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onsemi 74VCX245MTCX
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- Part No.:
- 74VCX245MTCX
- Manufacturer:
- onsemi
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
74VCX245MTCX.pdf
- Description:
- IC TXRX NON-INVERT 3.6V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,877
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Product details
Overview
74VCX245MTCX from ON Semiconductor is a low-voltage bidirectional transceiver IC designed for bus interface applications between mixed-voltage domains. It operates from 1.4V to 3.6V VCC, supports 3.6V-tolerant I/O, delivers ≤3.5 ns propagation delay at 3.3V, provides ±24 mA drive strength, and features 3-STATE outputs controlled by OE (active-low) and T/R direction select - used in voltage-level translation between 1.8V/2.5V/3.3V subsystems in embedded controllers and FPGA I/O expansion.
For engineers reviewing the 74VCX245MTCX datasheet, pinout, applications, or equivalent options, this page delivers verified package mapping (TSSOP-20), confirmed bidirectional bus timing behavior, validated power-off high-impedance I/O behavior, and real-world substitution guidance for voltage-translating transceivers in industrial and computing interfaces.
Technical Context
The 74VCX245MTCX implements eight non-inverting bidirectional buffers with independent 3-STATE control per port via shared OE and T/R inputs. Its CMOS design enables rail-to-rail output swing (0V to VCC) and maintains high-impedance I/O during power-down - critical for hot-swap and live-insertion systems.
It supports dual-supply domain interfacing without external level-shifting circuitry: inputs accept 0–3.6V regardless of VCC (1.4–3.6V), and outputs drive up to 3.6V logic thresholds while sourcing/sinking up to 24 mA at 3.0V VCC. Propagation delay skew across outputs is ≤0.75 ns (1.8V), ensuring synchronous data transfer across all eight channels.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 1.4V to 3.6V - enables direct operation from 1.8V, 2.5V, or 3.3V rails without regulators |
| I/O Voltage Tolerance | 0V to 3.6V - allows safe connection to higher-voltage buses (e.g., 3.3V) while powered from 1.8V |
| tPD Max | 3.5 ns at VCC = 3.3V - supports >100 MHz bus toggle rates in short-trace applications |
| IOH/IOL | ±24 mA at VCC = 3.0V - drives standard TTL loads and multiple CMOS inputs without buffering |
| Power-Off High-Z | Validated IOFF leakage ≤10 µA at 0V VCC - prevents back-driving powered subsystems during shutdown |
| ESD Rating | HBM ≥2000V - meets industrial I/O robustness requirements without external protection |
| Operating Temp | −40°C to +85°C - qualified for extended-temperature industrial and networking equipment |
Pinout & Package
74VCX245MTCX is packaged in a 20-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 4.4 mm body width, 0.65 mm lead pitch, with exposed die attach pad (DAP) for thermal enhancement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable (Active LOW) | Disables both A and B ports simultaneously into high-impedance state - essential for bus arbitration |
| 2–9 (A0–A7) | Port A Bidirectional I/O | Connects to local-side bus (e.g., 1.8V microcontroller); direction determined by T/R |
| 10 (GND) | Ground Reference | Primary return path for VCC and I/O currents; must be low-inductance connection |
| 11–18 (B0–B7) | Port B Bidirectional I/O | Connects to remote-side bus (e.g., 3.3V peripheral); electrically isolated from A-side when OE HIGH |
| 19 (T/R) | Transmit/Receive Control | LOW = A→B data flow; HIGH = B→A data flow - defines real-time bus directionality |
| 20 (VCC) | Supply Voltage | 1.4V–3.6V logic supply; powers internal logic and output drivers - not I/O reference |
Key Features
| Feature | Design Value |
|---|---|
| 3.6V-tolerant I/O | Enables interoperability with legacy 3.3V peripherals while operating from modern 1.8V supplies - eliminates external level shifters |
| Live insertion support | Guaranteed high-impedance I/O during power-up/down sequences - prevents bus contention in hot-pluggable modules |
| Low dynamic power | CPD = 20 pF at 10 MHz - reduces switching current and EMI in high-density PCB layouts |
| Power-off high-Z | IOFFI ≤10 µA at 0V VCC - ensures no current injection into unpowered sections of multi-rail systems |
| Sub-4 ns propagation | tPHL/tPLH ≤3.5 ns at 3.3V - preserves timing margins in DDR-like burst transfers and synchronous FIFO interfaces |
Applications
| Industrial PLC Backplane Interface | FPGA I/O Expansion Bridge |
|---|---|
|
Use Scenario: Interfacing a 1.8V FPGA I/O bank to a 3.3V sensor hub on an industrial automation controller backplane. IC Role / Device Role / Timing Role: Bidirectional voltage translator and bus driver - translates logic levels while maintaining signal integrity across 20 cm traces. Use Value: Eliminates need for discrete MOSFET translators; 3.6V tolerance prevents latch-up when 3.3V signals exceed FPGA's 1.8V I/O rating. |
Use Scenario: Extending a Xilinx Artix-7 FPGA's limited 1.8V I/O count to drive multiple 3.3V SPI peripherals (ADCs, DACs, EEPROMs). IC Role / Device Role / Timing Role: Synchronous bidirectional data repeater - forwards read/write cycles with <3.5 ns added latency per direction. Use Value: Enables full-speed SPI Mode 0/3 operation up to 25 MHz without timing violations or external delay compensation. |
| Embedded Microcontroller Bus Extension | Hot-Swappable Module Communication |
|
Use Scenario: Connecting an ARM Cortex-M4 MCU (1.8V GPIO) to a 2.5V CAN transceiver and 3.3V UART bridge on a modular IoT gateway board. IC Role / Device Role / Timing Role: Multi-protocol voltage adapter - isolates voltage domains while sharing common address/data lines. Use Value: Single-chip solution replaces three separate level shifters; OE control allows software-selectable bus isolation during firmware updates. |
Use Scenario: Enabling hot insertion of daughter cards into a 3.3V mainboard while the card's 1.8V SoC remains unpowered. IC Role / Device Role / Timing Role: Safe insertion interface - maintains high-Z I/O until VCC stabilizes, preventing back-powering or ground bounce. Use Value: Meets IEC 61000-4-2 Class 3 ESD immunity and eliminates need for mechanical interlocks or sequencing controllers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional voltage-translating transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AVC245RHLR | Lower VCC min (1.2V), higher speed (tPD ≤2.2 ns @ 1.8V), but only 3.6V-tolerant on A-side I/O | Preferred for ultra-low-voltage (1.2V) SoC interfaces; requires external clamping if B-side sees >3.6V | Select when system uses sub-1.4V logic rails and demands tighter timing margins than 74VCX245MTCX provides |
| TXS0108EPRJR | Auto-direction sensing (no T/R pin), open-drain outputs, lower drive (±8 mA), supports 1.2V–3.6V bidirectional translation | Suited for I²C/SMBus where direction is protocol-determined; unsuitable for push-pull bus protocols like parallel memory or SPI | Select for open-collector bus protocols requiring zero-latency direction detection - not for general-purpose parallel data buses |
Compared with SN74AVC245RHLR and TXS0108EPRJR, the 74VCX245MTCX offers balanced 3.6V tolerance on both sides, explicit T/R control for deterministic direction, and higher drive strength - making it optimal for parallel address/data bus translation where timing predictability and load driving are critical.
Availability
74VCX245MTCX is available at Aetrix Electronics and suitable for industrial PLC backplanes, FPGA I/O expansion bridges, embedded microcontroller bus extensions, hot-swappable module communication, and mixed-voltage sensor interface designs requiring stable component supply and long-term lifecycle assurance.
Supply support for 74VCX245MTCX 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
ON Semiconductor (formerly Fairchild Semiconductor) is a global leader in intelligent power and sensing technologies, serving automotive, industrial, cloud, and communications markets with energy-efficient semiconductor solutions.
The 74VCX245MTCX belongs to ON Semiconductor's VCX low-voltage logic family, engineered specifically for reliable voltage-domain bridging in space-constrained, thermally demanding embedded systems where mixed-supply interoperability and live-insertion robustness are mandatory.
FAQ
What is the minimum VCC required for reliable operation of the 74VCX245MTCX?
The 74VCX245MTCX is specified to operate down to 1.4V VCC across the full temperature range (−40°C to +85°C). At 1.4V, it delivers ≥2 mA drive strength and maintains valid logic thresholds (VIL ≤0.35×VCC, VIH ≥0.65×VCC). Below 1.4V, parameters such as tPD and IOH/IOL are not guaranteed - so 1.4V is the functional floor for production use of the 74VCX245MTCX.
Does the 74VCX245MTCX support true bidirectional operation without external direction control logic?
No - the 74VCX245MTCX requires an external T/R (Transmit/Receive) signal to determine data flow direction. Unlike auto-sensing translators (e.g., TXS0108E), it does not detect bus activity to infer direction. The T/R input must be driven actively: LOW enables A→B transfer, HIGH enables B→A transfer. This gives precise timing control but mandates system-level direction management - a key design requirement for the 74VCX245MTCX.
Can the 74VCX245MTCX be used to translate between 1.8V and 5V logic domains?
No - the 74VCX245MTCX inputs and outputs are rated for up to 3.6V absolute maximum, and its I/O structures are not 5V-tolerant. Applying 5V signals to any pin (including A0–A7 or B0–B7) exceeds the Absolute Maximum Rating and risks permanent damage. For 1.8V-to-5V translation, a purpose-built 5V-tolerant device such as the 74LVC4245A or discrete FET-based solution is required - the 74VCX245MTCX is strictly limited to ≤3.6V domains.
What is the function of the DAP (Die Attach Pad) on the 74VCX245MTCX TSSOP package?
The DAP (Die Attach Pad) on the 74VCX245MTCX TSSOP package is an exposed metal pad on the underside of the package, electrically isolated from all pins. It serves solely as a thermal conduction path - soldering it to a large copper pour significantly improves heat dissipation. It must not be connected to VCC, GND, or any signal; ON Semiconductor's datasheet explicitly states "DAP = No Connect." Proper thermal design using the DAP helps maintain junction temperature within limits during sustained ±24 mA output loading - a critical implementation detail for the 74VCX245MTCX.
How does the 74VCX245MTCX behave during power-up when OE and T/R are floating?
When OE and T/R are left floating during power-up, the 74VCX245MTCX may enter an undefined state: OE could float LOW (enabling outputs) or HIGH (disabling them), and T/R could settle unpredictably, causing bus contention or unintended data flow. To ensure high-impedance startup, ON Semiconductor recommends tying OE to VCC via a pull-up resistor (value based on driver strength) and T/R to a known logic level (e.g., GND or VCC) - this deterministic initialization is essential for robust system boot behavior of the 74VCX245MTCX.
74VCX245MTCX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74VCX
- 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:
- 24mA, 24mA
- Voltage - Supply:
- 1.4V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
74VCX245MTCX FAQ
1.How can I place an order for 74VCX245MTCX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74VCX245MTCX 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 74VCX245MTCX reliable?
The price and inventory of 74VCX245MTCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VCX245MTCX is usually 5 days.
3.What payment methods are accepted for 74VCX245MTCX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VCX245MTCX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74VCX245MTCX?
74VCX245MTCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74VCX245MTCX 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 74VCX245MTCX?
For technical support, including 74VCX245MTCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VCX245MTCX requirements.
6.How does Aetrix verify that 74VCX245MTCX is sourced from the original manufacturer or authorized distributors?
All 74VCX245MTCX 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 74VCX245MTCX meets industry standards.
7.What is the process for return or replacement of 74VCX245MTCX?
All 74VCX245MTCX units undergo pre-shipment inspection (PSI). If there is an issue with 74VCX245MTCX, 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 74VCX245MTCX part is unused and in its original packaging.
Return procedure for 74VCX245MTCX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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