Texas Instruments SN74AHC574DW

Overview

SN74AHC574DW from Texas Instruments is an octal edge-triggered D-type flip-flop with 3-state outputs, designed for bus interface applications including I/O port expansion and bidirectional data buffering. It operates from 2 V to 5.5 V, supports 5.5-V tolerant inputs, delivers ±25 mA output drive per channel, and features propagation delays as low as 5.6 ns (VCC = 5 V, CL = 15 pF) in SOIC-20 packaging.

For engineers reviewing the SN74AHC574DW datasheet, SN74AHC574DW pinout, SN74AHC574DW application, or SN74AHC574DW equivalent, key selection considerations include its 3-state output control via OE, latch-up immunity (>250 mA), ESD robustness (2000 V HBM), and compatibility with mixed-voltage systems (e.g., 5 V → 3.3 V level translation).

Technical Context

The SN74AHC574DW implements eight independent D-type latches synchronized to the rising edge of CLK, with asynchronous 3-state control via a single active-low OE input. Its CMOS AHC logic family ensures rail-to-rail output swing, balanced rise/fall times, and low dynamic power consumption.

It supports dual-supply voltage translation: inputs tolerate up to 5.5 V regardless of VCC (2–5.5 V), enabling direct interfacing between 5 V legacy logic and 3.3 V microcontrollers. Output enable timing parameters (tPZH/tPLZ < 11.5 ns at 5 V) ensure clean bus release without contention.

Key Specifications

Pinout & Package

SN74AHC574DW uses a 20-pin SOIC (DW) package measuring 12.80 mm × 10.3 mm (body: 12.8 mm × 7.5 mm), RoHS-compliant with NIPDAU lead finish and MSL Level-1 reflow rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV574APW and 74AC574SCX, the SN74AHC574DW uniquely balances 5.5-V input tolerance, 25 mA drive, and 5.6 ns propagation delay - making it optimal for mixed-voltage industrial and automotive bus interfaces where reliability and compatibility outweigh raw speed.

Availability

SN74AHC574DW is available at Aetrix Electronics and suitable for industrial I/O expansion, automotive body control modules, legacy system bus interfaces, and video signal routing requiring stable component supply and long-term lifecycle support.

Supply support for SN74AHC574DW 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 over 90 years of innovation in industrial, automotive, and communications markets.

The SN74AHC574DW belongs to TI's AHC logic family, engineered for high-speed, low-power, mixed-voltage digital interfacing in harsh environments - particularly targeting industrial automation, automotive electronics, and legacy system upgrades.

FAQ

What is the maximum clock frequency supported by the SN74AHC574DW?

The SN74AHC574DW supports a maximum clock frequency of 110 MHz under typical conditions (VCC = 5 V, CL = 15 pF), derived from its 5.6 ns maximum tPLH/tPHL propagation delay. At 50 pF load, fMAX drops to 75 MHz. These values assume proper bypassing, monotonic clock edges, and adherence to setup/hold timing (tsu = 3 ns, th = 1.5 ns).

Does the SN74AHC574DW require external pull-up or pull-down resistors on unused inputs?

Yes - all unused inputs of the SN74AHC574DW must be tied to either VCC or GND to prevent floating states that cause excessive ICC, noise susceptibility, or undefined output behavior. This requirement is explicitly stated in Section 5.3 of the datasheet and applies to all D inputs, CLK, and OE if not actively used.

Can the SN74AHC574DW safely interface a 5 V microcontroller with a 3.3 V FPGA?

Yes - the SN74AHC574DW supports 5.5-V tolerant inputs, allowing direct connection of 5 V logic signals (e.g., from a microcontroller) to its D and CLK pins while powered at 3.3 V. Its outputs swing rail-to-rail (0 V to 3.3 V), making them compatible with 3.3 V FPGA I/O standards without external level shifters.

What is the thermal resistance (RθJA) of the SN74AHC574DW in its SOIC-20 package?

The SN74AHC574DW in the DW (SOIC-20) package has a junction-to-ambient thermal resistance (RθJA) of 81.1 °C/W, as specified in Section 5.4 of the datasheet. This value assumes standard JEDEC High-K test board conditions and informs thermal design for continuous operation at full output loading across –40°C to +125°C ambient.

How does the output-enable (OE) functionality work on the SN74AHC574DW?

The SN74AHC574DW features a single active-low OE pin (Pin 1) that simultaneously controls all eight outputs. When OE is low, outputs reflect registered Q states; when OE is high, all outputs enter high-impedance (Hi-Z) mode - electrically disconnecting them from the bus. This enables multi-drop bus architectures without contention, and timing parameters (tPZH/tPLZ) ensure glitch-free transitions.