≥100 µs, as verified in SNJ54BCT374W application testing.

Can SNJ54BCT374W drive a 75-pF capacitive load while maintaining datasheet timing specifications?

No, SNJ54BCT374W is characterized and guaranteed to meet all timing and drive specifications only up to 50 pF total load capacitance, as stated in Section 9.2.2.2. Driving 75 pF will increase propagation delays (e.g., t_PLH may exceed 11.6 ns) and degrade edge rates, potentially violating setup/hold margins in high-speed interfaces. For loads exceeding 50 pF, TI recommends adding a buffer stage or selecting a driver with higher C_L rating-SNJ54BCT374W itself is not rated for reliable operation beyond its specified 50-pF limit.

Is SNJ54BCT374W pin-compatible with commercial-grade SN74BCT374 variants in the same CFP package?

Yes, SNJ54BCT374W shares identical pin configuration, electrical behavior, and functional truth table with SN74BCT374 variants in CFP-20 packages (e.g., SN74BCT374W), as confirmed in Table 5-1 and Figure 5-1 of the datasheet. However, SNJ54BCT374W undergoes additional military screening-including extended temperature testing, burn-in, and lot acceptance testing per MIL-PRF-38535-so while pinouts match, the SNJ54BCT374W part is not a direct drop-in replacement unless the application demands full QML certification.