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Texas Instruments SN74AHCT16540DLR
- Part No.:
- SN74AHCT16540DLR
- Manufacturer:
- Texas Instruments
- Package:
- 48-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
SN74AHCT16540DLR.pdf
- Description:
- IC BUFFER INVERT 5.5V 48SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,220
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Product details
Overview
SN74AHCT16540DLR from Texas Instruments is a 16-bit noninverting buffer/driver with dual 3-state control (OE1/OE2), TTL-compatible inputs, and flow-through pinout in 48-pin SSOP (DL) package. It operates from 4.5 V to 5.5 V, delivers ±8 mA output drive, supports 15 pF load propagation delays as low as 4 ns (tPLH/tPHL), and is rated for –40°C to 85°C industrial temperature range - used in wide-data-path bus interfacing for microprocessor peripheral expansion.
For engineers reviewing the SN74AHCT16540DLR datasheet, SN74AHCT16540DLR pinout, SN74AHCT16540DLR application, or SN74AHCT16540DLR equivalent, key selection criteria include dual active-low 3-state enable logic, distributed VCC/GND pins for noise suppression, EPIC™ process latch-up immunity (>250 mA), and compatibility with legacy TTL-level system buses requiring high-impedance isolation during data arbitration.
Technical Context
This device implements two independent 8-bit noninverting buffer sections, each controlled by a 2-input AND gate with active-low OE1 and OE2 inputs - enabling high-impedance output when either enable is high. Its flow-through architecture places inputs on one side and outputs on the opposite side, minimizing trace crossovers on PCBs.
Distributed power/ground pins (VCC and GND appear every 3–4 pins) reduce simultaneous switching noise; input clamp current exceeds ±20 mA; and ESD protection meets >2000 V HBM and >200 V machine model standards. The DL package is a plastic shrink small-outline (SSOP) with 0.5 mm pitch and 12.6 mm × 6.2 mm body size.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage (VCC) | 4.5 V to 5.5 V - ensures compatibility with 5 V TTL and CMOS logic rails without level shifting. |
| Input Voltage Compatibility | TTL-level (VIH = 2 V min, VIL = 0.8 V max) - directly interfaces with standard 5 V TTL outputs without pull-ups or translators. |
| Output Drive Current | ±8 mA at VOH/VOL - sufficient to drive 50 Ω transmission lines or multiple 74-series loads under worst-case conditions. |
| Propagation Delay (CL = 15 pF) | 4 ns min / 10 ns max (A→Y) - enables reliable operation in high-speed address/data bus applications up to ~100 MHz. |
| 3-State Enable Logic | Active-low 2-input AND (OE1 ∧ OE2) - provides dual-control redundancy; output goes high-Z if either OE is high. |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments including factory automation and embedded control systems. |
| Latch-Up Immunity | >250 mA per JESD 17 - prevents destructive latch-up during transient overvoltage or hot-insertion events. |
Pinout & Package
SN74AHCT16540DLR uses a 48-pin plastic shrink small-outline package (SSOP-DL), 12.6 mm × 6.2 mm body, 0.5 mm lead pitch, 1.2 mm max height, with pin 1 marked via corner bevel and seating plane defined per JEDEC MO-153.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE1, 1OE2, 2OE1, 2OE2 | Active-low 3-state enable inputs (2 per 8-bit section) | AND-gated logic: both must be low to enable corresponding Y outputs; tie to VCC via pull-up for power-up high-Z safety. |
| 1A1–1A8, 2A1–2A8 | Noninverting data inputs | Accept TTL-compatible signals; internally buffered with EPIC™ CMOS for low skew and noise immunity. |
| 1Y1–1Y8, 2Y1–2Y8 | Noninverting 3-state outputs | Drive bidirectional buses; high-Z state isolates sections during arbitration or standby. |
| VCC (Pins 7, 18, 29, 40) | Power supply | Distributed across package to minimize IR drop and switching noise coupling between sections. |
| GND (Pins 4, 11, 22, 33, 44) | Ground reference | Five dedicated ground pins reduce ground bounce and improve signal integrity in high-speed switching. |
Key Features
| Feature | Design Value |
|---|---|
| Flow-through pinout | Inputs on left side (1–24), outputs on right side (25–48) - eliminates layer jumps and reduces PCB routing complexity. |
| Distributed VCC/GND | Four VCC and five GND pins interleaved - lowers impedance of power delivery network and suppresses simultaneous switching noise. |
| EPIC™ process technology | Enhanced-Performance Implanted CMOS - achieves TTL-compatible input thresholds while maintaining CMOS power efficiency and speed. |
| High noise immunity | Dynamic VIH/VIL margins of 2 V/0.8 V with 1 ns input transition rate tolerance - resists crosstalk and EMI in dense board layouts. |
| Robust ESD/latch-up | 2000 V HBM ESD rating and >250 mA latch-up immunity - suitable for manufacturing handling and field-replaceable modules. |
Applications
| Industrial PLC Backplane Interface | Legacy Microprocessor Bus Expansion |
|---|---|
Use Scenario: Isolating and driving 16-bit address/data buses between CPU module and I/O expansion cards in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional bus buffer with configurable 3-state control, enabling time-multiplexed access to shared memory and peripherals. Use Value: Dual OE inputs allow independent gating of upper/lower byte sections, supporting partial bus cycles and reducing contention during interrupt servicing. |
Use Scenario: Extending 16-bit data paths from aging 80C188 or Z80-based controllers to external SRAM, EPROM, or peripheral ASICs. IC Role / Device Role / Timing Role: Noninverting level-shifting buffer that preserves TTL timing margins while adding drive strength and bus isolation. Use Value: 4 ns propagation delay (min) and 10 ns (max) ensure setup/hold compliance with 25 MHz bus clocks, even with 15 pF trace capacitance. |
| Test Equipment Signal Routing | Automated Test Fixture Control |
Use Scenario: Multiplexing and conditioning digital stimulus signals across multiple DUT channels in ATE systems with parallel test capability. IC Role / Device Role / Timing Role: High-impedance bus driver enabling dynamic reconfiguration of signal paths without hardware changes. Use Value: Flow-through layout simplifies routing of 16 synchronized signals, while distributed power pins maintain signal fidelity across all channels. |
Use Scenario: Driving relay matrices and opto-isolated I/O lines in production test fixtures where noise immunity and fail-safe power-up behavior are critical. IC Role / Device Role / Timing Role: 3-state buffer with OE pull-up recommendation - guarantees high-Z state at power-on to prevent unintended actuation. Use Value: Latch-up immunity >250 mA and 200 V machine-model ESD rating withstand repeated fixture insertion/removal and relay coil back-EMF. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 16-bit 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT16244DLR | Noninverting, but with individual 3-state controls per 4-bit group (4× OE) instead of dual 8-bit OE pairs. | Better suited for fine-grained bus partitioning; less optimal for full 16-bit atomic transfers. | Select when per-nibble enable control is required over full-byte coordination. |
| SN74LVCH16541ADLR | Lower-voltage (1.65–3.6 V), higher drive (±24 mA), but not TTL-input compatible - requires level translation for 5 V systems. | Targeted at mixed-voltage 3.3 V/2.5 V subsystems; incompatible with direct TTL interface. | Choose only in new 3.3 V designs with no legacy 5 V TTL components; avoid for drop-in replacement. |
Compared with SN74AHCT16244DLR and SN74LVCH16541ADLR, the SN74AHCT16540DLR uniquely balances TTL compatibility, dual-section coordinated 3-state control, and industrial temperature support - making it the preferred choice for retrofitting or maintaining 5 V bus architectures where timing predictability and noise resilience are prioritized over voltage scaling or granular enable flexibility.
Availability
SN74AHCT16540DLR is available at Aetrix Electronics and suitable for industrial PLC backplanes, legacy microprocessor bus expansion, automated test fixture control, and high-noise factory-floor signal routing requiring stable component supply and long-term lifecycle continuity.
Supply support for SN74AHCT16540DLR 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 industrial-grade logic families and automotive-qualified products.
The SN74AHCT16540DLR belongs to TI's Widebus™ family of high-speed, low-noise bus interface devices, designed specifically for robust 5 V data path expansion in noise-sensitive industrial and instrumentation applications.
FAQ
What is the recommended power-up sequence for SN74AHCT16540DLR to ensure safe 3-state initialization?
TI specifies tying both OE1 and OE2 inputs to VCC through a pull-up resistor at power-up to guarantee high-impedance outputs before valid control signals are established. The minimum resistor value depends on the driver's current-sinking capability - typically 4.7 kΩ suffices for most 5 V systems. This prevents bus contention during power ramp, which is critical in multi-driver backplane configurations where SN74AHCT16540DLR may share signal lines with other buffers or transceivers.
Does SN74AHCT16540DLR support hot-swap or live-insertion into an energized bus?
SN74AHCT16540DLR features robust latch-up immunity (>250 mA per JESD 17) and >2000 V HBM ESD protection, but TI does not characterize or guarantee hot-swap operation. Its inputs lack powered-off protection diodes, so applying signals while VCC is absent risks forward-biasing internal clamps. For true hot-swap use, external series resistors and TVS diodes are recommended - SN74AHCT16540DLR itself should only be inserted after VCC stabilization and OE assertion.
Can SN74AHCT16540DLR drive a 50 Ω transmission line directly?
Yes - SN74AHCT16540DLR delivers ±8 mA output current into loads down to 50 Ω at VOH/VOL specifications, and its 10 ns max propagation delay at 50 pF load confirms suitability for short-run 50 Ω traces. However, for longer lines or strict signal integrity requirements, TI recommends source termination (e.g., 33 Ω series resistor at driver output) to damp reflections, as SN74AHCT16540DLR's output impedance is not precisely controlled like a dedicated line driver IC.
How does the flow-through pinout of SN74AHCT16540DLR improve PCB layout versus traditional Z-pattern layouts?
The flow-through architecture places all 16 inputs on pins 1–24 (left side) and all 16 outputs on pins 25–48 (right side), enabling straight, parallel trace routing across the package without layer changes or vias. This reduces parasitic inductance/capacitance, minimizes crosstalk between adjacent signals, and simplifies length-matching for timing-critical buses - a measurable advantage over older Z-layout buffers like the SN74ALS16244 where inputs and outputs interleave.
Is SN74AHCT16540DLR pin-compatible with any ceramic-package variants of the same family?
No - SN74AHCT16540DLR uses a 48-pin SSOP (DL) package with 0.5 mm pitch, while the ceramic WD package variant (SN54AHCT16540WD) has 48 pins but 25-mil (0.635 mm) pitch and different mechanical dimensions. Pin numbering and function mapping match across the family, but physical mounting, solder stencil design, and thermal profiles differ significantly; direct PCB substitution is not possible without layout revision.
SN74AHCT16540DLR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 48-BSSOP (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- 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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-SSOP
SN74AHCT16540DLR FAQ
1.How can I place an order for SN74AHCT16540DLR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT16540DLR 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 SN74AHCT16540DLR reliable?
The price and inventory of SN74AHCT16540DLR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT16540DLR is usually 5 days.
3.What payment methods are accepted for SN74AHCT16540DLR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT16540DLR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT16540DLR?
SN74AHCT16540DLR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT16540DLR 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 SN74AHCT16540DLR?
For technical support, including SN74AHCT16540DLR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT16540DLR requirements.
6.How does Aetrix verify that SN74AHCT16540DLR is sourced from the original manufacturer or authorized distributors?
All SN74AHCT16540DLR 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 SN74AHCT16540DLR meets industry standards.
7.What is the process for return or replacement of SN74AHCT16540DLR?
All SN74AHCT16540DLR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT16540DLR, 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 SN74AHCT16540DLR part is unused and in its original packaging.
Return procedure for SN74AHCT16540DLR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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