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onsemi 74AC540SJX
- Part No.:
- 74AC540SJX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
74AC540SJX.pdf
- Description:
- IC BUFF INVERT 6V 20SOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,500
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Product details
Overview
74AC540SJX from onsemi is an octal inverting buffer/line driver with 3-state outputs, designed for memory and address bus driving, clock distribution, and microprocessor I/O port interfacing. It operates from 2.0 V to 6.0 V, delivers ±24 mA output drive, features flow-through pinout (inputs on one side, outputs on the other), and supports industrial temperature range (−40 °C to +85 °C).
For engineers reviewing the 74AC540SJX 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 package compatibility, and microprocessor bus interface suitability.
Technical Context
The 74AC540SJX implements eight independent inverting buffers, each with separate 3-state enable controlled by two active-low OE inputs (OE1 and OE2). Its flow-through architecture places all eight inputs on pins 1–8 and outputs on pins 13–20, enabling direct microprocessor data bus routing without layer crossover.
It uses advanced CMOS AC technology to achieve rail-to-rail output swing, TTL-compatible input thresholds, and guaranteed 3-state isolation (IOZ ≤ ±2.5 µA at VCC = 5.5 V). Propagation delays are specified under CL = 50 pF and support both 3.3 V and 5.0 V operation with defined edge-rate requirements (≥125 mV/ns).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0 V to 6.0 V - supports mixed-voltage system interfacing including 3.3 V and 5 V logic domains |
| Output Drive Strength | ±24 mA - sufficient to drive standard TTL loads or multiple CMOS inputs without external buffering |
| Propagation Delay (tPLH/tPHL) | ≤6.5 ns at VCC = 5.0 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 at VCC = 5.5 V - ensures minimal bus contention during disable, critical for shared bus integrity |
| Input Thresholds (VIH/VIL) | VIH = 3.15 V, VIL = 1.35 V at VCC = 4.5 V - provides robust noise margin (>1.1 V) against ground bounce and crosstalk |
| Operating Temperature | −40 °C to +85 °C - qualified for industrial-grade embedded control and automation applications |
Pinout & Package
74AC540SJX is housed in a Pb-free SOIC-20W package (case 751BJ), 7.5 mm wide, 12.8 mm long, 2.36 mm height, with 1.27 mm pitch and JEDEC MS-013 compliance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–8 | Inputs (D1–D8) | Inverting data inputs; accept TTL/CMOS logic levels; flow-through layout simplifies PCB trace routing from microprocessor D0–D7 |
| 9, 10 | OE1, OE2 | Active-low 3-state enable inputs; both must be LOW to activate outputs; dual control allows banked bus management |
| 11, 12 | GND, VCC | Power supply reference and supply rail; decoupling capacitor placement near these pins minimizes switching noise |
| 13–20 | Outputs (Y1–Y8) | Inverting 3-state outputs; sink/source ±24 mA; high-impedance state isolates bus when OE1/OE2 HIGH |
Key Features
| Feature | Design Value |
|---|---|
| Flow-through pinout | Inputs (pins 1–8) and outputs (pins 13–20) on opposite sides - eliminates PCB layer jumps and reduces signal skew in parallel bus layouts |
| 3-state inverting outputs | Dual active-low OE control (pins 9, 10) enables selective bus arbitration without external logic - ideal for bidirectional data bus direction control |
| Low ICC and IOZ | ICC ≤ 80 µA, IOZ ≤ ±2.5 µA - reduces standby power and prevents false triggering in multi-driver bus systems |
| Pb-free SOIC-20W | RoHS-compliant, JEDEC MS-013 package - ensures compatibility with lead-free reflow profiles and automated assembly lines |
Applications
| Microprocessor Address Bus Driver | Memory Address Latch Interface |
|---|---|
Use Scenario: Driving 8-bit address lines from an 8051 or Z80 microprocessor to external RAM or peripheral chips. IC Role / Device Role / Timing Role: Inverting 3-state buffer providing level translation and bus isolation between CPU and memory subsystem. Use Value: Flow-through pinout aligns with typical microprocessor pin layouts, reducing trace length and improving timing margin by minimizing capacitive loading. | Use Scenario: Interfacing between address latch (e.g., 74AC373) and memory chip address inputs in embedded controller designs. IC Role / Device Role / Timing Role: Octal inverting driver ensuring clean, high-current address signals reach memory devices with minimal skew. Use Value: ±24 mA drive strength guarantees fast address setup/hold times across temperature, supporting reliable 100 ns memory access cycles. |
| Industrial PLC I/O Expansion Module | Legacy ISA Bus Signal Conditioning |
Use Scenario: Buffering digital I/O signals in modular programmable logic controllers where field-side isolation and bus contention prevention are required. IC Role / Device Role / Timing Role: 3-state enabled octal driver managing shared backplane data lines between CPU and expansion modules. Use Value: Dual OE inputs allow synchronized enable/disable of two 4-bit groups, supporting flexible module addressing and hot-swap-safe operation. | Use Scenario: Replacing obsolete 74LS540 in legacy PC/industrial ISA bus add-in cards requiring TTL-compatible drivers with enhanced speed and drive. IC Role / Device Role / Timing Role: High-speed, low-power replacement for LS logic in ISA address/data bus transceivers. Use Value: 6.5 ns propagation delay at 5 V improves maximum ISA bus clock rate margin versus LS family (typ. 15 ns), while maintaining pin compatibility. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74AC541SJX | Non-inverting output logic (Y = D); identical pinout, AC specs, and SOIC-20W package | Used where signal polarity preservation is required (e.g., non-inverted data path in bus transceivers) | Select 74AC541SJX when inverting logic would disrupt system-level signal flow; otherwise 74AC540SJX is preferred for address inversion or complement generation |
| SN74ACT540N | TTL-compatible output drive (±24 mA), same function and pinout, but 20-pin PDIP package instead of SOIC-20W | Suitable for through-hole prototyping or legacy board repair where surface-mount is not feasible | Choose SN74ACT540N only for hand-soldered or socketed applications; 74AC540SJX offers superior thermal performance and density for production SMT designs |
Compared with 74AC541SJX and SN74ACT540N, the 74AC540SJX uniquely combines inverting logic, flow-through SOIC-20W packaging, and industrial temperature rating - making it optimal for space-constrained microprocessor bus interfaces requiring polarity inversion and high reliability.
Availability
74AC540SJX is available at Aetrix Electronics and suitable for industrial PLCs, embedded microcontroller systems, and legacy bus interface designs requiring stable component supply, RoHS compliance, and long-term lifecycle support.
Supply support for 74AC540SJX 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 74AC540SJX belongs to onsemi's Advanced CMOS (AC) logic family, engineered for high-speed, low-power, TTL-compatible digital interfacing in industrial and embedded control systems.
FAQ
What is the logic function of the 74AC540SJX?
The 74AC540SJX is an octal inverting buffer with 3-state outputs. Each of its eight channels performs Y = NOT(D), and outputs enter high-impedance state when either OE1 or OE2 is HIGH. This logic enables address complement generation and controlled bus driving in microprocessor systems. The 74AC540SJX truth table confirms active-low enable behavior and inverting transfer characteristic across all operating conditions.
Does the 74AC540SJX support 3.3 V operation?
Yes, the 74AC540SJX is fully specified for 3.3 V operation (VCC = 3.3 V ±0.3 V), with guaranteed propagation delay ≤8.0 ns and output drive ≥±24 mA. Input thresholds scale with VCC, ensuring TTL-compatible VIH (2.1 V min) and VIL (0.9 V max) at 3.3 V. The 74AC540SJX maintains full AC/DC specifications across 2.0–6.0 V, making it suitable for mixed-voltage board designs.
What is the purpose of the dual OE inputs (OE1 and OE2) on the 74AC540SJX?
The dual OE inputs (pins 9 and 10) provide independent 3-state control granularity: both OE1 and OE2 must be LOW to enable outputs. This design allows grouping of outputs (e.g., Y1–Y4 vs. Y5–Y8) via external logic, supporting segmented bus arbitration. In the 74AC540SJX, this feature enables flexible memory banking or I/O partitioning without additional gating logic, reducing component count in industrial control modules.
Is the 74AC540SJX pin-compatible with older 74LS540 devices?
The 74AC540SJX shares identical pinout and logic function with 74LS540, including input/output assignment and dual OE placement. However, it is not a drop-in replacement due to differences in DC characteristics (e.g., higher drive, lower ICC) and AC timing (faster propagation). System validation is required for voltage translation, noise margin, and timing closure when upgrading from LS to AC logic. The 74AC540SJX requires no PCB changes but may need updated timing analysis.
What package type is used for the 74AC540SJX?
The 74AC540SJX uses a Pb-free SOIC-20W package (case number 751BJ), measuring 12.8 mm × 7.5 mm × 2.36 mm with 1.27 mm lead pitch. This wide-body SOIC variant provides improved thermal dissipation over standard SOIC-20 and is optimized for automated SMT assembly. The 74AC540SJX marking includes "G" suffix denoting RoHS compliance, and the package meets JEDEC MS-013 mechanical standards.
74AC540SJX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74AC
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
74AC540SJX FAQ
1.How can I place an order for 74AC540SJX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AC540SJX 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 74AC540SJX reliable?
The price and inventory of 74AC540SJX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AC540SJX is usually 5 days.
3.What payment methods are accepted for 74AC540SJX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AC540SJX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74AC540SJX?
74AC540SJX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AC540SJX 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 74AC540SJX?
For technical support, including 74AC540SJX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AC540SJX requirements.
6.How does Aetrix verify that 74AC540SJX is sourced from the original manufacturer or authorized distributors?
All 74AC540SJX 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 74AC540SJX meets industry standards.
7.What is the process for return or replacement of 74AC540SJX?
All 74AC540SJX units undergo pre-shipment inspection (PSI). If there is an issue with 74AC540SJX, 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 74AC540SJX part is unused and in its original packaging.
Return procedure for 74AC540SJX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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