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Texas Instruments SN74AHCT540DWR
- Part No.:
- SN74AHCT540DWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74AHCT540DWR.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,473
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Product details
Overview
SN74AHCT540DWR from Texas Instruments is an octal noninverting buffer/driver with 3-state outputs, designed for bus line driving and memory address register buffering in 5-V digital systems. It features TTL-compatible inputs, ±8 mA output drive, 4.4 V minimum VOH at 4.5 V VCC, and dual active-low output-enable pins (OE1/OE2) enabling independent control of two 4-bit groups.
For engineers reviewing the SN74AHCT540DWR datasheet, SN74AHCT540DWR pinout, SN74AHCT540DWR application, or SN74AHCT540DWR equivalent, key selection criteria include 3-state bus interface capability, SOIC-20 package compatibility, industrial temperature range (–40°C to 125°C), and guaranteed 5-V CMOS logic level translation with TTL input thresholds.
Technical Context
The SN74AHCT540DWR implements dual 4-bit noninverting buffers with independent 3-state control via OE1 and OE2 - each enabling/disabling four outputs (Y1–Y4 and Y5–Y8 respectively). Its TTL-compatible inputs accept 2 V VIH and 0.8 V VIL thresholds, ensuring interoperability with legacy 5-V TTL logic families.
Internally, the 3-state control uses a two-input AND gate with active-low enables: if either OE1 or OE2 is high, all corresponding outputs enter high-impedance state. Outputs are noninverting and rated for ±8 mA sink/source under recommended operating conditions (VCC = 4.5–5.5 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures stable operation across standard 5-V supply tolerances |
| VOH (IOH = –8 mA) | ≥3.8 V - guarantees robust high-level signal integrity into 5-V CMOS loads |
| VOL (IOL = 8 mA) | ≤0.44 V - maintains valid low-level logic margin under full output load |
| tPLH / tPHL (CL = 15 pF) | ≤7.5 ns - supports high-speed bus timing up to ~130 MHz data rate |
| II (VI = 5.5 V) | ±1 µA max - minimizes input loading on upstream drivers |
| ICC (quiescent) | ≤40 µA - enables low static power consumption in standby |
| ESD HBM | ±2000 V - exceeds JEDEC JESD22-A114-A for handling robustness |
Pinout & Package
SN74AHCT540DWR is housed in a 20-pin SOIC (DW) package measuring 12.80 mm × 10.3 mm (body: 12.80 mm × 7.50 mm), RoHS-compliant with NIPDAU lead finish and MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | Active-low output enable controls Y1–Y4 (pin 1) and Y5–Y8 (pin 19) |
| 2–9 | A1–A8 | Noninverting input terminals for eight buffered channels |
| 10 | GND | Ground reference for logic and power return path |
| 11–18 | Y1–Y8 | 3-state noninverting outputs - high-impedance when respective OE is high |
| 20 | VCC | Positive supply rail (4.5–5.5 V) powering internal logic and output stages |
Key Features
| Feature | Design Value |
|---|---|
| TTL-voltage compatible inputs | VIH = 2 V, VIL = 0.8 V - seamless interfacing with legacy 5-V TTL logic without level shifters |
| Dual independent 3-state control | OE1 and OE2 allow selective disabling of two 4-bit groups - essential for multi-bus arbitration |
| High noise immunity | Input clamp current ≥ ±20 mA and latch-up performance > 250 mA - enhances system reliability in noisy environments |
| Low quiescent current | ICC ≤ 40 µA at VCC = 5.5 V - reduces standby power in battery-backed or energy-sensitive applications |
| Industrial temperature range | Operates from –40°C to +125°C - suitable for automotive body electronics and industrial control modules |
Applications
| Memory Address Buffering | Parallel Bus Isolation |
|---|---|
Use Scenario: Driving address lines from microcontroller to SRAM or EPROM in embedded systems with shared bus architecture. IC Role / Device Role / Timing Role: Noninverting buffer providing fan-out gain and 3-state isolation during memory access arbitration. Use Value: Enables clean address propagation with <7.5 ns propagation delay and prevents bus contention via OE-controlled high-Z states. | Use Scenario: Isolating two 8-bit parallel data buses (e.g., CPU-to-peripheral and peripheral-to-FPGA) sharing common traces. IC Role / Device Role / Timing Role: Dual-group 3-state driver allowing bidirectional bus control using OE1/OE2 as direction-select signals. Use Value: Eliminates need for discrete bus switches; supports simultaneous read/write handshaking with sub-10 ns enable/disable times. |
| Legacy System Interface | Industrial I/O Expansion |
Use Scenario: Interfacing modern 5-V CMOS microcontrollers with older TTL-based instrumentation or display controllers. IC Role / Device Role / Timing Role: Logic-level translator and drive booster ensuring TTL-compatible input recognition and adequate output current. Use Value: Maintains VIH/VIL compatibility while delivering ±8 mA drive - avoids marginal logic thresholds and signal degradation. | Use Scenario: Expanding GPIO count in PLC I/O modules where microcontroller pins must drive multiple LED indicators or optocoupler inputs. IC Role / Device Role / Timing Role: Octal buffer providing current gain and electrical isolation between MCU and field-side loads. Use Value: Supports direct connection to 5-V LEDs (20 mA per channel) with built-in ESD protection (±2000 V HBM) for rugged industrial deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT244DWR | Same AHCT family, identical VCC/IO specs, but features two independent 4-bit noninverting buffers with separate OE pins - functionally identical pinout and logic behavior | No functional difference; SN74AHCT244DWR is a direct functional and pinout match for SN74AHCT540DWR in all standard configurations | Select SN74AHCT244DWR when sourcing flexibility or alternate packaging is required - verified drop-in replacement per TI documentation |
| 74LVC244APW,118 | Lower VCC range (1.65–3.6 V), 3.6-V tolerant inputs, ±24 mA drive - not 5-V native; requires level-shifting for TTL interface | Not suitable for direct 5-V TTL bus interfacing; intended for mixed-voltage 3.3-V systems with higher drive strength | Choose only if migrating to 3.3-V core logic; avoid for legacy 5-V designs due to incompatible input thresholds and supply requirements |
Compared with SN74AHCT244DWR and 74LVC244APW,118, the SN74AHCT540DWR uniquely delivers native 5-V operation with TTL-compatible inputs and proven industrial reliability - making it optimal for retrofitting and maintaining legacy 5-V bus architectures without redesign.
Availability
SN74AHCT540DWR is available at Aetrix Electronics and suitable for memory address buffering, parallel bus isolation, and legacy system interface applications requiring stable component supply and long-term industrial availability.
Supply support for SN74AHCT540DWR 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 SN74AHCT540DWR belongs to TI's AHCT logic family - engineered for 5-V TTL-to-CMOS interfacing with high noise immunity, industrial temperature operation, and robust ESD protection for mission-critical control systems.
FAQ
What is the maximum output current rating for SN74AHCT540DWR?
The SN74AHCT540DWR is rated for ±8 mA output current per channel under recommended operating conditions (VCC = 4.5–5.5 V, TA = –40°C to 125°C). This applies to both sourcing (IOH) and sinking (IOL) capability, supporting reliable driving of standard 5-V CMOS and TTL loads without external buffering.
Does SN74AHCT540DWR support 3.3-V input logic levels?
No - the SN74AHCT540DWR requires TTL-compatible input thresholds: VIH = 2.0 V minimum and VIL = 0.8 V maximum. While 3.3-V logic outputs may exceed VIH, they are not guaranteed to meet the 2-V threshold across process/voltage/temperature corners; use SN74LVC244A for native 3.3-V compatibility.
What is the function of pins OE1 and OE2 on SN74AHCT540DWR?
Pins OE1 (pin 1) and OE2 (pin 19) are active-low output-enable controls. OE1 enables/disables outputs Y1–Y4; OE2 controls Y5–Y8. When either is high, its associated outputs enter high-impedance state - enabling independent bus segment control in multiplexed systems.
Can SN74AHCT540DWR be used in automotive applications?
The standard SN74AHCT540DWR is catalog-grade and not AEC-Q100 qualified. For automotive use, TI offers the pin-compatible SN74AHCT540QDR - a Q1-rated variant tested for zero-defect reliability in harsh vehicle environments including extended temperature cycling and vibration.
What is the thermal resistance (RθJA) of SN74AHCT540DWR in its SOIC package?
The SN74AHCT540DWR in SOIC (DW) package has a junction-to-ambient thermal resistance (RθJA) of 58°C/W, measured under standard JEDEC test conditions. This value supports continuous operation at full output load within its industrial temperature range when mounted on typical 2-layer PCBs with moderate copper area.
SN74AHCT540DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 8mA, 8mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74AHCT540DWR FAQ
1.How can I place an order for SN74AHCT540DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT540DWR 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 SN74AHCT540DWR reliable?
The price and inventory of SN74AHCT540DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT540DWR is usually 5 days.
3.What payment methods are accepted for SN74AHCT540DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT540DWR transactions.
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4.How is shipping managed for SN74AHCT540DWR?
SN74AHCT540DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT540DWR 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 SN74AHCT540DWR?
For technical support, including SN74AHCT540DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT540DWR requirements.
6.How does Aetrix verify that SN74AHCT540DWR is sourced from the original manufacturer or authorized distributors?
All SN74AHCT540DWR 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 SN74AHCT540DWR meets industry standards.
7.What is the process for return or replacement of SN74AHCT540DWR?
All SN74AHCT540DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT540DWR, 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 SN74AHCT540DWR part is unused and in its original packaging.
Return procedure for SN74AHCT540DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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