Overview
The SN74AVC4T245, produced by Texas Instruments, is a quad-bit dual-supply bus transceiver designed for asynchronous communication between two data buses. This device is optimized for universal low-voltage bidirectional translation between various voltage nodes, including 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V. It is particularly useful in applications where devices or systems operate at different interface voltages.
The SN74AVC4T245 features a fully configurable dual-rail design, allowing each port to operate over the full 1.2V to 3.6V power-supply range. The device supports high-speed translation and includes Ioff circuitry for partial-power-down mode operation, preventing backflow current when the device is powered down.
Key Specifications
| Parameter | Min | Max | Unit |
|---|---|---|---|
| Supply Voltage Range (VCCA, VCCB) | 1.2 | 3.6 | V |
| Input Voltage Range | -0.5 | 4.6 | V |
| Operating Free-Air Temperature | -40 | 85 | °C |
| Maximum Data Rate (1.8V to 3.3V) | - | 380 | Mbps |
| Junction-to-Ambient Thermal Resistance (RθJA) | - | 85.5 (D package) | °C/W |
| Package Types | - | SOIC, TVSOP, TSSOP, WQFN, UQFN, SOT | - |
Key Features
- Fully configurable dual-rail design allowing each port to operate over the full 1.2V to 3.6V power-supply range.
- Supports high-speed translation with data rates up to 380Mbps when translating from 1.8V to 3.3V.
- Ioff circuitry for partial-power-down mode operation, preventing backflow current when the device is powered down.
- VCC isolation feature ensures both ports are in the high-impedance state if either VCC input is at GND.
- Direction-control (DIR) and output-enable (OE) inputs for controlling data transmission and output states.
Applications
The SN74AVC4T245 is ideal for level-translation applications where devices or systems operate at different interface voltages. It is particularly useful in:
- Interfacing devices or systems with different voltage nodes (e.g., 1.2V, 1.8V, 2.5V, 3.3V).
- Applications requiring high-speed data translation.
- Systems where partial-power-down mode is necessary to conserve power.
- Designs that require push-pull drivers connected to the data I/Os.
Q & A
- What is the operating voltage range for the SN74AVC4T245?
The SN74AVC4T245 operates with supply voltages (VCCA and VCCB) ranging from 1.2V to 3.6V.
- What is the maximum data rate supported by the SN74AVC4T245?
The device supports data rates up to 380Mbps when translating signals from 1.8V to 3.3V.
- How does the direction-control (DIR) input work?
A high on the DIR input allows data transmission from the A port to the B port, while a low on DIR allows data transmission from the B port to the A port.
- What is the purpose of the output-enable (OE) input?
The OE input places both output ports in the high-impedance state when set to high, and enables the outputs when set to low.
- What is the Ioff feature in the SN74AVC4T245?
The Ioff feature disables the I/O output circuits when the device is in partial-power-down mode, preventing backflow current.
- What are the package options available for the SN74AVC4T245?
The device is available in SOIC, TVSOP, TSSOP, WQFN, UQFN, and SOT packages.
- How does the VCC isolation feature work?
If either VCC input is at GND, the VCC isolation feature ensures that both ports are in the high-impedance state.
- What is the junction-to-ambient thermal resistance for the SN74AVC4T245 in the D package?
The junction-to-ambient thermal resistance (RθJA) for the D package is 85.5°C/W.
- What are the typical applications for the SN74AVC4T245?
The device is used in level-translation applications, high-speed data translation, and systems requiring partial-power-down mode.
- How do you ensure proper device operation during power-up or power-down?
Tie the OE input to VCC through a pullup resistor to ensure the device is in the high-impedance state during power-up or power-down.
