SE98

SE98 DDR memory module temp sensor, 3.3 V Rev. 04 — 2 February 2009 Product data sheet 1. General description The NXP Semiconductors SE98 measures temperature from −40 °C to +125 °C communicating via the I2C-bus/SMBus. It is typically mounted on a Dual In-line Memory Module (DIMM) measuring the DRAM temperature in accordance with the new JEDEC (JC-42.4) Mobile Platform Memory Module Thermal Sensor Component specification. Placing the Temp Sensor (TS) on DIMM allows accurate monitoring of the DIMM module temperature to better estimate the DRAM case temperature (Tcase) to prevent it from exceeding the maximum operating temperature of 85 °C. The chip set throttles the memory traffic based on the actual temperatures instead of the calculated worst-case temperature or the ambient temperature using a temp sensor mounted on the motherboard. There is up to a 30 % improvement in thin and light notebooks that are using one or two 1G SO-DIMM modules, although other memory modules such as in server applications will also see an increase in system performance. Future uses of the TS will include more dynamic control over thermal throttling, the ability to use the Alarm Window to create multiple temperature zones for dynamic throttling and to save processor time by scaling the memory refresh rate. The TS consists of an Analog-to-Digital Converter (ADC) that monitors and updates its own temperature readings 8 times per second, converts the reading to a digital data, and latches them into the...