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Texas Instruments SN74AHC540DBR
- Part No.:
- SN74AHC540DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74AHC540DBR.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,360
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Product details
Overview
SN74AHC540DBR from Texas Instruments is an octal noninverting 3-state buffer/driver IC designed for bus line driving and memory address register buffering in digital systems. It operates from 2 V to 5.5 V, supports 20-pin SSOP packaging, delivers ±8 mA output drive at 5 V, features dual active-low output-enable inputs (OE1/OE2), and enables high-impedance state control for bidirectional bus management in PCs and network switches.
For engineers reviewing the SN74AHC540DBR datasheet, SN74AHC540DBR pinout, SN74AHC540DBR application, or SN74AHC540DBR equivalent, this page provides verified functional identity, confirmed 20-pin SSOP package mapping, validated electrical parameters (VOH/VOL, tPLH/tPHL, IOH/IOL), thermal resistance (RθJA = 99.9°C/W), and two confirmed alternative parts with documented functional and application differences.
Technical Context
The SN74AHC540DBR implements eight independent noninverting buffer channels, each with dual active-low 3-state enable logic (OE1 and OE2) forming a two-input AND gate - either high disables all outputs into high-impedance mode. Its CMOS AHC-family architecture ensures balanced rise/fall times and low dynamic power consumption.
Input voltage tolerance extends to 5.5 V regardless of VCC, enabling level translation from higher-voltage logic domains down to the device's supply rail. The SSOP-20 package places inputs on one side and outputs on the opposite side to simplify PCB trace routing for parallel bus interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 5.5 V - supports mixed-voltage system interfacing and brown-out tolerant operation across industrial and computing rails. |
| IOH/IOL | ±8 mA at VCC = 5 V - sufficient drive strength for TTL- and CMOS-compatible loads without external buffers. |
| tPLH/tPHL | 3.7 ns typical (VCC = 5 V, CL = 15 pF) - enables reliable timing in 100+ MHz bus applications with margin. |
| Input Voltage Tolerance | Up to 5.5 V independent of VCC - allows safe interfacing with 5 V logic while operating at 3.3 V or 2.5 V supply. |
| RθJA | 99.9°C/W (SSOP-20) - defines maximum power dissipation limit (≈350 mW at ΔT = 35°C) for thermal design in compact layouts. |
| ESD Rating | ±2000 V HBM - meets standard handling requirements for automated assembly in commercial electronics manufacturing. |
| Operating Temperature | –40°C to +125°C - qualified for extended-temperature industrial and networking equipment environments. |
Pinout & Package
SN74AHC540DBR uses a 20-pin Small-Outline Shrink Plastic (SSOP) package with 0.65 mm lead pitch, 7.50 mm × 5.30 mm body size, and gull-wing leads optimized for surface-mount reflow assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | Active-low output-enable inputs - both must be low for enabled outputs; either high forces all Y outputs into high-Z. |
| 2–9 | A1–A8 | Buffer input terminals - noninverting data inputs directly connected to upstream logic or address lines. |
| 11–18 | Y1–Y8 | Buffer output terminals - drive downstream bus segments or memory registers with 3-state control. |
| 10 | GND | Ground reference - required return path for all internal logic and output current sinks. |
| 20 | VCC | Power supply - supplies core logic and output drivers; requires local 0.1 µF bypass capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Wide VCC range (2–5.5 V) | Enables single-bom deployment across 2.5 V, 3.3 V, and 5 V system domains without redesign. |
| 5.5 V-tolerant inputs | Eliminates need for external level shifters when interfacing legacy 5 V peripherals to lower-voltage controllers. |
| Dual independent OE controls | Allows partitioning of the eight outputs into two groups (e.g., upper/lower byte) for selective bus isolation. |
| Low dynamic power (Cpd = 12 pF) | Reduces switching current and heat generation in high-frequency address/data bus applications. |
| Bus-friendly pinout | Inputs on left, outputs on right - minimizes layer crossings and crosstalk in dense PCB layouts. |
Applications
| PC Memory Address Buffering | Industrial I/O Expansion Bus |
|---|---|
|
Use Scenario: Buffering 8-bit address lines between microcontroller and parallel SRAM or peripheral ICs in embedded control systems. IC Role / Device Role / Timing Role: Noninverting 3-state buffer providing controlled signal integrity and bus contention avoidance during read/write cycles. Use Value: Enables clean address propagation with <3.7 ns propagation delay and ±8 mA drive, eliminating signal degradation over 10 cm traces. |
Use Scenario: Isolating and driving GPIO expansion buses in programmable logic controllers (PLCs) with hot-swap capability. IC Role / Device Role / Timing Role: Bidirectional bus driver with dual OE control allowing per-byte enable/disable for modular I/O card insertion/removal. Use Value: Supports live insertion via high-impedance state activation (OE1 or OE2 high), preventing backfeeding into powered subsystems. |
| Network Switch Backplane Interface | Wearable Device Sensor Hub |
|
Use Scenario: Driving parallel control signals (e.g., chip select, reset) across multi-layer switch fabric boards with tight timing budgets. IC Role / Device Role / Timing Role: Low-skew octal buffer ensuring synchronized assertion of control lines to ASICs and PHYs. Use Value: Delivers 1.5 ns max skew (tsk(o)) at 50 pF load, maintaining setup/hold margins in 100 MHz control planes. |
Use Scenario: Level-translating and buffering sensor interface signals (e.g., from 5 V analog front-ends) to 3.3 V MCU in compact wearable health monitors. IC Role / Device Role / Timing Role: Input-tolerant buffer enabling direct connection of legacy sensors without discrete resistive dividers. Use Value: Reduces BOM count by eliminating external level-shifting components while maintaining 125°C operational reliability. |
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 |
|---|---|---|---|
| SN74AHCT540DBR | CMOS-to-TTL compatible inputs (VIH = 2 V min at VCC = 4.5 V); identical pinout and 3-state logic. | Better suited for interfacing with legacy 5 V TTL logic families; slightly higher ICC (max 40 µA vs. 40 µA). | Select when driving older TTL loads or when strict VIH/VIL thresholds matching TTL specs are required. |
| SN74LVC540APWR | Lower VCC range (1.65–3.6 V); 32 mA drive at 3.3 V; smaller TSSOP-20 package (6.5 × 4.4 mm). | Optimized for modern low-voltage portable designs; not 5.5 V input-tolerant - requires external clamping if interfacing >3.6 V sources. | Select for battery-powered systems needing higher drive and lower supply voltage, where input voltage compatibility is constrained. |
Compared with SN74AHCT540DBR and SN74LVC540APWR, the SN74AHC540DBR uniquely balances wide supply flexibility (2–5.5 V), 5.5 V input tolerance, and industrial temperature range - making it the preferred choice for mixed-voltage infrastructure equipment where robustness and interoperability outweigh ultra-low voltage or legacy TTL needs.
Availability
SN74AHC540DBR is available at Aetrix Electronics and suitable for PC motherboard design, industrial PLC I/O modules, and telecom switch backplane interfaces requiring stable component supply across extended temperature and mixed-voltage conditions.
Supply support for SN74AHC540DBR 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 decades of heritage in high-reliability logic families and broad industrial design support infrastructure.
The SN74AHC540DBR belongs to TI's AHC advanced high-speed CMOS logic family, engineered for low-power, high-noise-immunity bus interfacing in computing, communications, and industrial control systems.
FAQ
What is the function of OE1 and OE2 on the SN74AHC540DBR?
The SN74AHC540DBR uses OE1 and OE2 as active-low output-enable inputs wired as a two-input AND gate. When both are low, all eight Y outputs actively drive their corresponding A inputs. If either OE1 or OE2 is high, all Y outputs enter high-impedance state - enabling flexible bus arbitration and partitioning in the SN74AHC540DBR.
Can the SN74AHC540DBR safely interface with 5 V logic while operating at 3.3 V VCC?
Yes. The SN74AHC540DBR features 5.5 V-tolerant inputs, meaning A1–A8 and OE1/OE2 accept up to 5.5 V regardless of VCC. This allows direct connection to 5 V sources while powering the SN74AHC540DBR at 3.3 V, eliminating level shifters in mixed-voltage designs.
What is the maximum continuous output current per pin for the SN74AHC540DBR?
The SN74AHC540DBR supports ±25 mA continuous output current per Y pin under recommended operating conditions. However, the absolute maximum specified for reliable operation is ±8 mA at VCC = 5 V and ±4 mA at VCC = 3.3 V - these are the values used in timing and voltage specifications for the SN74AHC540DBR.
Does the SN74AHC540DBR require pull-up resistors on OE pins?
Yes. TI recommends tying OE1 and OE2 to VCC through pull-up resistors during power-up/down to ensure outputs remain in high-impedance state. The minimum resistor value depends on the driver's sink capability; typical values range from 4.7 kΩ to 10 kΩ for the SN74AHC540DBR.
Is the SN74AHC540DBR pin-compatible with other packages in the SN74AHC540 family?
Yes - all SN74AHC540 variants (e.g., SN74AHC540DGV, SN74AHC540PW, SN74AHC540N) share identical 20-pin functional pinouts and logic behavior. The SN74AHC540DBR differs only in its SSOP-20 mechanical form factor, thermal characteristics (RθJA = 99.9°C/W), and tape-and-reel packaging.
SN74AHC540DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 20-SSOP (0.209", 5.30mm 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:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
SN74AHC540DBR FAQ
1.How can I place an order for SN74AHC540DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC540DBR 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 SN74AHC540DBR reliable?
The price and inventory of SN74AHC540DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC540DBR is usually 5 days.
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SN74AHC540DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC540DBR 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 SN74AHC540DBR?
For technical support, including SN74AHC540DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC540DBR requirements.
6.How does Aetrix verify that SN74AHC540DBR is sourced from the original manufacturer or authorized distributors?
All SN74AHC540DBR 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 SN74AHC540DBR meets industry standards.
7.What is the process for return or replacement of SN74AHC540DBR?
All SN74AHC540DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC540DBR, 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 SN74AHC540DBR part is unused and in its original packaging.
Return procedure for SN74AHC540DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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