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onsemi 74ACT240SJX
- Part No.:
- 74ACT240SJX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
74ACT240SJX.pdf
- Description:
- IC BUFF INVERT 5.5V 20SOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,601
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Product details
Overview
74ACT240SJX from onsemi is an octal inverting buffer/line driver with 3-state outputs, designed for memory address driving, bus-oriented transmission/reception, and clock distribution in high-density PCB layouts. It operates at 4.5 V to 5.5 V, delivers ±24 mA output drive, features TTL-compatible inputs, and supports industrial temperature range (−40°C to +85°C).
For engineers reviewing the 74ACT240SJX datasheet, pinout, applications, or equivalent options, key selection criteria include 3-state bus interface capability, TTL-level input compatibility, propagation delay under 9.5 ns at 5 V, and SOIC-20W Pb-free packaging for industrial-grade reliability.
Technical Context
The 74ACT240SJX implements dual independent 3-state enable logic (OE1/OE2) controlling two groups of four inverting outputs (O0–O3 and O4–O7), allowing selective bus isolation. Its TTL-compatible inputs accept 0.8 V (VIL) and 2.0 V (VIH) thresholds at 5 V supply, ensuring interoperability with legacy 5 V logic families.
Each output provides rail-to-rail switching with guaranteed VOH ≥ 4.4 V and VOL ≤ 0.44 V at ±24 mA load, while AC timing parameters-including tPLH/tPHL ≤ 9.5 ns and tPZH/tPHZ ≤ 10.5 ns-are specified at CL = 50 pF and VCC = 5.0 V ± 0.5 V across full temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL and CMOS systems without level shifting. |
| Output Drive | ±24 mA - sufficient to directly drive multiple TTL loads or terminate short PCB traces without external buffers. |
| Propagation Delay | ≤9.5 ns (tPLH/tPHL @ 5 V) - enables reliable operation in high-speed address/data buses up to ~100 MHz. |
| 3-State Enable Time | ≤9.5 ns (tPZH/tPZL @ 5 V) - supports fast bus arbitration and dynamic bus sharing in multiprocessor systems. |
| Input Compatibility | TTL-level (VIL = 0.8 V, VIH = 2.0 V @ 5 V) - allows direct connection to 74LS, 74F, and microcontroller GPIOs without interface logic. |
| Operating Temp | −40°C to +85°C - qualified for industrial control, instrumentation, and automotive under-hood auxiliary modules. |
| Package | SOIC-20W (Case 751BJ), Pb-free - surface-mount compatible with standard reflow profiles and IPC-compliant assembly. |
Pinout & Package
74ACT240SJX is housed in a 20-pin SOIC wide-body package (Case 751BJ), 7.5 mm × 12.8 mm footprint, 1.27 mm pitch, with exposed pad not present and moisture sensitivity level (MSL) rated per JEDEC J-STD-020B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | Independent 3-state enable inputs - low-active control for first and second group of four outputs (O0–O3 / O4–O7). |
| 2–9 | I0–I7 | Eight buffered inverting inputs - accepts TTL/CMOS logic levels; each drives corresponding inverted output. |
| 11–18 | O0–O7 | Eight inverting 3-state outputs - high-impedance when respective OE is high; sinks/sources ±24 mA when active. |
| 10 | GND | Ground reference - must be low-impedance connection to minimize ground bounce in high-speed switching. |
| 20 | VCC | Positive supply - bypassing with 0.1 µF ceramic capacitor near pin essential for stable AC performance. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state outputs | Enables bidirectional bus control with deterministic logic polarity and zero contention during disable. |
| TTL-compatible inputs | Eliminates need for level translators when interfacing with legacy 5 V logic families like 74LS and microcontrollers. |
| ±24 mA output drive | Drives up to 10 LSTTL loads or sustains signal integrity across 10 cm PCB traces at 50 MHz edge rates. |
| Low ICC and IOZ | Quiescent current ≤ 40 µA and 3-state leakage ≤ ±2.5 µA reduce system standby power and noise coupling. |
| Pb-free SOIC-20W | Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020B, supporting lead-free reflow assembly. |
Applications
| Memory Address Buffering | Microcontroller Bus Interface |
|---|---|
|
Use Scenario: Driving 16-bit address lines from a microcontroller to SRAM or EPROM in embedded control systems. IC Role / Device Role / Timing Role: Inverting buffer with 3-state control isolates address bus during DMA cycles or peripheral access. Use Value: Prevents bus contention during multi-master arbitration while maintaining <9.5 ns propagation delay for timing-critical memory access. |
Use Scenario: Interfacing an 8-bit MCU GPIO port to a shared data bus used by multiple peripherals. IC Role / Device Role / Timing Role: Octal inverting line driver with dual OE pins enables per-group bus enable/disable for modular peripheral control. Use Value: Allows time-multiplexed peripheral access without external logic, reducing BOM count and layout complexity. |
| Industrial PLC I/O Expansion | Legacy System Bus Repeater |
|
Use Scenario: Extending parallel I/O capacity in programmable logic controllers using backplane-mounted expansion modules. IC Role / Device Role / Timing Role: Level-shifting and fan-out buffer between controller ASIC and isolated I/O drivers. Use Value: TTL-compatible inputs accept direct connection to 5 V FPGA I/O banks; ±24 mA drive supports optocoupler LED biasing. |
Use Scenario: Repeating and regenerating aging ISA or VME bus signals in retro-computing or test equipment upgrades. IC Role / Device Role / Timing Role: Active repeater with inversion correction applied externally via complementary pairing. Use Value: Restores signal rise/fall times degraded over long backplane traces while preserving logic state via paired 74ACT240SJX units. |
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 |
|---|---|---|---|
| SN74ACT240N | PDIP-20 package, same electrical specs, higher thermal resistance (θJA = 70°C/W vs. SOIC's 100°C/W), no Pb-free marking. | Suitable for prototyping or through-hole legacy boards; not recommended for high-density SMT production. | Select SN74ACT240N only when manual soldering or socket-based testing is required. |
| 74ACT240MTCX | TSSOP-20 package (4.4 mm × 6.5 mm), identical AC/DC specs, lower profile, MSL-1 rating, tape-and-reel delivery. | Better suited for space-constrained portable or battery-powered devices where board area is critical. | Choose 74ACT240MTCX when footprint reduction or automated pick-and-place compatibility is prioritized over thermal mass. |
Compared with SN74ACT240N and 74ACT240MTCX, the 74ACT240SJX offers optimal balance of thermal performance, industrial-grade SOIC-20W mechanical robustness, and Pb-free compliance for volume SMT manufacturing-without requiring layout changes or signal integrity recalculations.
Availability
74ACT240SJX is available at Aetrix Electronics and suitable for industrial control systems, embedded memory interfaces, and legacy bus extension applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for 74ACT240SJX 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The 74ACT240SJX belongs to onsemi's legacy logic family, engineered for high-speed, low-power 5 V TTL/CMOS interoperability in industrial and computing infrastructure where reliability and long-term availability are critical.
FAQ
What is the maximum operating voltage for 74ACT240SJX?
The 74ACT240SJX has an absolute maximum supply voltage (VCC) of +6.5 V, but its recommended operating range is strictly 4.5 V to 5.5 V per the datasheet. Operation outside this window risks violating DC electrical characteristics such as VOH/VOL and may cause premature device failure or timing violations. Always regulate VCC to 5.0 V ± 0.5 V for guaranteed 74ACT240SJX performance.
Does 74ACT240SJX support non-inverting operation?
No, the 74ACT240SJX is exclusively an inverting octal buffer - all eight outputs (O0–O7) invert their corresponding inputs (I0–I7). To achieve non-inverting behavior, two 74ACT240SJX devices must be cascaded, or a complementary part like 74ACT244SJX (non-inverting) should be selected. The 74ACT240SJX truth table confirms inversion is intrinsic to its logic function.
Can 74ACT240SJX drive a 50 Ω transmission line directly?
No, the 74ACT240SJX is not designed for 50 Ω line driving. Its ±24 mA output drive corresponds to ~200 Ω effective impedance at 5 V, making it suitable for unterminated CMOS/TTL loads or short PCB traces (<10 cm), but not controlled-impedance RF or high-speed serial links. For 50 Ω termination, use a dedicated line driver IC or add series matching resistors when interfacing with 74ACT240SJX.
Is 74ACT240SJX pin-compatible with 74AC240SCX?
Yes, 74ACT240SJX and 74AC240SCX share identical pinout, package (SOIC-20W), and functional block diagram, but differ electrically: 74ACT240SJX has TTL-compatible inputs (VIL = 0.8 V), while 74AC240SCX uses CMOS inputs (VIL = 1.5 V at 5 V). Swapping them requires verifying input source compatibility - 74ACT240SJX can replace 74AC240SCX in TTL-driven systems, but not vice versa without level translation.
What is the thermal resistance (θJA) of 74ACT240SJX in SOIC-20W package?
The 74ACT240SJX in SOIC-20W (Case 751BJ) has a typical junction-to-ambient thermal resistance (θJA) of 100°C/W under standard JEDEC test conditions (1s2p board, 1 oz copper). This value assumes minimal copper pour; actual θJA improves significantly with internal ground/power planes or thermal vias. Thermal design must ensure TJ ≤ 140°C under worst-case ICC and output loading conditions for reliable 74ACT240SJX operation.
74ACT240SJX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.209", 5.30mm 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:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOP
74ACT240SJX FAQ
1.How can I place an order for 74ACT240SJX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ACT240SJX 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 74ACT240SJX reliable?
The price and inventory of 74ACT240SJX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACT240SJX is usually 5 days.
3.What payment methods are accepted for 74ACT240SJX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACT240SJX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ACT240SJX?
74ACT240SJX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ACT240SJX 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 74ACT240SJX?
For technical support, including 74ACT240SJX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACT240SJX requirements.
6.How does Aetrix verify that 74ACT240SJX is sourced from the original manufacturer or authorized distributors?
All 74ACT240SJX 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 74ACT240SJX meets industry standards.
7.What is the process for return or replacement of 74ACT240SJX?
All 74ACT240SJX units undergo pre-shipment inspection (PSI). If there is an issue with 74ACT240SJX, 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 74ACT240SJX part is unused and in its original packaging.
Return procedure for 74ACT240SJX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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