We are looking to purchase DS18B20 temperature sensors from a supplier who claims to manufacture them themselves - but I cannot work out if DS18B20 is a product name for Dallas instruments (i.e. buying from other sources is not recommended) or whether DS18B20 refers method of measuring temperature.
DS18B20 is the part number for a component made only by Maxim, formerly Dallas Semiconductor.
The 'DS' prefix stands for 'Dallas Semiconductor'.
DS18B20 is not some sort of general noun for what this component is.