Texas Instruments SN74HC377NE4

Overview

SN74HC377NE4 from Texas Instruments is a positive-edge-triggered octal D-type flip-flop with latched clock enable (CLKEN), operating across 2 V to 6 V. It features eight independent single-rail outputs, ±4-mA drive at 5 V, 12 ns typical propagation delay, and low 80-µA max ICC. It serves as a synchronous storage register in digital control logic and data buffering applications.

For engineers reviewing the SN74HC377NE4 datasheet, SN74HC377NE4 pinout, SN74HC377NE4 application, or SN74HC377NE4 equivalent, key selection criteria include clock-enable latching behavior, 20-pin PDIP package compatibility, 5-V TTL-level interfacing capability, and absence of asynchronous clear-distinguishing it from SN74HC273.

Technical Context

The SN74HC377NE4 implements eight edge-triggered D flip-flops sharing one CLK input and one latched CLKEN signal. Unlike the SN74HC273, it replaces common asynchronous clear with a clock-enable function that avoids false triggering during enable transitions.

Its functional mode table confirms Q output updates only on CLK↑ when CLKEN = L; otherwise, outputs retain prior state. Input voltage thresholds are defined per VCC (e.g., VIH = 3.15 V at VCC = 4.5 V), and timing parameters-including tpd = 12 ns (typ), tsu = 25 ns (max at 6 V), and fmax = 23 MHz (max at 6 V)-are specified under CL = 50 pF.

Key Specifications

Pinout & Package

SN74HC377NE4 is housed in a 20-pin plastic dual in-line package (PDIP-N), with nominal body size 25.40 mm × 6.35 mm and through-hole mounting compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC273N and SN74HCT377N, the SN74HC377NE4 uniquely provides latched clock enable-reducing external logic in gated-clock architectures-while maintaining full 2–6 V operation and superior noise immunity over HCT variants.

Availability

SN74HC377NE4 is available at Aetrix Electronics and suitable for industrial control panels, test equipment buffers, digital pattern generators, and embedded microcontroller I/O expansion requiring stable component supply and long-term manufacturability.

Supply support for SN74HC377NE4 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 heritage in industry-standard logic families.

The SN74HC377NE4 belongs to TI's 74HC high-speed CMOS logic product line, designed specifically for low-power, noise-immune digital interfacing and data registration in industrial and commercial systems.

FAQ

What is the maximum clock frequency supported by SN74HC377NE4?

The SN74HC377NE4 supports a maximum clock frequency of 23 MHz at VCC = 6 V and TA = 25 °C, as specified in the switching characteristics table. At 5 V, fmax is 20 MHz, and at 2 V, it drops to 4 MHz. These values assume CL = 50 pF and proper bypassing; actual system-level frequency may be lower depending on trace capacitance and loading.

Does SN74HC377NE4 have an asynchronous reset function?

No, SN74HC377NE4 does not include an asynchronous reset (clear) input. It uses a latched clock-enable (CLKEN) signal instead of the common clear found on SN74HC273. To achieve reset-like behavior, CLKEN must be held high while applying a clock edge-this preserves Q outputs without changing state. External logic is required for true asynchronous reset.

Can SN74HC377NE4 operate reliably at 3.3 V?

Yes, SN74HC377NE4 operates reliably across 2 V to 6 V, including 3.3 V. At VCC = 3.3 V, VIH is 2.31 V (70% of VCC) and VIL is 0.99 V (30% of VCC), providing >1.3 V noise margin. Propagation delay increases to ~18 ns (typ), and output drive reduces to ~±2.5 mA, which remains sufficient for driving modern 3.3-V CMOS loads.

What is the thermal resistance (RθJA) of SN74HC377NE4 in its PDIP package?

The junction-to-ambient thermal resistance (RθJA) for SN74HC377NE4 in the PDIP (N) package is 84.6 °C/W, as specified in the thermal information section. This value assumes standard JEDEC 2S2P test board conditions. For sustained operation near maximum ambient temperature, derating of power dissipation based on this RθJA is recommended.

How does the latched CLKEN input improve timing reliability compared to a simple enable?

The latched CLKEN input in SN74HC377NE4 is sampled on the rising edge of CLK and held internally, preventing metastability and false triggering caused by asynchronous enable transitions near clock edges. In contrast, a combinational enable would risk partial or inconsistent updates across the eight flip-flops. This latching ensures atomic, synchronized enable control-critical in deterministic control logic.