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Texas Instruments SN74AHCT245RGYR
- Part No.:
- SN74AHCT245RGYR
- Manufacturer:
- Texas Instruments
- Package:
- 20-VFQFN Exposed Pad
- Datasheet:
-
SN74AHCT245RGYR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,637
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Product details
Overview
SN74AHCT245RGYR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between 5 V buses. It operates from 4.5 V to 5.5 V, accepts TTL-compatible inputs (VIH = 2 V, VIL = 0.8 V), delivers ±8 mA output drive, and features direction control (DIR) and output enable (OE) logic for isolated bus communication in industrial control backplanes.
For engineers reviewing the SN74AHCT245RGYR datasheet, SN74AHCT245RGYR pinout, SN74AHCT245RGYR application, or SN74AHCT245RGYR equivalent, this page provides verified package mapping (VQFN-20), functional mode truth table, switching characteristics (tPLH/tPHL ≤ 10 ns @ 15 pF), thermal resistance (RθJA = 35.1 °C/W), and validated alternatives for 5 V bus interface redesigns.
Technical Context
The SN74AHCT245RGYR implements dual 8-bit bidirectional I/O paths controlled by DIR and OE pins, enabling A→B or B→A data flow with high-impedance isolation when OE is high. Its CMOS design with TTL-input thresholds supports mixed-voltage interfacing-e.g., translating 3.3 V logic levels to 5 V bus domains while maintaining noise immunity.
It uses slow-edge-rate outputs to suppress ringing on unterminated traces, and its latch-up performance exceeds 250 mA per JESD17. The device requires no external pullups on DIR/OE for basic operation but recommends a pullup on OE during power-up to ensure defined high-Z state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V logic rails and tolerance to supply droop. |
| Input Thresholds | VIH = 2 V, VIL = 0.8 V - guarantees reliable recognition of TTL-level signals from legacy controllers or FPGAs. |
| Output Drive | ±8 mA at VCC = 4.5 V - sufficient to drive 50 Ω transmission lines or multiple 74-series inputs without buffering. |
| Propagation Delay | tPLH/tPHL ≤ 10 ns @ CL = 15 pF - enables reliable operation up to ~50 MHz bus rates in point-to-point configurations. |
| Thermal Resistance | RθJA = 35.1 °C/W (VQFN-20) - allows >150 mW continuous power dissipation at TA = 85 °C with minimal heatsinking. |
| ESD Rating | HBM ±2000 V - meets industrial handling requirements without special ESD precautions beyond standard PCB practices. |
| Operating Temperature | –40 °C to +125 °C - qualified for extended-temperature industrial and automotive under-hood applications. |
Pinout & Package
VQFN-20 (RGY) package: 4.50 mm × 3.50 mm body, 0.5 mm pitch, exposed thermal pad (Pin 20 = GND). Designed for high-density PCB layouts and improved thermal performance over SOIC/SSOP variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | Low = B→A data flow; High = A→B data flow - determines real-time bus polarity without reconfiguration. |
| 2–9 (A1–A8) | Port A bidirectional I/O | Connects to microcontroller/data source bus; driven or sensed depending on DIR and OE state. |
| 10 (GND) | Ground reference | Primary return path for all signals and power; must be low-inductance connection to minimize ground bounce. |
| 11–18 (B1–B8) | Port B bidirectional I/O | Connects to peripheral/memory bus; electrically isolated from Port A when OE = high. |
| 19 (OE) | Output enable input | Active-low: Low = transceiver enabled; High = all A/B pins enter high-impedance state - critical for bus arbitration. |
| 20 (VCC) | Positive supply | 5 V nominal supply; requires local 0.1 µF ceramic bypass capacitor placed within 2 mm of pin. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Accepts 0.8 V / 2 V thresholds - eliminates level-shifter need when interfacing with legacy 5 V TTL or 3.3 V LVTTL sources. |
| Slow-edge-rate outputs | Controlled slew rate minimizes overshoot/undershoot on unterminated PCB traces - reduces EMI and signal integrity risk. |
| High-impedance isolation | OE-controlled 3-state outputs fully disconnect both ports - enables safe hot-plug insertion and multi-master bus sharing. |
| VQFN thermal performance | RθJA = 35.1 °C/W - 60% lower than SOIC-20 equivalent, supporting higher sustained data throughput in compact enclosures. |
| Overvoltage-tolerant inputs | Withstands VI up to 5.5 V regardless of VCC - allows safe interfacing with 5 V signals even during brownout conditions. |
Applications
| Industrial Backplane Interface | Microcontroller Bus Extension |
|---|---|
|
Use Scenario: Isolating CPU address/data bus from expansion slot peripherals in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional bus buffer with direction and enable control - synchronizes data flow between master and slave modules without clock domain crossing. Use Value: Enables hot-swap capability via OE-driven isolation and prevents bus contention during firmware updates or module replacement. |
Use Scenario: Extending GPIO or parallel interface from an MCU to off-chip SRAM or display controller. IC Role / Device Role / Timing Role: Level-translating transceiver - bridges 3.3 V MCU I/O to 5 V memory address/data lines using TTL-compatible thresholds. Use Value: Eliminates discrete level shifters; ±8 mA drive supports direct connection to 74ACT/74HC loads without fanout buffers. |
| Legacy System Upgrade | Test Equipment Signal Routing |
|
Use Scenario: Replacing obsolete 74LS245 in aging test fixtures requiring 5 V bus repeater functionality. IC Role / Device Role / Timing Role: Pin-compatible upgrade path - maintains identical logic behavior and timing margins while improving ESD robustness. Use Value: Delivers HBM ±2000 V protection versus LS-family's ~200 V, reducing field failure rates in manufacturing environments. |
Use Scenario: Configurable signal path routing in automated test equipment where DUT interfaces vary between 3.3 V and 5 V standards. IC Role / Device Role / Timing Role: Manual or software-controlled bus switch - DIR/OE pins allow dynamic reassignment of signal direction and channel enable/disable. Use Value: Reduces fixture complexity by consolidating multiple unidirectional buffers into one programmable bidirectional IC. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC245APWR | 3.3 V only (1.65–3.6 V), lower drive (±24 mA), faster tPD (5.4 ns), no TTL input compatibility. | Requires level shifting for 5 V systems; suited for modern low-voltage FPGA/CPU interconnects. | Select when migrating to 3.3 V domains and needing higher speed or lower power; not drop-in for 5 V designs. |
| SN74AHCT245PWRE4 | TSSOP-20 (6.5 mm × 4.4 mm), RθJA = 122.3 °C/W, same electrical specs, RoHS-compliant NiPdAu finish. | Larger footprint and higher thermal resistance - less suitable for thermally constrained or space-limited layouts. | Choose for legacy board compatibility where VQFN rework is impractical; verify thermal margin in high-power use cases. |
Compared with SN74LVC245APWR and SN74AHCT245PWRE4, the SN74AHCT245RGYR uniquely combines 5 V operation, TTL input compatibility, and superior thermal performance in a 4.5 mm × 3.5 mm footprint - making it optimal for industrial upgrades and compact 5 V bus architectures.
Availability
SN74AHCT245RGYR is available at Aetrix Electronics and suitable for industrial backplane interfaces, microcontroller bus extensions, legacy system upgrades, and test equipment signal routing requiring stable component supply across extended temperature ranges.
Supply support for SN74AHCT245RGYR 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 delivering analog and embedded processing solutions, with over 90 years of innovation in logic, power management, and signal chain technologies.
The SN74AHCT245RGYR belongs to TI's AHCT logic family, engineered for robust 5 V TTL-compatible interfacing in industrial, automotive, and communications infrastructure applications where reliability and noise immunity are critical.
FAQ
What is the maximum operating temperature for SN74AHCT245RGYR?
The SN74AHCT245RGYR is rated for operation from –40 °C to +125 °C ambient temperature. This extended range is validated per TI's production testing and supports deployment in harsh environments such as factory automation controls and automotive engine compartments where thermal stability is essential. The VQFN-20 package's low RθJA of 35.1 °C/W helps maintain junction temperature within safe limits under continuous load.
Does SN74AHCT245RGYR require external pull-up resistors on DIR or OE pins?
The SN74AHCT245RGYR does not require external pull-ups on DIR for basic operation, but TI strongly recommends tying OE to VCC through a pullup resistor (e.g., 10 kΩ) during power-up to guarantee high-impedance outputs before firmware initializes control lines. This prevents bus contention or unintended data leakage during reset sequences - a critical design practice confirmed in Section 8.1 of the official datasheet.
Can SN74AHCT245RGYR interface a 3.3 V microcontroller with a 5 V peripheral?
Yes, SN74AHCT245RGYR can safely interface a 3.3 V microcontroller with a 5 V peripheral because its inputs accept TTL voltage levels (VIH = 2 V, VIL = 0.8 V), allowing direct connection to 3.3 V logic outputs. Its outputs swing rail-to-rail (0 V to VCC) at 5 V, driving 5 V peripherals directly - eliminating external level shifters while maintaining signal integrity via controlled edge rates.
What is the meaning of "NRND" status for SN74AHCT245RGYR?
"NRND" (Not Recommended for New Designs) indicates TI no longer promotes SN74AHCT245RGYR for future projects due to newer alternatives like the LVC family, but the part remains in active production with full datasheet support and guaranteed supply for existing designs. Aetrix Electronics maintains inventory and offers lifecycle coordination to support long-term manufacturing continuity for legacy systems relying on this VQFN-20 variant.
How does the VQFN package of SN74AHCT245RGYR improve thermal performance over SOIC?
The SN74AHCT245RGYR's VQFN-20 package achieves RθJA = 35.1 °C/W - significantly lower than SOIC-20's 96.2 °C/W - due to its exposed thermal pad soldered directly to the PCB ground plane. This 63% reduction in junction-to-ambient resistance allows higher sustained power dissipation (e.g., >180 mW at 85 °C ambient) without thermal derating, making it ideal for compact, fanless industrial enclosures where heat buildup is a constraint.
SN74AHCT245RGYR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 20-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Logic Type:
- Transceiver, Non-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-VQFN (3.5x4.5)
SN74AHCT245RGYR FAQ
1.How can I place an order for SN74AHCT245RGYR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT245RGYR 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 SN74AHCT245RGYR reliable?
The price and inventory of SN74AHCT245RGYR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT245RGYR is usually 5 days.
3.What payment methods are accepted for SN74AHCT245RGYR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT245RGYR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT245RGYR?
SN74AHCT245RGYR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT245RGYR 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 SN74AHCT245RGYR?
For technical support, including SN74AHCT245RGYR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT245RGYR requirements.
6.How does Aetrix verify that SN74AHCT245RGYR is sourced from the original manufacturer or authorized distributors?
All SN74AHCT245RGYR 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 SN74AHCT245RGYR meets industry standards.
7.What is the process for return or replacement of SN74AHCT245RGYR?
All SN74AHCT245RGYR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT245RGYR, 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 SN74AHCT245RGYR part is unused and in its original packaging.
Return procedure for SN74AHCT245RGYR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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