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Texas Instruments SN74ALS540NSRG4
- Part No.:
- SN74ALS540NSRG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ALS540NSRG4.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,748
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Product details
Overview
SN74ALS540NSRG4 from Texas Instruments is an octal inverting buffer/line driver with 3-state outputs, designed for bus interfacing and memory address register buffering in TTL-compatible digital systems. It features dual output-enable inputs (OE1/OE2), pnp input structure for reduced DC loading, data flowthrough pinout (inputs and outputs on opposite sides), and supports 12 mA low-level output current at VCC = 4.5 V.
For engineers reviewing the SN74ALS540NSRG4 datasheet, SN74ALS540NSRG4 pinout, SN74ALS540NSRG4 application, or SN74ALS540NSRG4 equivalent, this device is selected for high-reliability 5 V logic isolation, bidirectional bus control in industrial controllers, and legacy system memory expansion where inverted data path and 3-state drive capability are required.
Technical Context
The SN74ALS540NSRG4 implements a dual-NOR 3-state control gate: either OE1 or OE2 high forces all eight Y outputs into high-impedance state. Its pnp input stage minimizes input current draw, reducing loading on upstream drivers. The device operates strictly within 4.5 V to 5.5 V supply range and is rated for 0°C to 70°C ambient operation.
Propagation delays are specified at CL = 50 pF with R1/R2 = 500 Ω: tPLH ≤ 12 ns and tPHL ≤ 9 ns (max) from A to Y; enable/disable times (tPZH/tPZL/tPHZ/tPLZ) range from 1 ns to 20 ns depending on transition direction and condition. Output voltage levels meet ALS-family specifications: VOH ≥ 2.4 V at IOH = –12 mA, VOL ≤ 0.4 V at IOL = 12 mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Advanced Low-Power Schottky (ALS), TTL-compatible input thresholds and output drive |
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across standard 5 V rail tolerances |
| Output Drive | 12 mA sink (IOL) at VOL ≤ 0.4 V - sufficient for driving multiple TTL loads or short PCB traces |
| Propagation Delay | ≤12 ns (A→Y, tPLH) - enables reliable timing in sub-100 MHz synchronous bus applications |
| 3-State Enable Logic | NOR-gated OE1/OE2 - single-line disable possible; both must be low for active output |
| Input Structure | pnp-based - reduces input current to ≤0.2 mA (IIL), minimizing loading on preceding logic stages |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded and industrial control environments |
Pinout & Package
SOP-20 (NS package): 20-pin small-outline plastic package, 0.65 mm lead pitch, 7.5 mm × 5.6 mm body size, 2.0 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1 (unlimited reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A1–A8 Inputs | Inverting data inputs; accept standard TTL logic levels (VIH ≥ 2 V, VIL ≤ 0.8 V) |
| 9 | GND | Ground reference for all internal circuitry and output drivers |
| 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 | Y1–Y8, OE1, OE2 | Y1–Y8: inverted 3-state outputs; OE1/OE2: active-low enable inputs (NOR logic) |
| 20 | VCC | +5 V supply connection; decoupling capacitor required near pin for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Inverting octal buffer function | Provides true logic inversion across all eight channels without external gates |
| Data flowthrough pinout | Inputs (A1–A8) on left side, outputs (Y1–Y8) on right side - simplifies PCB routing and reduces crosstalk |
| Dual 3-state enable (OE1/OE2) | Enables flexible bus arbitration: either enable line can independently place outputs in high-Z state |
| pnp input structure | Reduces input current to ≤0.2 mA, lowering power consumption and easing drive requirements from upstream logic |
| TTL-compatible interface | Direct replacement for 74LS/74S-series buffers without level-shifting or redesign |
Applications
| Industrial PLC Backplane Interface | Legacy Memory Address Buffering |
|---|---|
|
Use Scenario: Isolating and driving address lines between microcontroller and parallel SRAM/ROM in programmable logic controllers. IC Role / Device Role / Timing Role: Inverting buffer with 3-state control synchronizes address latching and prevents bus contention during read/write cycles. Use Value: Enables clean address transitions with <12 ns propagation delay and eliminates signal integrity issues via low-output-impedance drive. |
Use Scenario: Buffering CPU-generated address signals to multiple memory chips in retro-computing or instrumentation systems. IC Role / Device Role / Timing Role: Octal inverter provides fanout gain and level restoration while supporting memory chip select sequencing via OE control. Use Value: pnp inputs reduce loading on address latch outputs, preserving setup/hold timing margins across temperature. |
| 5 V Bus Transceiver Interface | Test Equipment Signal Conditioning |
|
Use Scenario: Bidirectional data bus isolation between processor and peripheral modules in automated test equipment. IC Role / Device Role / Timing Role: 3-state outputs allow shared bus access; inverting function matches complementary bus protocols. Use Value: Dual OE inputs support independent module enable/disable, preventing bus conflicts during hot-swap or fault recovery. |
Use Scenario: Driving calibrated logic signals to DUT inputs in benchtop functional testers requiring precise edge timing. IC Role / Device Role / Timing Role: Provides deterministic propagation delay (<12 ns) and matched channel-to-channel skew for synchronized stimulus delivery. Use Value: Tight delay consistency (tPLH/tPHL ≤ 12 ns/9 ns) ensures accurate timing alignment across all eight test channels. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS540N | Same electrical specs and logic function; PDIP-20 package instead of SOP-20 | Preferred for through-hole prototyping or legacy board repair where surface-mount is not feasible | Select when manual soldering, socketing, or thermal mass tolerance is prioritized over board space |
| SN74ALS540-1NSR | Identical NS package but rated for 48 mA IOL (vs. 12 mA) under tight VCC (4.75–5.25 V) conditions | Required for driving heavier capacitive loads (>100 pF) or longer traces without signal degradation | Choose only if verified load demands exceed 12 mA sink capability; otherwise, SN74ALS540NSRG4 offers full compatibility with lower power dissipation |
Compared with SN74ALS540N and SN74ALS540-1NSR, the SN74ALS540NSRG4 delivers optimal balance of surface-mount efficiency, commercial-temperature reliability, and standard ALS drive strength-making it ideal for new production designs where space, manufacturability, and proven 12 mA performance are key.
Availability
SN74ALS540NSRG4 is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, legacy memory address buffering, and 5 V bus transceiver applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for SN74ALS540NSRG4 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 SN74ALS540NSRG4 belongs to TI's legacy Advanced Low-Power Schottky (ALS) logic family, engineered for high-speed, low-power 5 V TTL interoperability in mission-critical industrial control and instrumentation systems.
FAQ
What is the logic function of the SN74ALS540NSRG4?
The SN74ALS540NSRG4 is an octal inverting buffer with 3-state outputs. Each of its eight channels accepts a true input (A1–A8) and delivers an inverted output (Y1–Y8). Its dual output-enable inputs (OE1 and OE2) implement a NOR gate: if either is high, all outputs enter high-impedance state. This function is confirmed in the SDAS025D datasheet Section 1 and logic diagram.
Does the SN74ALS540NSRG4 support 3.3 V operation?
No. The SN74ALS540NSRG4 is specified only for 4.5 V to 5.5 V supply operation per the recommended operating conditions table in SDAS025D. It does not guarantee functionality or parametric compliance at 3.3 V, and applying 3.3 V may result in undefined output states or excessive input leakage. Use 74LVC or 74AUP series for 3.3 V compatibility.
What is the maximum output current capability of the SN74ALS540NSRG4?
The SN74ALS540NSRG4 is rated for 12 mA low-level output current (IOL) at VOL ≤ 0.4 V when VCC = 4.5 V, as specified in the "Recommended Operating Conditions" table of SDAS025D. It is not rated for the 48 mA capability of the -1 variant unless explicitly marked SN74ALS540-1NSR. Exceeding 12 mA risks violating VOL specification and thermal limits.
Is the SN74ALS540NSRG4 pin-compatible with the SN74ALS541NSRG4?
No. While both are 20-pin SOP devices with identical pin count and physical footprint, the SN74ALS540NSRG4 provides inverted outputs (Y = NOT A), whereas the SN74ALS541NSRG4 provides non-inverting outputs (Y = A). Their input/output assignments match, but logic polarity differs - direct substitution will invert critical signal paths and cause system failure unless compensated in firmware or layout.
What package type does SN74ALS540NSRG4 use, and what are its key mechanical dimensions?
The SN74ALS540NSRG4 uses the SOP-20 (NS) package: 20-pin small-outline plastic with 0.65 mm lead pitch, 7.5 mm × 5.6 mm body size, and 2.0 mm maximum height. Lead finish is NiPdAu (RoHS-compliant), MSL rating is Level-1 (unlimited reflow), and it conforms to JEDEC MO-153. These details are documented in TI's DB0020A package outline drawing and Package Option Addendum.
SN74ALS540NSRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 15mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74ALS540NSRG4 FAQ
1.How can I place an order for SN74ALS540NSRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS540NSRG4 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 SN74ALS540NSRG4 reliable?
The price and inventory of SN74ALS540NSRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS540NSRG4 is usually 5 days.
3.What payment methods are accepted for SN74ALS540NSRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS540NSRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS540NSRG4?
SN74ALS540NSRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS540NSRG4 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 SN74ALS540NSRG4?
For technical support, including SN74ALS540NSRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS540NSRG4 requirements.
6.How does Aetrix verify that SN74ALS540NSRG4 is sourced from the original manufacturer or authorized distributors?
All SN74ALS540NSRG4 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 SN74ALS540NSRG4 meets industry standards.
7.What is the process for return or replacement of SN74ALS540NSRG4?
All SN74ALS540NSRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS540NSRG4, 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 SN74ALS540NSRG4 part is unused and in its original packaging.
Return procedure for SN74ALS540NSRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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