Texas Instruments SN74HC273NE4

Overview

SN74HC273NE4 from Texas Instruments is an octal positive-edge-triggered D-type flip-flop with active-low asynchronous clear, operating across 2 V to 6 V. It provides eight independent data registers, ±4-mA output drive at 5 V, 12 ns typical propagation delay, and 80-µA maximum ICC-used in synchronous data latching and clock-domain isolation in industrial control logic.

For engineers reviewing the SN74HC273NE4 datasheet, SN74HC273NE4 pinout, SN74HC273NE4 application, or SN74HC273NE4 equivalent, key selection criteria include its 20-pin PDIP package, direct-clear functionality, guaranteed timing over –40°C to +85°C, and compatibility with LSTTL loads without level-shifting.

Technical Context

The SN74HC273NE4 implements eight edge-triggered D flip-flops sharing a common clock (CLK) and global active-low clear (CLR), with individual D inputs and non-inverted Q outputs. Its CMOS architecture ensures rail-to-rail input thresholds, low static current, and noise-immune switching under defined setup/hold timing.

It operates strictly on the rising edge of CLK; D inputs are sampled only when CLR is high, and outputs remain latched during CLK low/high phases. The device requires no external pull-ups and supports fan-out of up to 10 LSTTL loads per output at 5 V.

Key Specifications

Pinout & Package

SN74HC273NE4 uses a 20-pin plastic dual in-line package (PDIP) with 24.33 mm × 6.35 mm body size and through-hole mounting. Pin 1 is marked by notch or dot; pin numbering follows standard counter-clockwise layout from top view.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC273NE4, SN74HC374N adds output enable but removes dedicated clear, while 74ACT273PC trades wider voltage range and lower power for higher speed and 5 V exclusivity-making SN74HC273NE4 optimal for cost-sensitive, industrial-temperature, multi-supply latching.

Availability

SN74HC273NE4 is available at Aetrix Electronics and suitable for industrial control systems, test equipment design, and legacy bus interface applications requiring stable component supply and long-term manufacturability.

Supply support for SN74HC273NE4 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 SN74HC273NE4 belongs to TI's 74HC high-speed CMOS logic series, designed for reliable, low-power digital interfacing and data registration in industrial, automotive, and communications equipment.

FAQ

What is the maximum clock frequency supported by SN74HC273NE4?

SN74HC273NE4 supports a maximum clock frequency of 21 MHz over its full operating temperature range (–40°C to +85°C) at VCC = 4.5 V. At VCC = 6 V, the limit rises to 25 MHz. These values derive from guaranteed timing parameters including minimum pulse width and setup/hold requirements-not typical or derated figures.

Does SN74HC273NE4 require external pull-up resistors on its inputs?

No, SN74HC273NE4 does not require external pull-up resistors on its inputs. Its CMOS inputs have leakage current ≤1 µA and defined VIH/VIL thresholds scaling with VCC. Unused inputs must be tied to VCC or GND per TI's recommendation to prevent floating states and undefined operation.

Can SN74HC273NE4 drive standard TTL loads directly?

Yes, SN74HC273NE4 can drive up to 10 LSTTL loads per output at VCC = 4.5 V or 5 V, meeting VOH ≥3.84 V and VOL ≤0.33 V under 4-mA sink/source conditions. This satisfies standard LSTTL input thresholds without additional buffering.

What is the function of the CLR pin on SN74HC273NE4?

The CLR pin on SN74HC273NE4 is an active-low asynchronous clear input that forces all eight Q outputs to logic low immediately, independent of the clock signal. It overrides normal D-to-Q transfer and remains effective even when CLK is static-essential for system initialization and fault-safe reset.

Is SN74HC273NE4 RoHS compliant?

Yes, SN74HC273NE4 is RoHS compliant, as confirmed by Texas Instruments' orderable addendum: it features NiPdAu (NIPDAU) lead finish, meets lead-free requirements, and carries Level-1 MSL rating with unlimited floor life under JEDEC J-STD-020 conditions.