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Texas Instruments SN74HCT245DBR
- Part No.:
- SN74HCT245DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74HCT245DBR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,787
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Product details
Overview
SN74HCT245DBR 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, CL = 50 pF), and operates across –40°C to +85°C. It enables robust signal integrity in ribbon-cable interconnects between MCUs and peripheral devices.
For engineers reviewing the SN74HCT245DBR datasheet, SN74HCT245DBR pinout, SN74HCT245DBR application, or SN74HCT245DBR equivalent, key selection criteria include its TTL-compatible inputs, active-low output enable (OE), direction-control (DIR) logic, and SSOP-20 package suitability for space-constrained industrial backplanes and point-of-sale interfaces.
Technical Context
The SN74HCT245DBR implements a standard '245 logic function with dual-bus isolation via independent DIR and OE controls. Its CMOS HCT process ensures TTL-voltage compatibility while maintaining low static current (≤80 µA) and balanced high/low output drive symmetry.
Directional data flow is determined solely by the DIR input level (high = A→B, low = B→A), while OE asserts high-impedance on all I/O ports when high. The device exhibits matched tpd (14 ns typ.) and tdis/ten (≈45 ns typ. at 5.5 V, CL = 50 pF), supporting reliable timing in synchronous and asynchronous bus architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - accommodates standard 5-V rail tolerance without level-shifting circuitry. |
| Propagation Delay (tpd) | 14 ns typical (VCC = 5.5 V, CL = 50 pF) - enables reliable operation up to ~35 MHz bus clock rates. |
| 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) - interfaces seamlessly with legacy 5-V TTL logic. |
| Quiescent Current (ICC) | 80 µA maximum - supports low-power system states without compromising bus drive capability. |
| ESD Rating | ±1500 V HBM - meets industrial handling requirements without additional protection circuitry. |
| Operating Temperature | –40°C to +85°C - qualified for commercial and industrial ambient environments. |
Pinout & Package
SN74HCT245DBR is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65-mm lead pitch and nominal body size 7.80 mm × 7.20 mm. The package is RoHS-compliant, moisture-sensitive level 1 (260°C peak reflow), and optimized for automated surface-mount assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | High = data flow A→B; Low = B→A; determines bidirectional path without external logic. |
| 2–9 (A1–A8) | Port A I/O channels | Bidirectional data terminals tied to local bus; function as input or output based on DIR state. |
| 10 (GND) | Ground reference | Primary return path for all signals and supply current; must be low-impedance for noise control. |
| 11–18 (B1–B8) | Port B I/O channels | Bidirectional data terminals tied to remote bus; mirror A-side behavior under DIR control. |
| 19 (OE) | Active-low output enable | High = all A/B pins enter high-impedance; enables bus isolation during arbitration or power-down. |
| 20 (VCC) | Power supply | 5-V supply input; requires local 0.1-µF bypass capacitor per TI layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional bus isolation | Independent DIR and OE controls allow dynamic direction switching and complete bus disconnection without contention. |
| High-current 3-state outputs | ±6-mA drive at 5 V eliminates need for external line drivers in ribbon-cable or backplane applications. |
| TTL-compatible inputs | VIH ≥ 2 V and VIL ≤ 0.8 V ensure interoperability with legacy 5-V TTL, LSTTL, and CMOS logic families. |
| Low static power consumption | 80-µA max ICC enables use in always-on subsystems without thermal or battery-life penalties. |
| Matched propagation characteristics | 14-ns typical tpd with <10% skew across all eight channels ensures deterministic timing in parallel data paths. |
Applications
| Factory Automation Interface | Point-of-Sale Peripheral Hub |
|---|---|
Use Scenario: Connecting PLC I/O modules to a central controller over extended ribbon cables in noisy industrial cabinets. IC Role / Device Role / Timing Role: Bidirectional signal repeater and bus isolator that restores signal integrity and prevents ground-loop coupling. Use Value: Enables reliable 5-V logic transmission over >30 cm cables where MCU GPIOs would otherwise fail due to capacitive loading and EMI. |
Use Scenario: Interfacing receipt printer, barcode scanner, and cash drawer to a single embedded host in compact retail terminals. IC Role / Device Role / Timing Role: Shared-bus transceiver managing concurrent peripheral access with direction arbitration and hot-swap isolation. Use Value: Eliminates bus contention during simultaneous peripheral polling and reduces PCB layer count via single shared data path. |
| Multi-Function Printer Engine | Telecom Line Card Interface |
Use Scenario: Bridging ASIC-based print engine control logic to motor driver ICs and sensor arrays across multi-layer board sections. IC Role / Device Role / Timing Role: Level-shifting and drive-strengthening buffer between low-drive ASIC outputs and high-capacitance motor control lines. Use Value: Prevents signal degradation on long internal traces, ensuring accurate stepper motor step timing and sensor readback fidelity. |
Use Scenario: Isolating FPGA-configured control logic from analog front-end components on telecom line cards subject to ESD and transient surges. IC Role / Device Role / Timing Role: Directionally gated interface enabling FPGA to read/write analog IC registers while maintaining fault containment. Use Value: Provides galvanic separation via 3-state disable during fault conditions, protecting FPGA I/O from latch-up or overvoltage events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT245DWR | SOIC-20 package (12.80 mm × 7.50 mm); identical electrical specs and pinout. | Requires larger PCB footprint and lower thermal performance (RθJA = 70.4°C/W vs. DB's 84.6°C/W). | Select for manual assembly, prototyping, or legacy SOIC-compatible layouts. |
| SN74LVC245APW | 3.3-V only operation (1.65–3.6 V); higher speed (tPD = 5.5 ns typ.); different voltage translation capability. | Not pin-compatible with 5-V systems; requires level-shifting if interfacing with TTL or 5-V peripherals. | Select only for new 3.3-V designs requiring faster timing or lower power; not a drop-in replacement. |
Compared with SN74HCT245DWR and SN74LVC245APW, the SN74HCT245DBR offers optimal balance of 5-V compatibility, SSOP space efficiency, and industrial temperature range-making it preferred for volume production in constrained, noise-immune industrial interfaces.
Availability
SN74HCT245DBR is available at Aetrix Electronics and suitable for factory automation interfaces, point-of-sale peripheral hubs, and telecom line card designs requiring stable component supply and long-term industrial lifecycle support.
Supply support for SN74HCT245DBR 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 over 50 years of industrial-grade product development.
The SN74HCT245DBR belongs to TI's 74HCT logic family, engineered for robust 5-V TTL-compatible bus interfacing in industrial, automotive, and communications equipment where reliability and noise immunity are critical.
FAQ
What is the operating voltage range for SN74HCT245DBR?
The SN74HCT245DBR operates from 4.5 V to 5.5 V. This range accommodates standard 5-V supply tolerances and ensures stable logic thresholds across variations in rail accuracy and load conditions. Operation outside this range may cause undefined behavior or damage, as specified in the absolute maximum ratings.
How does the direction control (DIR) pin function on SN74HCT245DBR?
The DIR pin on SN74HCT245DBR determines data flow direction: when high, data transfers from port A to port B; when low, data flows from port B to port A. This single-pin control eliminates the need for external multiplexing logic and enables real-time bidirectional bus arbitration in systems like printer engines or PLC backplanes.
Can SN74HCT245DBR drive standard TTL loads directly?
Yes, SN74HCT245DBR can drive up to 15 LSTTL loads directly due to its ±6-mA output drive capability at 5 V. This eliminates external buffer stages in applications such as ribbon-cable interconnects between MCUs and peripherals, reducing component count and signal path complexity.
What is the maximum propagation delay for SN74HCT245DBR under typical conditions?
The typical propagation delay (tpd) for SN74HCT245DBR is 14 ns at VCC = 5.5 V and CL = 50 pF. The maximum tpd is 25 ns under those same conditions, supporting reliable operation in 5-V digital systems with clock periods ≥50 ns (e.g., 20-MHz buses).
Is SN74HCT245DBR compatible with 3.3-V logic inputs?
No, SN74HCT245DBR is not guaranteed to recognize 3.3-V logic-high inputs reliably. Its VIH minimum is 2.0 V at VCC = 4.5 V, but proper TTL compatibility requires input high levels ≥2.0 V referenced to its own 5-V VCC. For mixed-voltage systems, level-shifting circuitry or a 3.3-V–compatible transceiver like SN74LVC245A is required.
SN74HCT245DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-SSOP (0.209", 5.30mm 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-SSOP
SN74HCT245DBR FAQ
1.How can I place an order for SN74HCT245DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT245DBR 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 SN74HCT245DBR reliable?
The price and inventory of SN74HCT245DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT245DBR is usually 5 days.
3.What payment methods are accepted for SN74HCT245DBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT245DBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT245DBR?
SN74HCT245DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT245DBR 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 SN74HCT245DBR?
For technical support, including SN74HCT245DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT245DBR requirements.
6.How does Aetrix verify that SN74HCT245DBR is sourced from the original manufacturer or authorized distributors?
All SN74HCT245DBR 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 SN74HCT245DBR meets industry standards.
7.What is the process for return or replacement of SN74HCT245DBR?
All SN74HCT245DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT245DBR, 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 SN74HCT245DBR part is unused and in its original packaging.
Return procedure for SN74HCT245DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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