What material are the leads made of on the ADXRS645

Here is a photo of what the leads look like after exposure to 175C for about 20 hours.

The ADXRS645 is packaged in a 15-lead brazed-lead ceramic package (DY-15-1). The leads are based on a ceramic-compatible alloy and have a nickel barrier with gold plating (Ni/Au). This finish is designed to be compatible with standard industry solders.

ADI does not specify a single required solder alloy for this device. For typical industrial environments up to around 125 °C, Sn63/Pb37 or SAC305 solders are commonly used with good results on Ni/Au-finished leads. In applications where the assembly will be exposed to higher temperatures for extended periods, such as the 175 °C condition you described, these standard solders can develop a dull or grainy appearance over time due to microstructural changes. In such cases, higher-melting alloys provide better long-term stability. Alloys such as Au80/Sn20 are often selected in designs that must operate reliably for long durations at elevated temperature.

With respect to the evaluation board (EVAL-ADXRS645Z), it is assembled through standard PCB manufacturing processes. The exact solder alloy used is not specified in the documentation, but it is typically SnPb or SAC. These boards are intended for functional evaluation and are not qualified for continuous high-temperature operation.