The DT-421 sensor package exhibits precise, monotonic temperature response over its useful range, and is designed to withstand repeated cycling to low temperatures without mechanical failure. The sensor chip is in direct contact with the epoxy dome, which causes increased voltage at 4.2 K and prevents full range conformity to the Curve 10. The anode lead is electrically connected to the platinum base, and should be isolated by the user for installation on metallic surfaces . The sensing element is mounted to a platinum disk and covered with a dome of Stycast epoxy. Repeatability at 4.2 K is required to be better than 50 mK over three thermal cycles for device acceptance.
Positive lead is right-hand ribbon with the platinum disk down and the leads towards the user.