Texas Instruments SN74HC273DWRE4

Overview

SN74HC273DWRE4 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 delivers 12 ns typical propagation delay at 5 V, ±4 mA output drive, and 80 µA maximum ICC, enabling reliable data latching in digital control and interface logic circuits.

For engineers reviewing the SN74HC273DWRE4 datasheet, SN74HC273DWRE4 pinout, SN74HC273DWRE4 application, or SN74HC273DWRE4 equivalent, key selection criteria include its 20-pin SOIC package, single-rail outputs per flip-flop, direct CLR functionality, and compatibility with LSTTL load driving requirements in synchronous register designs.

Technical Context

The SN74HC273DWRE4 implements eight independent D flip-flops sharing a common clock (CLK) and global active-low clear (CLR) input. Each flip-flop captures D-input data on the rising edge of CLK while maintaining state otherwise, with no effect from D when CLK is static.

Its CMOS design ensures rail-to-rail output swing, low input current (≤1 µA), and balanced rise/fall times. Timing parameters-including setup time (25 ns max at VCC = 4.5 V), hold time (0 ns), and pulse width (20 ns min for CLK/CLR)-are specified over –40°C to +85°C for industrial operation.

Key Specifications

Pinout & Package

SN74HC273DWRE4 is housed in a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm, with standard 1.27 mm pitch and surface-mount compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC273DWRE4, SN74HCT273N offers superior TTL input compatibility at modest power cost, while 74AC273PC trades higher ICC for significantly improved speed and drive strength - making each alternative optimal under distinct system constraints.

Availability

SN74HC273DWRE4 is available at Aetrix Electronics and suitable for industrial control panels, test equipment interfaces, and embedded data acquisition systems requiring stable component supply and long-term manufacturability.

Supply support for SN74HC273DWRE4 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.

SN74HC273DWRE4 belongs to the 74HC logic family, designed for low-power, high-noise-immunity digital interfacing and data synchronization in resource-constrained embedded systems.

FAQ

What is the maximum clock frequency supported by SN74HC273DWRE4?

The SN74HC273DWRE4 supports up to 25 MHz maximum clock frequency at VCC = 6 V, and 21 MHz at VCC = 4.5 V, as specified in its timing requirements table. These values reflect guaranteed operation across the full industrial temperature range (–40°C to +85°C), with typical performance reaching 50 MHz at 4.5 V under 25°C conditions. Always verify timing margins using worst-case propagation delay (34 ns) in your PCB layout.

Does SN74HC273DWRE4 require external pull-up resistors on unused inputs?

Yes - all unused inputs of SN74HC273DWRE4 must be tied to VCC or GND to prevent floating states that cause excessive current draw and logic instability. This requirement stems from CMOS input structure; TI explicitly recommends hard-wiring unused D and CLR pins per Section 6.3 of the datasheet. Leaving inputs unconnected may result in undefined outputs and increased ICC.

Can SN74HC273DWRE4 drive LED indicators directly?

No - SN74HC273DWRE4 is not rated for direct LED driving. Its ±4 mA output drive at 5 V is intended for logic-level interfacing, not current-sinking LEDs. Attempting to sink LED current risks exceeding absolute maximum output current (±25 mA per pin) and degrading timing or reliability. Use a dedicated driver transistor or buffer IC like ULN2003 for LED loads.

What is the purpose of the CLR pin on SN74HC273DWRE4?

The CLR (pin 1) on SN74HC273DWRE4 is an asynchronous active-low clear input that forces all eight Q outputs low immediately, independent of the clock signal. This provides deterministic system reset capability - essential for initializing state machines, clearing error conditions, or synchronizing multi-stage logic before enabling clocks. Its minimum pulse width is 20 ns at VCC = 4.5 V.

Is SN74HC273DWRE4 RoHS compliant and lead-free?

Yes - SN74HC273DWRE4 is RoHS compliant with lead-free terminations (NIPDAU finish) and meets JEDEC Level-1 moisture sensitivity standards (260°C peak reflow). The "E4" suffix denotes TI's green packaging standard, confirmed in the Package Option Addendum where it is listed as Active with "Yes" under RoHS column and "NIPDAU" under Lead Finish.