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Texas Instruments SN74HC540DBR
- Part No.:
- SN74HC540DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74HC540DBR.pdf
- Description:
- IC BUFFER INVERT 6V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,835
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Product details
Overview
SN74HC540DBR from Texas Instruments is an octal inverting buffer/line driver with 3-state outputs, designed for bus interface and data routing in digital systems. It operates from 2 V to 6 V, delivers ±6 mA output drive at 5 V, exhibits typical propagation delay of 8 ns, and features low ICC (80 μA max), enabling direct connection to LSTTL loads or high-impedance bus lines in industrial control and instrumentation applications.
For engineers reviewing the SN74HC540DBR datasheet, SN74HC540DBR pinout, SN74HC540DBR application, or SN74HC540DBR equivalent, key selection considerations include its inverted logic function, dual 3-state enable (OE1/OE2) architecture, data flow-through pinout for PCB layout optimization, and compatibility with HC-series timing and voltage thresholds across 2–6 V supply range.
Technical Context
The SN74HC540DBR implements eight independent inverting buffers, each with complementary output-enable control via a 2-input NOR gate (OE1 and OE2). When either OE input is high, all outputs enter high-impedance state-enabling bidirectional bus sharing without external logic.
Its data flow-through pinout places all eight inputs on one side and all eight outputs on the opposite side of the 20-pin SOIC package, reducing trace crossovers and improving signal integrity in dense layouts. The device adheres strictly to standard HC logic thresholds and switching behavior under recommended operating conditions (2–6 V, −40°C to +85°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 6 V - supports mixed-voltage system interfacing and battery-powered operation down to 2 V. |
| Output Drive (5 V) | ±6 mA - sufficient to directly drive 15 LSTTL loads or terminate stubs on medium-length PCB traces. |
| Propagation Delay (tpd) | Typ. 8 ns at 4.5 V, CL = 50 pF - enables reliable operation in 25 MHz+ synchronous bus environments. |
| Quiescent Current (ICC) | 80 μA max - minimizes standby power in always-on embedded controllers and sensor nodes. |
| Input Leakage Current | 1 μA max - ensures stable logic levels with high-impedance pull-ups/pull-downs and reduces I/O loading. |
| 3-State Enable Logic | NOR-gated OE1/OE2 - active-low enable per buffer group; any OE high forces all Y outputs to Hi-Z. |
| Logic Function | Inverting - A → Y̅ - required for polarity correction in legacy TTL-compatible data paths. |
Pinout & Package
SN74HC540DBR is housed in a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm with 1.27 mm lead pitch and 2.65 mm max height. Its data flow-through layout separates inputs (pins 1–8, 19–20) from outputs (pins 11–18), simplifying layer routing and minimizing crosstalk.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Buffer Inputs (A1–A8) | Active-high logic inputs driving inverted outputs; require defined VIH/VIL per supply voltage. |
| 11, 12, 13, 14, 15, 16, 17, 18 | Inverted Outputs (Y1–Y8) | 3-state capable; sink/source up to ±6 mA at 5 V; Hi-Z when OE1 or OE2 = high. |
| 19, 20 | Output Enables (OE1, OE2) | NOR logic inputs: both must be low for active outputs; either high disables all Y pins. |
| 10 | GND | Ground reference for all logic and output stages; requires low-inductance connection to plane. |
| 20 | VCC | Power supply (2–6 V); requires local 0.1-μF ceramic bypass capacitor adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting 3-state buffers | Enables polarity-aware bus arbitration and avoids external inverters in legacy HC/TTL designs. |
| Data flow-through pinout | Reduces PCB layer count by eliminating input-output trace crossings; improves signal routing efficiency. |
| High-current outputs | ±6 mA drive at 5 V allows direct fanout to 15 LSTTL loads without buffer amplification. |
| Low ICC consumption | 80 μA max quiescent current supports energy-sensitive applications like portable test equipment. |
| Wide VCC range | 2–6 V operation accommodates 3.3 V microcontrollers, 5 V peripherals, and 2.5 V logic domains. |
Applications
| Industrial PLC I/O Modules | Automotive Body Control Units |
|---|---|
Use Scenario: Isolating and buffering digital sensor inputs (e.g., door latch, seat position) before MCU sampling in harsh automotive environments. IC Role / Device Role / Timing Role: Inverting 3-state buffer providing level-shifted, noise-immune signal conditioning between 5 V sensors and 3.3 V microcontroller GPIOs. Use Value: Eliminates need for discrete inverters and pull-up networks while maintaining bus contention protection during MCU reset sequences. | Use Scenario: Driving LED status indicators and relay coils from microcontroller outputs in body control modules with shared power rails. IC Role / Device Role / Timing Role: Octal line driver delivering ±6 mA per channel to drive multiple LEDs or small solenoids without external transistors. Use Value: Reduces BOM count by consolidating eight discrete drivers into one SOIC package with predictable timing and thermal behavior. |
| Test Equipment Digital Pattern Generators | Legacy Bus Interface Adapters |
Use Scenario: Generating synchronized, inverted digital stimulus waveforms for IC functional testing across multiple DUT channels. IC Role / Device Role / Timing Role: Precision-timed inverting buffer with 8 ns tpd ensuring sub-25 MHz waveform fidelity and deterministic edge alignment. Use Value: Guarantees setup/hold compliance for high-speed DUTs while supporting programmable enable sequencing via OE1/OE2. | Use Scenario: Interfacing modern 3.3 V FPGAs to legacy 5 V parallel buses (e.g., ISA, GPIB) requiring logic inversion and bus hold capability. IC Role / Device Role / Timing Role: Bidirectional bus transceiver substitute using 3-state control to isolate FPGA from bus during read cycles. Use Value: Maintains signal integrity across voltage domains while preserving original bus protocol timing margins via HC-family propagation characteristics. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT540N | TTL-compatible input thresholds (VIH = 2 V min), otherwise identical pinout and function. | Better suited for mixed 5 V TTL/CMOS systems where input noise margin must match legacy TTL logic families. | Select SN74HCT540N when interfacing directly to 5 V TTL outputs; SN74HC540DBR preferred for pure CMOS or wide-VCC designs. |
| 74LCX540MTCX | Lower VCC range (2–3.6 V), higher speed (tpd = 5.5 ns typ), and enhanced ESD protection (±2 kV HBM). | Optimized for 3.3 V-only portable and low-power applications; not rated for 5 V operation. | Choose 74LCX540MTCX for battery-powered 3.3 V systems needing faster timing and robustness; SN74HC540DBR remains optimal for 2–6 V flexibility. |
Compared with SN74HCT540N and 74LCX540MTCX, the SN74HC540DBR uniquely balances wide supply range (2–6 V), proven industrial temperature rating (−40°C to +85°C), and SOIC packaging with full HC-series compatibility-making it the default choice for general-purpose bus buffering where voltage domain interoperability is essential.
Availability
SN74HC540DBR is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and test instrumentation requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for SN74HC540DBR 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 for industrial, automotive, and communications markets.
The SN74HC540DBR belongs to TI's industry-standard 74HC logic family, engineered for reliable bus interface, signal conditioning, and level translation in cost-sensitive, high-volume digital systems.
FAQ
What is the logic function of SN74HC540DBR?
The SN74HC540DBR provides eight independent inverting buffers with 3-state outputs. Each input A drives a corresponding inverted output Y̅; when either OE1 or OE2 is high, all outputs go high-impedance. This function is confirmed in the device functional table and block diagram of the official TI datasheet SCLS007F.
Does SN74HC540DBR support 3.3 V operation?
Yes, SN74HC540DBR fully supports 3.3 V operation within its 2 V to 6 V supply range. At VCC = 3.3 V, it meets all recommended operating conditions-including VIH = 2.0 V min, VIL = 0.8 V max, and tpd ≤ 12 ns (typical)-making it suitable for mixed-voltage interfaces between 3.3 V MCUs and 5 V peripherals.
What is the maximum output current per pin for SN74HC540DBR?
The SN74HC540DBR delivers ±6 mA per output pin at VCC = 5 V, as specified in the Electrical Characteristics table (IOH/IOL = ±6 mA). Absolute maximum continuous output current is ±35 mA per pin, but sustained operation above ±6 mA may exceed recommended thermal limits in SOIC packaging.
Is SN74HC540DBR pin-compatible with SN74HC240?
No, SN74HC540DBR is not pin-compatible with SN74HC240. While both are octal buffers, SN74HC540DBR has inverted outputs and dual OE inputs (pins 19–20), whereas SN74HC240 features non-inverting outputs and a single OE. Pin assignments differ significantly-e.g., SN74HC540DBR places all inputs on left side and outputs on right, unlike SN74HC240's interleaved layout.
What package type does SN74HC540DBR use?
SN74HC540DBR uses a 20-pin SOIC (DW) package with dimensions 12.80 mm × 7.50 mm, 1.27 mm lead pitch, and 2.65 mm max height. This is confirmed in TI's Package Mechanical Drawings (DW0020A) and Orderable Addendum, where "DBR" suffix denotes tape-and-reel packaging of the DW variant.
SN74HC540DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 20-SSOP (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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
SN74HC540DBR FAQ
1.How can I place an order for SN74HC540DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC540DBR 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 SN74HC540DBR reliable?
The price and inventory of SN74HC540DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC540DBR is usually 5 days.
3.What payment methods are accepted for SN74HC540DBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC540DBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC540DBR?
SN74HC540DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC540DBR 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 SN74HC540DBR?
For technical support, including SN74HC540DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC540DBR requirements.
6.How does Aetrix verify that SN74HC540DBR is sourced from the original manufacturer or authorized distributors?
All SN74HC540DBR 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 SN74HC540DBR meets industry standards.
7.What is the process for return or replacement of SN74HC540DBR?
All SN74HC540DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC540DBR, 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 SN74HC540DBR part is unused and in its original packaging.
Return procedure for SN74HC540DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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