Overview
The SN74AVCH2T45DCTT, produced by Texas Instruments, is a 2-bit, 2-supply, bus transceiver designed for asynchronous communication between two data buses. This device supports universal low-voltage bidirectional translation and level-shifting between various voltage nodes ranging from 1.2V to 3.6V. It features active bus-hold circuitry, which maintains unused or un-driven inputs at a valid logic state, and is fully specified for partial-power-down applications using Ioff circuitry to prevent damaging current backflow.
Key Specifications
| Parameter | Description | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| VCCA and VCCB Supply Voltage | Supply voltage range for A and B ports | 1.2 | - | 3.6 | V |
| Operating Free-Air Temperature | Operating temperature range | -40 | - | 85 | °C |
| Propagation Delay (tPLH, tPHL) | Low-to-high and high-to-low propagation delay | 2.9 | 3.1 | 5.2 | ns |
| Input Transition Rise or Fall Rate | Input transition rate | - | - | 5 | ns/V |
| Power Dissipation Capacitance | Capacitance per transceiver | - | 3-15 | - | pF |
| Junction-to-Ambient Thermal Resistance (RθJA) | Thermal resistance for DCT package | - | - | 183.1 | °C/W |
Key Features
- Active Bus-Hold Circuitry: Holds unused or un-driven inputs at a valid logic state.
- Universal Low-Voltage Translation: Supports bidirectional translation and level-shifting between 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V voltage nodes.
- Partial-Power-Down Capability: Ioff circuitry disables outputs to prevent damaging current backflow when powered down.
- VCC Isolation: Ensures both ports are in a high-impedance state if either VCC input is at GND.
- NanoFree Package Technology: Uses the die as the package, reducing size and improving thermal performance.
Applications
- Asynchronous Communication: Designed for communication between two data buses operating at different voltage levels.
- Level-Shifting: Ideal for translating signals between different voltage domains in mixed-voltage systems.
- Partial-Power-Down Systems: Suitable for applications where power management is critical, such as in battery-powered devices.
- Compact Designs: The small package sizes (DCT, DCU, YZP) make it suitable for space-constrained applications.
Q & A
- What is the voltage range supported by the SN74AVCH2T45?
The device supports supply voltages from 1.2V to 3.6V for both A and B ports.
- What is the purpose of the active bus-hold circuitry?
The active bus-hold circuitry holds unused or un-driven inputs at a valid logic state.
- How does the Ioff circuitry function?
The Ioff circuitry disables the outputs to prevent damaging current backflow when the device is powered down.
- What is the VCC isolation feature?
The VCC isolation feature ensures that if either VCC input is at GND, both ports are put in a high-impedance state.
- What package options are available for the SN74AVCH2T45?
The device is available in DCT (SSOP, 8 pins), DCU (VSSOP, 8 pins), and YZP (DSBGA, 8 pins) packages.
- What is the typical propagation delay for the SN74AVCH2T45?
The typical propagation delay ranges from 2.9 ns to 5.2 ns depending on the supply voltage.
- How does the direction-control (DIR) pin function?
The DIR pin controls the direction of data transmission between the A and B ports.
- What is the thermal resistance of the DCT package?
The junction-to-ambient thermal resistance (RθJA) for the DCT package is 183.1 °C/W.
- Can the SN74AVCH2T45 be used in partial-power-down applications?
Yes, the device is fully specified for partial-power-down applications using Ioff circuitry.
- What is the significance of NanoFree package technology?
NanoFree package technology uses the die as the package, reducing size and improving thermal performance.
