Background

Time Domain Reflectometry (TDR) is an electrical diagnostic technique that transmits an incident pulse and analyzes the reflected pulse to determine the characteristics of a transmission line. Comparators can be used in TDR systems to detect the time difference between the incident pulse and the reflected pulse on transmission lines. With the knowledge of a cable's velocity of propagation (VoP) and the speed of light (c), use of comparators in TDR systems allow for applications such as cable length testing and cable fault detection.

Design Challenges

• TDR systems rely on precise time measurements of the incident and reflected pulse, so faster devices introduce less error to TDR measurements.
• A high input voltage range and a low output voltage swing are necessary for the device to be able to withstand the high voltage incident pulse and propagate lower voltage logic levels for downstream MCU.
• Portable, battery-powered TDR systems rely on low power devices to extend system lifetime.

How TLV1872 Benefits The System

• TLV1872 has a low propagation delay which results in lower additive error to TDR time measurements.

• A separate input and output supply allows for TLV1872 to withstand and detect the high voltage incident pulse, while still propagating appropriate logic levels through a low voltage push-pull output.
• TLV1872 has a low quiescent current which makes the device great for use in battery-powered systems.