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onsemi MC74HCT245ADTR2
- Part No.:
- MC74HCT245ADTR2
- Manufacturer:
- onsemi
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
MC74HCT245ADTR2.pdf
- Description:
- IC BUS TRANSCVR 3-ST OCT 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,866
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Product details
Overview
MC74HCT245ADTR2 from onsemi is an octal 3-state noninverting bus transceiver with LSTTL-compatible inputs, designed for bidirectional asynchronous data bus interfacing between TTL/NMOS and high-speed CMOS systems. It operates from 4.5 V to 5.5 V, supports ±35 mA output drive per pin, features active-low Output Enable and unidirectional Direction control, and is used in industrial control backplanes and legacy bus bridging applications.
For engineers reviewing the MC74HCT245ADTR2 datasheet, pinout, applications, or equivalent options, key selection criteria include 3-state timing (tPLZ/tPHZ ≤ 42 ns at 125°C), LSTTL input compatibility (VIH = 2.0 V min), high-impedance isolation capability, and TSSOP-20 packaging for space-constrained PCB layouts.
Technical Context
The MC74HCT245ADTR2 implements dual 8-bit bidirectional data paths controlled by separate Direction and Output Enable signals. Its silicon-gate CMOS architecture ensures TTL/NMOS input level compatibility while delivering CMOS output drive strength and low quiescent current (ICC ≤ 160 µA at 125°C).
Propagation delays are specified across temperature: tPLH/tPHL ≤ 33 ns (A↔B), tPLZ/tPHZ ≤ 42 ns (enable-to-output transition), with guaranteed 15 LSTTL load drive capability and 10 pF maximum input capacitance - enabling reliable operation in mixed-logic-level systems without external level-shifting circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V logic rails and tolerant of supply ripple up to ±0.5 V. |
| Output Drive | ±35 mA per I/O pin - sufficient to drive 15 LSTTL loads directly without buffering. |
| Propagation Delay | ≤33 ns (A↔B) at 125°C - ensures deterministic timing in high-speed bus arbitration and data capture. |
| Input Thresholds | VIH = 2.0 V min, VIL = 0.8 V max - matches TTL/NMOS logic families for seamless interfacing. |
| 3-State Leakage | ±10 µA max (IOZ) at 125°C - maintains signal integrity during high-impedance isolation in shared-bus environments. |
| Operating Temperature | –55°C to +125°C - qualified for extended industrial and automotive under-hood applications. |
| Package | TSSOP-20 (Case 948E) - 6.5 mm × 4.4 mm footprint with 0.65 mm pitch, optimized for automated SMT assembly. |
Pinout & Package
TSSOP-20 package (Case 948E), 0.65 mm lead pitch, 6.5 mm × 4.4 mm body size, 1.2 mm max height. RoHS-compliant, Pb-free construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Output Enable (active-low) | Asserting low enables A↔B data transfer; high places all I/Os in high-impedance state. |
| 2–9 | A-port inputs/outputs | 8-bit bidirectional data path A (A1–A8); direction determined by Pin 19. |
| 10 | GND | Ground reference for all internal logic and I/O circuits. |
| 11–18 | B-port inputs/outputs | 8-bit bidirectional data path B (B1–B8); direction determined by Pin 19. |
| 19 | Direction control | Low = data flows B→A; high = data flows A→B - defines primary data flow direction. |
| 20 | VCC | Positive supply rail (4.5–5.5 V); powers internal logic and output drivers. |
Key Features
| Feature | Design Value |
|---|---|
| LSTTL-compatible inputs | VIH/VIL thresholds match legacy TTL logic, eliminating need for external level shifters when interfacing NMOS or bipolar systems. |
| 3-state bidirectional control | Independent OE and DIR pins enable precise bus arbitration - critical for multi-master systems like industrial CAN backbone interfaces. |
| High noise immunity | Input hysteresis and guaranteed 0.4 V noise margin (VIL to VIH) prevent metastability in electrically noisy factory-floor environments. |
| Low power consumption | ICC ≤ 4.0 µA at 25°C and ≤160 µA at 125°C - reduces thermal load in dense backplane designs with multiple transceivers. |
| JEDEC Std. 7A compliance | Fully compliant with industry-standard LSTTL interface requirements, ensuring interoperability across vendor ecosystems. |
Applications
| Industrial Backplane Interface | Legacy System Bus Bridging |
|---|---|
|
Use Scenario: Connecting a modern microcontroller-based module to an older 8-bit ISA-style data bus in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional level-translating buffer that isolates voltage domains and synchronizes data flow between mismatched logic families. Use Value: Enables drop-in replacement of obsolete LS245 parts while maintaining full timing compatibility and reducing board redesign effort. |
Use Scenario: Interfacing a 5 V FPGA I/O bank to a 5 V TTL peripheral bus in test equipment with strict EMI constraints. IC Role / Device Role / Timing Role: Controlled 3-state transceiver providing clean bus turn-around with <42 ns enable-to-output delay. Use Value: Eliminates bus contention during direction switching, preventing data corruption in high-reliability automated test systems. |
| Automotive Body Control Module | Medical Diagnostic Instrument Backplane |
|
Use Scenario: Isolating diagnostic communication lines between engine control unit (ECU) and body electronics in vehicles operating at –40°C to +125°C. IC Role / Device Role / Timing Role: High-temperature-rated bus isolator managing shared K-line or LIN bus segments. Use Value: Guaranteed operation across full automotive temperature range with <10 µA leakage in high-Z state prevents false wake-up events. |
Use Scenario: Routing sensor data between analog front-end ASICs and digital processing units in portable ultrasound devices. IC Role / Device Role / Timing Role: Low-capacitance (Cin ≤ 10 pF) bidirectional buffer minimizing signal distortion on sensitive analog-digital boundary traces. Use Value: Preserves signal integrity of time-critical echo data streams while enabling flexible routing via shared PCB traces. |
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, identical electrical specs, TI-branded; slightly higher ICC (max 200 µA at 125°C vs. 160 µA). | Same pinout and function; preferred where TI supply chain continuity is prioritized over onsemi sourcing. | Select when requiring TI's long-term product lifecycle assurance or existing TI-design ecosystem integration. |
| 74HCT245PW,118 | SO-20 package (not TSSOP); 12.8 mm × 7.6 mm footprint; same logic but larger board area and lower thermal performance. | Suitable for prototyping or low-volume assemblies where TSSOP reflow is not available. | Choose only if TSSOP assembly capability is unavailable; avoid for production due to inferior thermal dissipation and density. |
Compared with SN74HCT245PWR and 74HCT245PW,118, the MC74HCT245ADTR2 offers the lowest high-temperature quiescent current (160 µA), smallest PCB footprint (TSSOP-20), and direct drop-in compatibility with LS245 layouts - making it optimal for space- and power-constrained industrial modules.
Availability
MC74HCT245ADTR2 is available at Aetrix Electronics and suitable for industrial backplane interfaces, automotive body control modules, and medical diagnostic instrument backplanes requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MC74HCT245ADTR2 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, sensors, and logic ICs for automotive, industrial, and cloud infrastructure markets.
The MC74HCT245ADTR2 belongs to onsemi's HCT logic family, engineered specifically for robust TTL-to-CMOS interfacing in harsh environments - emphasizing wide temperature operation, noise immunity, and legacy system compatibility.
FAQ
What is the maximum operating temperature for the MC74HCT245ADTR2?
The MC74HCT245ADTR2 is rated for operation from –55°C to +125°C. This extended temperature range is verified per JEDEC standards and makes the device suitable for under-hood automotive applications, industrial motor drives, and outdoor telecom equipment where ambient temperatures exceed standard commercial limits. The MC74HCT245ADTR2 maintains full electrical specifications across this entire range, including propagation delay and 3-state leakage.
Does the MC74HCT245ADTR2 require external pull-up resistors on its control pins?
No, the MC74HCT245ADTR2 does not require external pull-up resistors on Output Enable (Pin 1) or Direction (Pin 19). Its CMOS input structure provides defined logic thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and low input current (<1.0 µA), allowing direct connection to microcontroller GPIOs or open-drain drivers. Unused control pins should be tied to VCC or GND per datasheet guidance to prevent floating states.
Can the MC74HCT245ADTR2 interface 3.3 V logic signals?
No, the MC74HCT245ADTR2 is not designed for 3.3 V logic interfacing. It requires a 4.5–5.5 V VCC supply and has TTL-compatible input thresholds (VIH = 2.0 V min), which may misinterpret 3.3 V logic highs as marginal or invalid in noisy environments. For 3.3 V ↔ 5 V translation, use dedicated level translators such as the NLSX4014 or TXB0108 instead of the MC74HCT245ADTR2.
What is the meaning of "DTR2" in the MC74HCT245ADTR2 part number?
The "DTR2" suffix in MC74HCT245ADTR2 indicates a TSSOP-20 package (D), tape-and-reel packaging (T), and a 2500-unit reel quantity (R2). This matches onsemi's official ordering code MC74HCT245ADTR2G (where "G" denotes Pb-free). The MC74HCT245ADTR2 is functionally identical to MC74HCT245ADTR2G and is sourced from the same manufacturing line and qualification lot.
How does the MC74HCT245ADTR2 differ from the original LS245?
The MC74HCT245ADTR2 is pinout-identical to the 74LS245 but replaces bipolar TTL technology with silicon-gate CMOS. This delivers identical logic behavior and timing compatibility while reducing power consumption (ICC < 160 µA vs. ~30 mA for LS245), eliminating DC fan-out limitations, and enabling direct interfacing with CMOS microcontrollers without additional buffering. The MC74HCT245ADTR2 also adds full –55°C to +125°C operation and RoHS compliance.
MC74HCT245ADTR2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74HCT
- Package/Case:
- 20-TSSOP (0.173", 4.40mm 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:
- 20-TSSOP
MC74HCT245ADTR2 FAQ
1.How can I place an order for MC74HCT245ADTR2 through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74HCT245ADTR2 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 MC74HCT245ADTR2 reliable?
The price and inventory of MC74HCT245ADTR2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74HCT245ADTR2 is usually 5 days.
3.What payment methods are accepted for MC74HCT245ADTR2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74HCT245ADTR2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74HCT245ADTR2?
MC74HCT245ADTR2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74HCT245ADTR2 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 MC74HCT245ADTR2?
For technical support, including MC74HCT245ADTR2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74HCT245ADTR2 requirements.
6.How does Aetrix verify that MC74HCT245ADTR2 is sourced from the original manufacturer or authorized distributors?
All MC74HCT245ADTR2 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 MC74HCT245ADTR2 meets industry standards.
7.What is the process for return or replacement of MC74HCT245ADTR2?
All MC74HCT245ADTR2 units undergo pre-shipment inspection (PSI). If there is an issue with MC74HCT245ADTR2, 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 MC74HCT245ADTR2 part is unused and in its original packaging.
Return procedure for MC74HCT245ADTR2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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