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onsemi MC74HCT245AFELG
- Part No.:
- MC74HCT245AFELG
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MC74HCT245AFELG.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOEIAJ
- Quantity:
- Payment:
- Shipping:
Inventory:1,785
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Product details
Overview
MC74HCT245AFELG from onsemi is an octal 3-state noninverting bus transceiver with LSTTL-compatible inputs, designed for bidirectional asynchronous data bus communication between TTL/NMOS and CMOS systems. It operates from 4.5 V to 5.5 V, supports –55 °C to +125 °C industrial temperature range, delivers 15 LSTTL load drive capability, and features active-low Output Enable and unidirectional Direction control for A↔B data flow.
For engineers reviewing the MC74HCT245AFELG datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, SOEIAJ-20 package mapping, confirmed propagation delays (max 33 ns), real-world interface roles in level-shifting and bus isolation, and two validated alternative parts with documented technical and application differences.
Technical Context
The MC74HCT245AFELG implements a dual-bus transceiver architecture with independent 3-state control: Output Enable (pin 1) places all I/Os in high-impedance, while Direction (pin 19) selects A→B or B→A data path. Its silicon-gate CMOS design ensures TTL/NMOS input compatibility (VIH = 2.0 V min, VIL = 0.8 V max) and direct interfacing to CMOS, NMOS, and TTL loads.
Internal logic conforms to JEDEC Standard No. 7A, with guaranteed DC electrical performance across –55 °C to +125 °C: VOH ≥ 4.4 V at 4.5 V VCC (IOUT = –6 mA), VOL ≤ 0.4 V (IOUT = 6 mA), and IOZ ≤ ±10 µA in 3-state. Propagation delay tPLH/tPHL is 33 ns max at 125 °C with CL = 50 pF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Enables stable operation in 5 V legacy TTL/NMOS and modern CMOS systems without external regulation. |
| Propagation Delay | 33 ns max (A↔B) at 125 °C - Ensures timing compliance in high-speed industrial bus arbitration and memory-mapped I/O. |
| Output Drive | 15 LSTTL loads - Supports direct fanout to multiple legacy TTL devices without buffer amplification. |
| Input Compatibility | LSTTL-level inputs (VIH ≥ 2.0 V, VIL ≤ 0.8 V) - Eliminates need for external level shifters when interfacing 5 V TTL outputs. |
| 3-State Leakage | ±10 µA max (IOZ) at 125 °C - Maintains bus integrity during high-impedance isolation in multi-master systems. |
| Operating Temperature | –55 °C to +125 °C - Qualified for under-hood automotive, industrial control, and aerospace avionics environments. |
| Package | SOEIAJ-20 (Case 967) - Surface-mount, 0.5 mm pitch, 12.6 mm × 7.6 mm footprint compatible with standard reflow profiles. |
Pinout & Package
MC74HCT245AFELG is housed in a 20-pin SOEIAJ (JEDEC MS-013AC) package, measuring 12.6 mm × 7.6 mm × 2.35 mm, with gull-wing leads, Pb-free finish, and RoHS compliance. Pin 1 is Output Enable (active-low), pin 10 is GND, pin 19 is Direction, and pin 20 is VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Output Enable (OE̅) | Active-low global 3-state control: asserts high-impedance on all A/B I/Os when high. |
| 2–9 | A1–A8 | Port A data inputs/outputs - Bidirectionally connected to first bus segment; driven by Direction state. |
| 10 | GND | Ground reference for all internal logic and I/O - Must be low-impedance connection to system ground plane. |
| 11–18 | B1–B8 | Port B data inputs/outputs - Bidirectionally connected to second bus segment; directionally coupled to A port. |
| 19 | Direction (DIR) | Controls data flow direction: DIR = low → B→A; DIR = high → A→B. |
| 20 | VCC | Positive supply input - Requires local 4.5–5.5 V decoupling (≤100 nF ceramic) adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| LSTTL-compatible inputs | VIH = 2.0 V min, VIL = 0.8 V max - Directly accepts TTL/NMOS logic levels without pull-ups or voltage translation. |
| High noise immunity | Input hysteresis not specified; guaranteed VIH/VIL margins provide >1.2 V noise margin at 5 V supply. |
| Low quiescent current | ICC = 4.0 µA typical at 25 °C - Minimizes standby power in battery-backed or energy-sensitive applications. |
| Robust 3-state control | tPLZ/tPHZ = 42 ns max at 125 °C - Ensures clean bus release timing in time-critical arbitration protocols. |
| Pb-free & RoHS compliant | Meets EU Directive 2011/65/EU - Suitable for environmentally regulated industrial and medical equipment. |
Applications
| Industrial PLC Backplane Interface | Automotive Body Control Module |
|---|---|
Use Scenario: Isolating CPU address/data bus from field I/O expansion slots in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional bus transceiver enabling CPU read/write access to modular analog/digital I/O cards via shared backplane. Use Value: 33 ns max propagation delay meets 30 MHz bus timing; 15 LSTTL drive supports up to 15 peripheral modules per segment. |
Use Scenario: Level-shifting between 5 V microcontroller GPIO and 5 V LIN transceiver or sensor interface ICs. IC Role / Device Role / Timing Role: Noninverting transceiver translating MCU port signals to LIN subsystem while maintaining signal integrity. Use Value: LSTTL-compatible inputs eliminate external pull-up resistors; –55 °C to +125 °C rating matches under-dash thermal requirements. |
| Test Equipment Digital Pattern Generator | Avionics Data Acquisition Unit |
Use Scenario: Driving multiple DUT (device-under-test) inputs simultaneously from a single pattern generator output bank. IC Role / Device Role / Timing Role: Fanout buffer with 3-state enable, allowing dynamic routing of test vectors to different DUT channels. Use Value: Active-low OE allows synchronized channel disable; 0.4 V max VOL ensures reliable low-level recognition across 15 TTL loads. |
Use Scenario: Interfacing radiation-tolerant FPGA I/O banks to legacy ARINC 429 line drivers in flight control computers. IC Role / Device Role / Timing Role: Bus isolator preventing FPGA I/O contention during hot-swap of ARINC interface modules. Use Value: ±10 µA 3-state leakage prevents false triggering on high-impedance lines; JEDEC Std. 7A compliance ensures EMI resilience. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT245PWR | TSSOP-20 package (0.65 mm pitch); 30 ns max tPLH at 25 °C vs. 33 ns for MC74HCT245AFELG; identical DC specs. | Higher density layout; lower thermal resistance (450 mW max vs. 450 mW for SOEIAJ); no lead coplanarity concerns. | Select when board space is constrained and reflow profile supports fine-pitch TSSOP; verify mechanical clearance for taller SOEIAJ body. |
| 74HCT245D,653 | SOIC-20W package (Case 751D); 28 ns max tPLH at 85 °C; same pinout but wider body (7.6 mm vs. 7.6 mm width, 12.95 mm length). | Legacy PCB compatibility with existing SOIC footprints; higher moisture sensitivity level (MSL3 vs. MSL1 for SOEIAJ). | Choose for drop-in replacement in mature designs using SOIC-20; confirm humidity bake requirements before reflow. |
Compared with SN74HCT245PWR and 74HCT245D,653, the MC74HCT245AFELG offers identical logic function and DC characteristics but differs in mechanical form factor (SOEIAJ-20), thermal performance (450 mW max power dissipation), and JEDEC marking compliance - making it suitable for Japanese-market industrial equipment requiring EIAJ-standard packaging.
Availability
MC74HCT245AFELG is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, automotive body control modules, test equipment digital pattern generators, and avionics data acquisition units requiring stable component supply across extended temperature ranges.
Supply support for MC74HCT245AFELG 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The MC74HCT245AFELG belongs to the HCT logic family, engineered for seamless interoperability between legacy TTL/NMOS systems and modern CMOS platforms - targeting industrial automation, transportation, and ruggedized computing applications.
FAQ
Is MC74HCT245AFELG still in production?
No, MC74HCT245AFELG is marked as discontinued per onsemi's November 2025 datasheet revision. However, Aetrix Electronics maintains limited legacy inventory and supports obsolescence mitigation through cross-reference analysis, last-time buy coordination, and qualified alternatives like SN74HCT245PWR and 74HCT245D,653 for ongoing production.
What is the maximum operating temperature for MC74HCT245AFELG?
The MC74HCT245AFELG is rated for –55 °C to +125 °C, verified across all electrical parameters in the datasheet's Recommended Operating Conditions table. This full industrial temperature range applies specifically to the SOEIAJ-20 package variant and is confirmed in both DC and AC Electrical Characteristics sections.
Does MC74HCT245AFELG require external pull-up resistors on its inputs?
No, MC74HCT245AFELG does not require external pull-up resistors because its LSTTL-compatible inputs have VIH = 2.0 V minimum and VIL = 0.8 V maximum - fully compatible with standard TTL output levels. Unused inputs must still be tied to VCC or GND per datasheet guidance to prevent floating states.
Can MC74HCT245AFELG interface directly with 3.3 V CMOS logic?
No, MC74HCT245AFELG is not designed for direct 3.3 V CMOS interfacing: its minimum VIH is 2.0 V at 4.5–5.5 V supply, but 3.3 V CMOS outputs may not reliably exceed that threshold. For 3.3 V ↔ 5 V translation, a dedicated level shifter or HCT-family device with dual-supply capability is required - MC74HCT245AFELG functions only as a 5 V bus transceiver.
What is the pin 1 function on MC74HCT245AFELG?
Pin 1 of MC74HCT245AFELG is Output Enable (OE̅), an active-low control input. When OE̅ is high, all A and B port I/Os enter high-impedance state; when low, data flows bidirectionally based on the Direction (pin 19) setting. This behavior is explicitly defined in the FUNCTION TABLE and PIN ASSIGNMENT sections of the official onsemi datasheet.
MC74HCT245AFELG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74HCT
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOEIAJ-20
MC74HCT245AFELG FAQ
1.How can I place an order for MC74HCT245AFELG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74HCT245AFELG 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 MC74HCT245AFELG reliable?
The price and inventory of MC74HCT245AFELG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74HCT245AFELG is usually 5 days.
3.What payment methods are accepted for MC74HCT245AFELG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74HCT245AFELG transactions.
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4.How is shipping managed for MC74HCT245AFELG?
MC74HCT245AFELG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74HCT245AFELG 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 MC74HCT245AFELG?
For technical support, including MC74HCT245AFELG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74HCT245AFELG requirements.
6.How does Aetrix verify that MC74HCT245AFELG is sourced from the original manufacturer or authorized distributors?
All MC74HCT245AFELG 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 MC74HCT245AFELG meets industry standards.
7.What is the process for return or replacement of MC74HCT245AFELG?
All MC74HCT245AFELG units undergo pre-shipment inspection (PSI). If there is an issue with MC74HCT245AFELG, 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 MC74HCT245AFELG part is unused and in its original packaging.
Return procedure for MC74HCT245AFELG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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