Texas Instruments SN74AHC574DWG4

Overview

SN74AHC574DWG4 from Texas Instruments is an octal edge-triggered D-type flip-flop with 3-state outputs, designed for bus interface applications requiring high capacitive load drive and logic-level translation. It operates from 2 V to 5.5 V, features ±25 mA output drive per channel, 110 MHz maximum clock frequency at 5 V, and supports bidirectional bus buffering in industrial and consumer systems including network switches and infotainment units.

For engineers reviewing the SN74AHC574DWG4 datasheet, SN74AHC574DWG4 pinout, SN74AHC574DWG4 application, or SN74AHC574DWG4 equivalent, key selection criteria include its 20-pin SOIC (DW) package, 3-state enable control via OE, propagation delay under 11 ns at 5 V, and compatibility with mixed-voltage 3.3 V/5 V system interfaces.

Technical Context

The SN74AHC574DWG4 implements eight independent D-type latches synchronized to the rising edge of CLK, with asynchronous 3-state control via OE. Its CMOS AHC logic family ensures rail-to-rail output swing, low static current (≤40 µA), and input tolerance up to 5.5 V-enabling robust 5 V → 3.3 V level translation without external components.

Each output drives loads up to 50 pF with controlled edge rates (≤20 ns/V at 5 V), minimizing ringing on PCB traces. The device supports bus-hold-free operation only when all unused inputs are tied to VCC or GND, and thermal performance is characterized by RθJA = 81.1°C/W in the DW package.

Key Specifications

Pinout & Package

SN74AHC574DWG4 uses a 20-pin SOIC (DW) package measuring 12.80 mm × 10.3 mm, with 1.27 mm pitch and surface-mount footprint compatible with IPC-7351B SOIC-20 standards.

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, SN74AHC574DWG4 delivers optimal balance of voltage flexibility (2–5.5 V), 3-state bus driving capability, and industrial temperature support-making it preferred for mixed-signal embedded systems where interoperability and reliability outweigh raw speed.

Availability

SN74AHC574DWG4 is available at Aetrix Electronics and suitable for network switches, automotive infotainment systems, and smart TV timing controllers requiring stable component supply across multi-year production cycles.

Supply support for SN74AHC574DWG4 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.

SN74AHC574DWG4 belongs to the AHC logic family, engineered for high-speed, low-power, mixed-voltage digital interfacing in space-constrained industrial and consumer electronics.

FAQ

What is the maximum clock frequency supported by SN74AHC574DWG4 at 3.3 V?

At VCC = 3.3 V ± 0.3 V and CL = 50 pF, SN74AHC574DWG4 supports a maximum clock frequency of 45 MHz. This value is specified in Section 5.8 of the datasheet under Switching Characteristics and reflects guaranteed timing performance across the full operating temperature range (–40°C to +125°C). The device achieves higher frequencies (up to 75 MHz) at 5 V operation.

Does SN74AHC574DWG4 require external pull-up or pull-down resistors on its inputs?

No, SN74AHC574DWG4 does not require external pull-up or pull-down resistors on its inputs-but all unused inputs must be actively tied to VCC or GND. Floating inputs can cause undefined logic states and increased ICC due to internal shoot-through current. This requirement is explicitly stated in Section 5.3 of the datasheet and applies to OE, CLK, and any unconnected D inputs.

Can SN74AHC574DWG4 safely interface a 5 V microcontroller with a 3.3 V FPGA?

Yes, SN74AHC574DWG4 supports 5.5-V tolerant inputs, allowing direct connection of 5 V logic signals (e.g., from a microcontroller) to its D and OE pins while powered at 3.3 V. Its outputs swing rail-to-rail, delivering clean 3.3 V logic levels to the FPGA. This eliminates need for discrete level translators in bidirectional or unidirectional data paths.

What is the thermal resistance (RθJA) of SN74AHC574DWG4 in its SOIC package?

The junction-to-ambient thermal resistance (RθJA) for SN74AHC574DWG4 in the DW (SOIC-20) package is 81.1°C/W, as specified in Section 5.4 (Thermal Information) of the datasheet. This value assumes standard JEDEC 2S2P board conditions and is critical for calculating maximum allowable power dissipation in thermally constrained layouts.

How does the 3-state output control work on SN74AHC574DWG4?

SN74AHC574DWG4 uses an active-low Output Enable (OE) input: when OE is low, all eight Q outputs drive logic-high or logic-low states based on registered D inputs; when OE is high, all Q outputs enter high-impedance (Hi-Z) mode, electrically disconnecting from the bus. This behavior is defined in Table 7-1 (Function Table) and enables safe multi-drop bus sharing without external bus switches.