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Texas Instruments SN74BCT245NG4
- Part No.:
- SN74BCT245NG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74BCT245NG4.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,744
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Product details
Overview
SN74BCT245NG4 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-level systems. It features direction control (DIR), output enable (OE), ±128 mA sink capability on B-port, 5 V supply operation, and isolation when OE is high - used in memory address register buffering and legacy bus interfacing.
For engineers reviewing the SN74BCT245NG4 datasheet, SN74BCT245NG4 pinout, SN74BCT245NG4 application, or SN74BCT245NG4 equivalent, key selection criteria include 3-state drive strength (IOL = 64 mA on B-port), propagation delay (tPLH/tPHL ≤ 7 ns at 5 V), thermal resistance (θJA = 69°C/W in PDIP), and compatibility with 5 V TTL logic families in industrial control backplanes.
Technical Context
The SN74BCT245NG4 implements dual 8-bit bidirectional data paths controlled by DIR and OE inputs. Its B-port outputs deliver higher drive strength (64 mA sink) than A-port (24 mA sink), enabling asymmetric bus loading where B connects to heavier-loaded subsystems like memory arrays or I/O expanders.
It operates strictly within 4.5 V–5.5 V VCC range and supports TTL-compatible input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V). All unused inputs must be tied to VCC or GND per TI SCBA004 guidance to prevent floating-node-induced shoot-through or increased ICCZ current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - mandates regulated 5 V supply; no 3.3 V operation. |
| B-port IOL | 64 mA - drives heavy capacitive loads (e.g., >100 pF traces + multiple TTL inputs) without voltage droop. |
| tPLH / tPHL | ≤7 ns at 5 V, CL = 50 pF - enables reliable 100+ MHz bus toggling in synchronous edge-triggered designs. |
| θJA (PDIP) | 69°C/W - limits continuous power dissipation to ~175 mW at 70°C ambient before thermal derating. |
| ESD Rating | 2000 V HBM - meets JEDEC JESD22-A114A for handling robustness in assembly environments. |
| ICCZ (Standby) | 10–15 mA - quiescent current when outputs disabled; critical for low-power idle states in buffered address paths. |
Pinout & Package
SN74BCT245NG4 uses a 20-pin plastic dual in-line package (PDIP-N), 7.62 mm pitch, 24.2 mm body length, with through-hole mounting and industry-standard pin 1 index notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | Low = B→A data flow; High = A→B data flow; TTL-compatible threshold. |
| 2–9 (A1–A8) | A-side I/O port | Bi-directional TTL I/O pins; 24 mA sink capability; internal 3-state when OE high. |
| 10 (GND) | Ground reference | Primary return path for all I/O and supply currents; requires low-impedance PCB plane. |
| 11 (VCC) | Power supply | 5 V ±5% supply input; decoupling capacitor (0.1 µF ceramic) required adjacent to pin. |
| 12 (OE) | Output enable input | Active-low control; High = all outputs high-impedance; TTL-compatible threshold. |
| 13–20 (B1–B8) | B-side I/O port | Bi-directional TTL I/O pins; 64 mA sink capability; higher drive than A-port for bus termination. |
Key Features
| Feature | Design Value |
|---|---|
| Asymmetric drive strength | B-port delivers 64 mA sink vs. A-port's 24 mA - optimizes signal integrity when driving long traces or multiple loads from B side. |
| True 3-state isolation | OE-controlled high-impedance state prevents bus contention during hot-swap or multi-master arbitration. |
| TTL-compatible interface | VIH ≥ 2 V and VIL ≤ 0.8 V ensure direct connection to legacy 5 V TTL logic without level-shifting. |
| Robust ESD protection | 2000 V Human-Body Model rating reduces field failure risk during manual handling and board insertion. |
| Controlled switching behavior | Specified tPZH/tPZL (≤10.9 ns) ensures predictable enable/disable timing for synchronized bus gating. |
Applications
| Industrial Backplane Interfacing | Memory Address Buffering |
|---|---|
|
Use Scenario: Isolating CPU address bus from peripheral expansion slots in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional address latch buffer with DIR set to fixed A→B mode and OE synchronized to memory access strobes. Use Value: Prevents address bus contention during DMA cycles; 64 mA B-port drive sustains signal integrity across 15 cm backplane traces. |
Use Scenario: Driving multiplexed address lines to SRAM and EPROM chips in embedded instrumentation. IC Role / Device Role / Timing Role: Unidirectional address driver (A→B), with OE gated by chip-select logic to isolate memory during reset. Use Value: Eliminates need for discrete pull-up resistors; 24 mA A-port sink handles TTL fan-out without added loading. |
| Legacy Bus Translation | Test Equipment Signal Routing |
|
Use Scenario: Bridging ISA bus segments in retro-computing diagnostic hardware. IC Role / Device Role / Timing Role: Full-duplex transceiver with DIR toggled per cycle to support bidirectional data bursts. Use Value: Matches ISA timing budgets with sub-7 ns propagation; 3-state isolation avoids bus lockups during interrupt servicing. |
Use Scenario: Configurable signal path routing in automated test equipment mainframes. IC Role / Device Role / Timing Role: Reconfigurable bus switch controlled by FPGA GPIOs (DIR/OE), enabling dynamic DUT interface mapping. Use Value: Enables single-board support of multiple DUT protocols via software-defined direction and enable states. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS245N | Lower drive (IOL = 24 mA on both ports); slower (tPLH up to 15 ns); higher ICCZ (40 mA) | Suitable only for light-load, low-speed legacy systems; cannot replace SN74BCT245NG4 in high-fanout or timing-critical paths. | Select only if backward compatibility with LS-TTL voltage margins and speed is required and B-port loading < 20 mA. |
| SN74AHCT245N | CMOS input structure (VIH = 2 V min); same 64 mA B-port drive; identical pinout and timing | Accepts mixed 3.3 V/5 V control signals; lower static power but same dynamic performance as SN74BCT245NG4. | Preferred for new designs needing 3.3 V logic compatibility while retaining 5 V bus drive capability. |
Compared with SN74LS245N, SN74BCT245NG4 delivers 2.7× higher B-port drive and 50% faster propagation for dense backplanes; versus SN74AHCT245N, it offers superior noise immunity in electrically noisy industrial environments due to TTL input hysteresis.
Availability
SN74BCT245NG4 is available at Aetrix Electronics and suitable for industrial backplane interfacing, memory address buffering, legacy bus translation, and test equipment signal routing requiring stable component supply and long-term obsolescence management.
Supply support for SN74BCT245NG4 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74BCT245NG4 belongs to TI's BCT logic family, engineered specifically for high-drive, 5 V TTL-compatible bus interfacing in mission-critical industrial control and legacy system upgrades.
FAQ
What is the maximum operating temperature range for SN74BCT245NG4?
The SN74BCT245NG4 is rated for 0°C to 70°C ambient operation, consistent with commercial-grade PDIP packaging. It must not be operated outside this range, as electrical characteristics (e.g., VOL, tPLH) are only guaranteed within these limits per the SCBS013H datasheet revision May 2002.
Can SN74BCT245NG4 operate with a 3.3 V supply?
No. SN74BCT245NG4 requires a minimum VCC of 4.5 V and is specified only for 4.5 V–5.5 V operation. Applying 3.3 V will result in undefined logic levels, excessive ICCZ current, and potential functional failure - it is not a 3.3 V tolerant device.
What happens if the DIR or OE inputs are left floating on SN74BCT245NG4?
Leaving DIR or OE floating violates TI's SCBA004 guideline and may cause erratic output states, increased ICCZ current, or oscillation. Both inputs must be actively pulled to VCC or GND using ≤10 kΩ resistors to ensure deterministic 3-state control and stable bus isolation.
Is SN74BCT245NG4 pin-compatible with SN74LS245N?
Yes - SN74BCT245NG4 and SN74LS245N share identical 20-pin PDIP-N pinout, terminal functions, and mechanical footprint. However, direct substitution requires verification of B-port loading and timing margins, as SN74BCT245NG4 provides significantly higher drive and faster switching.
Does SN74BCT245NG4 support hot-swap operation?
SN74BCT245NG4 is not hot-swap rated. While its 3-state outputs provide bus isolation, it lacks built-in current limiting, slew-rate control, or undervoltage lockout required for safe live-insertion. External protection circuitry is mandatory for hot-swap use cases.
SN74BCT245NG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74BCT
- 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:
- 3mA, 24mA; 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74BCT245NG4 FAQ
1.How can I place an order for SN74BCT245NG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74BCT245NG4 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 SN74BCT245NG4 reliable?
The price and inventory of SN74BCT245NG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74BCT245NG4 is usually 5 days.
3.What payment methods are accepted for SN74BCT245NG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74BCT245NG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74BCT245NG4?
SN74BCT245NG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74BCT245NG4 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 SN74BCT245NG4?
For technical support, including SN74BCT245NG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74BCT245NG4 requirements.
6.How does Aetrix verify that SN74BCT245NG4 is sourced from the original manufacturer or authorized distributors?
All SN74BCT245NG4 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 SN74BCT245NG4 meets industry standards.
7.What is the process for return or replacement of SN74BCT245NG4?
All SN74BCT245NG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74BCT245NG4, 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 SN74BCT245NG4 part is unused and in its original packaging.
Return procedure for SN74BCT245NG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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