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STMicroelectronics 74AC240MTR
- Part No.:
- 74AC240MTR
- Manufacturer:
- STMicroelectronics
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
74AC240MTR.pdf
- Description:
- IC BUFF INVERT 6V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,959
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Product details
Overview
74AC240MTR 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 in industrial control and embedded systems. It operates from 2V to 6V, delivers 24mA output drive (|IOH|/IOL), features 4.2ns typical propagation delay at 5V, and provides 2kV ESD immunity.
For engineers reviewing the 74AC240MTR datasheet, 74AC240MTR pinout, 74AC240MTR application, or 74AC240MTR equivalent, key selection criteria include symmetrical 24mA drive capability, 50Ω transmission line compatibility, latch-up immunity, 3-state enable timing (tPZL/tPLZ ≤ 10.5ns at 5V), and TSSOP-20 packaging for space-constrained PCB layouts.
Technical Context
The 74AC240 implements two independent 4-bit inverting 3-state buffers, each controlled by a dedicated active-low output enable (1G, 2G). Its C2MOS sub-micron fabrication enables rail-to-rail input tolerance (0–VCC) and low quiescent current (4µA max).
Propagation delays are balanced (tPLH ≅ tPHL), output impedance is symmetrical (|IOH| = IOL ≥ 24mA), and noise immunity meets VNIH/VNIL ≥ 28% VCC - enabling robust operation in noisy industrial environments with fast edge rates (dt/dv ≤ 8 ns/V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Operating Range | 2V to 6V - supports mixed-voltage system interfacing (e.g., 3.3V logic driving 5V buses) |
| tPD (Typ.) | 4.2ns at VCC = 5V - enables >100MHz bus toggle rates in address/data path buffering |
| IOL / IOH (Min.) | 24mA - drives 50Ω transmission lines directly without external termination resistors |
| ICC (Max.) | 4µA at TA = 25°C - ultra-low static power for battery-backed or energy-sensitive subsystems |
| VNIH / VNIL (Min.) | 28% VCC - rejects high-amplitude noise spikes on shared control buses |
| ESD Immunity | 2kV HBM - protects against handling-induced discharge during board assembly and field service |
| CIN / COUT | 5pF / 9pF - minimizes capacitive loading on upstream drivers and downstream receivers |
Pinout & Package
TSSOP-20 package: 4.4mm × 6.5mm body, 0.65mm pitch, lead-free, RoHS-compliant surface-mount outline with exposed pad not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | Output Enable (1G, 2G) | Active-low enables respective 4-bit buffer group; high-Z when asserted |
| 2,4,6,8 | Data Inputs (1A1–1A4) | Inverting inputs for first buffer group; compatible with TTL/CMOS logic levels |
| 3,5,7,9 | Data Outputs (1Y1–1Y4) | Inverted buffered outputs; drive strength matched to 50Ω line impedance |
| 11,13,15,17 | Data Inputs (2A1–2A4) | Inverting inputs for second independent buffer group |
| 12,14,16,18 | Data Outputs (2Y1–2Y4) | Inverted outputs with symmetrical rise/fall times and matched impedance |
| 10 | GND | Reference return for all I/O and supply currents; decoupling required within 5mm |
| 20 | VCC | Positive supply rail; requires local 100nF ceramic bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| 3-State Output Control | Dual independent enable inputs (1G/2G) allow selective isolation of two 4-bit data paths |
| Transmission Line Drive | 24mA drive into 50Ω loads eliminates need for series termination resistors on PCB traces |
| Balanced Propagation Delay | tPLH ≅ tPHL ensures minimal skew between rising/falling edges in timing-critical bus cycles |
| Latch-Up Immunity | Improved process design prevents destructive latch-up under transient overvoltage conditions |
| Rail-to-Rail Input Voltage | VI range = 0 to VCC allows direct interface with both 3.3V and 5V logic families without level shifters |
Applications
| Industrial PLC Backplane Interface | Embedded Memory Address Buffering |
|---|---|
Use Scenario: Isolating CPU address bus from multiple peripheral modules on a DIN-rail mounted controller backplane. IC Role / Device Role / Timing Role: Inverting 3-state buffer providing direction-controlled, noise-immune address latching with <10ns enable/disable timing. Use Value: Prevents bus contention during module hot-swap; 28% VCC noise margin rejects EMI from motor drives and relays. | Use Scenario: Driving SRAM/Flash address lines in a low-power medical data logger with intermittent wake-up cycles. IC Role / Device Role / Timing Role: Low-quiescent-current (4µA) buffer enabling fast address assertion while minimizing standby power draw. Use Value: Extends battery life by reducing leakage across 8-bit address path; 24mA drive ensures setup/hold compliance at 20MHz access rates. |
| Automotive Body Control Module | Test Equipment Digital Pattern Generator |
Use Scenario: Interfacing microcontroller GPIOs to CAN transceiver configuration pins and sensor multiplexer selects. IC Role / Device Role / Timing Role: Level-shifting and bus-isolation buffer operating across 2V–6V supply range to accommodate battery voltage fluctuations. Use Value: Maintains logic integrity during cold-crank (6.5V) and deep-discharge (2.2V) conditions without external regulators. | Use Scenario: Generating synchronized, high-fidelity digital stimulus waveforms for IC functional testing at 50MHz. IC Role / Device Role / Timing Role: Precision-delayed (4.2ns typ.), low-skew inverter buffer shaping clock and data edges before DUT input. Use Value: Enables sub-nanosecond edge placement accuracy; 5pF input capacitance minimizes driver loading and jitter accumulation. |
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 |
|---|---|---|---|
| SN74AC240N | DIP-20 package; higher COUT (12pF vs. 9pF); 10ns max tPLH at 5V | Suitable for prototyping and through-hole legacy designs; less suitable for high-density routing | Select for breadboard evaluation or repair of existing DIP-based systems |
| 74LVC240APW | Lower VCC range (1.65–3.6V); 24mA drive only at 3.3V; 3.5ns tPD typ. at 3.3V | Optimized for modern 3.3V-only systems; incompatible with 5V buses | Select when full 5V tolerance is unnecessary and board uses only 3.3V logic rails |
Compared with SN74AC240N and 74LVC240APW, the 74AC240MTR uniquely balances 5V bus compatibility, TSSOP-20 footprint efficiency, and 24mA drive across 2–6V - making it optimal for industrial upgrades requiring mixed-voltage interoperability and space-constrained layouts.
Availability
74AC240MTR is available at Aetrix Electronics and suitable for industrial PLC backplanes, embedded memory subsystems, automotive body controllers, and automated test equipment requiring stable component supply and long-term obsolescence management.
Supply support for 74AC240MTR 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, delivering silicon solutions for automotive, industrial, and power management applications since 1987.
The 74AC logic family was engineered for high-speed, low-power, pin-compatible upgrades to legacy 74LS and 74F devices - targeting industrial control, instrumentation, and communications infrastructure where reliability and voltage flexibility are critical.
FAQ
What is the maximum output current per pin for continuous DC operation?
The 74AC240MTR supports ±24mA DC output current per pin under specified conditions (VOH at VCC−0.1V, VOL at 0.1V), with absolute maximum ratings allowing ±50mA short-duration pulses. Continuous operation above 24mA risks exceeding thermal limits and violating VOH/VOL specifications - derating is required above 85°C ambient.
Does the 74AC240MTR support hot insertion into a live bus?
No - while the device includes 2kV HBM ESD protection and improved latch-up immunity, it lacks powered-off protection circuitry (e.g., Ioff). Inserting or removing the TSSOP-20 package while VCC or signals are active may cause bus contention, ground bounce, or damage due to uncontrolled current paths.
Can the 74AC240MTR drive a 100Ω differential pair directly?
No - its 24mA drive is optimized for single-ended 50Ω loads. Driving a 100Ω differential pair would require 50mA per leg to achieve proper termination and signal integrity. Use a dedicated LVDS or RS-422 driver for differential signaling; this device is intended for parallel bus and point-to-point single-ended interconnects.
Is the 74AC240MTR functionally identical to the 74ACT240?
No - the 74ACT240 uses TTL-compatible input thresholds (VIH = 2.0V min), while the 74AC240 has CMOS thresholds (VIH = 2.1V at 3V, scaling with VCC). The ACT version draws higher ICC (max 80µA vs. 4µA) and exhibits faster tPD (3.5ns typ. at 5V), but lacks the AC's rail-to-rail input tolerance and lower power profile.
74AC240MTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- 74AC
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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:
- 24mA, 24mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
74AC240MTR FAQ
1.How can I place an order for 74AC240MTR through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AC240MTR 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 74AC240MTR reliable?
The price and inventory of 74AC240MTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AC240MTR is usually 5 days.
3.What payment methods are accepted for 74AC240MTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AC240MTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74AC240MTR?
74AC240MTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AC240MTR 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 74AC240MTR?
For technical support, including 74AC240MTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AC240MTR requirements.
6.How does Aetrix verify that 74AC240MTR is sourced from the original manufacturer or authorized distributors?
All 74AC240MTR 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 74AC240MTR meets industry standards.
7.What is the process for return or replacement of 74AC240MTR?
All 74AC240MTR units undergo pre-shipment inspection (PSI). If there is an issue with 74AC240MTR, 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 74AC240MTR part is unused and in its original packaging.
Return procedure for 74AC240MTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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