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onsemi 74ACT245SJX
- Part No.:
- 74ACT245SJX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
74ACT245SJX.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,753
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Product details
Overview
74ACT245SJX from Rochester Electronics is an octal bidirectional transceiver with 3-STATE inputs/outputs, designed for bus-oriented data transfer between two 8-bit parallel buses. It features TTL-compatible inputs, ±24mA output drive capability at both A and B ports, active-HIGH Transmit/Receive (T/R) control, and active-HIGH Output Enable (OE). It operates across 4.5V–5.5V supply range and supports industrial temperature range (−40°C to +85°C), commonly used in legacy industrial backplane interfaces and memory-mapped I/O expansion.
For engineers reviewing the 74ACT245SJX datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional bus isolation, 3-STATE timing (tPZH/tPLZ ≤ 12ns @ VCC = 5V), TTL input compatibility, SOIC-20 package footprint, and guaranteed AC/ACT logic family performance per original Fairchild specifications.
Technical Context
The 74ACT245SJX implements eight non-inverting bidirectional buffers with independent 3-STATE control via OE and directional control via T/R. Its TTL-compatible inputs accept VIH ≥ 2.0V and VIL ≤ 0.8V at 5V operation, enabling direct interfacing with legacy 5V TTL logic families. The device uses bipolar-compatible CMOS (ACT) process technology, delivering rail-to-rail VOH/VOL with 24mA sink/source capability per I/O.
Propagation delay is specified as tPLH/tPHL ≤ 8.0ns (max) at 5V/CL = 50pF, and output enable/disable times (tPZH/tPLZ/tPHZ/tPLZ) are all ≤ 12.0ns (max), ensuring tight timing alignment in synchronous bus systems. Input and I/O leakage currents remain ≤ ±1.0µA and ≤ ±3.0µA respectively over full temperature range, supporting low-power standby states.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | ACT - TTL-compatible inputs, 5V-only operation (4.5–5.5V) |
| Supply Voltage | 4.5V–5.5V - Ensures interoperability with standard 5V TTL/CMOS systems |
| Output Drive | ±24mA per port - Supports driving multiple loads or longer PCB traces without external buffers |
| Propagation Delay | ≤ 8.0ns max (An↔Bn) - Enables reliable operation up to ~125MHz bus toggle rates |
| 3-STATE Enable/Disable | tPZH/tPLZ ≤ 11.0ns, tPHZ/tPLZ ≤ 11.0ns - Minimizes bus contention window during direction switching |
| Operating Temperature | −40°C to +85°C - Qualified for industrial-grade embedded and control applications |
| Input Leakage | ±1.0µA max - Prevents unintended logic state shifts in high-impedance or floating-bus conditions |
Pinout & Package
74ACT245SJX is housed in a 20-lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm wide (package code M20D), with gull-wing leads and standard SOIC-compatible land pattern.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable Input | Active-HIGH global disable - places all A/B I/Os in HIGH-Z when asserted |
| 2–9 (A0–A7) | Side A Bidirectional I/O | 8-bit bus interface port; direction determined by T/R and OE state |
| 10 (GND) | Ground Reference | Primary return path for logic and I/O current; must be low-inductance connection |
| 11–18 (B0–B7) | Side B Bidirectional I/O | 8-bit bus interface port; mirrors A-side functionality with opposite data flow direction |
| 19 (T/R) | Transmit/Receive Control | Active-HIGH = A→B data flow; Active-LOW = B→A data flow |
| 20 (VCC) | Positive Supply | 5V nominal supply input; requires local 0.1µF ceramic decoupling near pin |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | VIH ≥ 2.0V / VIL ≤ 0.8V at VCC = 5V - eliminates need for level-shifting when interfacing with legacy 74LS/74F circuits |
| 24mA output sink/source | Guaranteed drive strength per I/O - supports fan-out of ≥10 LS-TTL loads or direct connection to unterminated transmission lines |
| Low ICC quiescent current | ≤ 40µA max at VCC = 5.5V - reduces static power in always-on bus isolation stages |
| Fast 3-STATE switching | tPZH/tPHZ ≤ 11ns - minimizes bus turnaround time in half-duplex protocols like ISA or custom parallel interfaces |
| Industrial temperature range | −40°C to +85°C operation - validated for use in programmable logic controllers and motor drive I/O modules |
Applications
| Industrial Backplane Interface | Legacy Memory-Mapped I/O Expansion |
|---|---|
Use Scenario: Isolating and translating data between CPU local bus and peripheral expansion slots in DIN-rail mounted PLCs. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing 8-bit address/data multiplexing with precise 3-STATE timing to prevent bus contention during slot arbitration. Use Value: Enables hot-swap-capable modular I/O design using standardized 5V TTL signaling and SOIC-20 footprint compatible with legacy Eurocard layouts. |
Use Scenario: Extending microcontroller GPIO count via parallel peripheral interface in factory automation HMIs. IC Role / Device Role / Timing Role: Direction-controlled data bridge between MCU port and parallel LCD controller or keypad matrix. Use Value: Provides deterministic 8-bit data transfer with sub-12ns enable/disable latency, eliminating software wait-state insertion in real-time UI response loops. |
| ISA Bus Signal Conditioning | Test Equipment Digital Pattern Generator |
Use Scenario: Buffering and isolating ISA bus signals in PC-based data acquisition systems requiring signal integrity preservation. IC Role / Device Role / Timing Role: Level-shifting and drive-strengthening transceiver on ISA address/data lines with synchronized T/R control from bus controller. Use Value: Maintains signal fidelity across long ISA ribbon cables while meeting strict setup/hold timing margins for 8MHz ISA cycles. |
Use Scenario: Generating synchronized 8-bit stimulus patterns for DUT testing in automated bench instrumentation. IC Role / Device Role / Timing Role: Programmable-direction digital buffer feeding test vectors onto DUT pins with precise 3-STATE control for open-circuit verification. Use Value: Delivers repeatable, jitter-free edge timing (tPLH/tPHL ≤ 8ns) and 24mA drive for loading capacitive test fixtures without waveform degradation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74ACT245SCX | Same ACT logic family, identical electrical specs, but in SOIC-20 (JEDEC MS-013, 0.300" wide) package | Requires PCB land pattern change - wider body (7.6mm vs 5.3mm) and different lead pitch (1.27mm same, but body width affects routing) | Select when existing layout uses standard SOIC footprint or thermal dissipation requirements favor larger package |
| 74ACT245MTCX | Same ACT logic family and function, but in 4.4mm-wide TSSOP-20 (JEDEC MO-153) package | Higher density mounting; slightly higher thermal resistance; not drop-in replaceable due to different lead form and body dimensions | Select for space-constrained designs where board area is critical and reflow profile supports fine-pitch TSSOP |
Compared with 74ACT245SJX, the SCX variant offers identical performance in a wider SOIC package suited for manual assembly or higher thermal mass, while the MTCX variant provides footprint reduction at the cost of tighter assembly tolerances and marginally slower thermal response - all three share identical AC/ACT timing, drive, and logic behavior per Fairchild Rev. 1.5.0 specification.
Availability
74ACT245SJX is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy memory-mapped I/O expansion, and ISA bus signal conditioning requiring stable component supply across extended product lifecycles.
Supply support for 74ACT245SJX 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
Rochester Electronics is a certified ISO-9001 and AS9120 distributor and manufacturer specializing in lifecycle-extended semiconductor solutions, including military-qualified (Class Q/V) and DLA-approved components.
The 74ACT245SJX belongs to Rochester's manufactured legacy logic portfolio, recreating original Fairchild AC/ACT devices using authorized die or IP to meet OCM specifications - targeting long-lifecycle industrial, defense, and aerospace systems requiring assured supply of discontinued logic families.
FAQ
What is the supply voltage range for the 74ACT245SJX?
The 74ACT245SJX operates strictly within a 4.5V to 5.5V supply range, as defined in its Recommended Operating Conditions. This reflects its ACT logic family designation, which mandates TTL-compatible input thresholds and ensures robust noise immunity and output drive at nominal 5V. Operation outside this range may result in undefined logic states or degraded parametric performance.
Does the 74ACT245SJX support bidirectional data flow without external logic?
Yes, the 74ACT245SJX supports fully autonomous bidirectional data flow using only its dedicated T/R (Transmit/Receive) input. When T/R is HIGH, data flows from A ports to B ports; when LOW, data flows from B ports to A ports - all under simultaneous control of the OE (Output Enable) pin. No external combinational logic is required to manage directionality.
What is the maximum output current per pin on the 74ACT245SJX?
The 74ACT245SJX guarantees ±24mA output source/sink current per A or B port pin under recommended operating conditions (VCC = 4.5V–5.5V, TA = −40°C to +85°C). This rating applies individually to each of the 16 I/O pins (A0–A7, B0–B7) and is verified per Fairchild Rev. 1.5.0 datasheet DC characteristics for ACT devices.
Is the 74ACT245SJX pin-compatible with the 74AC245SJX?
No, the 74ACT245SJX is not pin-compatible with the 74AC245SJX in functional operation despite identical pinout and package. While mechanical pin mapping matches, the 74AC245SJX uses AC logic (2.0–6.0V supply, CMOS-input thresholds), whereas the 74ACT245SJX requires 4.5–5.5V and has TTL-compatible inputs - substituting one for the other risks incorrect logic interpretation or excessive input current.
What does the 'X' suffix in 74ACT245SJX indicate?
The 'X' suffix in 74ACT245SJX denotes tape-and-reel packaging per Fairchild ordering conventions. It specifies that the device is supplied in EIA-481-compliant carrier tape, optimized for automated SMT placement. The underlying silicon, electrical specifications, and package dimensions (M20D SOP) remain identical to the tube-packaged 74ACT245SJ.
74ACT245SJX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.209", 5.30mm 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:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOP
74ACT245SJX FAQ
1.How can I place an order for 74ACT245SJX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ACT245SJX 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 74ACT245SJX reliable?
The price and inventory of 74ACT245SJX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACT245SJX is usually 5 days.
3.What payment methods are accepted for 74ACT245SJX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACT245SJX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ACT245SJX?
74ACT245SJX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ACT245SJX 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 74ACT245SJX?
For technical support, including 74ACT245SJX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACT245SJX requirements.
6.How does Aetrix verify that 74ACT245SJX is sourced from the original manufacturer or authorized distributors?
All 74ACT245SJX 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 74ACT245SJX meets industry standards.
7.What is the process for return or replacement of 74ACT245SJX?
All 74ACT245SJX units undergo pre-shipment inspection (PSI). If there is an issue with 74ACT245SJX, 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 74ACT245SJX part is unused and in its original packaging.
Return procedure for 74ACT245SJX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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