My Inquiry
My Account
Texas Instruments SN74HC240NG4
- Part No.:
- SN74HC240NG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74HC240NG4.pdf
- Description:
- IC BUFFER INVERT 6V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,623
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74HC240NG4 from Texas Instruments is an octal inverting buffer/line driver with 3-state outputs, designed for memory address and bus driving applications. It operates across 2V–6V, delivers ±6mA output drive at 5V, exhibits typical propagation delay of 9ns, and consumes ≤80µA ICC - enabling high-density, low-power bus interfacing in industrial control and embedded systems.
For engineers reviewing the SN74HC240NG4 datasheet, SN74HC240NG4 pinout, SN74HC240NG4 application, or SN74HC240NG4 equivalent, key selection criteria include its dual 4-bit inverting architecture, independent OE controls per group, 3-state output behavior, and compatibility with LSTTL loads in space-constrained PCB layouts.
Technical Context
The SN74HC240NG4 implements two independent 4-bit inverting buffer sections, each with dedicated output-enable (OE) inputs. When OE is low, inverted logic passes from A inputs to Y outputs; when OE is high, all eight outputs enter high-impedance state - enabling bidirectional bus sharing without external logic.
Its CMOS HC-family design ensures rail-to-rail input thresholds, low input current (≤1µA), and robust noise immunity. The device supports mixed-voltage interfacing within its 2V–6V supply range and drives up to 15 LSTTL loads while maintaining stable timing performance across –40°C to +85°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2V to 6V - enables direct interface with 3.3V and 5V logic domains without level shifters. |
| Output Drive Capability | ±6mA at 5V - sufficient to directly drive 15 LSTTL loads or terminate short PCB traces. |
| Propagation Delay (tpd) | Typical 9ns at VCC = 4.5V, CL = 50pF - supports >50MHz bus toggle rates in synchronous systems. |
| Quiescent Current (ICC) | Max 80µA at 6V - minimizes standby power in battery-backed or energy-sensitive applications. |
| Input Leakage Current | Max 1µA - prevents unintended logic transitions on unterminated or high-impedance control lines. |
| 3-State Enable/Disable Time | ten = 25ns, tdis = 32ns at 4.5V - ensures clean bus arbitration with minimal contention window. |
Pinout & Package
SN74HC240NG4 is supplied in a 20-pin PDIP (Plastic Dual In-line Package) with 0.300-inch body width and standard through-hole mounting. Pin spacing is 0.100 inch, compatible with legacy prototyping and industrial PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 19OE | Active-low output enable inputs | Independently control 3-state behavior of Group 1 (pins 2,4,6,8 → 17,15,13,11) and Group 2 (pins 18,16,14,12 → 3,5,7,9). |
| 1A1–1A4, 2A1–2A4 | Input terminals | Eight logic inputs accepting standard CMOS voltage thresholds; must be tied to VCC or GND if unused to prevent floating states. |
| 1Y1–1Y4, 2Y1–2Y4 | Inverting buffered outputs | Drive inverted copies of respective A inputs when OE is low; present high-Z impedance otherwise - essential for shared bus topology. |
| VCC (Pin 20), GND (Pin 10) | Power supply connections | Require local 0.1µF ceramic bypass capacitor at VCC pin to suppress switching noise and ensure timing stability. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffer architecture | Enables bidirectional data flow on common buses by allowing controlled isolation of upstream/downstream logic domains. |
| Wide 2V–6V supply range | Supports interoperability between 3.3V microcontrollers and 5V peripherals without external level translation circuitry. |
| Low ICC (≤80µA) | Reduces system-level quiescent power in always-on industrial controllers and remote sensor nodes. |
| High noise immunity | CMOS input structure with hysteresis-free thresholds ensures reliable operation in electrically noisy factory environments. |
| Pin-compatible with LS-TTL drivers | Allows drop-in replacement of obsolete 74LS240 in legacy designs while improving speed and reducing power consumption. |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
|
Use Scenario: Driving address lines from a microcontroller to multiple SRAM or EPROM chips on a shared memory bus. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating MCU address outputs during read cycles and enabling clean signal integrity across parallel traces. Use Value: Prevents bus contention during multi-chip access and reduces address setup time via 9ns propagation delay. |
Use Scenario: Interfacing PLC I/O modules to a central controller over a 24V-tolerant RS-485 or CAN physical layer. IC Role / Device Role / Timing Role: Level-shifting and buffering digital control signals between isolated logic domains while maintaining precise edge timing. Use Value: Enables deterministic signal routing with <25ns enable/disable latency, critical for real-time cyclic communication. |
| Legacy System Upgrade | Test Equipment Signal Conditioning |
|
Use Scenario: Replacing aging 74LS240 buffers in field-deployed instrumentation hardware requiring extended service life. IC Role / Device Role / Timing Role: Pin-compatible CMOS upgrade delivering identical functionality with lower power and higher noise margin. Use Value: Eliminates thermal derating concerns and extends operational lifetime without board redesign or firmware changes. |
Use Scenario: Conditioning TTL-compatible trigger and clock signals inside automated test equipment (ATE) racks. IC Role / Device Role / Timing Role: Isolating sensitive measurement circuitry from noisy digital sequencers using controlled 3-state gating. Use Value: Reduces crosstalk-induced jitter by decoupling source and load capacitances via high-Z output state. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT240N | TTL-compatible input thresholds (VIH = 2.0V min); identical pinout and 3-state behavior. | Better suited for mixed 5V TTL/CMOS systems where input noise margins must match legacy TTL logic families. | Select when interfacing with older 74LS or 74F devices where VIH/VIL thresholds must align precisely. |
| 74AC240PC | Faster tpd = 5.5ns at 5V; higher ICC = 40mA max; requires tighter layout due to faster edges. | Preferred in high-speed data acquisition systems needing sub-10ns timing precision and higher drive strength. | Choose only when SN74HC240NG4's 9ns delay is insufficient and board layout supports AC-series EMI mitigation. |
Compared with SN74HC240NG4, SN74HCT240N offers superior compatibility with TTL inputs but no speed improvement, while 74AC240PC delivers significantly faster switching at the cost of higher power and stricter layout requirements - making SN74HC240NG4 the optimal balance of speed, efficiency, and ease of integration in general-purpose industrial designs.
Availability
SN74HC240NG4 is available at Aetrix Electronics and suitable for industrial control panels, legacy system refurbishment, and test equipment manufacturing requiring stable component supply and long-term obsolescence management.
Supply support for SN74HC240NG4 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with over 50 years of innovation in industrial, automotive, and communications markets.
The SN74HC240NG4 belongs to TI's industry-standard 74HC logic family, engineered for high noise immunity, low power consumption, and seamless interoperability in mixed-voltage digital systems.
FAQ
What is the function of the OE pins on the SN74HC240NG4?
The SN74HC240NG4 features two independent active-low output-enable pins: 1OE (Pin 1) controls Group 1 outputs (1Y1–1Y4), and 2OE (Pin 19) controls Group 2 outputs (2Y1–2Y4). When an OE pin is low, its corresponding four outputs invert and pass data from A inputs to Y outputs; when high, those outputs enter high-impedance state - enabling selective bus access without contention.
Can SN74HC240NG4 operate at 3.3V supply voltage?
Yes, SN74HC240NG4 is fully specified for operation from 2V to 6V, including 3.3V nominal supply. At 3.3V, it maintains guaranteed VOH ≥ 3.15V and VOL ≤ 0.1V under load, supports 15 LSTTL-equivalent fanout, and delivers typical tpd of ~13ns - making it ideal for interfacing 3.3V microcontrollers with 5V peripherals.
Does SN74HC240NG4 require external pull-up resistors on its outputs?
No, SN74HC240NG4 does not require external pull-up resistors on its outputs. Its 3-state outputs present high impedance (IOZ ≤ ±5µA) when disabled, and actively drive to defined logic levels (VOH/VOL) when enabled. Pull-ups are unnecessary unless interfacing with open-drain systems - which SN74HC240NG4 is not designed for.
What is the maximum operating temperature for SN74HC240NG4?
The SN74HC240NG4 is rated for operation from –40°C to +85°C ambient temperature. This industrial-grade range is validated across all electrical parameters in the datasheet, including propagation delay, output drive, and leakage current - ensuring reliable performance in factory automation, motor drives, and outdoor-rated electronics.
How does SN74HC240NG4 differ from SN74HC244NG4?
SN74HC240NG4 provides inverting outputs (A → ¬Y), while SN74HC244NG4 provides non-inverting outputs (A → Y). Both share identical pinout, 3-state control, supply range, and drive capability. The choice depends strictly on signal polarity requirements: SN74HC240NG4 is used where inversion is needed or acceptable; SN74HC244NG4 where signal integrity demands true-level buffering.
SN74HC240NG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74HC240NG4 FAQ
1.How can I place an order for SN74HC240NG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC240NG4 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 SN74HC240NG4 reliable?
The price and inventory of SN74HC240NG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC240NG4 is usually 5 days.
3.What payment methods are accepted for SN74HC240NG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC240NG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC240NG4?
SN74HC240NG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC240NG4 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 SN74HC240NG4?
For technical support, including SN74HC240NG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC240NG4 requirements.
6.How does Aetrix verify that SN74HC240NG4 is sourced from the original manufacturer or authorized distributors?
All SN74HC240NG4 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 SN74HC240NG4 meets industry standards.
7.What is the process for return or replacement of SN74HC240NG4?
All SN74HC240NG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC240NG4, 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 SN74HC240NG4 part is unused and in its original packaging.
Return procedure for SN74HC240NG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74HC240NG4 Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
