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Texas Instruments SN74HCT245DWR
- Part No.:
- SN74HCT245DWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HCT245DWR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:777
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Product details
Overview
SN74HCT245DWR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in 5-V logic systems. It features ±6-mA output drive at 5 V, 14-ns typical propagation delay (VCC = 5.5 V), and operates across –40°C to +85°C. It is used in industrial backplane interfaces where bus isolation and drive strength enhancement are required.
For engineers reviewing the SN74HCT245DWR datasheet, SN74HCT245DWR pinout, SN74HCT245DWR application, or SN74HCT245DWR equivalent, key selection criteria include its 3-state control architecture, TTL-compatible inputs, 20-pin SOIC (DW) package, and compatibility with LSTTL load driving up to 15 units.
Technical Context
The SN74HCT245DWR implements a dual-control logic interface: DIR selects data direction (A→B or B→A), while active-low OE enables/disables all eight I/O channels simultaneously. Its CMOS HCT process ensures TTL-voltage compatibility on inputs and rail-to-rail output swing under 4.5–5.5 V supply.
It delivers balanced propagation delay (tpd ≤ 25 ns max at CL = 50 pF, VCC = 4.5 V), fast enable/disable timing (ten/tdis ≤ 58/50 ns), and low static ICC (≤ 80 µA). The center-aligned VCC/GND pin configuration minimizes switching noise in high-density PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - supports standard 5-V rail with ±10% tolerance; no external regulation needed. |
| Propagation Delay (tpd) | 14 ns typical (VCC = 5.5 V, CL = 50 pF) - enables reliable 35-MHz bus operation in synchronous systems. |
| Output Drive | ±6 mA at 5 V - directly drives up to 15 LSTTL loads without external buffers. |
| Input Compatibility | TTL-voltage compatible (VIH = 2 V min, VIL = 0.8 V max) - interoperable with legacy 5-V TTL logic families. |
| Quiescent Current | 80 µA maximum - suitable for low-power standby modes in industrial controllers. |
| ESD Rating | ±1500 V HBM - meets standard handling requirements for automated assembly lines. |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded applications. |
Pinout & Package
SN74HCT245DWR is housed in a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm, with standard 0.050″ (1.27 mm) lead pitch and gull-wing leads. Pin 1 is marked by a beveled corner or dot; pins are numbered counter-clockwise from top-left when viewed top-down.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | High = A→B data flow; Low = B→A; determines real-time bus direction without reset. |
| 2–9 (A1–A8) | Port A bidirectional I/O | Connects to local bus (e.g., MCU side); functions as input or output depending on DIR state. |
| 10 (GND) | Ground reference | Primary return path for all signals; must be low-impedance and adjacent to VCC for noise suppression. |
| 11–18 (B1–B8) | Port B bidirectional I/O | Connects to remote bus (e.g., peripheral side); mirrors A-port behavior under DIR control. |
| 19 (OE) | Active-low output enable | High = all A/B ports enter high-impedance state; enables bus arbitration and hot-swap isolation. |
| 20 (VCC) | Power supply | 5-V nominal supply; requires local 0.1-µF ceramic bypass capacitor placed within 2 mm of pin. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional data routing | Single DIR pin configures full 8-bit A↔B path in either direction-eliminates need for separate transmit/receive ICs. |
| 3-state output control | OE pin disables all outputs simultaneously, enabling multi-master bus sharing without contention risk. |
| TTL-compatible inputs | Accepts standard TTL logic thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V) - interoperates with 74LS, 74ALS, and microcontroller GPIOs. |
| Low power consumption | 80 µA max ICC allows integration into always-on industrial monitoring nodes without thermal derating. |
| Robust ESD protection | ±1500 V HBM rating ensures reliability during board handling and reflow soldering in contract manufacturing. |
Applications
| Factory Automation Interface | Industrial Backplane Extension |
|---|---|
|
Use Scenario: Connecting PLC CPU modules to distributed I/O racks over 1-meter ribbon cables. IC Role / Device Role / Timing Role: Bidirectional signal repeater that restores edge integrity and compensates for cable attenuation. Use Value: Enables reliable 10-MHz data transfer across lossy interconnects where MCU GPIOs alone fail due to rise-time degradation. |
Use Scenario: Isolating control bus segments in motor drive cabinets to prevent noise coupling between power and logic sections. IC Role / Device Role / Timing Role: Direction-controlled bus buffer that decouples upstream/downstream domains while maintaining timing coherence. Use Value: Prevents ground loop currents and reduces EMI-induced bit errors by breaking DC continuity between subsystems. |
| Multi-Function Printer Data Path | Telecom Shelf Management Bus |
|
Use Scenario: Routing scan engine data to image processor and print controller via shared parallel bus. IC Role / Device Role / Timing Role: Dual-directional data switch enabling time-multiplexed access to shared memory resources. Use Value: Eliminates need for discrete multiplexers and reduces PCB layer count by consolidating bidirectional control in one 20-pin IC. |
Use Scenario: Interfacing shelf controller FPGA to hot-swappable line cards using a common management bus. IC Role / Device Role / Timing Role: Bus isolator activated during card insertion/removal to prevent bus contention. Use Value: Allows safe live insertion of line cards without system reboot or bus lockup-critical for carrier-grade uptime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC245APW | Lower voltage range (1.65–3.6 V), higher speed (tpd = 5.3 ns typ), but only ±24 mA drive at 3.3 V. | Requires 3.3-V system redesign; unsuitable for legacy 5-V infrastructure. | Select when migrating to low-voltage logic and higher bandwidth is prioritized over backward compatibility. |
| 74ACT245SCX | Same 4.5–5.5 V range and 20-pin SOIC, but higher ICC (40 mA max) and faster tpd (8.5 ns typ). | Higher power draw limits use in thermally constrained enclosures; not drop-in due to different AC characteristics. | Choose for high-speed backplanes where propagation delay dominates over quiescent current budget. |
Compared with SN74HCT245DWR, SN74LVC245APW enables modern low-voltage designs but sacrifices 5-V interoperability, while 74ACT245SCX improves timing margin at the cost of thermal density-making SN74HCT245DWR optimal for stable, mixed-voltage industrial upgrades.
Availability
SN74HCT245DWR is available at Aetrix Electronics and suitable for factory automation interfaces, industrial backplane extensions, and telecom shelf management requiring stable component supply across extended product lifecycles.
Supply support for SN74HCT245DWR 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 SN74HCT245DWR belongs to TI's 74HCT logic family, engineered for robust 5-V TTL-compatible interfacing in harsh industrial environments where noise immunity and long-term reliability are critical.
FAQ
What is the maximum capacitive load the SN74HCT245DWR can drive reliably?
The SN74HCT245DWR is characterized for CL = 50 pF and CL = 150 pF loads. At 5.5 V supply, typical propagation delay remains ≤25 ns (CL = 50 pF) and ≤34 ns (CL = 150 pF). Driving >150 pF may increase tpd unpredictably and cause ringing; external series termination is recommended for >200-pF traces.
Can unused channels of the SN74HCT245DWR be left floating?
No. All unused A and B port pins on the SN74HCT245DWR must be tied to VCC or GND-never left floating-to prevent undefined logic states and excessive ICC. TI recommends 10-kΩ pull-up/down resistors for unused channels, as shown in Figure 11-1 of the official datasheet.
Does the SN74HCT245DWR support hot-swap operation?
The SN74HCT245DWR supports controlled hot-swap via its active-low OE pin: asserting OE high places all I/Os in high-impedance state before insertion, preventing bus contention. However, VCC sequencing must still follow TI's recommended power-up order (GND first, then VCC) to avoid latch-up.
What is the thermal resistance (RθJA) of the SN74HCT245DWR in its SOIC (DW) package?
The SN74HCT245DWR in SOIC (DW) package has RθJA = 70.4°C/W, measured per JEDEC JESD51-2 with 1-inch² copper pad. This value assumes standard 2-layer PCB layout; adding internal copper planes or thermal vias can reduce junction temperature by up to 15°C under full-load conditions.
Is the SN74HCT245DWR RoHS compliant?
Yes. The SN74HCT245DWR is RoHS compliant (lead-free, NiPdAu finish) and rated Level-1-260C-UNLIM for moisture sensitivity. Its part marking "HCT245" and packaging code "DWR" (2000-piece tape-and-reel) confirm full compliance per TI's latest orderable addendum.
SN74HCT245DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74HCT245DWR FAQ
1.How can I place an order for SN74HCT245DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT245DWR 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 SN74HCT245DWR reliable?
The price and inventory of SN74HCT245DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT245DWR is usually 5 days.
3.What payment methods are accepted for SN74HCT245DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT245DWR transactions.
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4.How is shipping managed for SN74HCT245DWR?
SN74HCT245DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT245DWR 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 SN74HCT245DWR?
For technical support, including SN74HCT245DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT245DWR requirements.
6.How does Aetrix verify that SN74HCT245DWR is sourced from the original manufacturer or authorized distributors?
All SN74HCT245DWR 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 SN74HCT245DWR meets industry standards.
7.What is the process for return or replacement of SN74HCT245DWR?
All SN74HCT245DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT245DWR, 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 SN74HCT245DWR part is unused and in its original packaging.
Return procedure for SN74HCT245DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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