Texas Instruments SN74AHCT273DW

Overview

SN74AHCT273DW from Texas Instruments is an octal positive-edge-triggered D-type flip-flop with direct asynchronous clear, TTL-compatible inputs (VIH = 2 V, VIL = 0.8 V), 5 V supply operation (4.5–5.5 V), and eight independent data-to-output paths. It functions as a synchronous storage register in digital control logic, commonly used in PC motherboard I/O buffering and network switch data latching.

For engineers reviewing the SN74AHCT273DW datasheet, SN74AHCT273DW pinout, SN74AHCT273DW application, or SN74AHCT273DW equivalent, key selection criteria include its 8-bit parallel latch capability, 120 MHz max clock frequency at 15 pF load, ±8 mA output drive, -40°C to +125°C operating range, and SOIC-20 package compatibility with legacy 5 V system designs.

Technical Context

This device implements eight independent edge-triggered D flip-flops sharing a common clock (CLK) and global asynchronous clear (CLR) input. Each flip-flop transfers data from its dedicated D input to the corresponding Q output on the rising edge of CLK, with no effect when CLK is static.

Its TTL-voltage-compatible inputs enable direct interfacing with 3.3 V logic while operating from a 5 V supply-supporting level translation without external biasing. The design includes robust ESD protection (2000 V HBM, 1000 V CDM) and latch-up immunity exceeding 250 mA per JESD17.

Key Specifications

Pinout & Package

SN74AHCT273DW uses a 20-pin SOIC (DW) package measuring 12.80 mm × 10.3 mm with 1.27 mm pitch. The body size is 12.8 mm × 7.5 mm, and it features gull-wing leads compatible with standard reflow profiles (MSL Level-1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AHCT273DW, SN74AHC273DW trades speed and drive for lower quiescent current, while 74LVX273M abandons 5 V operation entirely-making SN74AHCT273DW the sole choice for legacy 5 V systems requiring TTL compatibility and robust drive.

Availability

SN74AHCT273DW is available at Aetrix Electronics and suitable for PC motherboard I/O buffering, industrial PLC input registration, and network switch data path latching requiring stable component supply across extended product lifecycles.

Supply support for SN74AHCT273DW 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 U.S.-based semiconductor company founded in 1930, specializing in analog and embedded processing technologies with over 90,000 active products and global manufacturing and test facilities.

The SN74AHCT273DW belongs to TI's 74AHCT logic family, engineered for seamless integration between 3.3 V and 5 V digital systems through TTL-compatible inputs and robust industrial temperature operation.

FAQ

What is the maximum clock frequency supported by the SN74AHCT273DW?

The SN74AHCT273DW supports a maximum clock frequency of 120 MHz when loaded with 15 pF, as specified in the switching characteristics table. At 50 pF load, the maximum usable frequency drops to 75 MHz. These values assume VCC = 5 V ± 0.5 V and TA = 25°C; derating applies at temperature extremes or higher capacitive loads. The SN74AHCT273DW's tPLH/tPHL ≤ 8.8 ns enables reliable operation in high-speed control loops.

Does the SN74AHCT273DW support 3.3 V logic inputs while operating from a 5 V supply?

Yes, the SN74AHCT273DW accepts TTL-level inputs (VIH = 2 V, VIL = 0.8 V) and is fully compatible with 3.3 V logic families when powered from a 5 V supply. This allows direct connection to 3.3 V microcontrollers, FPGAs, or ASICs without external level shifters. The SN74AHCT273DW's input structure is designed specifically for this mixed-voltage use case, with overvoltage tolerance up to 5.5 V on input pins.

What is the function of Pin 1 (CLR) on the SN74AHCT273DW?

Pin 1 of the SN74AHCT273DW is the asynchronous clear (CLR) input, active-low. When asserted (logic low), it forces all eight Q outputs to logic low immediately-regardless of the clock state or data inputs. This function is essential for system initialization, error recovery, and deterministic state reset. The SN74AHCT273DW requires no minimum pulse width on CLR, and its timing is validated down to 5 ns per the datasheet.

Is the SN74AHCT273DW pin-compatible with other packages in the same family?

No-the SN74AHCT273DW (SOIC-20) shares identical logic functionality and pin numbering with SN74AHCT273DBR (SSOP-20), SN74AHCT273PWR (TSSOP-20), and SN74AHCT273NSR (SOP-20), but mechanical dimensions, thermal resistance, and PCB footprint differ. While electrical pin assignments match across packages, the SN74AHCT273DW cannot be substituted without layout revision due to its larger 12.80 mm × 10.3 mm body and 1.27 mm lead pitch.

What decoupling capacitance is recommended for the SN74AHCT273DW?

Texas Instruments recommends a 0.1 µF ceramic capacitor placed within 3 mm of the VCC pin (Pin 20) and GND pin (Pin 10) of the SN74AHCT273DW. For systems with multiple power domains or high-noise environments, paralleling a 1 µF tantalum or ceramic capacitor improves low-frequency ripple suppression. The SN74AHCT273DW's ICC = 4–40 µA and ΔICC = 1.35–1.5 mA make proper decoupling critical to maintain timing accuracy and reduce ground bounce.