SCES530K December 2003 – February 2025 SN74AVC1T45
PRODUCTION DATA
Figure 8-3 shows the SN74AVC1T45 being used in a bidirectional logic level-shifting application. Because the SN74AVC1T45 does not have an output-enable (OE) pin, the system designer should take precautions to avoid bus contention between SYSTEM-1 and SYSTEM-2 when changing directions.
Figure 8-3 Bidirectional Logic Level-Shifting ApplicationThe following table provides data transmission from SYSTEM-1 to SYSTEM-2 and then from SYSTEM-2 to SYSTEM-1.
| STATE | DIR CTRL | I/O-1 | I/O-2 | DESCRIPTION |
|---|---|---|---|---|
| 1 | H | Out | In | SYSTEM-1 data to SYSTEM-2 |
| 2 | H | Hi-Z | Hi-Z | SYSTEM-2 is getting ready to send data to SYSTEM-1. I/O-1 and I/O-2 are disabled. The bus-line state depends on pullup or pulldown.(1) |
| 3 | L | Hi-Z | Hi-Z | DIR bit is flipped. I/O-1 and I/O-2 still are disabled. The bus-line state depends on pullup or pulldown.(1) |
| 4 | L | In | Out | SYSTEM-2 data to SYSTEM-1 |