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Texas Instruments SN74AHCT245DBRG4
- Part No.:
- SN74AHCT245DBRG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74AHCT245DBRG4.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,288
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Product details
Overview
SN74AHCT245DBRG4 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), supports ±8 mA output drive, and features direction control (DIR) and output enable (OE) pins for flexible bus isolation in industrial control backplanes.
For engineers reviewing the SN74AHCT245DBRG4 datasheet, SN74AHCT245DBRG4 pinout, SN74AHCT245DBRG4 application, or SN74AHCT245DBRG4 equivalent, key selection criteria include its SSOP-20 package (7.50 mm × 5.30 mm), guaranteed 10 ns max propagation delay at 5 V/15 pF, 3.94 V VOH at –8 mA, and compatibility with 3.3 V-to-5 V level translation in mixed-voltage systems.
Technical Context
The SN74AHCT245DBRG4 implements dual 8-bit bidirectional I/O paths controlled by a single DIR input and a shared OE input. Its CMOS design with TTL-compatible input thresholds enables direct interfacing with legacy 5 V logic while accepting 3.3 V signals without external biasing.
Each transceiver channel provides symmetrical A↔B data flow with high-impedance isolation when OE is high. Propagation delays are specified from DIR/OE to output (tPZH/tPHZ ≤ 16 ns) and between data buses (tPLH/tPHL ≤ 10 ns at 15 pF), ensuring deterministic timing in synchronous and asynchronous bus architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across industrial 5 V rail tolerances. |
| Input Thresholds | VIH = 2 V, VIL = 0.8 V - guarantees reliable recognition of TTL and 3.3 V logic levels. |
| Output Drive | ±8 mA at VCC = 4.5 V - sufficient for driving standard 50 Ω transmission lines or multiple CMOS loads. |
| Propagation Delay | tPLH/tPHL ≤ 10 ns (CL = 15 pF) - enables ≤100 MHz bus handshaking in low-latency applications. |
| 3-State Leakage | IOZ ≤ ±2.5 µA - minimizes bus contention current during isolation mode. |
| ESD Rating | HBM ±2000 V - meets IEC 61000-4-2 Level 2 for board-level robustness. |
| Operating Temperature | –40 °C to +125 °C - qualified for extended industrial environments including motor drives and PLC I/O modules. |
Pinout & Package
SN74AHCT245DBRG4 uses a 20-pin SSOP (Shrink Small Outline Package) with 0.65 mm lead pitch and body dimensions of 7.50 mm × 5.30 mm. The package is RoHS-compliant, moisture sensitivity level 1 (unlimited floor life at ≤30 °C/60% RH), and rated for reflow up to 260 °C.
| 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 directionality. |
| 2–9 A1–A8 | Port A I/O Terminals | Bidirectional data pins connected to local bus; high-impedance when OE = high. |
| 10 GND | Ground Reference | Primary return path for all internal logic and output currents - must be low-inductance. |
| 11–18 B1–B8 | Port B I/O Terminals | Bidirectional data pins connected to remote bus; isolated when OE = high. |
| 19 OE | Output Enable Input | Low = active transceivers; High = all A/B pins enter high-Z - critical for bus arbitration. |
| 20 VCC | Power Supply | 5 V supply pin requiring local 0.1 µF bypass capacitor - powers internal logic and output drivers. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-Compatible Inputs | Accepts 0.8 V/2 V thresholds - eliminates need for external level-shifting circuitry when interfacing with legacy 5 V microcontrollers. |
| Slow Edge Rate Control | Minimizes output ringing and EMI - enables clean signal integrity on unterminated PCB traces up to 15 cm. |
| 3-State Output Isolation | IOZ ≤ ±2.5 µA at VCC = 5.5 V - prevents leakage-induced bus contention during power sequencing or fault conditions. |
| Wide Temperature Range | –40 °C to +125 °C operation - supports deployment in under-hood automotive ECUs and industrial motor controllers without derating. |
| Overvoltage-Tolerant Inputs | VI up to 5.5 V regardless of VCC - allows safe hot-plug operation into live 5 V buses during system maintenance. |
Applications
| Industrial Backplane Interface | Microcontroller Bus Expansion |
|---|---|
|
Use Scenario: Connecting a 5 V FPGA I/O bank to a legacy ISA-style peripheral bus operating at 5 V. IC Role / Device Role / Timing Role: Bidirectional data bridge enabling read/write cycles between master and slave devices with precise DIR-controlled direction switching. Use Value: Eliminates need for discrete logic gates or dual unidirectional buffers, reducing component count and layout area by 40% versus discrete solutions. |
Use Scenario: Expanding GPIO count of an ARM Cortex-M4 MCU by interfacing external SRAM and parallel LCD controller. IC Role / Device Role / Timing Role: Synchronous bus transceiver synchronized to MCU address strobe, using OE for cycle-based enable/disable. Use Value: Enables 8-bit parallel data transfer at up to 50 MHz with <10 ns skew between bits - maintains timing margin for 80 ns SRAM access. |
| 3.3 V-to-5 V Level Translation | Isolated Reset Hold Circuit |
|
Use Scenario: Interfacing a 3.3 V SoC's UART TX/RX lines to a 5 V RS-232 transceiver requiring 5 V logic levels. IC Role / Device Role / Timing Role: Unidirectional level shifter (A→B mode) translating 3.3 V logic highs to 5 V-compliant VOH ≥ 3.94 V at –8 mA load. Use Value: Achieves full 5 V logic swing without pull-up resistors or external voltage translators - reduces BOM cost by $0.12 per interface. |
Use Scenario: Holding a processor reset line low during power-up sequencing until regulated 5 V rail stabilizes. IC Role / Device Role / Timing Role: Controlled buffer where OE is driven by power-good signal, isolating reset line until system is ready. Use Value: Prevents premature CPU release by maintaining reset assertion for >100 ms with zero leakage current - improves boot reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC245A | Lower VCC range (1.65–3.6 V); 3.3 V only; higher speed (tPD ≤ 5.3 ns); lower drive (±24 mA) | Not suitable for 5 V-only systems; requires level shifters for 5 V interfaces | Select for 3.3 V domains needing faster timing and lower power; avoid for native 5 V bus bridging. |
| 74ACT245 | Higher drive (±24 mA); wider VCC (4.5–5.5 V); same pinout; no overvoltage-tolerant inputs | More susceptible to input damage if driven above VCC; less tolerant of mixed-voltage hot-swap | Choose for high-current 5 V bus loading where input overvoltage risk is mitigated by system design. |
Compared with SN74LVC245A and 74ACT245, SN74AHCT245DBRG4 uniquely balances 5 V bus compatibility, TTL input tolerance, and overvoltage-safe operation - making it optimal for retrofitting legacy 5 V systems with modern mixed-voltage peripherals.
Availability
SN74AHCT245DBRG4 is available at Aetrix Electronics and suitable for industrial automation backplanes, microcontroller bus expansion, 3.3 V-to-5 V level translation, and isolated reset hold circuits requiring stable component supply across extended temperature ranges.
Supply support for SN74AHCT245DBRG4 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 connectivity technologies, with over 50 years of innovation in logic and interface ICs.
SN74AHCT245DBRG4 belongs to TI's AHCT logic family, engineered for robust 5 V bus interfacing in industrial and automotive applications where TTL compatibility, noise immunity, and wide temperature operation are essential.
FAQ
What is the maximum propagation delay of SN74AHCT245DBRG4 at 5 V?
The maximum propagation delay for SN74AHCT245DBRG4 is 10 ns (tPLH/tPHL) under recommended conditions (VCC = 5 V, CL = 15 pF, TA = 25 °C). At worst-case industrial temperature (–40 °C to +125 °C), the limit increases to 10 ns for tPLH/tPHL and 16 ns for tPZH/tPHZ - all values confirmed in Section 6.6 of the official TI datasheet SCLS233S.
Does SN74AHCT245DBRG4 support 3.3 V input signals?
Yes, SN74AHCT245DBRG4 accepts 3.3 V logic levels directly: its VIH threshold is 2 V and VIL is 0.8 V, both met by standard 3.3 V CMOS outputs. This enables seamless 3.3 V-to-5 V level translation without external components - verified in Section 6.3 Recommended Operating Conditions and Section 8.3 Feature Description.
What package type is used by SN74AHCT245DBRG4?
SN74AHCT245DBRG4 uses a 20-pin SSOP (Shrink Small Outline Package) with body size 7.50 mm × 5.30 mm and 0.65 mm lead pitch. This is explicitly listed in the Package Information table and confirmed in the Orderable Addendum where "DB" denotes SSOP and "G4" indicates RoHS-compliant NiPdAu finish.
Can SN74AHCT245DBRG4 be used in automotive applications?
SN74AHCT245DBRG4 is a catalog-grade device rated for –40 °C to +125 °C, but it is not AEC-Q100 qualified. For automotive use, TI offers the pin-compatible SN74AHCT245-Q1 variant - documented in the "Other Qualified Versions" section of the datasheet addendum. Using SN74AHCT245DBRG4 in automotive systems requires full system-level qualification by the end customer.
How should unused inputs be handled on SN74AHCT245DBRG4?
All unused inputs (DIR, OE, A1–A8, B1–B8) on SN74AHCT245DBRG4 must be tied to VCC or GND to prevent floating states - as mandated in Section 9.4.1 Layout Guidelines. Leaving inputs unconnected risks undefined logic behavior, increased ICC, and potential latch-up. OE should be pulled to VCC via a resistor during power-up to ensure initial high-Z state.
SN74AHCT245DBRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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-SSOP
SN74AHCT245DBRG4 FAQ
1.How can I place an order for SN74AHCT245DBRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT245DBRG4 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 SN74AHCT245DBRG4 reliable?
The price and inventory of SN74AHCT245DBRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT245DBRG4 is usually 5 days.
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Once your SN74AHCT245DBRG4 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 SN74AHCT245DBRG4?
For technical support, including SN74AHCT245DBRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT245DBRG4 requirements.
6.How does Aetrix verify that SN74AHCT245DBRG4 is sourced from the original manufacturer or authorized distributors?
All SN74AHCT245DBRG4 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 SN74AHCT245DBRG4 meets industry standards.
7.What is the process for return or replacement of SN74AHCT245DBRG4?
All SN74AHCT245DBRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT245DBRG4, 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 SN74AHCT245DBRG4 part is unused and in its original packaging.
Return procedure for SN74AHCT245DBRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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