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onsemi MC74VHCT245ADW
- Part No.:
- MC74VHCT245ADW
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MC74VHCT245ADW.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,307
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Product details
Overview
MC74VHCT245ADW from onsemi is an octal non-inverting bus transceiver with 3-state outputs, designed for bidirectional data transmission between two 8-bit buses. It operates at 4.5–5.5 V supply, supports ±8 mA output drive, features TTL-compatible inputs, and has propagation delay of 6.5 ns (max) at VCC = 5 V. It is used in microcontroller peripheral interfacing and memory address/data bus isolation.
For engineers reviewing the MC74VHCT245ADW datasheet, pinout, applications, or equivalent options, key selection considerations include its 5 V-only operation, symmetric bidirectional control via DIR and OE pins, 3-state output compatibility with legacy TTL systems, and SOIC-20W wide-body package thermal performance.
Technical Context
The MC74VHCT245ADW implements dual-rail CMOS logic with TTL-level input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V), enabling direct interface with standard TTL outputs. Its DIR pin controls data flow direction (A→B or B→A), while active-low OE enables/disables both output banks simultaneously.
It uses advanced VHCT (Very High Speed CMOS-TTL compatible) process technology to achieve low propagation delay (tPD = 6.5 ns max) and high noise immunity (VNL = 0.5 V min, VNH = 0.5 V min) at 5 V. Output drive strength is symmetrical: −8 mA (high) / +8 mA (low) into 50 pF load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with legacy 5 V TTL and CMOS systems without level-shifting. |
| Propagation Delay | 6.5 ns (max) at VCC = 5 V - enables reliable operation in 80 MHz bus timing windows. |
| Output Drive | ±8 mA - sufficient to drive 10 LSTTL loads or 50 pF capacitive bus lines. |
| Input Thresholds | VIL ≤ 0.8 V, VIH ≥ 2.0 V - guarantees robust recognition of TTL logic levels. |
| 3-State Leakage | ±10 µA (max) - prevents signal contention when outputs are disabled in shared-bus configurations. |
| Operating Temperature | −40 °C to +85 °C - supports industrial-grade embedded system deployment. |
Pinout & Package
MC74VHCT245ADW is housed in a 20-pin SOIC wide-body (SOIC-20W) package with 1.27 mm pitch, 7.5 mm body width, and exposed pad for enhanced thermal dissipation in high-duty-cycle bus applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Active-low Output Enable | Drives all A- and B-side outputs into high-impedance state when high; required for bus arbitration. |
| 2 (A0) | Bus A Input/Output | Bi-directional I/O terminal; direction determined by DIR pin state. |
| 3 (A1) | Bus A Input/Output | Same electrical behavior as A0; part of 8-bit A-side port. |
| 19 (B7) | Bus B Input/Output | Most significant bit of B-side port; matches A7 in bidirectional pairing. |
| 20 (DIR) | Direction Control | Low = A→B data flow; High = B→A - enables full-duplex bus isolation without external logic. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-Compatible Inputs | Enables direct connection to legacy 5 V TTL outputs without pull-up resistors or level translators. |
| Symmetric Bidirectional Control | Single DIR pin configures entire 16-bit path (8×A↔8×B), reducing PCB routing complexity vs. discrete gate solutions. |
| High-Speed VHCT Core | Delivers 6.5 ns propagation delay at 5 V-critical for maintaining setup/hold timing in fast microcontroller peripheral buses. |
| SOIC-20W Thermal Profile | Wide-body package improves power dissipation margin during sustained 8 mA output switching across all channels. |
Applications
| Microcontroller Peripheral Interface | Memory Bus Isolation |
|---|---|
Use Scenario: Interfacing an 8-bit microcontroller's data bus to external peripherals (e.g., ADC, DAC, UART) with voltage-level matching and bus contention prevention. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing data flow direction and enabling/disabling under MCU GPIO control. Use Value: Eliminates need for separate drivers and direction logic; maintains 5 V TTL timing integrity with sub-7 ns delay. | Use Scenario: Isolating address/data lines between a microprocessor and SRAM or EPROM to prevent back-driving during reset or sleep modes. IC Role / Device Role / Timing Role: 3-state buffer providing controlled bus separation with simultaneous enable/disable of all 16 lines. Use Value: Prevents data corruption during power sequencing; ±8 mA drive sustains signal integrity over 10 cm PCB traces. |
| Legacy System Bus Expansion | Industrial I/O Module Communication |
Use Scenario: Extending a vintage 8-bit ISA or PC/104 bus to add custom function cards while preserving signal timing and loading specs. IC Role / Device Role / Timing Role: Level-translating repeater ensuring TTL-compatible signaling across extended bus segments. Use Value: Matches original bus electrical characteristics (VOH/VOL, tPLH/tPHL) without requiring redesign of host controller firmware. | Use Scenario: Connecting PLC CPU modules to distributed digital I/O terminals over long backplane traces in factory automation cabinets. IC Role / Device Role / Timing Role: Robust bus driver with high noise immunity (VNL/VNH ≥ 0.5 V) and ESD-tolerant I/O. Use Value: Maintains data integrity in electrically noisy environments; SOIC-20W package withstands repeated thermal cycling in industrial enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC245APWR | Supports 1.65–3.6 V operation; lower drive (±24 mA), but not TTL-compatible input thresholds. | Used in mixed-voltage 3.3 V systems; requires external level-shifting for legacy 5 V interfaces. | Select when migrating to low-voltage logic; avoid if interfacing directly to 5 V TTL sources. |
| 74ACT245SC | Higher speed (tPD = 5.5 ns), same 5 V supply, but higher ICC (12 mA typical) and no SOIC-20W thermal option. | Favored in high-frequency test equipment where minimal delay outweighs power/thermal trade-offs. | Prefer for <10 ns timing-critical paths; verify thermal derating in dense layouts without exposed pad. |
Compared with SN74LVC245APWR and 74ACT245SC, the MC74VHCT245ADW uniquely balances 5 V TTL compatibility, SOIC-20W thermal reliability, and 6.5 ns delay-making it optimal for industrial retrofits and mixed-legacy designs where voltage translation must be avoided.
Availability
MC74VHCT245ADW is available at Aetrix Electronics and suitable for microcontroller peripheral interface, memory bus isolation, and legacy system bus expansion requiring stable component supply and long-term industrial availability.
Supply support for MC74VHCT245ADW 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 is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MC74VHCT245ADW belongs to onsemi's VHCT logic family, engineered specifically for seamless integration into 5 V TTL-based systems requiring high-speed, low-power bus interfacing without level-shifting overhead.
FAQ
What is the maximum operating frequency supported by the MC74VHCT245ADW?
The MC74VHCT245ADW does not specify a maximum clock frequency in its datasheet because it is an asynchronous bus transceiver. Its usable data rate is determined by propagation delay (6.5 ns max) and system timing margins. For clean 8-bit parallel transfers, it reliably supports bus cycles up to approximately 80 MHz in well-designed layouts with matched trace lengths and proper termination.
Can the MC74VHCT245ADW operate at 3.3 V supply?
No, the MC74VHCT245ADW is specified only for 4.5 V to 5.5 V operation. Its internal VHCT circuitry and TTL-compatible input thresholds require 5 V nominal supply to meet guaranteed VIL/VIH and output drive specifications. Operating below 4.5 V may result in undefined logic states or insufficient output swing.
Is the MC74VHCT245ADW pin-compatible with the 74HC245?
No, the MC74VHCT245ADW is not pin-compatible with the 74HC245. While both are octal bus transceivers in 20-pin SOIC packages, the MC74VHCT245ADW uses SOIC-20W (wide-body, 7.5 mm), whereas standard 74HC245 typically uses narrow SOIC-20 (6.0 mm). Additionally, pin functions differ: MC74VHCT245ADW places DIR on pin 20 and OE on pin 1, while 74HC245 places DIR on pin 1 and OE on pin 19-requiring PCB layout revision.
Does the MC74VHCT245ADW have built-in ESD protection?
Yes, the MC74VHCT245ADW includes on-chip ESD protection rated to ±2 kV per HBM (Human Body Model) and ±200 V per MM (Machine Model), as verified in onsemi's qualification testing. This meets industrial I/O interface requirements but does not replace system-level TVS diodes for harsh environments like factory floors or outdoor installations.
How does the DIR pin control data direction in the MC74VHCT245ADW?
The DIR pin on the MC74VHCT245ADW is a static control input: when DIR = LOW, data flows from A-side pins (A0–A7) to B-side pins (B0–B7); when DIR = HIGH, data flows from B-side to A-side. This direction setting remains active until changed, independent of OE state-allowing direction to be configured before enabling outputs.
MC74VHCT245ADW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74VHCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- 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:
- 8mA, 8mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
MC74VHCT245ADW FAQ
1.How can I place an order for MC74VHCT245ADW through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74VHCT245ADW 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 MC74VHCT245ADW reliable?
The price and inventory of MC74VHCT245ADW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74VHCT245ADW is usually 5 days.
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MC74VHCT245ADW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74VHCT245ADW 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 MC74VHCT245ADW?
For technical support, including MC74VHCT245ADW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74VHCT245ADW requirements.
6.How does Aetrix verify that MC74VHCT245ADW is sourced from the original manufacturer or authorized distributors?
All MC74VHCT245ADW 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 MC74VHCT245ADW meets industry standards.
7.What is the process for return or replacement of MC74VHCT245ADW?
All MC74VHCT245ADW units undergo pre-shipment inspection (PSI). If there is an issue with MC74VHCT245ADW, 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 MC74VHCT245ADW part is unused and in its original packaging.
Return procedure for MC74VHCT245ADW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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