Texas Instruments CD74HC273ME4

Overview

CD74HC273ME4 from Texas Instruments is a high-speed CMOS octal D-type flip-flop with asynchronous active-low reset, positive-edge clock triggering, and 2V–6V operation. It provides synchronized 8-bit data latching for bus interfaces, operates across –55°C to 125°C, and delivers 30 ns typical propagation delay (CL = 50 pF, VCC = 4.5 V) in SOIC-20 packaging.

For engineers reviewing the CD74HC273ME4 datasheet, CD74HC273ME4 pinout, CD74HC273ME4 application, or CD74HC273ME4 equivalent, this device serves as a robust, temperature-hardened register for industrial control I/O expansion, synchronous data capture in test equipment, and 8-bit state storage in legacy TTL-compatible systems requiring low-power CMOS logic.

Technical Context

The CD74HC273ME4 implements eight independent D-type flip-flops sharing one common clock (CLK) and one asynchronous clear (CLR) input. All Q outputs update synchronously on the rising edge of CLK, while CLR forces all Q outputs low regardless of clock state - enabling deterministic initialization without timing dependency.

It uses silicon-gate CMOS technology with buffered inputs, balanced push-pull outputs capable of driving 10 LSTTL loads, and exhibits matched tPLH/tPHL propagation delays (<10 ns skew between channels at 4.5 V). Its noise immunity (NIL/NIH = 30% of VCC at 5 V) and wide supply range support mixed-voltage system interfacing.

Key Specifications

Pinout & Package

CD74HC273ME4 is supplied in a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm, with standard JEDEC MS-013 footprint and gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC273ME4, SN74HC273N offers identical electrical behavior in a through-hole package for lab use, while CD74HCT273M trades supply flexibility for guaranteed compatibility with 5 V TTL signaling - making CD74HC273ME4 the optimal choice for mixed-voltage or low-power industrial designs.

Availability

CD74HC273ME4 is available at Aetrix Electronics and suitable for industrial automation, automotive diagnostics, and test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC273ME4 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 high-reliability logic IC development.

CD74HC273ME4 belongs to TI's CDx4HC(T)273 family of high-speed CMOS octal D-type flip-flops, designed specifically for robust data synchronization and state retention in harsh-environment digital systems.

FAQ

What is the maximum clock frequency supported by CD74HC273ME4 at 3.3 V supply?

At VCC = 3.3 V, the CD74HC273ME4 supports a maximum clock frequency of 25 MHz (typical) over the full operating temperature range. This value is derived from interpolation of the published fMAX specifications at 2 V (5 MHz), 4.5 V (30 MHz), and 6 V (35 MHz), confirmed by TI's characterization data for HC-family devices operating at intermediate voltages.

Does CD74HC273ME4 require external pull-up resistors on unused inputs?

Yes - all unused inputs on CD74HC273ME4 must be terminated to either VCC or GND. Floating CMOS inputs cause excessive current draw and potential oscillation. A 10 kΩ pull-up or pull-down resistor is recommended per unused input, as specified in TI's application guidance for HC-series logic to ensure stable operation and prevent ESD-induced latch-up.

Can CD74HC273ME4 drive a 50 pF capacitive load while meeting timing specs?

Yes - CD74HC273ME4 is fully characterized for CL = 50 pF in its switching characteristics table. At VCC = 4.5 V and TA = 25°C, it achieves 30 ns typical tPLH/tPHL with 50 pF load, and remains within 45 ns max across –55°C to +125°C. Driving larger capacitances degrades timing and increases power dissipation, so 50 pF is the validated upper limit for guaranteed spec compliance.

Is CD74HC273ME4 pin-compatible with CD74HCT273M?

No - although CD74HC273ME4 and CD74HCT273M share identical SOIC-20 (DW) packaging and pin numbering, they are not functionally interchangeable without circuit review. The HCT version has different input threshold voltages (VIH min = 2.0 V vs. 3.15 V for HC), limiting its use to 5 V-only systems. Swapping them may cause logic misreads in 3.3 V or mixed-voltage designs.

What thermal derating applies to CD74HC273ME4 in a 60°C ambient environment?

In a 60°C ambient environment, CD74HC273ME4 maintains full specification compliance up to its maximum junction temperature of 150°C. With RθJA = 58°C/W (SOIC-20), the allowable power dissipation is (150 – 60)/58 ≈ 1.55 W - far exceeding its typical 0.5 mW quiescent + ~1 mW dynamic power at 10 MHz. No thermal derating is required for standard operation.