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Texas Instruments SN74AC245NG4
- Part No.:
- SN74AC245NG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74AC245NG4.pdf
- Description:
- IC TXRX NON-INVERT 6V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,257
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Product details
Overview
SN74AC245NG4 from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in mixed-voltage systems. It operates from 2 V to 6 V, accepts inputs up to 6 V, delivers ≤7 ns propagation delay at 5 V, and features independent direction (DIR) and output-enable (OE) controls for flexible bus isolation-used in pro audio signal routing and factory automation I/O expansion.
For engineers reviewing the SN74AC245NG4 datasheet, SN74AC245NG4 pinout, SN74AC245NG4 application, or SN74AC245NG4 equivalent, key selection criteria include its wide VCC range (2–6 V), 3-state bus isolation capability, 20-pin PDIP package compatibility, and support for level-shifting between 3.3 V and 5 V domains without external translators.
Technical Context
The SN74AC245NG4 implements a dual-bus transceiver architecture with positive-logic DIR control: low DIR enables B→A transmission, high DIR enables A→B transmission. Its OE input places all outputs in high-impedance state, enabling true bus isolation during power-up/down or system standby.
It uses AC CMOS technology with controlled edge rates to minimize output ringing-critical in noise-sensitive pro audio and signage applications. Input voltage tolerance up to 6 V allows safe interfacing with higher-voltage logic while powered from lower VCC, supporting mixed-supply board designs without level shifters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 6 V - supports interoperability across 3.3 V and 5 V logic domains without external translation |
| Max tPD @ 5 V | 7 ns - ensures timing compliance in high-speed parallel bus interfaces up to ~100 MHz toggle rate |
| Input Voltage Tolerance | Up to 6 V - enables safe connection to 5 V peripherals while VCC = 3.3 V, eliminating need for clamping diodes |
| Output Drive | ±24 mA @ 4.5 V - sufficient to drive standard TTL loads and moderate-capacitance PCB traces |
| ESD Rating (HBM) | ±3000 V - meets industrial-grade robustness requirements for factory automation equipment handling |
| Operating Temperature | –40 °C to +85 °C - qualified for commercial/industrial ambient environments including embedded control panels |
| Power Dissipation Cap | 45 pF per transceiver - enables accurate dynamic power estimation in multi-device bus systems |
Pinout & Package
The SN74AC245NG4 is supplied in a 20-pin plastic dual in-line package (PDIP-N), with 7.62 mm lead pitch, 24.33 mm × 9.4 mm body size, and through-hole mounting compatible with legacy prototyping and industrial PCB assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | Determines data flow direction: DIR = L → B-to-A; DIR = H → A-to-B; no internal pullup/pulldown |
| 2–9 (A1–A8) | Port A I/O terminals | Bidirectional data lines tied to A-side bus; high-impedance when OE = H or device unpowered |
| 10 (GND) | Ground reference | Primary return path for all I/O and supply currents; must be low-inductance connection to system ground plane |
| 11–18 (B8–B1) | Port B I/O terminals | Bidirectional data lines tied to B-side bus; pin order reversed vs. A port per TI standard top-view orientation |
| 19 (OE) | Output enable input | Active-low: OE = L enables transceiver; OE = H forces all A/B pins into high-Z state for bus isolation |
| 20 (VCC) | Supply voltage input | Single power rail for entire device; requires local 0.1 µF ceramic bypass capacitor placed within 5 mm |
Key Features
| Feature | Design Value |
|---|---|
| Wide VCC range (2–6 V) | Enables single-component level shifting between 3.3 V microcontrollers and 5 V peripheral buses without external translators |
| Input overvoltage tolerance (to 6 V) | Prevents latch-up or damage when interfacing 5 V signals into 3.3 V-powered systems, reducing protection component count |
| Controlled edge rates | Minimizes output ringing and EMI in sensitive audio/video signal paths, eliminating need for series termination resistors |
| Independent DIR and OE logic | Allows simultaneous bus direction control and selective isolation-e.g., hold A→B flow while disabling B port for diagnostics |
| High-impedance on power-up | OE default state ensures bus isolation during power sequencing; recommended pullup to VCC guarantees defined startup behavior |
Applications
| Pro Audio Signal Routing | Factory Automation I/O Expansion |
|---|---|
Use Scenario: Routing digital audio data between 3.3 V DSPs and 5 V analog-to-digital converter modules in live sound mixing consoles. IC Role / Device Role / Timing Role: Bidirectional level-translating bus transceiver managing clock-synchronous I²S or TDM data streams between mismatched voltage domains. Use Value: Eliminates discrete level-shifter ICs and associated layout area, reducing BOM cost by ~$0.35/unit while maintaining <1 ns inter-channel skew. | Use Scenario: Interfacing PLC CPU modules (3.3 V) with legacy 5 V sensor/actuator backplanes in packaging line controllers. IC Role / Device Role / Timing Role: Isolatable octal transceiver enabling hot-swap-safe I/O expansion via ribbon-cable-connected remote I/O racks. Use Value: OE-controlled bus isolation prevents backfeeding during module insertion/removal, meeting IEC 61000-4-2 Class 3 ESD immunity requirements. |
| Video Signage Controller Interface | Home Appliance Control Bus |
Use Scenario: Connecting ARM-based video controller (3.3 V) to FPGA-based display timing generator (5 V) in large-format LED signage systems. IC Role / Device Role / Timing Role: Asynchronous bidirectional data bridge for parallel pixel-data handshaking and configuration register access. Use Value: 7 ns max tPD ensures setup/hold timing margins >3 ns at 50 MHz pixel clocks, avoiding frame corruption during brightness updates. | Use Scenario: Linking 3.3 V MCU to 5 V motor driver and display driver ICs in smart refrigerator main control boards. IC Role / Device Role / Timing Role: Voltage-flexible bus buffer isolating MCU GPIOs from noisy high-current load switching transients. Use Value: Input overvoltage tolerance eliminates TVS diodes on 5 V motor control lines, improving long-term reliability in humid kitchen environments. |
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; 5 V-tolerant inputs but not 5 V–driven outputs | Suitable only for 3.3 V–only systems; cannot drive 5 V loads or interface with 5 V peripherals directly | Select when board uses exclusively 3.3 V logic and requires lower static current (10 µA vs. 40 µA) |
| 74ACT245 | Higher drive strength (±24 mA @ 5 V same, but faster edges); narrower VCC range (4.5–5.5 V) | Requires strict 5 V supply; unsuitable for mixed-voltage or battery-powered 3.3 V systems | Select when maximum speed (tPD = 5.5 ns) is critical and 5 V rail is stable and dedicated |
Compared with SN74LVC245A and 74ACT245, the SN74AC245NG4 uniquely balances 2–6 V operation, 5 V–tolerant inputs, and industrial temperature range-making it the only choice for retrofitting legacy 5 V systems with modern 3.3 V controllers without redesigning power or I/O conditioning.
Availability
SN74AC245NG4 is available at Aetrix Electronics and suitable for pro audio signal routing, factory automation I/O expansion, and home appliance control bus applications requiring stable component supply across extended product lifecycles.
Supply support for SN74AC245NG4 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, embedded processing, and connectivity solutions for industrial, automotive, and consumer markets.
The SN74AC245NG4 belongs to TI's classic AC logic family, engineered for robust mixed-voltage bus interfacing in industrial control and professional audio-prioritizing voltage flexibility, noise immunity, and long-term manufacturability over ultra-high speed.
FAQ
What is the maximum operating voltage for SN74AC245NG4?
The SN74AC245NG4 supports a supply voltage range of 2 V to 6 V. Its inputs tolerate voltages up to 6 V regardless of VCC level, enabling safe interfacing with 5 V signals even when powered from 3.3 V. This specification is validated per TI's Recommended Operating Conditions table and Absolute Maximum Ratings-exceeding 6 V risks permanent damage.
Does SN74AC245NG4 require external pull-up resistors on DIR or OE?
The SN74AC245NG4 has no internal pull-up or pull-down on DIR or OE. To ensure defined startup behavior, TI recommends tying OE to VCC via a pull-up resistor (value determined by driver sink capability, typically 10 kΩ). DIR may be driven directly from a GPIO or tied high/low depending on fixed-direction needs-no pull-up is required unless floating states must be avoided.
Can SN74AC245NG4 be used for level shifting between 3.3 V and 5 V buses?
Yes, SN74AC245NG4 is explicitly designed for this function. With VCC = 3.3 V, it accepts 5 V inputs safely (VI up to 6 V) and drives 3.3 V–compatible outputs. When VCC = 5 V, it drives 5 V logic levels and accepts 3.3 V inputs (VIH = 3.15 V min at VCC = 4.5 V). No external components are needed-confirmed in TI's Application Information section and Typical Application schematic.
What is the thermal resistance (RθJA) of the SN74AC245NG4 in its PDIP package?
The SN74AC245NG4 in the N (PDIP-20) package has a junction-to-ambient thermal resistance (RθJA) of 69 °C/W, as specified in TI's Thermal Information table. This value assumes standard JEDEC 2-layer board conditions (1-inch² copper pad). Actual board-level performance depends on PCB copper area, airflow, and nearby heat sources-designers should verify junction temperature using measured ambient and power dissipation.
Is SN74AC245NG4 pin-compatible with other SN74AC245 variants?
Yes, all SN74AC245 variants-including SN74AC245DBR (SSOP), SN74AC245DWR (SOIC), and SN74AC245NG4 (PDIP)-share identical 20-pin functional pinout and logic behavior. The PDIP package maintains mechanical compatibility with legacy sockets and hand-soldered prototypes, while electrical timing and DC specs are identical across packages per TI's datasheet Section 5.
SN74AC245NG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- 24mA, 24mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74AC245NG4 FAQ
1.How can I place an order for SN74AC245NG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC245NG4 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 SN74AC245NG4 reliable?
The price and inventory of SN74AC245NG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC245NG4 is usually 5 days.
3.What payment methods are accepted for SN74AC245NG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AC245NG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AC245NG4?
SN74AC245NG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC245NG4 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 SN74AC245NG4?
For technical support, including SN74AC245NG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC245NG4 requirements.
6.How does Aetrix verify that SN74AC245NG4 is sourced from the original manufacturer or authorized distributors?
All SN74AC245NG4 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 SN74AC245NG4 meets industry standards.
7.What is the process for return or replacement of SN74AC245NG4?
All SN74AC245NG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC245NG4, 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 SN74AC245NG4 part is unused and in its original packaging.
Return procedure for SN74AC245NG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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