My Inquiry
My Account
Texas Instruments SN74ALS245ANSR
- Part No.:
- SN74ALS245ANSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ALS245ANSR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,476
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74ALS245ANSR 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, and features pnp input structure to reduce DC loading. It is used in industrial backplane interfaces and legacy microprocessor data bus isolation.
For engineers reviewing the SN74ALS245ANSR datasheet, SN74ALS245ANSR pinout, SN74ALS245ANSR application, or SN74ALS245ANSR equivalent, key selection criteria include 3-state control timing (tPZH/tPLZ ≤ 20 ns), VCC=5 V compatibility, SOP-20 package thermal resistance (θJA = 60°C/W), and guaranteed IOL=24 mA drive capability under commercial temperature range (0°C to 70°C).
Technical Context
This device implements dual-directional bus communication via DIR-controlled signal flow and OE-gated 3-state output enable/disable. Its pnp input stage minimizes input current draw, reducing loading on upstream drivers. The logic diagram confirms independent channel operation across all eight A/B pairs with shared DIR and OE control lines.
Switching behavior is characterized under CL = 50 pF, R1 = R2 = 500 Ω, and full VCC (4.5–5.5 V) range. Propagation delays (tPLH/tPHL) are asymmetric: 3–10 ns for A→B/B→A paths, while enable/disable times (tPZH/tPLZ) range 4–15 ns - critical for bus arbitration timing in multiplexed systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL and LSTTL logic rails. |
| Max tpd | 10 ns at VCC = 5 V - enables reliable operation in high-speed 8-bit data paths up to ~50 MHz clock-equivalent rates. |
| IOL (min) | 24 mA - drives standard TTL loads directly without external buffers; sufficient for 10-unit load fanout. |
| VIK | –1.5 V - provides robust negative-going transient immunity on inputs during bus contention or hot-swap events. |
| θJA | 60°C/W (NS package) - defines thermal derating limit; requires ≤ 150 mW power dissipation for <25°C ambient rise. |
| Operating Temp | 0°C to 70°C - qualifies for commercial-grade embedded control and instrumentation applications. |
Pinout & Package
The SN74ALS245ANSR is housed in a 20-pin SOP (Small Outline Package) with 0.65 mm lead pitch and 2 mm maximum height per TI DB0020A drawing. Pin 1 is located at the top-left corner with index area marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DIR | Direction Control Input | Low = B→A data flow; High = A→B data flow; determines signal path polarity for all 8 channels. |
| OE | Output Enable Input | Low = outputs active; High = all A/B outputs enter high-impedance state for bus isolation. |
| A1–A8 | Input/Output Port A | Bidirectional I/O pins connected to first data bus; function as inputs or outputs depending on DIR state. |
| B1–B8 | Input/Output Port B | Bidirectional I/O pins connected to second data bus; mirror A-side behavior under DIR control. |
| GND | Ground Reference | Power return path for logic and output stages; must be low-impedance to maintain noise margin. |
| VCC | Supply Voltage | +5 V supply rail; decoupling capacitor required within 1 cm of pin to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| 3-State Outputs | Enables direct connection to shared data buses without external bus switches or pull-ups. |
| pnp Input Structure | Reduces input current to ≤0.1 mA, minimizing loading on preceding drivers and improving fanout. |
| Asymmetric Timing Control | Separate tPZH/tPLZ (enable/disable) and tPLH/tPHL (propagation) specs allow precise bus arbitration design. |
| TTL-Compatible Logic Levels | VIH = 2 V, VIL = 0.8 V - interoperates with standard 74LS/74ALS families without level-shifting. |
Applications
| Industrial Backplane Interface | Legacy Microprocessor Bus Isolation |
|---|---|
Use Scenario: Isolating CPU address/data buses from peripheral expansion slots in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional bus transceiver enabling read/write cycles between MPU and I/O modules via DIR-controlled direction and OE-gated bus release. Use Value: Eliminates need for discrete bus switches; 24 mA drive supports 10-unit TTL load per line; 10 ns tpd meets 80C85/8088 bus timing budgets. | Use Scenario: Interfacing Z80 or 6502-based subsystems with shared memory-mapped peripherals. IC Role / Device Role / Timing Role: Directional data bridge synchronizing asynchronous bus segments using OE for cycle-controlled tristate gating. Use Value: pnp inputs reduce loading on vintage MPU bus drivers; –1.5 V VIK withstands negative glitches common in retro-computing environments. |
| Test Equipment Data Path Switching | Automated Test Fixture Signal Routing |
Use Scenario: Reconfigurable signal routing between DUT ports and measurement instruments in ATE platforms. IC Role / Device Role / Timing Role: Programmable bus coupler controlled by FPGA GPIO to establish dynamic A↔B connectivity paths. Use Value: 20-pin SOP footprint simplifies PCB layout; 60°C/W θJA allows dense placement in air-cooled test racks. | Use Scenario: Multiplexing sensor analog/digital signals onto shared acquisition channels in production test fixtures. IC Role / Device Role / Timing Role: Level-translating and isolating digital control lines between fixture controller and DUT interface boards. Use Value: Guaranteed 24 mA sink capability drives LED indicators and relay drivers directly; OE pin enables synchronized fixture reset sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AS245NSR | Faster tpd (7.5 ns max), higher IOL (64 mA), but increased ICC (95 mA active) and wider VIH/VIL thresholds. | Better suited for high-speed, high-drive applications where power budget permits; not drop-in due to timing and current differences. | Select when >50 MHz bus toggle rates or >40 mA per line drive is required; verify OE timing margins. |
| SN74ALS245ADBR | SSOP-20 package (DB), same electrical specs, but smaller footprint (16.4 mm width vs NS's 24.4 mm) and lower θJA (55°C/W). | Preferred for space-constrained PCBs requiring improved thermal performance; pinout identical, layout change needed. | Choose for compact industrial controllers where board area is limited and thermal headroom is critical. |
Compared with SN74AS245NSR and SN74ALS245ADBR, the SN74ALS245ANSR offers optimal balance of speed (10 ns), drive strength (24 mA), and thermal efficiency (60°C/W) in the widely supported SOP-20 package - making it ideal for cost-sensitive, medium-speed bus isolation where legacy compatibility is essential.
Availability
SN74ALS245ANSR is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy microprocessor bus isolation, and automated test fixture signal routing requiring stable component supply across long-lifecycle programs.
Supply support for SN74ALS245ANSR 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The SN74ALS245ANSR belongs to TI's legacy 74ALS logic family, engineered for reliable 5 V TTL system interfacing with enhanced speed-power tradeoffs over standard 74LS devices.
FAQ
What is the maximum propagation delay of the SN74ALS245ANSR at 5 V?
The SN74ALS245ANSR has a maximum propagation delay (tPLH/tPHL) of 10 ns when operating at VCC = 5 V with CL = 50 pF and R1/R2 = 500 Ω. This value applies to both A→B and B→A signal paths and is specified across the full commercial temperature range (0°C to 70°C). The SN74ALS245ANSR datasheet confirms this in the switching characteristics table on page 4.
Does the SN74ALS245ANSR support bidirectional data flow?
Yes, the SN74ALS245ANSR supports fully bidirectional data flow between its A and B buses. Direction is controlled by the DIR input: logic low enables B→A transmission, while logic high enables A→B transmission. This functionality is implemented per channel across all eight A/B pairs, and the SN74ALS245ANSR logic diagram on page 2 explicitly shows this dual-path architecture.
What package type and dimensions does the SN74ALS245ANSR use?
The SN74ALS245ANSR uses a 20-pin SOP (Small Outline Package) with package drawing DB0020A. Its dimensions are 7.5 mm × 5.6 mm × 2.0 mm (L × W × H), with 0.65 mm lead pitch and pin 1 located in the top-left quadrant. The TI package outline drawing confirms these mechanical specifications, and the tape-and-reel packaging uses 24.4 mm reel width with Q1 pin-1 orientation.
Can the SN74ALS245ANSR drive standard TTL loads directly?
Yes, the SN74ALS245ANSR can drive standard TTL loads directly. It guarantees IOL ≥ 24 mA per output at VOL ≤ 0.4 V, supporting up to 10-unit TTL loads (each unit load = 1.6 mA) without external buffering. This capability is verified in the SN74ALS245ANSR electrical characteristics table on page 3, under "VOL" test conditions with IOL = 24 mA.
Is the SN74ALS245ANSR RoHS compliant?
Yes, the SN74ALS245ANSR is RoHS compliant. According to TI's Package Option Addendum, the orderable part number SN74ALS245ANSR carries RoHS = "Yes", uses NiPdAu (NIPDAU) lead finish, and has MSL rating Level-1-260C-UNLIM. This compliance is confirmed in TI's official packaging documentation dated 15-Jul-2026.
SN74ALS245ANSR 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:
- 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:
- 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
SN74ALS245ANSR FAQ
1.How can I place an order for SN74ALS245ANSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS245ANSR 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 SN74ALS245ANSR reliable?
The price and inventory of SN74ALS245ANSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS245ANSR is usually 5 days.
3.What payment methods are accepted for SN74ALS245ANSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS245ANSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS245ANSR?
SN74ALS245ANSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS245ANSR 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 SN74ALS245ANSR?
For technical support, including SN74ALS245ANSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS245ANSR requirements.
6.How does Aetrix verify that SN74ALS245ANSR is sourced from the original manufacturer or authorized distributors?
All SN74ALS245ANSR 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 SN74ALS245ANSR meets industry standards.
7.What is the process for return or replacement of SN74ALS245ANSR?
All SN74ALS245ANSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS245ANSR, 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 SN74ALS245ANSR part is unused and in its original packaging.
Return procedure for SN74ALS245ANSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74ALS245ANSR Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
