Overview
The SN74LVC8T245PWRE4, produced by Texas Instruments, is an 8-bit non-inverting bus transceiver designed for bidirectional voltage level translation. This device is optimized for asynchronous communication between two data buses and supports a wide range of voltage levels from 1.65 V to 5.5 V on both its A and B ports. The SN74LVC8T245PWRE4 is particularly useful in systems where different voltage domains need to communicate, making it a versatile component for various electronic applications.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Operating Voltage Range (VCCA and VCCB) | 1.65 to 5.5 | V |
| Operating Temperature Range | -40 to 85 | °C |
| Number of Bits | 8 | |
| Package Type | TSSOP (PW) | |
| Number of Pins | 24 | |
| Junction-to-Ambient Thermal Resistance (RθJA) | 90.7 | °C/W |
| ESD Protection | 4000-V Human-Body Model, 100-V Machine Model, 1000-V Charged-Device Model | |
| Propagation Delay Time (tpd) at 3.3 V | 6.3 ns | ns |
Key Features
- Control inputs (VIH/VIL levels) 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 allowing 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.
- 3-state outputs for high-impedance mode when OE is high.
- Direction-control (DIR) and output-enable (OE) inputs for flexible data transmission control.
- Input circuitry on both A and B ports is always active, requiring a logic HIGH or LOW level to prevent excess current.
Applications
- Asynchronous communication between two data buses with different voltage levels.
- Voltage level translation between 1.8-V, 2.5-V, 3.3-V, and 5.5-V voltage nodes.
- Systems requiring partial-power-down applications with Ioff circuitry.
- Embedded systems, servers, and other electronic devices needing bidirectional voltage translation.
- Cable modem termination systems and other communication equipment.
Q & A
- What is the operating voltage range of the SN74LVC8T245PWRE4?
The operating voltage range for both VCCA and VCCB is from 1.65 V to 5.5 V.
- What is the purpose of the DIR and OE inputs?
The DIR (direction-control) and OE (output-enable) inputs control the direction of data transmission and the state of the output ports, respectively.
- 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.
- What kind of ESD protection does the SN74LVC8T245PWRE4 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 maximum propagation delay time at 3.3 V?
The maximum propagation delay time (tpd) at 3.3 V is 6.3 ns.
- How does the device handle partial-power-down applications?
The device is fully specified for partial-power-down applications using Ioff circuitry, which disables the outputs to prevent damaging current backflow.
- What is the thermal resistance (RθJA) of the TSSOP (PW) package?
The junction-to-ambient thermal resistance (RθJA) for the TSSOP (PW) package is 90.7 °C/W.
- What are the typical applications of the SN74LVC8T245PWRE4?
Typical applications include asynchronous communication between two data buses, voltage level translation, and use in embedded systems, servers, and communication equipment.
- How do the input circuitries on the A and B ports operate?
The input circuitry on both A and B ports is always active and must have a logic HIGH or LOW level applied to prevent excess current.
- What is the significance of the 3-state outputs?
The 3-state outputs allow the device to place both output ports into the high-impedance mode when the OE input is high.
