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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

STMicroelectronics M74HC240TTR

Name: M74HC240TTR
Brand: STMicroelectronics
SKU: M74HC240TTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M74HC240TTR

Manufacturer:: STMicroelectronics

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-TSSOP (0.173", 4.40mm Width)

Datasheet:: M74HC240TTR.pdf

Description:: IC BUFFER INVERT 6V 20TSSOP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

M74HC240TTR from STMicroelectronics is an advanced high-speed CMOS octal bus buffer with 3-state inverted outputs, designed for memory address driving and bidirectional bus interfacing. It features symmetrical output impedance (|IOH| = IOL ≥ 6 mA), wide supply range (2–6 V), propagation delay of 10 ns (typ. at 6 V), and high noise immunity (VNIH/VNIL ≥ 28% VCC). Used in industrial control backplanes and legacy 5 V logic systems.

For engineers reviewing the M74HC240TTR datasheet, M74HC240TTR pinout, M74HC240TTR application, or M74HC240TTR equivalent, key selection criteria include 3-state enable timing (tPZL/tPLZ ≤ 32 ns at 6 V), rail-to-rail input compatibility (VI = 0 to VCC), and TSSOP-20 thermal performance (max PD = 300 mW above 65 °C).

Technical Context

The M74HC240TTR implements two independent 4-bit inverting 3-state buffers, each controlled by a dedicated active-low output enable (1G, 2G). Its C2MOS silicon gate process enables low ICC (4 µA max at 25 °C) while maintaining TTL-compatible drive strength across 2–6 V operation.

All inputs include ESD and transient voltage protection. Propagation delays are balanced (tPLH ≅ tPHL), and output transition times remain consistent across VCC (6–10 ns typ. at 6 V, CL = 50 pF), supporting reliable timing in synchronous bus architectures.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	2 V to 6 V - supports mixed-voltage system interfacing and battery-backed 3.3 V/5 V designs
Propagation Delay (tPD)	10 ns (typ. at VCC = 6 V, CL = 50 pF) - enables ≤50 MHz bus toggle rates in buffered address paths
Output Drive Strength	\|IOH\| = IOL ≥ 6 mA (min) - sufficient to drive 50 pF loads with <10 ns rise/fall under worst-case conditions
Quiescent Current (ICC)	4 µA (max at TA = 25 °C) - enables ultra-low static power in always-on control logic
Noise Immunity	VNIH/VNIL ≥ 28% VCC (min) - rejects >1.2 V peak noise on 5 V buses without false triggering
3-State Enable/Disable Time	tPZL/tPLZ ≤ 32 ns (max at VCC = 6 V) - ensures clean bus release before next cycle in multiplexed memory systems

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, exposed pad not present, JEDEC MO-153 compliant.

Pin/Terminal	Circuit Role	Design Meaning
1, 19	Output Enable (1G, 2G)	Active-low enables respective 4-bit buffer group; tied high disables all outputs to high-Z
2,4,6,8 / 11,13,15,17	Data Inputs (1A1–1A4, 2A1–2A4)	Inverting inputs - logic high yields low output when enabled
3,5,7,9 / 12,14,16,18	Data Outputs (1Y1–1Y4, 2Y1–2Y4)	Inverted buffered outputs - high-Z when corresponding G is high
10	GND	Logic and power ground reference; decoupling capacitor required within 5 mm
20	VCC	Positive supply; must be bypassed locally to GND with 100 nF ceramic capacitor

Key Features

Feature	Design Value
Inverting 3-state octal buffer	Two independent 4-bit groups with separate enable pins - enables selective bus partitioning in multi-master systems
High noise immunity	VNIH/VNIL ≥ 28% VCC - eliminates need for external Schmitt triggers in noisy industrial environments
Symmetrical output drive	\|IOH\| = IOL ≥ 6 mA - ensures matched rise/fall times and reduced signal skew on shared data lines
Wide voltage operation	2–6 V supply range - interoperable with 3.3 V microcontrollers and 5 V legacy peripherals without level shifters

Applications

Industrial PLC Backplane

Legacy Memory Address Buffering

Use Scenario: Isolating CPU address bus from multiple peripheral modules in modular I/O racks.

IC Role / Device Role / Timing Role: Inverting 3-state buffer providing direction-controlled address latching and bus contention prevention.

Use Value: Enables hot-swap module insertion without address bus glitches due to fast disable time (tPLZ ≤ 32 ns at 6 V).

Use Scenario: Driving 20-bit address lines for EPROM/Flash memory in retro-computing or test equipment.

IC Role / Device Role / Timing Role: Level-shifting and fanout expansion for microprocessor address outputs.

Use Value: Supports 5 V TTL-compatible loading while operating from 3.3 V supply via VCC tolerance - reduces BOM count.

Automotive Body Control Module

Test Equipment Signal Conditioning

Use Scenario: Interfacing microcontroller GPIOs to relay driver ICs requiring inverted enable signals.

IC Role / Device Role / Timing Role: Inverting logic-level translator with 3-state isolation during sleep mode.

Use Value: Quiescent current ≤ 4 µA prevents battery drain during vehicle off-state; -40 to 125 °C rating ensures under-hood reliability.

Use Scenario: Generating synchronized, inverted stimulus patterns for DUT input testing in ATE systems.

IC Role / Device Role / Timing Role: Precision-timed inverting buffer with matched tPLH/tPHL for deterministic edge alignment.

Use Value: Balanced propagation delays (Δt < 2 ns) eliminate setup/hold violations in high-speed pattern generators.

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal inverting 3-state buffer applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74HC240PW	Same logic function, identical AC specs, but TI's PW package has larger footprint (7.2 × 5.3 mm vs. 6.5 × 4.4 mm) and higher thermal resistance	Less suitable for space-constrained PCBs; requires different land pattern and stencil	Select if existing design uses TI's SOIC-20 footprint and no board rework is allowed
74VHC240FT	Higher speed (tPD = 5.5 ns typ. at 5 V), lower ICC (2 µA), but narrower VCC range (2–5.5 V) and no -55 °C rating	Not qualified for extended temperature automotive or military use	Prefer for commercial-grade high-speed applications where 0.5 V headroom at VCC = 6 V is unnecessary

Compared with SN74HC240PW and 74VHC240FT, the M74HC240TTR offers the widest temperature range (-55 to +125 °C), smallest TSSOP footprint, and guaranteed 6 V operation - making it optimal for ruggedized embedded systems where thermal margin and board area are critical.

Availability

M74HC240TTR is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, legacy memory subsystems, and automated test equipment requiring stable component supply over extended lifecycles.

Supply support for M74HC240TTR 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, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.

The M74HC240TTR belongs to ST's high-speed HC logic family, engineered for robustness in harsh environments and backward compatibility with legacy 74-series systems while delivering improved power efficiency and noise immunity.

FAQ

Is the M74HC240TTR pin-compatible with standard 74LS240 devices?

Yes - it is pin- and function-compatible with the 74LS240, including identical pin numbering and inverted 3-state behavior. However, it operates at higher speeds (10 ns vs. 25 ns typical) and draws significantly less quiescent current (4 µA vs. ~20 mA), requiring no additional heat sinking in most layouts.

What is the maximum capacitive load this device can drive reliably?

The M74HC240TTR is characterized up to 50 pF (AC specs), but its 6 mA output drive supports stable operation into ≥100 pF with acceptable rise/fall times (<25 ns) at VCC = 6 V. For loads >75 pF, add series termination or reduce trace length to maintain signal integrity.

Does this part support partial power-down or I/O floating when VCC = 0 V?

No - the M74HC240TTR lacks Ioff protection. When VCC = 0 V, inputs and outputs may sink current if driven externally, risking latch-up or damage. Always power VCC before applying input signals, or use external isolation diodes in hot-swap scenarios.

Can both output enable inputs (1G and 2G) be tied together for unified control?

Yes - tying 1G and 2G together simplifies control logic and provides full 8-bit 3-state operation. Ensure the combined enable net has adequate drive strength (fanout ≤ 10 LS-TTL loads) and meets setup/hold timing relative to input transitions per the truth table.

M74HC240TTR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: 74HC

Package/Case:: 20-TSSOP (0.173", 4.40mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Logic Type:: Buffer, Inverting

Number of Elements:: 2

Number of Bits per Element:: 4

Input Type:: -

Output Type:: 3-State

Current - Output High, Low:: 7.8mA, 7.8mA

Voltage - Supply:: 2V ~ 6V

Operating Temperature:: -55°C ~ 125°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-TSSOP

M74HC240TTR FAQ

1.How can I place an order for M74HC240TTR through Aetrix?

Please submit a Request for Quotation (RFQ) for M74HC240TTR 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 M74HC240TTR reliable?

The price and inventory of M74HC240TTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M74HC240TTR is usually 5 days.

3.What payment methods are accepted for M74HC240TTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M74HC240TTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M74HC240TTR?

M74HC240TTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M74HC240TTR 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 M74HC240TTR?

For technical support, including M74HC240TTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M74HC240TTR requirements.

6.How does Aetrix verify that M74HC240TTR is sourced from the original manufacturer or authorized distributors?

All M74HC240TTR 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 M74HC240TTR meets industry standards.

7.What is the process for return or replacement of M74HC240TTR?

All M74HC240TTR units undergo pre-shipment inspection (PSI). If there is an issue with M74HC240TTR, 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 M74HC240TTR part is unused and in its original packaging.

Return procedure for M74HC240TTR:

1.Submit a request within 90 days.

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

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