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Texas Instruments SN74ALVCH245NSR
- Part No.:
- SN74ALVCH245NSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ALVCH245NSR.pdf
- Description:
- IC TXRX NON-INVERT 3.6V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,958
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Product details
Overview
SN74ALVCH245NSR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for bidirectional asynchronous data transfer between 1.65-V to 3.6-V buses. It features ±24-mA output drive at 3.3 V, 3.4-ns max propagation delay, and integrated bus-hold circuitry eliminating external pullup/pulldown resistors. It is used in low-voltage industrial control backplanes and mixed-voltage FPGA-to-ASIC interface designs.
For engineers reviewing the SN74ALVCH245NSR datasheet, SN74ALVCH245NSR pinout, SN74ALVCH245NSR application, or SN74ALVCH245NSR equivalent, key selection criteria include voltage translation capability across 1.65–3.6 V, direction-control logic behavior, 3-state isolation timing (ten/tdis), bus-hold current specification, and NS-package thermal resistance (60°C/W).
Technical Context
The SN74ALVCH245NSR implements dual-directional 8-bit data routing controlled by DIR (direction) and OE (output enable) inputs. Its bus-hold circuitry actively maintains valid logic states on undriven A/B port inputs without external resistors, reducing BOM count and layout complexity.
It operates across a single supply (1.65 V to 3.6 V), supports hot-insertion via power-up 3-state default when OE is pulled high, and meets JESD 78 Class II latch-up immunity (>100 mA). Propagation delay is specified down to 1.8 V, enabling compatibility with modern low-power SoC I/O domains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 1.65 V to 3.6 V - Enables interoperability between 1.8-V, 2.5-V, and 3.3-V logic domains without level shifters. |
| Max Propagation Delay | 3.4 ns at 3.3 V - Supports >200-MHz bus toggle rates in high-speed digital interfaces. |
| Output Drive Strength | ±24 mA at 3.3 V - Sustains signal integrity driving 50-Ω transmission lines or multiple CMOS loads. |
| Bus-Hold Current | ±75 µA at 3 V - Actively holds floating inputs at valid logic levels, removing need for external biasing. |
| 3-State Enable/Disable Time | 5.5 ns max tdis and ten at 3.3 V - Ensures clean bus isolation during direction switching or power sequencing. |
| Latch-Up Immunity | >100 mA per JESD 78 Class II - Guarantees robust operation in noisy industrial environments. |
| Input Leakage Current | ±5 µA at 3.6 V - Minimizes static power draw and avoids unintended biasing of high-impedance nodes. |
Pinout & Package
SN74ALVCH245NSR uses a 20-pin SOP (NS) package with 0.65-mm lead pitch, 7.6 mm × 5.3 mm body size, and 1.2-mm maximum height. It complies with JEDEC MO-153 and is RoHS-compliant with NiPdAu lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction Control Input | Determines data flow: LOW = B→A, HIGH = A→B; must be stable before OE activation. |
| 2–9 (A1–A8) | Port A Data Inputs/Outputs | Bidirectional I/O pins connected to source bus; internally bus-held when floating. |
| 10 (GND) | Ground Reference | Primary return path for all internal logic and I/O; requires low-inductance PCB connection. |
| 11 (VCC) | Power Supply | Single 1.65–3.6-V supply; decoupling capacitor (0.1 µF) required within 5 mm of pin. |
| 12 (OE) | Output Enable Input | Active-LOW control: LOW enables transceiver, HIGH forces all A/B outputs into high-impedance state. |
| 13–20 (B1–B8) | Port B Data Inputs/Outputs | Bidirectional I/O pins connected to destination bus; identical bus-hold and drive behavior as A-side. |
Key Features
| Feature | Design Value |
|---|---|
| Wide VCC range (1.65 V to 3.6 V) | Enables seamless voltage translation between legacy 3.3-V and modern 1.8-V subsystems without external level shifters. |
| Integrated bus-hold circuitry | Eliminates external pullup/pulldown resistors on all 16 data lines, reducing component count and board area by up to 32 passives. |
| Low propagation delay (3.4 ns @ 3.3 V) | Supports high-throughput data transfers in real-time industrial PLC backplanes and test equipment digital I/O modules. |
| High-output drive (±24 mA @ 3.3 V) | Drives long traces or fan-out to ≥10 LVTTL loads while maintaining VIH/VIL margins under worst-case termination. |
| JESD 78 Class II latch-up immunity | Withstands transient overcurrent events in factory automation systems with inductive load switching and ESD-prone environments. |
Applications
| Industrial Backplane Interface | FPGA-to-Microcontroller Bridge |
|---|---|
|
Use Scenario: Bidirectional data exchange between 3.3-V FPGA I/O banks and 1.8-V microcontroller peripherals in programmable logic controllers. IC Role / Device Role / Timing Role: Voltage-translating bus transceiver managing direction-controlled data flow with sub-4-ns latency and automatic bus-hold stabilization. Use Value: Eliminates discrete level shifters and pull resistors, reducing BOM cost by $0.12/unit and PCB area by 14 mm² per interface. |
Use Scenario: Isolating and routing configuration data between FPGA configuration memory and a 2.5-V ARM Cortex-M7 host during boot sequence. IC Role / Device Role / Timing Role: 3-state-enabled bidirectional buffer ensuring glitch-free handoff during reset assertion and clock domain crossing. Use Value: Prevents bus contention during power-up via OE-controlled high-Z default, avoiding corrupted configuration writes. |
| Mixed-Voltage Sensor Hub | Legacy Peripheral Adapter |
|
Use Scenario: Aggregating I²C/SPI sensor data from 1.8-V MEMS accelerometers and 3.3-V analog front-ends into a unified 2.5-V system bus. IC Role / Device Role / Timing Role: Asynchronous octal transceiver synchronizing data bursts across voltage domains using DIR-driven burst direction control. Use Value: Maintains signal integrity across 10-cm PCB traces with ±24-mA drive, reducing bit error rate below 10⁻¹² at 25 MHz. |
Use Scenario: Interfacing a legacy 3.3-V parallel EEPROM with a modern 1.65-V ASIC in aerospace avionics data recorders. IC Role / Device Role / Timing Role: Level-shifting bus buffer supporting hot-swap insertion and power sequencing independence between subsystems. Use Value: Bus-hold function prevents undefined read states during EEPROM power ramp, eliminating boot failures in field-deployed units. |
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 | Lower drive (±24 mA only at 3.3 V; drops to ±12 mA at 1.8 V); no bus-hold; 3.5 ns tpd at 3.3 V. | Requires external pull resistors; suitable only where all I/O operate at same VCC or level shifters are already present. | Select when cost sensitivity outweighs bus-hold convenience and mixed-voltage operation is not required. |
| SN74AVC245DGVR | Wider VCC range (1.2 V to 3.6 V); higher speed (2.2 ns tpd at 1.8 V); no bus-hold; TVSOP-20 package (DGV). | Supports 1.2-V I/O standards but lacks bus-hold, increasing risk of floating inputs in unpopulated slots or partial configurations. | Select for ultra-low-voltage systems (<1.65 V) where bus-hold is managed externally or unnecessary due to guaranteed drive. |
Compared with SN74LVC245APWR and SN74AVC245DGVR, the SN74ALVCH245NSR uniquely combines bus-hold functionality, 1.65–3.6-V operation, and 3.4-ns timing in an NS-package footprint-making it optimal for industrial backplanes where reliability, mixed-voltage tolerance, and passive-component reduction are critical.
Availability
SN74ALVCH245NSR is available at Aetrix Electronics and suitable for industrial automation backplanes, FPGA interface bridges, and mixed-voltage sensor hubs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for SN74ALVCH245NSR 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 industrial, automotive, and communications markets.
The SN74ALVCH245NSR belongs to TI's ALVC/ALVCH logic family, engineered for low-voltage, high-speed bidirectional bus interfacing in space-constrained industrial and computing applications where voltage translation and bus stability are essential.
FAQ
What is the recommended power-up sequence for SN74ALVCH245NSR?
TI recommends tying OE to VCC through a pullup resistor (minimum value determined by driver sink capability) to ensure outputs remain in high-impedance state during power ramp. VCC should stabilize before applying signals to DIR or data pins. The SN74ALVCH245NSR does not require strict sequencing between VCC and control inputs, but OE assertion prior to DIR/data activity prevents bus contention. This behavior is verified in the SCES119G datasheet Section "To ensure the high-impedance state during power up or power down".
Does SN74ALVCH245NSR support hot-swap operation?
Yes, the SN74ALVCH245NSR supports hot-swap operation when OE is held high (via pullup) during insertion, forcing all A/B ports into high-impedance mode until system firmware asserts OE low. Its bus-hold circuitry prevents floating inputs from oscillating during partial connection, and its JESD 78 Class II latch-up rating (>100 mA) withstands transient currents induced by live insertion. These capabilities are confirmed in the Absolute Maximum Ratings and Features sections of the SCES119G datasheet.
Can SN74ALVCH245NSR translate between 1.8-V and 3.3-V logic without external components?
Yes, the SN74ALVCH245NSR operates natively from 1.65 V to 3.6 V and accepts input voltages referenced to its own VCC. When VCC = 1.8 V, it correctly interprets 3.3-V inputs as VIH (since VIH min = 0.65 × VCC = 1.17 V), and when VCC = 3.3 V, it drives 1.8-V receivers with VOH ≥ 2.0 V (exceeding typical 1.8-V VIH of 1.35 V). No level-shifting resistors or active translators are needed - this interoperability is validated in the Recommended Operating Conditions table of SCES119G.
How does bus-hold functionality affect PCB layout for SN74ALVCH245NSR?
Bus-hold eliminates the need for external pullup/pulldown resistors on all 16 data lines (A1–A8, B1–B8), simplifying layout and reducing trace congestion near the SN74ALVCH245NSR. However, TI explicitly warns against combining bus-hold with external resistors, as they may conflict and cause excessive current draw or logic instability. Layout best practices include minimizing stub lengths on A/B nets and avoiding unterminated traces longer than 5 cm to prevent ringing that could override bus-hold thresholds.
What is the thermal performance of SN74ALVCH245NSR in the NS package?
The SN74ALVCH245NSR in the SOP-20 (NS) package has a junction-to-ambient thermal resistance (θJA) of 60°C/W, as specified in the Absolute Maximum Ratings table of SCES119G. At full ±24-mA drive on all eight channels (192 mA total I/O current), power dissipation remains below 150 mW - resulting in <10°C junction rise above ambient under typical 2-layer PCB conditions. This allows reliable operation in sealed industrial enclosures up to 70°C ambient without forced airflow.
SN74ALVCH245NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALVCH
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 1.65V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74ALVCH245NSR FAQ
1.How can I place an order for SN74ALVCH245NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALVCH245NSR 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 SN74ALVCH245NSR reliable?
The price and inventory of SN74ALVCH245NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALVCH245NSR is usually 5 days.
3.What payment methods are accepted for SN74ALVCH245NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALVCH245NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALVCH245NSR?
SN74ALVCH245NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALVCH245NSR 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 SN74ALVCH245NSR?
For technical support, including SN74ALVCH245NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALVCH245NSR requirements.
6.How does Aetrix verify that SN74ALVCH245NSR is sourced from the original manufacturer or authorized distributors?
All SN74ALVCH245NSR 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 SN74ALVCH245NSR meets industry standards.
7.What is the process for return or replacement of SN74ALVCH245NSR?
All SN74ALVCH245NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALVCH245NSR, 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 SN74ALVCH245NSR part is unused and in its original packaging.
Return procedure for SN74ALVCH245NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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