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Texas Instruments SN74BCT543NT
- Part No.:
- SN74BCT543NT
- Manufacturer:
- Texas Instruments
- Package:
- 24-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74BCT543NT.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,866
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Product details
Overview
SN74BCT543NT from Texas Instruments is an octal transceiver IC with dual-directional 3-state latched data flow, operating at 4.5–5.5 V supply, supporting 0°C to 70°C industrial temperature range, and featuring BiCMOS logic for low ICCZ (9–15 mA) and fast propagation delays (tPLH/tPHL ≤ 8.8 ns). It serves as a bidirectional bus interface in microprocessor system address/data buffering.
For engineers reviewing the SN74BCT543NT datasheet, SN74BCT543NT pinout, SN74BCT543NT application, or SN74BCT543NT equivalent, key selection criteria include independent A↔B latch-enable and output-enable control, 128 mA sink capability per output, 16 pF I/O capacitance, and compatibility with 5-V TTL/CMOS systems requiring temporary storage and direction-controlled bus isolation.
Technical Context
The SN74BCT543NT implements two independent sets of D-type latches-one for A-to-B and one for B-to-A data paths-each controlled by dedicated CE, LE, and OE inputs. Its BiCMOS architecture enables high-speed switching while reducing quiescent current versus standard bipolar TTL.
It supports true 3-state outputs with separate enable logic per direction, allowing simultaneous latching on one side while driving the other. Input clamp current exceeds −18 mA, and ESD protection meets MIL-STD-883C Method 3015 (>2000 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage (VCC) | 4.5 V to 5.5 V - Ensures robust operation across standard 5-V rail tolerances without level-shifting. |
| Operating Temperature | 0°C to 70°C - Qualified for commercial/industrial embedded systems, not extended or military grade. |
| Output Sink Current (IOL) | 64 mA per pin - Supports direct drive of multiple TTL loads or moderate fanout without external buffers. |
| Propagation Delay (tPLH/tPHL) | ≤ 8.8 ns (A↔B) - Enables use in high-speed 5-V bus interfaces up to ~100 MHz effective throughput. |
| I/O Capacitance (Cio) | 16 pF - Minimizes signal integrity degradation and timing skew on shared PCB traces. |
| Quiescent Supply Current (ICCZ) | 9–15 mA - Significantly lower than legacy TTL equivalents, reducing power budget impact in idle states. |
| Input Clamp Current (IIK) | −18 mA - Provides robust transient immunity during hot-swap or bus contention events. |
Pinout & Package
SN74BCT543NT is supplied in a 24-pin plastic DIP (Dual In-line Package) with 300-mil body width, through-hole mounting, and industry-standard pin spacing (0.100″). The package is RoHS-compliant and rated for wave soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | LEBA | Latch Enable for B-to-A path - Controls transparency/storage mode of B-side latches. |
| 2 | OEBA | Output Enable for B-to-A path - Activates 3-state drivers on A outputs when low. |
| 3–10 | A1–A8 | A-side bidirectional I/O ports - Serve as input (latched) or output (driven) depending on CEBA/OEBA state. |
| 11 | CEAB | Chip Enable for A-to-B path - Must be low to allow A data capture or B output activation. |
| 12 | GND | Ground reference - Common return for all internal logic and I/O circuits. |
| 13 | VCC | Positive supply - Powers internal BiCMOS circuitry and output drivers (4.5–5.5 V). |
| 14 | CEBA | Chip Enable for B-to-A path - Must be low to allow B data capture or A output activation. |
| 15–22 | B1–B8 | B-side bidirectional I/O ports - Functionally identical to A ports but controlled by CEBA/LEBA/OEBA. |
| 23 | LEAB | Latch Enable for A-to-B path - Controls transparency/storage mode of A-side latches. |
| 24 | OEAB | Output Enable for A-to-B path - Activates 3-state drivers on B outputs when low. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent latch paths | Enables concurrent A→B and B→A data staging without interference - critical for full-duplex bus arbitration. |
| Separate CE/LE/OE per direction | Allows precise timing control: e.g., latch new A data while holding prior B data active on outputs. |
| BiCMOS process technology | Reduces ICCZ by >50% vs. standard TTL, lowering thermal load and improving power efficiency in dense layouts. |
| 3-State true outputs | Eliminates bus contention risk - outputs go fully high-Z when disabled, enabling multi-driver shared-bus topologies. |
| MIL-STD-883C ESD rating | Exceeds 2000 V HBM - enhances reliability during handling, board assembly, and field operation in noisy environments. |
Applications
| Microprocessor Bus Interface | Memory Address Latching |
|---|---|
|
Use Scenario: Interfacing an 8-bit microcontroller data bus to peripheral devices with mismatched timing or voltage domains. IC Role / Device Role / Timing Role: Bidirectional data transceiver with independent latch control - isolates CPU and peripheral timing, buffers data during read/write cycles. Use Value: Eliminates need for discrete latch + buffer combinations; reduces PCB area and interconnect delay by integrating both functions in one 24-pin DIP. |
Use Scenario: Capturing and holding memory address bits during multiplexed address/data bus cycles (e.g., in 8085/8086-based systems). IC Role / Device Role / Timing Role: A-side latches store address bits while B-side drives address lines to RAM/ROM - synchronized via LEAB and CEAB. Use Value: Provides deterministic setup/hold timing (tsu = 4.5 ns, th = 1.5 ns), ensuring reliable address decoding even at maximum clock rates. |
| Industrial Control Backplane | Legacy System Bus Extender |
|
Use Scenario: Isolating and extending parallel I/O between PLC modules over long backplane traces subject to noise and skew. IC Role / Device Role / Timing Role: Direction-controlled transceiver with 3-state outputs - prevents bus conflicts during module insertion/removal or fault conditions. Use Value: 128 mA sink capability and 16 pF I/O capacitance maintain signal integrity across 10+ inch traces at 5 V, minimizing added termination. |
Use Scenario: Upgrading aging TTL-based instrumentation where original 74LS543 or 74ALS543 parts are obsolete. IC Role / Device Role / Timing Role: Pin-compatible drop-in replacement with improved speed (8.8 ns vs. 15–20 ns) and lower power (ICCZ = 9–15 mA vs. >30 mA). Use Value: Maintains existing PCB layout and firmware while delivering faster throughput and cooler operation - no redesign required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT543N | AC-family CMOS; higher noise margin (VIH = 3.5 V), lower ICC (2 µA), but slower tPLH (11.5 ns) and no BiCMOS drive strength. | Preferred in low-power, noise-immune systems where 5-V TTL compatibility is secondary to static power savings. | Select SN74ACT543N only if system prioritizes ultra-low standby current over drive capability and speed. |
| 74F543N | Fast TTL family; faster tPLH (6.5 ns) but higher ICCZ (35 mA), no BiCMOS efficiency, and limited ESD rating (<500 V). | Suitable for legacy designs already using F-series parts and requiring maximum speed at cost of power and ruggedness. | Choose 74F543N only when matching existing F-TTL timing budgets and thermal management allows higher dissipation. |
Compared with SN74ACT543N and 74F543N, the SN74BCT543NT delivers optimal balance of speed (≤8.8 ns), drive strength (64 mA), and quiescent efficiency (9–15 mA) for 5-V TTL-system upgrades - making it the preferred choice where BiCMOS advantages directly impact thermal and timing margins.
Availability
SN74BCT543NT is available at Aetrix Electronics and suitable for microprocessor bus interfacing, memory address latching, and industrial control backplane applications requiring stable component supply and long-term obsolescence mitigation.
Supply support for SN74BCT543NT 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 SN74BCT543NT belongs to TI's BCT (Bipolar-CMOS Transceiver) logic family, designed specifically to replace high-power TTL transceivers in 5-V systems while delivering superior speed-power tradeoffs and enhanced ruggedness.
FAQ
What is the maximum operating temperature range for the SN74BCT543NT?
The SN74BCT543NT is characterized for operation from 0°C to 70°C - the commercial/industrial temperature range. It is not rated for extended or military-grade operation; for −55°C to 125°C performance, the SN54BCT543 variant must be used instead. This specification is confirmed in the "recommended operating conditions" table of the official SCBS026C datasheet.
Does the SN74BCT543NT support true bidirectional data flow without external control logic?
Yes, the SN74BCT543NT supports fully independent bidirectional data flow using dedicated control inputs: CEAB/LEAB/OEAB manage A-to-B transfer, while CEBA/LEBA/OEBA handle B-to-A transfer. No external logic is needed to coordinate direction - each path operates autonomously, enabling simultaneous latching and driving in opposite directions as required in full-duplex bus architectures.
Is the SN74BCT543NT pin-compatible with older TTL transceivers like the 74LS543?
Yes, the SN74BCT543NT uses the same 24-pin DIP (NT) footprint and identical pinout as the 74LS543 and 74ALS543, including matching LEAB, OEAB, CEAB, A1–A8, B1–B8, VCC, and GND assignments. This enables direct replacement in legacy designs without PCB modification - verified via TI's mechanical drawing MCER004A and functional comparison in SCBS026C.
What is the output drive capability of the SN74BCT543NT, and how does it compare to standard TTL?
The SN74BCT543NT provides 64 mA sink current per output (IOL), significantly exceeding standard TTL (e.g., 74LS543: 8 mA) and matching advanced TTL families like 74F. This enables direct interfacing with multiple TTL loads or moderate-current peripherals without external buffers - a key advantage confirmed in the "electrical characteristics" section of the SCBS026C datasheet.
Can the SN74BCT543NT be used in mixed-voltage systems with 3.3-V logic?
No - the SN74BCT543NT is strictly a 5-V device with VIH = 2.0 V minimum and VIL = 0.8 V maximum, and its outputs swing rail-to-rail within 4.5–5.5 V. It lacks 3.3-V tolerant inputs or level-shifting capability. Direct connection to 3.3-V logic risks overvoltage damage or unreliable switching; a dedicated level translator or voltage-compatible transceiver (e.g., SN74LVC543) is required for such interfaces.
SN74BCT543NT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74BCT
- Package/Case:
- 24-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 24-PDIP
SN74BCT543NT FAQ
1.How can I place an order for SN74BCT543NT through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74BCT543NT 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 SN74BCT543NT reliable?
The price and inventory of SN74BCT543NT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74BCT543NT is usually 5 days.
3.What payment methods are accepted for SN74BCT543NT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74BCT543NT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74BCT543NT?
SN74BCT543NT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74BCT543NT 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 SN74BCT543NT?
For technical support, including SN74BCT543NT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74BCT543NT requirements.
6.How does Aetrix verify that SN74BCT543NT is sourced from the original manufacturer or authorized distributors?
All SN74BCT543NT 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 SN74BCT543NT meets industry standards.
7.What is the process for return or replacement of SN74BCT543NT?
All SN74BCT543NT units undergo pre-shipment inspection (PSI). If there is an issue with SN74BCT543NT, 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 SN74BCT543NT part is unused and in its original packaging.
Return procedure for SN74BCT543NT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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