TruTherm™ Enabling PowerWise® Energy-Efficient System Design

TruTherm™ BJT Beta Compensation Technology Temperature Sensor Optimized for INTEL® 45nm Penryn Processors, Provides Pinpoint-Accurate Temperature Readings

TruTherm™ (True Thermal Measurement) transistor model beta compensation technology is a method of measuring temperature on integrated circuits designed in deep sub-micron (45nm, 65nm, 90nm) processes. This breakthrough technology allows deep sub-micron CPUs, ASICs, and FPGAs to reach higher speeds and integration. Internal thermal diodes connected to external temperature sensors are used to accurately monitor the temperature of these devices. In sub-micron geometries, readings based on these internal diodes can vary greatly from individual processor to processor. Therefore, traditional approaches to accurately monitor these diodes are no longer sufficient. For the 45nm Penryn processor a BJT Model (Beta Correction Enabled) temperature sensor is a must have for accurate temperature sensing. National was the first to introduce the use of the BJT model (TruTherm™) which corrects for Beta Variations during spring of 2005 at Intel Developers Forum (IDF).

LM95245 was selected for the Santa Rosa Refresh and Montevina Customer Reference Boards for Intel 45nm Penryn processors. LM95245 also measures the temperature of older Intel processors on 65nm and 90nm process technologies. We have released a family of products addressing your system needs by aiding the designer to get more performance from the system platforms while minimizing power consumption.

Benefits of TruTherm™

We have the most accurate temperature sensor in the market for sub-micron 45nm, 65nm and 90nm Intel processors. Accurate temperature measurement is one of the key steps in a PowerWise® system design. The pinpoint accuracy of TruTherm technology

• Allows system designers to optimize acoustic performance of their system by enabling precise fan control.
• Reduces the power consumption of the fans by allowing them to run at the optimal speed all the time.
• Enables reducing the system guard bands in temperature measurements, which translate to the designers being able to use smaller heatsinks or fans in the system, further reducing the power consumption and the acoustic noise.
• Reduces the chance of the device overheating and additionally overall system life is extended.

Selection Guide: Remote Diode Temp Sensors
Temperature Sensing for Sub Micron CPU's, ASICS & FPGA's

Part Number	Description		Processor/Thermal Junction	TruTherm™ BJT Transistor Support	No. of Remote Channels	Local Channel	Tcrit	Selectable Addresses
LM86 / LM89 / LM99	±0.75°C, MSOP-8		2N3904	NO	1		1	Factory set
LM95235	±0.75°C, MSOP-8		65nm, 90nm	Yes	1		1	Address Pin
LM95245	±0.75°C, MSOP-8		45nm, 65nm	Yes	1		1	Address Pin
LM95231	±1.25°C, MSOP-8		90nm	Yes	2		-	Factory set
LM95241	±1.25°C, MSOP-8		65nm, 90nm	Yes	2		-	Factory set
LM95213	±1.1°C, LLP-14		2N3904	No	2		3	Address Pin
LM95233	± 0.875°C, LLP-14		65nm, 90nm	Yes	2		3	Address Pin
LM95214	±1.1°C, LLP-14		2N3904	No	4		3	Address Pin
LM95234	±0.875°C, LLP-14		65nm, 90nm	Yes	4		3	Address Pin
LM96194	±2.5°C, LLP-48		65nm	Yes	2-4		-	Full hdwr monitor
LM94	±2.5°C, TSSOP-56		65nm	Yes	2-4		-	Full hdwr monitor

Products Featuring TruTherm™ Technology

National is onto their 3^rd generation of TruTherm™ products with the recent release of LM95245. Our product families offer industries highest-precision, single, dual, quad remote-diode temperature sensing.

The LM95245 (targeted for 45nm, 65nm) & LM95235 (targeted for 65nm and 90nm) are pin compatible 11-bit digital temperature sensors with a two-wire SMBus interface, that can monitor the temperature of one remote diode as well as its own temperature. The LM95234 is the four channel flavor and LM95233 is pin-compatible with the LM95234 and can monitor up to 2 remote diodes. The LM95241 is a precision, dual Remote Diode Temperature Sensor (RDTS) with a two-wire serial interface that is compatible with SMBus 2.0.

The LM94 hardware monitor has a two-wire digital interface that is compatible with SMBus 2.0. Using a sigma-delta Analog-to-Digital Converter (ADC), the LM94 measures the temperature of up to four remote diode connected transistors as well as its own die, and up to 16 power supply voltages and supports dual processors. It also monitors and controls up to four cooling fans. All of these products feature a precision sigma-delta ADC for reduced sensitivity to noise and include analog and digital filtering, remote-diode fault detection, and local temperature sensing. These products also support the traditional diode mode remote temperature monitoring. The LM94 integrates both look-up table and proportional integral fan control methods for optimal fan speed control. The LM96194 includes all of the fan control features of the LM94 but is targeted for single processor systems where as the LM94 is targeted for dual processor systems.

All of these products feature a precision sigma-delta ADC for reduced sensitivity to noise and include analog and digital filtering, remote-diode fault detection, and local temperature sensing. These products also support the traditional diode mode remote temperature monitoring.

Press Release:

• National Expands Family of Precision Temperature Sensors with Patent-Pending TruTherm Technology
• National Technology Revolutionizes Temperature Sensing for Sub-Micron CPUs, ASICs and FPGAs
• TruTherm Technology Presentation