Abstract

Level shifting one voltage signal level into another voltage signal level from a host or driver to a peripheral is not always straight forward. System engineers often select auto-sensing bidirectional voltage translators due to their perceived ease-of-use. In certain use cases, the driver and peripheral both can act as a driver, in which case the transmitter and receiver can both drive their data lines. A voltage translator needs to auto-sense the direction to send or receive the signals but also account for fast data transfer and good signal integrity. How does the voltage translator not only auto-sense the direction to send or receive the signals but also account for fast data transfer and good signal integrity? Auto-sensing devices must be designed with weaker drive strength to enable being overdriven by their hosts. Such small drive strength can impact signal integrity at higher speeds. As systems become increasingly sophisticated with more level shifters and more peripherals, there is an ever expanding need for increased data throughput and signal integrity. This is where one-shots (also known as monostable multi-vibrators' or edge rate accelerators), can help. This application note discusses the major contributors and challenges for auto-sensing level shifters at high speeds and how one-shots impact such challenges.

For replacing auto-sensing level shifters with more suitable recommendations dependent on application types, see Do’s and Don’ts for TXB and TXS Voltage Level-Shifters with Edge Rate Accelerators.