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onsemi 74AC540SJ
- Part No.:
- 74AC540SJ
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
74AC540SJ.pdf
- Description:
- IC BUFF INVERT 6V 20SOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,781
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Product details
Overview
74AC540SJ from onsemi is an octal inverting buffer/line driver with 3-state outputs, designed for memory and address bus driving, clock distribution, and microprocessor output port interfacing. It operates from 2.0 V to 6.0 V, delivers ±24 mA output drive, features flow-through pinout (inputs and outputs on opposite sides), and supports −40 °C to +85 °C industrial temperature range.
For engineers reviewing the 74AC540SJ datasheet, pinout, applications, or equivalent options, key selection criteria include 3-state control logic (dual OE inputs), high-speed propagation (≤8.0 ns at 5 V), low ICC/IOZ leakage, Pb-free SOIC-20W packaging, and compatibility with TTL/CMOS voltage thresholds across 3.3 V and 5 V systems.
Technical Context
The 74AC540SJ implements dual independent 3-state enable controls (OE1 and OE2) for grouped output control, supporting flexible bus arbitration. Its flow-through architecture places all eight inputs on one side and all eight outputs on the opposite side of the SOIC-20W package, minimizing PCB trace crossovers when used as a microprocessor I/O port expander.
Each output provides true inverting logic with rail-to-rail swing, guaranteed VOH ≥ 4.4 V and VOL ≤ 0.44 V at IO = ±24 mA under 5 V operation. Input thresholds are compatible with both TTL (VIH = 2.0 V min) and CMOS (VIH = 70% VCC) logic families across its full 2.0–6.0 V supply range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0 V to 6.0 V - supports mixed-voltage system interfacing and legacy 5 V or modern 3.3 V logic domains |
| Output Drive Strength | ±24 mA - sufficient to directly drive standard TTL loads or terminate unterminated transmission lines |
| Propagation Delay (tPLH/tPHL) | ≤6.5 ns at 5 V, CL = 50 pF - enables reliable operation in high-speed address/data buses up to ~100 MHz |
| 3-State Leakage (IOZ) | ±2.5 µA max - ensures minimal bus contention current when outputs are disabled |
| Input Thresholds (VIH/VIL) | VIH = 3.15 V, VIL = 1.35 V at VCC = 4.5 V - guarantees noise margin >0.8 V in 5 V systems |
| Operating Temperature | −40 °C to +85 °C - qualified for industrial-grade embedded control and automation applications |
Pinout & Package
74AC540SJ is housed in a Pb-free SOIC-20W package (Case 751BJ), 13.0 mm × 7.6 mm body, 1.27 mm pitch, with pin 1 marked by notch or bevel. The flow-through layout places inputs (A1–A8) on pins 1–8 and 19–20, outputs (Y1–Y8) on pins 11–18, and dual OE controls on pins 9 (OE1) and 10 (OE2).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–8 | Inputs A1–A8 | Inverting data inputs; referenced to GND/VCC, accept TTL- or CMOS-level signals |
| 9 | OE1 | Active-low 3-state enable for outputs Y1–Y4; must be LOW to enable |
| 10 | OE2 | Active-low 3-state enable for outputs Y5–Y8; independent of OE1 |
| 11–18 | Outputs Y1–Y8 | Inverting 3-state outputs; HIGH = logic 0, LOW = logic 1, Z = high-impedance |
| 19–20 | VCC / GND | Power supply and ground; decoupling capacitor placement critical for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Flow-through pinout | Inputs on left side (pins 1–8, 19–20), outputs on right side (pins 11–18) - simplifies PCB routing for microprocessor port expansion |
| Dual independent 3-state enables | OE1 controls Y1–Y4; OE2 controls Y5–Y8 - allows partial bus gating without disabling entire octal bank |
| High-current drive capability | ±24 mA per output - eliminates need for external buffers when driving multiple TTL inputs or stub-loaded buses |
| Pb-free SOIC-20W package | JEDEC MS-013 compliant, RoHS-compliant, 1.27 mm pitch - supports automated SMT assembly and industrial reflow profiles |
Applications
| Memory Address Buffering | Microprocessor Output Port |
|---|---|
Use Scenario: Driving 16-bit address bus between microcontroller and SRAM/Flash memory in embedded control systems. IC Role / Device Role / Timing Role: Octal inverting buffer with 3-state control isolates CPU address lines during DMA cycles or peripheral access. Use Value: Dual OE inputs allow selective gating of upper/lower address byte groups, reducing bus contention and enabling clean address transitions. | Use Scenario: Expanding GPIO capability of an 8-bit MCU to drive LED arrays, relays, or discrete logic in industrial HMI panels. IC Role / Device Role / Timing Role: Inverting line driver providing level-shifted, current-boosted outputs compatible with 5 V peripherals. Use Value: Flow-through pinout minimizes trace length and crosstalk; ±24 mA drive supports direct LED sinking without series resistors in some configurations. |
| Clock Distribution Network | Bus Transceiver Interface |
Use Scenario: Distributing a system clock signal to multiple synchronous peripherals (ADCs, DACs, FPGAs) while maintaining edge integrity. IC Role / Device Role / Timing Role: Low-skew inverting buffer with sub-7 ns propagation delay preserves timing margins in multi-load clock trees. Use Value: Guaranteed VOH/VOL at 24 mA ensures robust logic levels even under capacitive loading up to 50 pF per node. | Use Scenario: Bidirectional data bus isolation between two processor subsystems sharing a common memory-mapped peripheral interface. IC Role / Device Role / Timing Role: Direction-controlled 3-state driver enabling half-duplex data transfer with precise enable timing coordination. Use Value: Independent OE1/OE2 permits staggered enable/disable sequencing to prevent bus glitches during handshaking transitions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer with 3-state applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74ACT540SCX | Faster tPLH/tPHL (≤5.5 ns at 5 V); higher ICC (12 µA typ); identical pinout and logic function | Better suited for >100 MHz bus timing; higher static power may limit battery-powered use | Select when speed is critical and supply current budget allows +50% ICC increase |
| SN74AC540N | Dual-in-line (PDIP-20) package; same AC electrical specs; higher thermal resistance (θJA = 70°C/W vs. 50°C/W) | Preferred for prototyping or through-hole legacy designs; less suitable for high-density SMT layouts | Select for breadboard evaluation or replacement in existing DIP-based systems |
Compared with 74AC540SJ, the 74ACT540SCX offers superior speed at the cost of higher quiescent current, while the SN74AC540N provides identical logic performance in a through-hole package-making the 74AC540SJ optimal for space-constrained, thermally managed SMT industrial designs requiring balanced speed, drive, and leakage.
Availability
74AC540SJ is available at Aetrix Electronics and suitable for memory buffering, microprocessor I/O expansion, clock distribution, and bus transceiver applications requiring stable component supply and long-term industrial availability.
Supply support for 74AC540SJ 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 74AC540SJ belongs to onsemi's advanced CMOS logic family, engineered specifically for high-speed, low-power bus interface and address/data driving in industrial control, instrumentation, and programmable logic systems.
FAQ
What is the logic function of the 74AC540SJ?
The 74AC540SJ is an octal inverting buffer with 3-state outputs. Each input (A1–A8) drives a corresponding inverted output (Y1–Y8) when enabled; outputs go to high-impedance (Z) when either OE1 or OE2 is HIGH. Its truth table confirms active-low enable behavior and strict inversion: Yn = NOT(An) when OE is LOW.
Does the 74AC540SJ support 3.3 V operation?
Yes, the 74AC540SJ is fully specified for 3.3 V operation (VCC = 3.3 V ±0.3 V). At this voltage, it guarantees VIH = 2.1 V, VIL = 0.9 V, VOH ≥ 2.9 V, and VOL ≤ 0.1 V at ±50 mA, meeting LVTTL and mixed-voltage interface requirements without level shifters.
What is the purpose of having two separate OE inputs on the 74AC540SJ?
The dual OE inputs (OE1 for Y1–Y4, OE2 for Y5–Y8) allow independent 3-state control of two four-bit groups. This enables partial bus gating-for example, holding upper address bits active while tri-stating lower bits during memory page switching-reducing bus turnaround time and avoiding contention in multi-master systems.
Can the 74AC540SJ replace the 74LS540 in an existing design?
The 74AC540SJ can replace the 74LS540 in most cases due to identical pinout, logic function, and 3-state behavior-but requires verification of VCC range (74LS540 is 4.75–5.25 V only; 74AC540SJ supports 2.0–6.0 V) and output drive (74AC540SJ sources/sinks ±24 mA vs. ±15 mA for 74LS540), which may affect termination and fanout.
Is the 74AC540SJ RoHS-compliant and lead-free?
Yes, the 74AC540SJ is manufactured in a Pb-free SOIC-20W package (Case 751BJ) and complies with RoHS Directive 2011/65/EU. The "G" suffix in the marking (e.g., AC540AWLYYWWG) explicitly denotes Pb-free construction, verified per onsemi's material declarations and JEDEC J-STD-609 standards.
74AC540SJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74AC
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOP
74AC540SJ FAQ
1.How can I place an order for 74AC540SJ through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AC540SJ 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 74AC540SJ reliable?
The price and inventory of 74AC540SJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AC540SJ is usually 5 days.
3.What payment methods are accepted for 74AC540SJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AC540SJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74AC540SJ?
74AC540SJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AC540SJ 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 74AC540SJ?
For technical support, including 74AC540SJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AC540SJ requirements.
6.How does Aetrix verify that 74AC540SJ is sourced from the original manufacturer or authorized distributors?
All 74AC540SJ 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 74AC540SJ meets industry standards.
7.What is the process for return or replacement of 74AC540SJ?
All 74AC540SJ units undergo pre-shipment inspection (PSI). If there is an issue with 74AC540SJ, 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 74AC540SJ part is unused and in its original packaging.
Return procedure for 74AC540SJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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