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Texas Instruments SN74ABT657ADWR
- Part No.:
- SN74ABT657ADWR
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ABT657ADWR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,576
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Product details
Overview
SN74ABT657ADWR from Texas Instruments is an octal transceiver with integrated parity generator/checker and 3-state outputs, designed for bidirectional data bus interfacing in industrial control and legacy computing systems. It supports 8-bit data flow in either direction (A↔B), generates or verifies odd/even parity on the ninth bit (PARITY), and features –32-mA high-drive IOH and 64-mA IOL at VCC = 5 V.
For engineers reviewing the SN74ABT657ADWR datasheet, SN74ABT657ADWR pinout, SN74ABT657ADWR application, or SN74ABT657ADWR equivalent, key selection criteria include its 24-pin SOIC (DW) package, 1.8–4.6 ns propagation delay (A→B), OE-controlled 3-state operation, and guaranteed operation from –40°C to 85°C.
Technical Context
This BiCMOS transceiver implements a flow-through pin architecture with separate T/R (transmit/receive) and OE (output enable) controls. Data direction is determined solely by T/R logic level: high enables A→B transmission; low enables B→A reception. Parity mode (odd/even) is selected via ODD/EVEN input, and ERR output asserts low on parity mismatch during receive mode.
It integrates real-time parity generation during transmit (PARITY output set to maintain selected parity sense across eight A-bus bits plus PARITY) and parity checking during receive (ERR reflects match/mismatch between B-bus + PARITY). Power-up/down high-impedance behavior is guaranteed below 2.1 V VCC, and latch-up immunity exceeds 500 mA per JESD-17.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL/CMOS logic rails |
| Propagation Delay (A→B) | 1 ns (min) to 4.6 ns (max) at 5 V - enables reliable timing in 20+ MHz bus systems |
| Output Drive (IOL / IOH) | 64 mA / –32 mA - drives heavy capacitive loads and multiple TTL inputs without buffering |
| Input Hysteresis | 100 mV - improves noise immunity on control lines (T/R, OE, ODD/EVEN) |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded applications |
| ESD Protection | >2000 V HBM - withstands handling and board-level ESD events per MIL-STD-883 |
| Power-Up State | High-impedance below 2.1 V VCC - prevents bus contention during power sequencing |
Pinout & Package
SN74ABT657ADWR is packaged in a 24-pin SOIC (DW) with 300-mil body width and standard JEDEC MS-013 footprint. Pin numbering follows top-view convention with Pin 1 at bottom-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | T/R | Transmit/Receive direction control: high = A→B, low = B→A |
| 2–9 | A1–A8 | 8-bit data inputs/outputs (A port); bidirectional under T/R and OE control |
| 10 | ODD/EVEN | Selects parity mode: high = odd, low = even |
| 11 | ERR | Parity error indicator: low = mismatch detected during receive mode |
| 12 | OE | Output enable: high = all ports (A, B, PARITY) in high-Z state |
| 13–20 | B1–B8 | 8-bit data inputs/outputs (B port); bidirectional under T/R and OE control |
| 21 | GND | Ground reference for both logic and output stages |
| 22 | GND | Second ground pin for improved noise rejection and current return path |
| 23 | PARITY | Parity bit: output during transmit, input during receive |
| 24 | VCC | +5-V supply for BiCMOS core and output drivers |
Key Features
| Feature | Design Value |
|---|---|
| Integrated parity generator/checker | Eliminates need for external XOR networks and reduces PCB area by >30% in parity-critical bus interfaces |
| Flow-through pinout (A/B aligned) | Enables straight PCB trace routing between microcontroller and peripheral buses, cutting layout time and signal skew |
| High-drive 3-state outputs | Drives up to 16 LSTTL loads directly, supporting legacy backplane and ISA-style bus designs |
| BiCMOS EPIC-IIB process | Reduces static current to 250 µA (typ) in disabled state while maintaining TTL-compatible voltage thresholds |
| Power-up/down high-Z guarantee | Prevents bus conflicts during hot-swap or uncontrolled power sequencing without external pull-ups |
Applications
| Industrial PLC Backplane Interface | Legacy PC/ISA Bus Expansion |
|---|---|
Use Scenario: Interfacing a microcontroller-based I/O module to a 16-bit industrial backplane with parity-checked data transfers. IC Role / Device Role / Timing Role: Bidirectional octal transceiver managing A-port (MCU side) ↔ B-port (backplane side) data flow with real-time parity generation on transmit and verification on receive. Use Value: Ensures data integrity across noisy factory-floor environments using hardware-level parity, eliminating software overhead and reducing firmware complexity. | Use Scenario: Adding memory-mapped peripheral cards to an ISA bus system requiring parity validation per Intel specification. IC Role / Device Role / Timing Role: Acts as a bus transceiver between ISA slot data lines and local card logic, asserting ERR on parity violation to trigger system NMI. Use Value: Meets ISA bus parity requirements with sub-5 ns propagation delay, enabling full 8-MHz bus operation without timing margin loss. |
| Test Equipment Digital I/O Module | Avionics Data Acquisition Subsystem |
Use Scenario: Building a modular digital I/O board for automated test equipment that must validate communication integrity across long ribbon cables. IC Role / Device Role / Timing Role: Provides isolated, direction-controlled data path between FPGA controller and DUT connector, with PARITY used to detect cable-induced bit flips. Use Value: Hardware parity detection reduces false-fail rates in production test by catching physical-layer errors before software interpretation. | Use Scenario: Implementing a radiation-tolerant data acquisition interface in a DO-254-compliant avionics subsystem where fault detection is mandatory. IC Role / Device Role / Timing Role: Serves as a deterministic, latch-up-immune (≥500 mA) transceiver between ADC FIFO and flight computer bus, with ERR flag feeding into health monitoring logic. Use Value: JESD-17 latch-up immunity and MIL-STD-883 ESD rating support deployment in safety-critical airborne environments without additional protection circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal transceiver with parity applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT657ADW | Same die, identical electrical specs, same 24-pin SOIC (DW) package - differs only in tape-and-reel vs. tube packaging | No functional difference; DW variant uses tube packaging (25 pcs), while ADWR uses tape-and-reel (2000 pcs) | Select SN74ABT657ADWR for automated SMT assembly; choose SN74ABT657ADW for prototyping or low-volume hand-soldering. |
| 74ACT16652DLR | 16-bit version in 48-pin SSOP; higher drive (–24 mA / 24 mA), no parity function, CMOS-only (no BiCMOS) | Lacks parity generation/checking; requires external logic for parity, increasing component count and board area | Use only when 16-bit width and absence of parity checking are acceptable; not a functional substitute for parity-critical designs. |
Compared with SN74ABT657ADWR, SN74ABT657ADW offers identical performance in tube format for manual assembly, while 74ACT16652DLR provides double width but omits parity-making SN74ABT657ADWR the sole choice for compact, self-contained 8-bit parity-aware bus interfacing.
Availability
SN74ABT657ADWR is available at Aetrix Electronics and suitable for industrial PLC backplanes, legacy ISA expansion systems, automated test equipment I/O modules, and avionics data acquisition subsystems requiring stable component supply over extended product lifecycles.
Supply support for SN74ABT657ADWR 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The ABT logic family-including SN74ABT657ADWR-is engineered for high-speed, low-noise 5-V TTL-compatible bus interfacing with enhanced drive strength and robustness in electrically noisy environments.
FAQ
What is the maximum clock/data rate supported by SN74ABT657ADWR?
The SN74ABT657ADWR does not operate on a clock signal-it is asynchronous. Its 4.6 ns maximum propagation delay (A→B at VCC = 5 V) supports reliable operation on buses with signal periods ≥9.2 ns, enabling use in 100+ Mbps parallel data links such as ISA and custom industrial backplanes. Timing margins must account for trace capacitance and load.
How does the ERR output behave during parity checking in receive mode?
In receive mode (T/R = low), the ERR output of SN74ABT657ADWR goes low when the number of high bits across B1–B8 plus the PARITY input does not match the selected parity sense (odd/even). For example, if ODD/EVEN = high (odd parity), PARITY = high, and exactly three B-bus bits are high, ERR remains high (no error); if four B-bus bits are high, ERR asserts low.
Can SN74ABT657ADWR be used with 3.3-V logic systems?
No-SN74ABT657ADWR is specified only for 4.5 V to 5.5 V VCC operation and has TTL-compatible input thresholds (VIH = 2 V min, VIL = 0.8 V max). Direct connection to 3.3-V systems risks undriven inputs and potential damage due to VI exceeding VCC. Level-shifting or buffer isolation is required for mixed-voltage interfacing.
Is there a pin-compatible replacement for SN74ABT657ADWR with extended temperature range?
No direct pin-compatible replacement exists for SN74ABT657ADWR with extended temperature range. The military-grade SN54ABT657A operates from –55°C to 125°C but uses ceramic DIP (JT) or CERDIP (FK) packages-not the SOIC (DW) footprint of SN74ABT657ADWR. No 24-pin SOIC variant of the 54-series is offered by Texas Instruments.
What is the purpose of the dual GND pins (Pins 21 and 22) on SN74ABT657ADWR?
The dual GND pins (21 and 22) on SN74ABT657ADWR provide separate low-impedance return paths for logic core and output driver circuits, reducing ground bounce (VOLP < 1 V typical) and improving noise immunity in high-speed switching. This layout minimizes crosstalk between control signals and high-current I/O transitions, critical for maintaining signal integrity in dense PCB layouts.
SN74ABT657ADWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- Package/Case:
- 24-SOIC (0.295", 7.50mm 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:
- 32mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
SN74ABT657ADWR FAQ
1.How can I place an order for SN74ABT657ADWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT657ADWR 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 SN74ABT657ADWR reliable?
The price and inventory of SN74ABT657ADWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT657ADWR is usually 5 days.
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4.How is shipping managed for SN74ABT657ADWR?
SN74ABT657ADWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT657ADWR 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 SN74ABT657ADWR?
For technical support, including SN74ABT657ADWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT657ADWR requirements.
6.How does Aetrix verify that SN74ABT657ADWR is sourced from the original manufacturer or authorized distributors?
All SN74ABT657ADWR 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 SN74ABT657ADWR meets industry standards.
7.What is the process for return or replacement of SN74ABT657ADWR?
All SN74ABT657ADWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT657ADWR, 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 SN74ABT657ADWR part is unused and in its original packaging.
Return procedure for SN74ABT657ADWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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