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onsemi 74VHCT245AM
- Part No.:
- 74VHCT245AM
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
74VHCT245AM.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,151
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Product details
Overview
74VHCT245AM from onsemi is an octal bus transceiver with 3-STATE outputs, designed for bidirectional asynchronous communication between data buses. It operates at 4.5–5.5 V, delivers 5.4 ns typical propagation delay, supports 5 V ↔ 3 V level translation, and features power-down protection on all I/O pins. It is used in industrial control backplanes and mixed-voltage memory interface systems.
For engineers reviewing the 74VHCT245AM datasheet, pinout, applications, or equivalent options, key selection criteria include its T/R-controlled directionality, OE-gated 3-STATE isolation, ±25 mA output drive, input/output voltage tolerance up to 6.5 V, and TSSOP20 package compatibility with space-constrained PCB layouts.
Technical Context
The 74VHCT245AM implements a dual-bus architecture with independent A-side (A0–A7) and B-side (B0–B7) I/O ports, where data flow direction is controlled by the T/R input. Its CMOS silicon gate process enables TTL-compatible speed while maintaining low static current (≤4 µA at 25°C).
It features robust input/output protection allowing 0 V to 5.5 V signals regardless of VCC, enabling safe interfacing between 5 V and 3 V domains. The device enters high-impedance state when OE is HIGH, fully isolating both busses without leakage path constraints.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures stable operation across industrial-grade 5 V supply tolerances. |
| tPD (Typ) | 5.4 ns at VCC = 5 V, CL = 50 pF - Enables reliable timing in high-speed digital backplane designs up to ~100 MHz. |
| IOL/IOH | ±8 mA - Sufficient drive strength for fan-out to 10+ standard CMOS loads without external buffering. |
| VIH/VIL | 2.0 V / 0.8 V - TTL-compatible input thresholds allow direct connection to legacy 5 V logic families. |
| IOZ (Max) | ±2.5 µA at TA = −40°C to +85°C - Guarantees minimal leakage during 3-STATE isolation in extended temperature environments. |
| ESD Rating | 2000 V HBM - Provides baseline ESD resilience for handling and board-level integration without special precautions. |
Pinout & Package
TSSOP20 (Case 948AQ), 4.4 mm × 6.5 mm body, 0.65 mm pitch, Pb-free, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable Input | Active-LOW global enable: drives all outputs to 3-STATE when HIGH; must be pulled LOW for normal operation. |
| 2 (T/R) | Transmit/Receive Control | Determines data direction: LOW = B→A, HIGH = A→B; no internal pull-up/pull-down. |
| 3–10 (A0–A7) | Side A I/O Port | Bidirectional port: inputs when data flows from B to A, outputs when data flows from A to B. |
| 11 (GND) | Ground Reference | Primary return path for VCC and all I/O currents; requires low-inductance PCB connection. |
| 12–19 (B0–B7) | Side B I/O Port | Bidirectional port: complements A0–A7; shares same direction control via T/R pin. |
| 20 (VCC) | Power Supply | 5 V nominal supply; decoupling capacitor (0.1 µF) required within 5 mm of this pin. |
Key Features
| Feature | Design Value |
|---|---|
| 5 V ↔ 3 V Interface Capability | Input/output pins tolerate 0 V to 5.5 V independent of VCC, enabling safe interconnection between 5 V microcontrollers and 3 V peripherals. |
| Low Quiescent Current | ICC ≤ 4 µA at 25°C ensures negligible standby power draw in battery-backed or energy-sensitive systems. |
| Pin-Compatible with 74HCT245 | Direct drop-in replacement for legacy 74HCT245 designs without layout changes or firmware updates. |
| High-Speed Propagation | 7.7 ns max tPD over full temperature range supports synchronous data transfer in real-time industrial networks. |
Applications
| Industrial Backplane Interfacing | Microcontroller I/O Expansion |
|---|---|
Use Scenario: Connecting multiple 5 V sensor nodes to a central 3 V FPGA-based controller across a 20 cm PCB backplane. IC Role / Device Role / Timing Role: Bidirectional voltage-translating bus transceiver managing data flow direction via T/R signal synchronized to system clock edges. Use Value: Eliminates need for discrete level-shifting ICs per line, reducing component count and signal skew across 8 parallel data lines. | Use Scenario: Expanding GPIO count of an ARM Cortex-M4 MCU operating at 3.3 V to drive legacy 5 V industrial actuators. IC Role / Device Role / Timing Role: Unidirectional buffer (A→B mode) with OE-controlled activation, driven by MCU GPIO and timed to avoid bus contention. Use Value: Provides 8-bit parallel output drive at 8 mA per pin, meeting minimum sink current requirements of electromechanical relays. |
| Memory Subsystem Isolation | Legacy Peripheral Bridging |
Use Scenario: Isolating a 5 V SRAM bank from a 3 V SoC during sleep mode using OE gating. IC Role / Device Role / Timing Role: 3-STATE-enabled bus isolator; OE tied to SoC power-management signal to cut off all I/O leakage paths. Use Value: Reduces standby current by >95% compared to direct connection, extending battery life in portable instrumentation. | Use Scenario: Interfacing a modern 3 V UART controller to a legacy 5 V RS-232 transceiver requiring TTL-level inputs. IC Role / Device Role / Timing Role: Level translator and driver: converts 3 V logic highs to >4.4 V outputs compatible with 5 V receiver thresholds. Use Value: Meets VOH ≥ 4.4 V at IOH = –50 µA, ensuring noise margin >1.2 V against 5 V supply ripple. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC245A | Lower VCC range (1.65–3.6 V); no 5 V tolerant inputs without external resistors. | Designed for 3.3 V-only systems; unsuitable for direct 5 V ↔ 3 V translation without additional circuitry. | Select only if entire system operates at ≤3.6 V and no 5 V signals are present on I/O lines. |
| 74HCT245N | Same logic function and pinout; DIP-20 package; higher ICC (≤20 µA) and slower tPD (max 25 ns). | Preferred for through-hole prototyping or legacy DIP-based industrial controllers where thermal performance is less critical. | Choose for manual assembly, breadboarding, or replacement in existing DIP-20 footprints without redesign. |
Compared with SN74LVC245A and 74HCT245N, the 74VHCT245AM uniquely combines 5 V tolerance, 5.4 ns speed, and TSSOP20 footprint-making it optimal for compact, mixed-voltage embedded systems requiring production-ready surface-mount reliability.
Availability
74VHCT245AM is available at Aetrix Electronics and suitable for industrial backplane interfacing, microcontroller I/O expansion, and memory subsystem isolation requiring stable component supply and long-term lifecycle support.
Supply support for 74VHCT245AM 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 focused on energy-efficient electronics, delivering power management, analog, logic, and sensing solutions for automotive, industrial, and cloud infrastructure markets.
The VHCT logic family, including the 74VHCT245AM, was engineered for high-speed, low-power bidirectional bus interfacing in mixed-voltage embedded systems-prioritizing interoperability, ruggedness, and thermal efficiency in harsh environments.
FAQ
What is the maximum operating temperature range for the 74VHCT245AM?
The 74VHCT245AM is rated for continuous operation from −40°C to +85°C. This industrial temperature range is validated per JEDEC JESD78 and confirmed in the AC/DC electrical characteristics tables of the official onsemi datasheet (Rev. 2, October 2024). Thermal derating is not required within this span, and the device maintains full 3-STATE functionality and propagation delay compliance across the full range.
Can the 74VHCT245AM safely interface a 5 V microcontroller with a 3 V ADC?
Yes, the 74VHCT245AM can safely interface a 5 V microcontroller with a 3 V ADC. Its inputs and outputs tolerate 0 V to 5.5 V regardless of VCC, and it operates correctly with VCC = 5 V while driving 3 V logic levels. When configured with T/R = LOW and OE = LOW, the B-side outputs deliver VOH ≥ 4.4 V and VOL ≤ 0.1 V, which exceed standard 3 V CMOS input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), ensuring robust signal integrity.
Is the 74VHCT245AM pin-compatible with the 74HCT245?
Yes, the 74VHCT245AM is pin- and function-compatible with the 74HCT245. Both devices share identical TSSOP20 pinout, truth table behavior, and logic symbol. The 74VHCT245AM improves upon the 74HCT245 with faster propagation delay (5.4 ns vs. 25 ns typ), lower ICC (4 µA vs. 20 µA), and enhanced input/output voltage tolerance-making it a direct drop-in upgrade in existing 74HCT245 designs without layout or firmware changes.
What is the recommended decoupling for the 74VHCT245AM?
A 0.1 µF ceramic capacitor placed within 5 mm of the VCC pin (Pin 20) and GND pin (Pin 11) is the minimum recommended decoupling for the 74VHCT245AM. For systems with high-frequency switching or multiple transceivers, add a 4.7 µF tantalum or aluminum electrolytic capacitor near the power rail entry point. Layout best practices require short, wide traces between VCC/GND and the capacitor pads to minimize inductance and suppress supply bounce during 3-STATE transitions.
Does the 74VHCT245AM support hot-swap or live-insertion?
No, the 74VHCT245AM does not support hot-swap or live-insertion. While its I/O pins tolerate 0 V to 5.5 V independent of VCC, the device lacks dedicated hot-swap control circuitry (e.g., slew-rate limiting, undervoltage lockout, or fault reporting). Applying signals before VCC stabilization may cause undefined states or increased current consumption. Power sequencing-VCC first, then I/O signals-is required per onsemi's recommended operating conditions to ensure reliable initialization and prevent latch-up.
74VHCT245AM 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
74VHCT245AM FAQ
1.How can I place an order for 74VHCT245AM through Aetrix?
Please submit a Request for Quotation (RFQ) for 74VHCT245AM 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 74VHCT245AM reliable?
The price and inventory of 74VHCT245AM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHCT245AM is usually 5 days.
3.What payment methods are accepted for 74VHCT245AM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VHCT245AM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74VHCT245AM?
74VHCT245AM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74VHCT245AM 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 74VHCT245AM?
For technical support, including 74VHCT245AM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHCT245AM requirements.
6.How does Aetrix verify that 74VHCT245AM is sourced from the original manufacturer or authorized distributors?
All 74VHCT245AM 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 74VHCT245AM meets industry standards.
7.What is the process for return or replacement of 74VHCT245AM?
All 74VHCT245AM units undergo pre-shipment inspection (PSI). If there is an issue with 74VHCT245AM, 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 74VHCT245AM part is unused and in its original packaging.
Return procedure for 74VHCT245AM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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