Overview
The SN74LVC8T245PWE4, produced by Texas Instruments, is an 8-bit dual-supply bus transceiver designed for bidirectional voltage level translation. This device is optimized to operate with two separate configurable power-supply rails, VCCA and VCCB, which can be set between 1.65 V and 5.5 V. This allows for universal low-voltage bidirectional translation between various voltage nodes such as 1.8 V, 2.5 V, 3.3 V, and 5.5 V. The SN74LVC8T245 is particularly useful for asynchronous communication between two data buses, enabling data transmission from the A bus to the B bus or vice versa based on the logic levels of the direction-control (DIR) and output-enable (OE) inputs.
Key Specifications
| Parameter | Min | Max | Unit |
|---|---|---|---|
| VCCA and VCCB Supply Voltage | 1.65 | 5.5 | V |
| Operating Temperature Range | -40 | 85 | °C |
| Input Voltage (VI) | -0.5 | 6.5 | V |
| Output Voltage (VO) | -0.5 | 6.5 | V |
| Propagation Delay Time (tPLH/tPHL) | 1.2 | 9.3 | ns |
| ESD Protection (Human-Body Model) | 4000 | V | |
| Package Type | TSSOP (PW) | ||
| Number of Pins | 24 |
Key Features
- Control inputs VIH/VIL levels are referenced to VCCA voltage.
- VCC isolation feature – if either VCC input is at GND, all outputs are in the high-impedance state.
- Fully configurable dual-rail design allows each port to operate over the full 1.65-V to 5.5-V power-supply range.
- Latch-up performance exceeds 100 mA per JESD 78, class II.
- ESD protection exceeds JESD 22 standards (4000-V Human-Body Model, 100-V Machine Model, 1000-V Charged-Device Model).
- Designed for asynchronous communication between two data buses with direction-control (DIR) and output-enable (OE) inputs.
- Ioff circuitry disables the outputs, preventing damaging current backflow during power-down.
Applications
The SN74LVC8T245PWE4 is suitable for a variety of applications requiring bidirectional voltage level translation, including:
- Asynchronous communication between two data buses with different voltage levels.
- Low-voltage logic translation in mixed-voltage systems.
- Partial-power-down applications where Ioff circuitry is necessary.
- Systems requiring high ESD protection and latch-up performance.
Q & A
- What is the operating voltage range for the SN74LVC8T245PWE4?
The operating voltage range for both VCCA and VCCB is from 1.65 V to 5.5 V.
- What types of voltage nodes can the SN74LVC8T245PWE4 translate between?
The device can translate between 1.8-V, 2.5-V, 3.3-V, and 5.5-V voltage nodes.
- How does the direction-control (DIR) input function?
The DIR input determines the direction of data transmission between the A and B ports. When DIR is high, data is transmitted from A to B, and when DIR is low, data is transmitted from B to A.
- What is the purpose of the output-enable (OE) input?
The OE input enables or disables the output ports. When OE is low, the outputs are enabled; when OE is high, the outputs are in the high-impedance state.
- What is the significance of the VCC isolation feature?
The VCC isolation feature ensures that if either VCC input is at GND, all outputs are in the high-impedance state, preventing backflow currents.
- What kind of ESD protection does the SN74LVC8T245PWE4 offer?
The device offers ESD protection exceeding JESD 22 standards, including 4000-V Human-Body Model, 100-V Machine Model, and 1000-V Charged-Device Model.
- What is the latch-up performance of the SN74LVC8T245PWE4?
The latch-up performance exceeds 100 mA per JESD 78, class II.
- How does the Ioff circuitry function in the SN74LVC8T245PWE4?
The Ioff circuitry disables the outputs during power-down, preventing damaging current backflow through the device.
- What is the typical propagation delay time for the SN74LVC8T245PWE4?
The propagation delay time (tPLH/tPHL) ranges from 1.2 ns to 9.3 ns.
- What package types are available for the SN74LVC8T245PWE4?
The device is available in various packages including TSSOP (PW), SSOP, QSOP, and TVSOP.
