Texas Instruments SN74AHC08DR

Overview

SN74AHC08DR from Texas Instruments is a quadruple 2-input positive-AND gate IC operating across 2 V to 5.5 V, delivering 8 ns typical propagation delay at 5 V (CL = 15 pF), ±25 mA output drive capability, and ESD protection exceeding ±2000 V HBM. It performs Boolean Y = A • B logic in server power sequencing and network switch control circuits.

For engineers reviewing the SN74AHC08DR datasheet, SN74AHC08DR pinout, SN74AHC08DR application, or SN74AHC08DR equivalent, this page provides verified package mapping (SOIC-14), confirmed electrical specs (VOH ≥ 3.94 V at IOH = –8 mA, VOL ≤ 0.36 V at IOL = 4 mA), thermal resistance (RθJA = 124.5°C/W), and two validated alternative parts with documented functional and parametric differences.

Technical Context

The SN74AHC08DR implements four independent AND gates in a single SOIC-14 package, each performing Y = A • B in positive logic. Its CMOS AHC-family architecture ensures rail-to-rail output swing, high noise immunity, and input overvoltage tolerance up to 5.5 V regardless of VCC level.

It features slow output transition rates (100 ns/V at 3.3 V, 20 ns/V at 5 V) to suppress ringing, low static current (ICC ≤ 20 µA over –40°C to 125°C), and latch-up immunity exceeding 250 mA per JESD17 - enabling robust operation in industrial and computing environments without external current limiting.

Key Specifications

Pinout & Package

SN74AHC08DR uses a 14-pin SOIC (D) package measuring 8.65 mm × 3.90 mm, with standard 1.27 mm pitch and gull-wing leads. Pin 1 is located at the top-left corner adjacent to the index notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar AND gate applications.

Compared with SN74LVC08ADR and 74AHC08D,112, the SN74AHC08DR offers superior latch-up immunity (250 mA vs unspecified for LVC, 200 mA for Nexperia), wider guaranteed operating margin at 2 V, and TI's extended product lifecycle support - making it optimal for long-lifecycle industrial compute platforms.

Availability

SN74AHC08DR is available at Aetrix Electronics and suitable for server power sequencing, network switch control logic, PC motherboard fan control, and POS terminal input validation requiring stable component supply and long-term manufacturability.

Supply support for SN74AHC08DR 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 computing markets.

The SN74AHC08DR belongs to TI's AHC logic family, engineered for high-noise-immunity, rail-to-rail performance, and robust operation in extended-temperature computing infrastructure - not general-purpose logic but mission-critical timing and control.

FAQ

What is the maximum output current per pin for SN74AHC08DR?

The SN74AHC08DR supports ±8 mA per output pin at VCC = 5 V, with absolute maximum continuous output current rated at ±25 mA. This allows direct driving of multiple downstream AHC inputs or small LEDs without external buffers, provided total device current remains ≤50 mA. Exceeding these limits risks thermal overstress or parametric shift.

Does SN74AHC08DR support mixed-voltage interfacing between 3.3 V and 5 V systems?

Yes, SN74AHC08DR supports mixed-voltage operation: its inputs tolerate up to 5.5 V regardless of VCC level, and it operates from 2 V to 5.5 V. When powered at 3.3 V, it correctly interprets 5 V inputs as logic high and outputs 3.3 V-compatible levels - enabling seamless bridging between 3.3 V controllers and 5 V peripherals without level shifters.

What is the recommended bypass capacitor for SN74AHC08DR?

A 0.1 µF ceramic capacitor is recommended for SN74AHC08DR, placed as close as possible (<2 mm) to the VCC (Pin 14) and GND (Pin 7) pins. This minimizes high-frequency supply impedance during switching transitions, preventing ground bounce and ensuring stable 4.3 ns min propagation delay performance. Larger bulk capacitance (e.g., 1 µF) may be added in parallel for low-frequency ripple suppression.

Can unused inputs on SN74AHC08DR be left floating?

No, unused inputs on SN74AHC08DR must be tied to either VCC or GND. Floating inputs cause undefined logic states, increased ICC, and potential oscillation due to CMOS input stage sensitivity. The datasheet mandates termination - typically VCC for AND gate inputs to default-enable functionality or GND to force low output - to ensure deterministic behavior and prevent EMI generation.

What is the thermal resistance (RθJA) of SN74AHC08DR in its SOIC package?

The SN74AHC08DR in SOIC-14 (D) package has a junction-to-ambient thermal resistance (RθJA) of 124.5°C/W, measured under JEDEC-standard conditions. This value assumes a 1-inch² copper pad on a 1-layer board; actual board layout (copper area, layers, airflow) will affect real-world thermal performance. Derating is required above 85°C ambient to maintain TJ < 125°C.