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Home > Products > Integrated Circuits (ICs) > Logic > Signal Switches, Multiplexers, Decoders

STMicroelectronics M74HC298B1R

Name: M74HC298B1R
Brand: STMicroelectronics
SKU: M74HC298B1R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M74HC298B1R

Manufacturer:: STMicroelectronics

Category:: Signal Switches, Multiplexers, Decoders

Package:: 16-DIP (0.300", 7.62mm)

Datasheet:: M74HC298B1R.pdf

Description:: IC MULTIPLEXER 4 X 2:1 16DIP

Quantity:: RFQ Add To RFQ list

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Inventory:1,675

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Product details

Overview

M74HC298B1R from STMicroelectronics is a high-speed CMOS quad 2-channel multiplexer/register with edge-triggered clocking, pin- and function-compatible with 74-series 298 logic. It features dual-word selection (A1/B1/C1/D1 or A2/B2/C2/D2), negative-edge clock capture, symmetrical 4 mA output drive, 79 MHz max clock frequency at 6 V, and operation from 2 V to 6 V supply.

For engineers reviewing the M74HC298B1R datasheet, M74HC298B1R pinout, M74HC298B1R application, or M74HC298B1R equivalent, key selection criteria include word-select timing margins, negative-edge register behavior, dual-input multiplexing capability, and DIP-16 package compatibility with legacy 74-series layouts.

Technical Context

The M74HC298B1R implements four independent 2:1 data selectors feeding D-type flip-flops clocked on the falling edge of CLOCK. WORD SELECT determines which of two parallel 4-bit words (Word 1 or Word 2) is latched to QA–QD outputs. All inputs include ESD protection diodes and transient voltage clamping.

Its C2MOS silicon gate process enables low ICC (4 µA max at 25°C), high noise immunity (28% VCC min), and balanced tPLH/tPHL propagation delays. The device operates across –55°C to +125°C with input rise/fall time support up to 1000 ns at 2 V and down to 400 ns at 6 V.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	2 V to 6 V - supports mixed-voltage system interfacing and battery-powered 3.3 V/5 V designs
fMAX	79 MHz (typ.) at VCC = 6 V - enables high-throughput data routing in synchronous logic systems
IOL / IOH	±4 mA (min) - drives standard TTL loads and multiple 74HC inputs without buffering
tPLH / tPHL	13 ns / 13 ns (typ., VCC = 6 V) - ensures deterministic setup/hold timing for cascaded register stages
VNIH / VNIL	28% VCC (min) - provides robust noise margin against ground bounce and supply ripple
ICC (quiescent)	4 µA (max, TA = 25°C) - suitable for ultra-low-power standby modes in portable instrumentation
Operating Temp	–55°C to +125°C - qualified for industrial control, automotive under-hood, and aerospace environments

Pinout & Package

Package: Plastic DIP-16 (0.300" wide), JEDEC MS-001, body dimensions 20.0 mm × 6.8 mm × 3.3 mm.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 5, 6 A2, B2, C2, D2	Word 2 Data Inputs	Second set of 4-bit parallel data inputs selected when WORD SELECT = HIGH
3, 4, 7, 9 A1, B1, C1, D1	Word 1 Data Inputs	First set of 4-bit parallel data inputs selected when WORD SELECT = LOW
10 WORD SELECT	Word Selection Control	Static-level control determining active input word; no internal debouncing required
11 CLOCK	Negative-Edge Clock Input	Triggers synchronous latching of selected word to QA–QD on falling transition only
12–15 QA, QB, QC, QD	Registered Outputs	Edge-triggered outputs retain latched word until next CLOCK falling edge
8 GND	Ground Reference	0 V return path for all logic and power currents; requires low-impedance PCB plane
16 VCC	Positive Supply	Primary power rail; decoupling capacitor (100 nF) recommended within 1 cm of pin

Key Features

Feature	Design Value
Dual-word multiplexing + register	Enables time-multiplexed acquisition of two sensor banks or memory banks with synchronized output hold
Negative-edge clock triggering	Eliminates need for external inverters when synchronizing with rising-edge master clocks
74-series pin/function compatibility	Direct drop-in replacement for legacy 74LS298/74ALS298 in existing DIP-16 footprints
High noise immunity (28% VCC)	Reduces susceptibility to crosstalk in dense PCB layouts with shared ground planes
Wide VCC range (2–6 V)	Supports direct interface with 3.3 V microcontrollers and 5 V legacy peripherals without level shifters

Applications

Data Acquisition System

Industrial PLC I/O Module

Use Scenario: Simultaneous sampling of two sets of analog sensors (e.g., temperature and pressure) using shared ADC resources.

IC Role / Device Role / Timing Role: Multiplexes and registers sensor data words prior to serial readout; WORD SELECT toggles between channels, CLOCK aligns sampling to system timing.

Use Value: Reduces component count by eliminating separate multiplexers and D-flip-flop arrays while ensuring glitch-free channel switching.

Use Scenario: Isolating and latching field I/O status (e.g., 4 digital inputs per group) before CPU polling cycle.

IC Role / Device Role / Timing Role: Acts as synchronized input latch; WORD SELECT selects between local and remote I/O racks, CLOCK captures state on scan boundary.

Use Value: Guarantees atomic snapshot of 8-bit input state with deterministic timing, avoiding metastability in multi-rack configurations.

Legacy Bus Interface Adapter

Test Equipment Signal Routing

Use Scenario: Adapting 8-bit parallel data between 5 V ISA bus and 3.3 V FPGA controller with direction-controlled word selection.

IC Role / Device Role / Timing Role: Level-tolerant multiplexer/register bridging mismatched voltage domains; WORD SELECT controls bus direction, CLOCK synchronizes transfers.

Use Value: Enables bidirectional data handshaking without external level translators or glue logic.

Use Scenario: Routing calibration signals between multiple instrument sources (e.g., reference DACs) and DUT inputs in automated test systems.

IC Role / Device Role / Timing Role: Provides glitch-free signal path selection and stable output hold during reconfiguration; CLOCK edges trigger path updates.

Use Value: Prevents transient glitches during signal switching, critical for precision DC and low-frequency AC measurements.

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-channel multiplexer/register applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74HC298N	Same logic function and pinout; TI version rated for –40°C to +85°C only (vs. –55°C to +125°C)	Limited to commercial/industrial ambient; not suitable for extended temperature deployments	Select when operating temperature ≤ 85°C and TI supply chain preference applies
74VHC298N	Higher fMAX (110 MHz typ. at 5 V); lower ICC (2 µA max); but reduced noise margin (20% VCC)	Better speed/power trade-off for high-frequency logic, but less tolerant of noisy supply rails	Select for timing-critical paths where supply stability exceeds 95% and ambient ≤ 85°C

Compared with SN74HC298N and 74VHC298N, the M74HC298B1R offers superior extended-temperature qualification and higher noise immunity-critical for ruggedized instrumentation-while maintaining full 74-series footprint compatibility and proven reliability in long-lifecycle industrial designs.

Availability

M74HC298B1R is available at Aetrix Electronics and suitable for industrial PLC I/O modules, legacy bus interface adapters, and precision test equipment requiring stable component supply over extended product lifecycles.

Supply support for M74HC298B1R 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, Switzerland, specializing in automotive, industrial, and power management ICs with vertical manufacturing capabilities.

The M74HC298B1R belongs to ST's high-speed HC logic family, designed specifically for reliable, low-power, pin-compatible upgrades of legacy 74-series logic in mission-critical industrial and instrumentation systems.

FAQ

What is the clocking behavior of the M74HC298B1R?

The M74HC298B1R uses negative-edge clock triggering: the selected word (Word 1 or Word 2) is latched to QA–QD outputs only on the falling edge of the CLOCK signal. This eliminates race conditions when cascading with rising-edge synchronous logic and avoids need for external clock inversion.

Can M74HC298B1R operate at 3.3 V?

Yes. The device is fully specified for VCC = 2 V to 6 V, including 3.3 V operation. At 3.3 V, it delivers 4 mA output drive, 25 ns typical propagation delay, and maintains 28% VCC noise margin (0.92 V), making it compatible with 3.3 V microcontrollers and FPGAs without level shifting.

Is M74HC298B1R pin-compatible with older 74LS298 devices?

Yes-M74HC298B1R is pin- and function-compatible with 74LS298 and 74ALS298 in DIP-16 packages. However, it requires no external pull-ups, draws significantly less current, and operates over wider voltage and temperature ranges, enabling direct drop-in replacement with improved performance and reliability.

Does M74HC298B1R require external decoupling capacitors?

Yes. A 100 nF ceramic capacitor must be placed between VCC (pin 16) and GND (pin 8), located within 1 cm of the IC, to suppress high-frequency supply noise generated during output transitions and ensure stable operation at maximum clock frequency.

M74HC298B1R Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: 74HC

Package/Case:: 16-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Type:: Multiplexer

Circuit:: 4 x 2:1

Independent Circuits:: 1

Current - Output High, Low:: 5.2mA, 5.2mA

Voltage Supply Source:: Single Supply

Voltage - Supply:: 2V ~ 6V

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 16-DIP

M74HC298B1R FAQ

1.How can I place an order for M74HC298B1R through Aetrix?

Please submit a Request for Quotation (RFQ) for M74HC298B1R 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 M74HC298B1R reliable?

The price and inventory of M74HC298B1R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M74HC298B1R is usually 5 days.

3.What payment methods are accepted for M74HC298B1R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M74HC298B1R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M74HC298B1R?

M74HC298B1R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M74HC298B1R 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 M74HC298B1R?

For technical support, including M74HC298B1R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M74HC298B1R requirements.

6.How does Aetrix verify that M74HC298B1R is sourced from the original manufacturer or authorized distributors?

All M74HC298B1R 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 M74HC298B1R meets industry standards.

7.What is the process for return or replacement of M74HC298B1R?

All M74HC298B1R units undergo pre-shipment inspection (PSI). If there is an issue with M74HC298B1R, 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 M74HC298B1R part is unused and in its original packaging.

Return procedure for M74HC298B1R:

1.Submit a request within 90 days.

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

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