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Texas Instruments SN74ALS245ANSRG4
- Part No.:
- SN74ALS245ANSRG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ALS245ANSRG4.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,628
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Product details
Overview
SN74ALS245ANSRG4 from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in TTL-compatible systems. It operates from 4.5 V to 5.5 V, delivers max propagation delay of 10 ns at 5 V, supports ±24 mA output drive (IOL/IOH), and uses pnp inputs to reduce DC loading. It is used in industrial backplane interfaces and legacy system bus isolation.
For engineers reviewing the SN74ALS245ANSRG4 datasheet, SN74ALS245ANSRG4 pinout, SN74ALS245ANSRG4 application, or SN74ALS245ANSRG4 equivalent, key selection criteria include 3-state control timing (tPZH/tPLZ ≤ 20 ns), VCC=5 V compatibility, SOP-20 package footprint, and ALS logic family noise immunity and fanout capability.
Technical Context
This device implements dual-directional bus communication via DIR input: low enables B→A transmission, high enables A→B transmission. Output-enable (OE) provides independent 3-state control - active-low assertion disables all outputs to high-impedance state, isolating both buses.
It belongs to the ALS (Advanced Low-Power Schottky) logic family, featuring pnp input stages that lower input current (II ≤ ±0.1 mA) and improve noise margin over standard LS. Its switching characteristics are specified under CL = 50 pF, R1 = R2 = 500 Ω, and operate across 0°C to 70°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL power rails and tolerates supply ripple. |
| Max Propagation Delay | 10 ns at VCC = 5 V - enables reliable operation in 100 MHz bus clock domains with setup/hold margin. |
| IOL / IOH | 24 mA / –15 mA - drives standard TTL loads directly without external buffers; supports fanout ≥20. |
| 3-State Enable Time | tPZH ≤ 20 ns - fast bus release prevents contention during direction or enable transitions. |
| Input Loading | pnp inputs limit II ≤ ±0.1 mA - reduces DC loading on upstream drivers, easing fanout design. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded and industrial control applications. |
Pinout & Package
SOP-20 (Small Outline Package, 20-pin, 0.65 mm pitch, 7.5 mm × 5.6 mm body, 2.0 mm max height) per JEDEC MO-150.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A1–A8 I/O | Octal A-side bidirectional data terminals; connected to source bus when DIR = H and OE = L. |
| 11, 12, 13, 14, 15, 16, 17, 18 | B1–B8 I/O | Octal B-side bidirectional data terminals; connected to destination bus when DIR = L and OE = L. |
| 9 | GND | Ground reference for all internal logic and I/O circuits. |
| 10 | VCC | Positive supply rail (4.5–5.5 V); powers internal gates and output drivers. |
| 19 | DIR | Direction control input: LOW = B→A, HIGH = A→B; TTL-compatible threshold (VIL ≤ 0.8 V, VIH ≥ 2 V). |
| 20 | OE | Output-enable input: LOW = enabled, HIGH = 3-state; asynchronous, overrides DIR for bus isolation. |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous bidirectional control | Independent DIR and OE pins allow dynamic bus direction reversal and safe hot-swap isolation without clock synchronization. |
| ALS logic family performance | Combines LS speed (10 ns tpd) with 1/3 the power of standard LS, enabling higher-density bus interfaces. |
| pnp input structure | Reduces input current to ≤ ±0.1 mA, minimizing loading on preceding drivers and improving cascaded fanout stability. |
| 3-state output drive strength | ±24 mA sink/source capability meets TTL bus termination requirements without external pull-ups or drivers. |
Applications
| Industrial Backplane Interface | Legacy System Bus Isolation |
|---|---|
Use Scenario: Connecting microcontroller local bus to a multi-slot industrial backplane carrying sensor/actuator data. IC Role / Device Role / Timing Role: Bidirectional level-shifting and contention-free bus transceiver between CPU and peripheral slots. Use Value: DIR-controlled direction switching and OE-gated isolation prevent bus conflicts during slot insertion/removal or firmware updates. | Use Scenario: Isolating aging ISA or STD bus segments in refurbished test equipment to avoid ground loops and signal integrity degradation. IC Role / Device Role / Timing Role: 3-state buffer providing galvanic separation and timing-matched data handoff between bus segments. Use Value: 10 ns propagation delay and 20 ns enable/disable times preserve original bus timing margins while adding fault containment. |
| Microcontroller Expansion Port | EPROM Programming Adapter |
Use Scenario: Extending GPIO count of an 8-bit MCU using external parallel memory or peripheral ICs via shared address/data bus. IC Role / Device Role / Timing Role: Octal transceiver managing bidirectional data flow between MCU port and external devices. Use Value: pnp inputs minimize MCU port loading; 24 mA drive supports direct connection to multiple CMOS/TTL loads. | Use Scenario: Adapting a modern programmer to program vintage EPROMs requiring 5 V TTL-level address/data/control signals. IC Role / Device Role / Timing Role: Level-consistent bidirectional interface between programmer controller and EPROM DQ/AD pins. Use Value: Guaranteed 5 V operation and 10 ns timing ensure reliable programming pulse fidelity and verification readback accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS245AN | PDIP-20 package; same electrical specs and timing; no RoHS exemption required. | Preferred for through-hole prototyping or legacy PCB rework where SOP footprint is unavailable. | Select when manual soldering, breadboarding, or socket-based testing is required. |
| SN74AS245NSR | AS family: faster tpd (7.5 ns), higher IOL (64 mA), but increased ICC (95 mA vs. 55 mA) and reduced noise margin. | Better suited for high-speed, low-latency bus extensions where power efficiency is secondary. | Choose only if sub-8 ns propagation is mandatory and thermal/power budget allows. |
Compared with SN74ALS245AN and SN74AS245NSR, SN74ALS245ANSRG4 offers optimal balance of speed (10 ns), power (55 mA ICC), and noise immunity for commercial industrial bus interfaces - making it the preferred choice where reliability and compatibility outweigh marginal speed gains.
Availability
SN74ALS245ANSRG4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus isolation, microcontroller expansion ports, and EPROM programming adapters requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS245ANSRG4 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 logic solutions for industrial, automotive, and communications markets.
SN74ALS245ANSRG4 belongs to TI's legacy TTL logic portfolio, specifically the Advanced Low-Power Schottky (ALS) family, engineered for robust 5 V bus interfacing with optimized speed-power-noise tradeoffs in industrial control systems.
FAQ
What is the maximum operating temperature range for SN74ALS245ANSRG4?
The SN74ALS245ANSRG4 is rated for commercial operation from 0°C to 70°C. This range is confirmed in the recommended operating conditions table of the official Texas Instruments datasheet SDAS272A, and applies specifically to the SOP-20 (NS) package variant including the G4 suffix. It is not rated for extended temperature ranges such as –40°C to 85°C or military –55°C to 125°C.
Does SN74ALS245ANSRG4 support 3.3 V logic levels?
No, SN74ALS245ANSRG4 does not support 3.3 V logic operation. It requires a VCC supply of 4.5 V to 5.5 V and is designed for TTL-compatible input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V). Driving its inputs from 3.3 V logic may result in marginal or non-compliant high-level recognition, and powering it at 3.3 V violates absolute maximum ratings and will cause functional failure.
What is the meaning of the "G4" suffix in SN74ALS245ANSRG4?
Per Texas Instruments packaging nomenclature, the "G4" suffix in SN74ALS245ANSRG4 indicates RoHS-compliant lead finish (NiPdAu/NiPdAu over Cu, i.e., matte tin over nickel-palladium-gold) and green molding compound. It confirms compliance with JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1) and peak reflow tolerance up to 260°C, as documented in TI's Package Option Addendum for this part.
Can SN74ALS245ANSRG4 replace SN74ALS245ADWR in a design?
Yes, SN74ALS245ANSRG4 can replace SN74ALS245ADWR electrically and functionally, as both share identical ALS logic specifications, timing, and DC parameters. However, they differ in package: NS (SOP) vs. DW (SOIC). The NS package has a narrower body (5.6 mm vs. 7.5 mm), different lead pitch (0.65 mm vs. 1.27 mm), and distinct land pattern - PCB layout revision is required for mechanical compatibility.
Is there a -1 version of SN74ALS245ANSRG4 with higher output current?
No, the -1 version (e.g., SN74ALS245A-1NSR) exists but is not offered with the G4 suffix in TI's official ordering matrix. SN74ALS245ANSRG4 corresponds to the standard-output variant (IOL = 24 mA), not the enhanced 48 mA -1 version. The -1 version is only listed for N, DW, and NS packages without G4 - confirming SN74ALS245ANSRG4 retains the base ALS245A specification.
SN74ALS245ANSRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-SOIC (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:
- 15mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74ALS245ANSRG4 FAQ
1.How can I place an order for SN74ALS245ANSRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS245ANSRG4 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 SN74ALS245ANSRG4 reliable?
The price and inventory of SN74ALS245ANSRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS245ANSRG4 is usually 5 days.
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SN74ALS245ANSRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS245ANSRG4 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 SN74ALS245ANSRG4?
For technical support, including SN74ALS245ANSRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS245ANSRG4 requirements.
6.How does Aetrix verify that SN74ALS245ANSRG4 is sourced from the original manufacturer or authorized distributors?
All SN74ALS245ANSRG4 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 SN74ALS245ANSRG4 meets industry standards.
7.What is the process for return or replacement of SN74ALS245ANSRG4?
All SN74ALS245ANSRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS245ANSRG4, 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 SN74ALS245ANSRG4 part is unused and in its original packaging.
Return procedure for SN74ALS245ANSRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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