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NXP Semiconductors 74HCT240DB,112
- Part No.:
- 74HCT240DB,112
- Manufacturer:
- NXP Semiconductors
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
74HCT240DB,112.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,934
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Product details
Overview
74HCT240DB,112 from Nexperia is an octal inverting 3-state buffer/line driver IC used for bus isolation and signal conditioning in digital systems. It features dual independent 4-bit sections (1A0–1A3 / 2A0–2A3), two active-low output enables (1OE, 2OE), TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 5 V), propagation delay of 9 ns (typ) at 5 V/15 pF, and operates from −40 °C to +125 °C. It is commonly deployed in industrial control backplanes and microcontroller I/O expansion interfaces.
For engineers reviewing the 74HCT240DB,112 datasheet, 74HCT240DB,112 pinout, 74HCT240DB,112 application, or 74HCT240DB,112 equivalent, key selection criteria include its TTL-level input compatibility, dual 4-bit enable control, 3-state output drive capability (±6 mA), SO20 package footprint, and guaranteed operation across extended temperature range - critical for legacy bus interface and board-level signal routing designs.
Technical Context
The 74HCT240DB,112 implements two independent 4-bit inverting buffers, each controlled by a dedicated active-low output enable (1OE for outputs 1Y0–1Y3; 2OE for 2Y0–2Y3). Its TTL-compatible inputs accept standard 5 V logic levels while operating from a single 4.5–5.5 V supply, enabling direct interfacing with legacy microcontrollers and FPGAs without level translation.
All eight outputs are 3-state capable with high-impedance OFF-state leakage ≤ ±5 μA (VCC = 5.5 V), and the device supports simultaneous bus driving and tri-state arbitration. Input clamping diodes allow safe interfacing to voltages exceeding VCC when current-limiting resistors are used - a feature leveraged in mixed-voltage system debug and test access points.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Octal inverting 3-state buffer; dual 4-bit sections with independent enables |
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with 5 V TTL and mixed-signal systems |
| Input Thresholds | VIH = 2.0 V min, VIL = 0.8 V max - matches standard TTL logic families without level shifters |
| Propagation Delay | 9 ns (typ) at VCC = 5.0 V, CL = 15 pF - supports 30+ MHz bus toggle rates in synchronous applications |
| Output Drive | ±6 mA at VOH/VOL - sufficient to drive 50 Ω transmission lines or 10 LSTTL loads |
| Operating Temp | −40 °C to +125 °C - qualified for industrial and under-hood automotive auxiliary circuits |
| ESD Rating | HBM > 2000 V, CDM > 1000 V - robust handling during PCB assembly and field service |
Pinout & Package
74HCT240DB,112 is supplied in a plastic small outline package (SO20, SOT163-1) with 20 leads, 7.5 mm body width, and standard 1.27 mm lead pitch. Pin 1 is marked by a beveled corner or notch on the package top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output enable inputs - each controls four inverting outputs; tied HIGH disables respective section |
| 2, 4, 6, 8 | 1A0–1A3 | First 4-bit inverting input group - drives outputs 1Y0–1Y3 when 1OE = LOW |
| 3, 5, 7, 9 | 2Y0–2Y3 | Second 4-bit inverting output group - driven by 2A0–2A3 when 2OE = LOW |
| 10 | GND | Ground reference for all logic and power domains - must be low-impedance connection |
| 11, 13, 15, 17 | 2A0–2A3 | Second 4-bit inverting input group - drives outputs 2Y0–2Y3 when 2OE = LOW |
| 12, 14, 16, 18 | 1Y0–1Y3 | First 4-bit inverting output group - driven by 1A0–1A3 when 1OE = LOW |
| 20 | VCC | Positive supply rail - decoupling capacitor (100 nF) required within 10 mm of this pin |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Accepts standard 5 V TTL logic levels (VIH ≥ 2.0 V, VIL ≤ 0.8 V) - eliminates need for external level translators |
| Dual independent enables | 1OE and 2OE allow selective activation of two 4-bit buses - enables flexible memory-mapped I/O or peripheral multiplexing |
| Clamped inputs | Integrated input clamp diodes permit safe overvoltage tolerance up to VCC + 0.5 V with current limiting - useful for JTAG/debug port sharing |
| High noise immunity | Typical noise margin > 0.8 V at VCC = 5 V - resists EMI in motor drive and power supply proximity |
| Extended temperature range | Specified from −40 °C to +125 °C - supports deployment in industrial PLCs and automotive body control modules |
Applications
| Industrial Backplane Interface | Microcontroller I/O Expansion |
|---|---|
|
Use Scenario: Isolating and buffering address/data lines between a main controller and multiple slave modules on a DIN-rail mounted PLC backplane. IC Role / Device Role / Timing Role: Inverting 3-state buffer providing bidirectional bus contention control and signal integrity restoration across 200 mm traces. Use Value: Enables hot-swap capability via controlled 3-state sequencing and reduces crosstalk-induced setup/hold violations by driving 15 pF loads with <9 ns delay. |
Use Scenario: Expanding GPIO count of an ARM Cortex-M0+ MCU to drive 8-channel LED indicators and pushbutton inputs in a smart sensor node. IC Role / Device Role / Timing Role: Level-shifting buffer translating MCU's 3.3 V outputs to 5 V logic while inverting signals for common-anode LED drive. Use Value: Eliminates discrete transistor arrays; TTL input compatibility allows direct connection to MCU pins without pull-ups or voltage dividers. |
| Legacy Bus Arbitration | Test Access Port Multiplexing |
|
Use Scenario: Managing shared ISA-style data bus among three legacy peripherals (ADC, DAC, UART) in a test instrumentation rack. IC Role / Device Role / Timing Role: Dual-section 3-state driver enabling time-multiplexed bus access with hardware-controlled enable timing. Use Value: Prevents bus contention during state transitions; ±6 mA drive strength sustains signal integrity across 30 cm ribbon cable runs. |
Use Scenario: Sharing a single JTAG header between FPGA configuration, MCU debug, and CPLD programming on a multi-FPGA development board. IC Role / Device Role / Timing Role: Signal isolator with clamped inputs allowing safe 5 V test equipment connection to 3.3 V target logic domains. Use Value: Input clamping diodes protect downstream devices from accidental 5 V probe contact; 3-state outputs prevent back-driving during reconfiguration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74HCT240D,653 | Same logic function, identical SO20 package (SOT163-1), but rated only to +85 °C ambient | Limited to commercial/office environments; unsuitable for industrial enclosures with elevated ambient | Select when cost sensitivity outweighs extended temperature requirement and thermal derating is acceptable |
| SN74HCT240N | DIP-20 package (0.3" wide), same electrical specs, no thermal enhancement; Ptot = 500 mW (vs. 500 mW in SO20) | Designed for through-hole prototyping and legacy board repair; lacks SO20's thermal performance in dense layouts | Choose for hand-soldered evaluation or replacement in existing DIP-based systems where rework is constrained |
Compared with 74HCT240DB,112, the 74HCT240D,653 sacrifices extended temperature support for lower unit cost, while SN74HCT240N trades surface-mount efficiency and thermal reliability for mechanical compatibility with breadboards and socketed designs - making DB,112 optimal for production-grade industrial PCBs requiring long-term thermal stability.
Availability
74HCT240DB,112 is available at Aetrix Electronics and suitable for industrial control backplanes, microcontroller I/O expansion, legacy bus arbitration, and test access port multiplexing requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for 74HCT240DB,112 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
Nexperia is a global semiconductor expert delivering high-performance logic, analog, and MOSFET solutions optimized for efficiency, reliability, and manufacturability in high-volume applications.
The 74HCT240DB,112 belongs to Nexperia's 74HCT logic family, engineered specifically for seamless integration with legacy TTL systems while maintaining CMOS power efficiency and robustness in industrial environments.
FAQ
What is the maximum clock frequency supported by the 74HCT240DB,112?
The 74HCT240DB,112 is not a clocked device and has no internal clock; it is a combinational buffer. Its usable toggle rate depends on propagation delay (9 ns typ) and load capacitance. With 15 pF load and 5 V supply, it supports reliable data bus toggling up to approximately 30 MHz, assuming adequate setup/hold margins and PCB layout control.
Can 74HCT240DB,112 drive a 50 Ω transmission line directly?
Yes - with VOH ≥ 3.7 V and VOL ≤ 0.4 V at ±6 mA (VCC = 4.5 V), the 74HCT240DB,112 can drive a 50 Ω line terminated at the far end. However, series termination (e.g., 33 Ω at source) is recommended to suppress reflections, especially for trace lengths >10 cm or edge rates <2 ns.
Is the GND pin (Pin 10) electrically connected to the exposed pad in SO20 packages?
No - the SO20 package (SOT163-1) used for 74HCT240DB,112 does not include an exposed thermal pad. Pin 10 is the sole GND connection. Unlike QFN variants, this package relies on lead-frame conduction; no thermal pad soldering or grounding is applicable.
Does 74HCT240DB,112 support mixed-voltage operation (e.g., 3.3 V inputs with 5 V VCC)?
No - the 74HCT240DB,112 requires input voltages compatible with its VCC-supply-referenced TTL thresholds. With VCC = 5 V, VIH must be ≥2.0 V and VIL ≤0.8 V. Applying 3.3 V inputs meets VIH but risks marginal noise margin; for true 3.3 V–5 V interfacing, a 74LVC240 or level translator is required.
74HCT240DB,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74HCT
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
74HCT240DB,112 FAQ
1.How can I place an order for 74HCT240DB,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HCT240DB,112 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 74HCT240DB,112 reliable?
The price and inventory of 74HCT240DB,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HCT240DB,112 is usually 5 days.
3.What payment methods are accepted for 74HCT240DB,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HCT240DB,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HCT240DB,112?
74HCT240DB,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HCT240DB,112 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 74HCT240DB,112?
For technical support, including 74HCT240DB,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HCT240DB,112 requirements.
6.How does Aetrix verify that 74HCT240DB,112 is sourced from the original manufacturer or authorized distributors?
All 74HCT240DB,112 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 74HCT240DB,112 meets industry standards.
7.What is the process for return or replacement of 74HCT240DB,112?
All 74HCT240DB,112 units undergo pre-shipment inspection (PSI). If there is an issue with 74HCT240DB,112, 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 74HCT240DB,112 part is unused and in its original packaging.
Return procedure for 74HCT240DB,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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