Overview
The SN74AVC4T245, produced by Texas Instruments, is a 4-bit, dual-supply noninverting bidirectional voltage level translation device. This component is designed to facilitate asynchronous communication between two data buses operating at different voltage levels. It supports voltage translation between various low-voltage nodes such as 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V, making it versatile for a wide range of applications. The device features control inputs for direction and output enable, allowing for flexible data transmission and high-impedance state control during power-up or power-down sequences.
Key Specifications
| Parameter | Description | Value |
|---|---|---|
| VCCA/VCCB Range | Supply voltage range for A and B ports | 1.2V to 3.6V |
| Maximum Data Rate | Maximum data rate for signal translation (e.g., 1.8V to 3.3V) | Up to 380 Mbps |
| Package Types | Available package types | SOIC (16), TVSOP (16), TSSOP (16), VQFN (16), UQFN (16) |
| Thermal Resistance (RθJA) | Junction-to-ambient thermal resistance | 85.5°C/W (SOIC), 126.0°C/W (TVSOP), 112.0°C/W (TSSOP) |
| ESD Rating | Electrostatic discharge rating | HBM: 2000 V, CDM: 1000 V |
| Control Inputs | Direction (DIR) and Output Enable (OE) inputs | Referenced to VCCA |
Key Features
- Dual-Supply Design: Allows each port to operate over the full 1.2-V to 3.6-V power-supply range.
- Configurable Voltage Translation: Supports universal low-voltage bidirectional translation between various voltage nodes.
- High-Speed Data Transfer: Maximum data rate up to 380 Mbps for signal translation.
- Output Enable and Direction Control: Control inputs for direction (DIR) and output enable (OE) to manage data transmission and high-impedance states.
- Partial Power-Down Capability: Ioff circuitry disables outputs to prevent damaging current backflow when powered down.
- VCC Isolation Feature: Ensures both ports are in the high-impedance state if either VCC input is at GND.
Applications
The SN74AVC4T245 is ideal for level-translation applications where devices or systems operate at different interface voltages. It is particularly useful in:
- Interface Voltage Translation: Translating signals between different voltage domains in a system.
- Asynchronous Communication: Facilitating data transfer between two data buses operating asynchronously.
- Power Management Systems: Managing power states and preventing backflow currents during power-down sequences.
Q & A
- What is the voltage range supported by the SN74AVC4T245?
The SN74AVC4T245 supports a voltage range of 1.2V to 3.6V for both VCCA and VCCB.
- What is the maximum data rate for signal translation?
The maximum data rate can be up to 380 Mbps, for example, when translating a signal from 1.8V to 3.3V.
- What are the available package types for the SN74AVC4T245?
The available package types include SOIC (16), TVSOP (16), TSSOP (16), VQFN (16), and UQFN (16).
- How does the device handle partial power-down?
The device features Ioff circuitry that disables the outputs to prevent damaging current backflow when powered down.
- What is the purpose of the VCC isolation feature?
The VCC isolation feature ensures that both ports are in the high-impedance state if either VCC input is at GND.
- How do the control inputs (DIR and OE) function?
The direction (DIR) input controls the direction of data transmission, and the output enable (OE) input activates or places the outputs in the high-impedance state.
- What is the significance of the high-impedance state during power-up or power-down?
The high-impedance state during power-up or power-down is ensured by tying OE to VCC through a pullup resistor, preventing unwanted data transmission.
- What are the thermal resistance values for different packages?
The junction-to-ambient thermal resistance (RθJA) varies by package type, such as 85.5°C/W for SOIC, 126.0°C/W for TVSOP, and 112.0°C/W for TSSOP.
- What is the ESD rating of the SN74AVC4T245?
The ESD rating is HBM: 2000 V, CDM: 1000 V.
- Why is it important to hold unused inputs at VCCI or GND?
Holding unused inputs at VCCI or GND ensures proper device operation and prevents excess ICC and ICCZ currents.
