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Home > Products > Integrated Circuits (ICs) > Logic > Gates and Inverters

STMicroelectronics 74AC02B

Name: 74AC02B
Brand: STMicroelectronics
SKU: 74AC02B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74AC02B

Manufacturer:: STMicroelectronics

Category:: Gates and Inverters

Package:: 14-DIP (0.300", 7.62mm)

Datasheet:: 74AC02B.pdf

Description:: IC GATE NOR 4CH 2-INP 14DIP

Quantity:: RFQ Add To RFQ list

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Inventory:4,688

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Product details

Overview

74AC02B from STMicroelectronics is a quad 2-input NOR gate in plastic DIP-14 package, operating from 2V to 6V supply, delivering 4.2ns typical propagation delay at 5V, ±24mA symmetrical output drive, and 2µA max quiescent current at 25°C - used in high-speed digital logic interfacing, address decoding, and control signal arbitration in industrial PLC I/O modules.

For engineers reviewing the 74AC02B datasheet, 74AC02B pinout, 74AC02B application, or 74AC02B equivalent, key selection criteria include guaranteed 50Ω transmission line driving, latch-up immunity, ESD tolerance (2kV), and compatibility with legacy 74-series logic families under wide temperature range (–55°C to +125°C).

Technical Context

The 74AC02B implements four independent NOR gates using sub-micron C2MOS technology with three-stage buffered outputs, enabling stable switching and high noise immunity (28% VCC). Input thresholds are rail-proportional (VIH = 2.1V min at 3V, 3.15V at 4.5V), supporting mixed-voltage system interfacing.

Propagation delays are balanced (tPLH ≅ tPHL), and output impedance is symmetrical (|IOH| = |IOL| ≥ 24mA), ensuring consistent rise/fall times on 50Ω lines. Absolute maximum VCC is +7V, but recommended operation is strictly 2–6V with transient input slew rate limited to 8 ns/V.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	2V to 6V - supports dual-supply systems and battery-backed logic without level shifters
tPD (Typ.)	4.2ns at VCC = 5V - enables >100MHz toggle rates in synchronous control paths
IOL / IOH	≥24mA - drives standard 50Ω PCB traces directly without external buffers
VNIH / VNIL	28% VCC min - rejects noise spikes up to 1.4V on 5V rails
ICC (Max)	2µA at TA = 25°C - suitable for low-power standby modes in energy-sensitive designs
ESD Rating	2kV HBM - protects against handling-induced discharge during board assembly
Operating Temp	–55°C to +125°C - qualified for under-hood automotive and industrial motor control environments

Pinout & Package

74AC02B is housed in a 14-pin plastic dual in-line package (DIP-14) with 0.3" body width and 2.54mm lead pitch. Pin 7 is GND; Pin 14 is VCC. Four NOR gates share common power/ground rails.

Pin/Terminal	Circuit Role	Design Meaning
1, 4, 10, 13	1Y, 2Y, 3Y, 4Y	Active-low NOR outputs - sink/source ≥24mA, compatible with TTL and CMOS loads
2, 5, 8, 11	1A, 2A, 3A, 4A	First inputs per gate - accept 0–VCC logic levels with rail-proportional thresholds
3, 6, 9, 12	1B, 2B, 3B, 4B	Second inputs per gate - identical electrical specs to A inputs; fully interchangeable
7	GND	Ground reference - must be low-impedance connection to minimize ground bounce in fast switching
14	VCC	Positive supply - requires local 100nF ceramic decoupling within 1cm of pin

Key Features

Feature	Design Value
Symmetrical Output Drive	\|IOH\| = \|IOL\| ≥ 24mA ensures matched rise/fall times on 50Ω transmission lines
Balanced Propagation Delays	tPLH ≅ tPHL minimizes duty cycle distortion in clocked logic and pulse generation
High Noise Immunity	VNIH/VNIL = 28% VCC provides robust operation in electrically noisy industrial enclosures
Wide Supply Range	2V–6V operation allows direct interface with 3.3V microcontrollers and 5V legacy peripherals
Latch-Up Immunity	Enhanced process design prevents destructive latch-up under transient overvoltage conditions

Applications

Industrial Control Logic

Automotive Body Controller

Use Scenario: Discrete safety interlock monitoring in CNC machine tool cabinets where redundant NOR-based voting logic validates emergency stop signals.

IC Role / Device Role / Timing Role: Quad NOR gate implementing fail-safe combinatorial logic with <5ns delay uncertainty across all four channels.

Use Value: Eliminates need for external Schmitt triggers or RC filtering due to 28% VCC noise margin and rail-proportional input thresholds.

Use Scenario: Window lift control arbitration in door module ECUs, resolving simultaneous UP/DOWN commands into safe stop state.

IC Role / Device Role / Timing Role: Gate-level priority encoder core - each NOR pair resolves two switch inputs into mutually exclusive motor direction enable.

Use Value: 24mA drive capability directly interfaces with pre-driver ICs without buffer stages, reducing BOM count and PCB area.

Test Equipment Signal Conditioning

Legacy System Bus Interface

Use Scenario: Glitch suppression and signal synchronization in automated test fixture timing paths before FPGA capture.

IC Role / Device Role / Timing Role: Pulse-stretching and race-condition resolution element in 50Ω coaxial signal chains.

Use Value: Guaranteed 50Ω line driving and <8.5ns max propagation delay at –40°C to +85°C ensure deterministic timing across environmental stress tests.

Use Scenario: Address decode enable logic bridging 3.3V ARM processor bus to 5V peripheral memory and I/O expanders.

IC Role / Device Role / Timing Role: Level-tolerant NOR gate performing active-low chip select generation with no external biasing.

Use Value: 2V–6V VCC range and rail-proportional VIH/VIL allow direct connection between mixed-voltage domains without translators.

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input NOR gate applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74AC02N	TI-manufactured; identical AC specs but slightly higher ICC (4µA max) and lower ESD rating (1.5kV HBM)	Approved for TI-specific reference designs; same pinout and thermal profile	Select when sourcing from TI-authorized channels or requiring TI's qualification documentation
74VHC02N	Higher VCC max (7V), slower tPD (7.5ns typ), lower drive (±8mA), wider temp range (–40°C to +125°C)	Better suited for low-power, non-critical timing paths where speed is secondary to voltage margin	Choose for cost-sensitive consumer applications where 4.2ns delay is unnecessary and 7V absolute max adds margin

Compared with SN74AC02N and 74VHC02N, the 74AC02B delivers superior speed/noise immunity trade-off for industrial real-time logic, while maintaining full 74-series pin/function compatibility and extended temperature support.

Availability

74AC02B is available at Aetrix Electronics and suitable for industrial control logic, automotive body controllers, test equipment signal conditioning, and legacy system bus interface applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74AC02B 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, MCU, power, and logic devices for industrial, automotive, and consumer markets.

The 74AC logic family targets high-speed, low-power, mixed-voltage digital interfacing - optimized for noise resilience, transmission line driving, and drop-in replacement of legacy 74LS and 74HC devices.

FAQ

Is 74AC02B pin-compatible with standard 7402 devices?

Yes, 74AC02B is functionally and physically pin-compatible with industry-standard 7402 quad NOR gates in DIP-14 packages. All four gates use identical pin assignments (e.g., Pins 1–2–3 for Gate 1), and it maintains the same 14-pin layout, allowing direct replacement without PCB modification.

What is the maximum capacitive load the 74AC02B can drive reliably?

The 74AC02B is characterized for CL = 50 pF with RL = 500 Ω and input rise/fall times ≤3 ns. While it can drive heavier loads, sustained operation above 50 pF may increase propagation delay and cause ringing on unterminated lines; for >100 pF, series termination or buffer staging is recommended.

Does 74AC02B support 3.3V-only operation?

Yes, 74AC02B operates fully across 2V–6V, including 3.3V nominal supply. At VCC = 3.3V, VIH is guaranteed ≥2.1V and VIL ≤1.5V, making it interoperable with 3.3V LVTTL and LVCMOS logic families without level translation.

Can 74AC02B be used in place of 74HC02 in existing designs?

Yes, with caveats: 74AC02B offers faster speed (4.2ns vs. ~8ns), higher drive (24mA vs. 8mA), and better noise immunity than 74HC02. However, its higher ICC at high frequency and stricter input slew rate limit (8 ns/V) require verification of power integrity and signal edge control in legacy HC designs.

74AC02B Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: 74AC

Package/Case:: 14-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Logic Type:: NOR Gate

Number of Circuits:: 4

Number of Inputs:: 2

Features:: -

Voltage - Supply:: 2V ~ 6V

Current - Quiescent (Max):: 2 µA

Current - Output High, Low:: 24mA, 24mA

Input Logic Level - Low:: 0.9V ~ 1.65V

Input Logic Level - High:: 2.1V ~ 3.85V

Max Propagation Delay @ V, Max CL:: 8ns @ 5V, 50pF

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 14-DIP

74AC02B FAQ

1.How can I place an order for 74AC02B through Aetrix?

Please submit a Request for Quotation (RFQ) for 74AC02B on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 74AC02B reliable?

The price and inventory of 74AC02B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AC02B is usually 5 days.

3.What payment methods are accepted for 74AC02B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AC02B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74AC02B?

74AC02B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74AC02B order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 74AC02B?

For technical support, including 74AC02B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AC02B requirements.

6.How does Aetrix verify that 74AC02B is sourced from the original manufacturer or authorized distributors?

All 74AC02B products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 74AC02B meets industry standards.

7.What is the process for return or replacement of 74AC02B?

All 74AC02B units undergo pre-shipment inspection (PSI). If there is an issue with 74AC02B, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 74AC02B part is unused and in its original packaging.

Return procedure for 74AC02B:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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