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Texas Instruments SN74LVC240ANSR
- Part No.:
- SN74LVC240ANSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74LVC240ANSR.pdf
- Description:
- IC BUFFER INVERT 3.6V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,780
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Product details
Overview
SN74LVC240A from Texas Instruments is an octal noninverting buffer/driver with dual 3-state output banks, operating from 1.65V to 3.6V supply, supporting 5.5V-tolerant inputs, delivering ≤6.5ns propagation delay at 3.3V, and enabling mixed-mode signal interfacing (e.g., 5V logic driving 3.3V bus). It is used in digital bus isolation, signal redriving, and controller reset hold applications.
For engineers reviewing the SN74LVC240A datasheet, SN74LVC240A pinout, SN74LVC240A application, or SN74LVC240A equivalent, key selection criteria include 3-state bank control timing, Ioff-enabled live insertion, ground bounce (VOLP <0.8V) and undershoot (VOHV >2V) performance at 3.3V, and compatibility with 20-pin TSSOP, VQFN, SOIC, SSOP, SOP, and TVSOP packages.
Technical Context
The SN74LVC240A implements two independent 4-channel banks (Bank 1: pins 1A1–1A4 / 1Y1–1Y4; Bank 2: pins 2A1–2A4 / 2Y1–2Y4), each controlled by its own active-low output enable (1OE on pin 1, 2OE on pin 19). Each channel performs noninverting logic (Yn = An), with CMOS inputs and balanced push-pull outputs capable of ±50mA drive.
Its Ioff feature disables all outputs when VCC = 0V, preventing back-drive current and enabling safe hot-plug operation. Input voltage tolerance up to 5.5V allows direct interfacing with 5V systems while powered from 3.3V or lower supplies - critical for legacy-to-modern voltage domain bridging without level shifters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.65V to 3.6V - enables operation across low-voltage embedded rails including 1.8V, 2.5V, and 3.3V systems. |
| Input Voltage Tolerance | Up to 5.5V - permits direct connection to 5V logic without external clamping or translation. |
| Max Propagation Delay | 6.5ns at VCC = 3.3V - supports ≥100MHz signal redriving in short-haul digital buses. |
| Output Drive Strength | ±50mA per output - sufficient to drive 50pF loads or moderate transmission lines without external buffering. |
| Ioff Current | ±10μA max at VI/VO = 5.5V - ensures negligible leakage during partial power-down or hot-swap events. |
| ESD Rating (HBM) | ±2000V - meets industrial-grade robustness requirements for board-level handling and integration. |
| Operating Temperature | –40°C to +125°C - qualified for automotive under-hood and industrial control environments. |
Pinout & Package
SN74LVC240A is available in multiple 20-pin surface-mount packages: RKS (VQFN, 4.5mm × 2.5mm), PW (TSSOP, 6.5mm × 6.4mm), DGS (VSSOP, 5.1mm × 4.9mm), DGV (TVSOP, 5.0mm × 6.4mm), DB (SSOP, 7.2mm × 7.8mm), NS (SOP, 12.6mm × 7.8mm), and DW (SOIC, 12.8mm × 10.3mm). Pin functions are identical across all variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 19OE | Active-low bank enable inputs | Control high-impedance state for Bank 1 (pins 1A1–1A4 → 1Y1–1Y4) and Bank 2 (2A1–2A4 → 2Y1–2Y4) independently. |
| 1A1–1A4, 2A1–2A4 | Input terminals | Noninverting data inputs; tolerate up to 5.5V regardless of VCC level. |
| 1Y1–1Y4, 2Y1–2Y4 | 3-state output terminals | Drive high/low or enter high-Z; support bus sharing and contention-free multiplexing. |
| VCC (Pin 20) | Positive supply | Primary power rail; sets logic thresholds and output voltage levels (VOH/VOL). |
| GND (Pin 10) | Ground reference | Return path for all I/O and supply currents; must be low-impedance for noise control. |
Key Features
| Feature | Design Value |
|---|---|
| Mixed-mode signal interface | 5V-tolerant inputs with 3.3V (or lower) VCC enable seamless interoperation between legacy 5V and modern low-voltage logic domains. |
| Ioff partial-power-down protection | Outputs disable automatically when VCC = 0V, eliminating back-drive current and enabling live insertion into powered-backplane systems. |
| Low ground bounce & undershoot | Typical VOLP <0.8V and VOHV >2V at VCC = 3.3V reduce switching noise coupling into shared supply/ground planes. |
| Fast 3-state enable/disable | ten ≤ 8ns and tdis ≤ 7ns at 3.3V allow rapid bus arbitration and dynamic signal routing in real-time control systems. |
| Latch-up immunity | Exceeds 100mA per JESD17 - ensures robustness against transient overcurrent events in noisy industrial environments. |
Applications
| Bus Isolation | Signal Redriving |
|---|---|
Use Scenario: Isolating microcontroller GPIOs from a shared peripheral bus during firmware updates or fault recovery. IC Role / Device Role / Timing Role: Octal buffer with independent 3-state banks acts as bidirectional bus gate, enabling selective access while holding other devices in high-Z. Use Value: Prevents bus contention during reset sequences; Ioff ensures no back-drive when MCU is unpowered. |
Use Scenario: Restoring edge integrity and timing margin on a 10cm PCB trace carrying 50MHz clock/data signals. IC Role / Device Role / Timing Role: Noninverting driver compensates for capacitive loading and trace loss, maintaining <6.5ns tpd budget. Use Value: Enables reliable signal delivery to downstream FPGA or ADC without adding jitter or skew. |
| Controller Reset Hold | LED Indicator Driving |
Use Scenario: Holding system enable lines low during processor reset to prevent spurious peripheral activation. IC Role / Device Role / Timing Role: 3-state output holds signal asserted while upstream controller resets; OE pin synchronized to reset deassertion. Use Value: Eliminates need for RC timing networks; provides precise, voltage-rail-independent hold duration. |
Use Scenario: Driving multiple discrete LEDs from a 3.3V microcontroller with limited GPIO sink capability. IC Role / Device Role / Timing Role: Buffer provides ±50mA per channel to directly drive common-anode or common-cathode LED arrays. Use Value: Avoids external transistor stages; 5.5V input tolerance allows direct connection to 5V LED supply rails. |
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 |
|---|---|---|---|
| SN74LVC244A | Noninverting octal buffer with same pinout and electrical specs, but single OE pin (not dual-bank). | Lacks independent bank control - unsuitable where asynchronous bus partitioning is required. | Select SN74LVC244A only if unified enable suffices and layout rework for dual-OE is impractical. |
| 74LVC240PW,118 (Nexperia) | Functionally identical octal inverting buffer with dual OE; differs in inversion logic (Yn = NOT An) and minor thermal metrics. | Requires logic inversion in upstream signal path; not drop-in for noninverting designs. | Choose only if inverting behavior aligns with system architecture and JEDEC-compliant sourcing is prioritized. |
Compared with SN74LVC240A, SN74LVC244A simplifies control but sacrifices bank-level isolation, while 74LVC240PW,118 offers second-source availability at the cost of signal polarity change - both require schematic and timing validation before substitution.
Availability
SN74LVC240A is available at Aetrix Electronics and suitable for industrial control panels, automotive body electronics, and embedded test equipment requiring stable component supply, long-term lifecycle assurance, and multi-package flexibility (TSSOP, VQFN, SOIC).
Supply support for SN74LVC240A 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 expertise in high-reliability interface IC design.
The SN74LVC240A belongs to TI's LVC (Low-Voltage CMOS) logic family, engineered for voltage-flexible, noise-resilient digital interfacing in space-constrained, mixed-voltage systems - particularly where 3.3V/2.5V/1.8V logic must coexist with 5V peripherals.
FAQ
What is the function of the two OE pins on the SN74LVC240A?
The SN74LVC240A features two independent active-low output enable pins: 1OE (pin 1) controls Bank 1 outputs (1Y1–1Y4), and 2OE (pin 19) controls Bank 2 outputs (2Y1–2Y4). When asserted low, each OE enables its respective bank's noninverting outputs; when high, it places those outputs in high-impedance state. This dual-control architecture enables selective bus segmentation and dynamic signal routing without affecting the other bank - a key advantage over single-OE alternatives like the SN74LVC244A.
Can the SN74LVC240A safely interface a 5V microcontroller with a 3.3V FPGA?
Yes - the SN74LVC240A supports mixed-mode operation: its inputs tolerate up to 5.5V regardless of VCC level, so 5V logic signals from the microcontroller can be applied directly while VCC is supplied at 3.3V. The outputs then swing between 0V and ~3.3V, matching the FPGA's input thresholds. No external level translators are needed, provided the FPGA inputs are 3.3V-tolerant. This capability is explicitly validated in TI's datasheet Section 7.3.1 and Recommended Operating Conditions.
Does the SN74LVC240A support hot-plug or live-insertion scenarios?
Yes - the SN74LVC240A incorporates Ioff circuitry that disables all outputs when VCC = 0V, limiting off-state leakage to ±10μA maximum. This prevents back-driving of powered circuitry during insertion into a live backplane or hot-swap module. TI confirms this behavior in Section 7.3.2 and Electrical Characteristics (Ioff parameter), making SN74LVC240A suitable for modular industrial I/O systems where field-replaceable cards must be inserted without system shutdown.
What is the maximum capacitive load the SN74LVC240A can drive while maintaining specified timing?
The SN74LVC240A is characterized and guaranteed to meet all timing specifications (including tpd ≤6.5ns at 3.3V) with a total load capacitance ≤50pF, as stated in Section 8.2.1.1 of the datasheet. Exceeding 50pF increases propagation delay and may degrade edge rates, potentially violating setup/hold margins in high-speed interfaces. For heavier loads, add series damping resistors or use dedicated line drivers - do not rely on increased drive strength alone, as output current remains limited to ±50mA.
Which package options for SN74LVC240A offer the smallest footprint and thermal resistance?
The RKS (VQFN-20) package delivers the smallest footprint (4.5mm × 2.5mm) and best thermal performance among SN74LVC240A variants, with RθJA = 87.2°C/W and RθJC(bot) = 44.3°C/W - significantly lower than TSSOP (120.3°C/W) or SOIC (114.8°C/W). Its exposed thermal pad (connected to GND) enhances heat dissipation in compact, thermally constrained layouts such as portable instrumentation or dense motor-control PCBs. All pin functions remain identical across packages.
SN74LVC240ANSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 1.65V ~ 3.6V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74LVC240ANSR FAQ
1.How can I place an order for SN74LVC240ANSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC240ANSR 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 SN74LVC240ANSR reliable?
The price and inventory of SN74LVC240ANSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC240ANSR is usually 5 days.
3.What payment methods are accepted for SN74LVC240ANSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LVC240ANSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LVC240ANSR?
SN74LVC240ANSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC240ANSR 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 SN74LVC240ANSR?
For technical support, including SN74LVC240ANSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC240ANSR requirements.
6.How does Aetrix verify that SN74LVC240ANSR is sourced from the original manufacturer or authorized distributors?
All SN74LVC240ANSR 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 SN74LVC240ANSR meets industry standards.
7.What is the process for return or replacement of SN74LVC240ANSR?
All SN74LVC240ANSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC240ANSR, 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 SN74LVC240ANSR part is unused and in its original packaging.
Return procedure for SN74LVC240ANSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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