August 2006 LM95234 Quad Remote Diode and Local Temperature Sensor with SMBus Interface and TruTherm™ Technology General Description LM95234 is an 11-bit digital temperature sensor with a 2-wire System Management Bus (SMBus) interface that can monitor the temperature of four remote diodes as well as its own temperature. The LM95234 can be used to very accurately monitor the temperature of up to four external devices such as microprocessors, graphics processors or diodeconnected 2N3904s. The LM95234’s TruTherm technology allows sensing of 90nm or 65nm process thermal diodes accurately. The LM95234 reports temperature in two different formats for +127.875˚C/–128˚C range and 0˚C/255˚C range. The LM95234 TCRIT1, TCRIT2 and TCRIT3 outputs are triggered when any unmasked channel exceeds its corresponding programmable limit and can be used to shutdown the system, to turn on the system fans or as a microcontroller interrupt function. The current status of the TCRIT1, TCRIT2 and TCRIT3 pins can be read back from the status registers. Mask registers are available for further control of the TCRIT outputs. Two LM95234 remote temperature channels have programmable digital filters while the other two remote channels utilize a fault-queue to minimize unwanted TCRIT events when temperature spikes are encountered. For optimum flexibility and accuracy, each LM95234 channel includes registers for sub-micron process or 2N3904 diode model selection as well as offset correction. A three level address pin allows connection of up to 3 LM95234s to the same SMBus master. The LM95234 includes power saving functions such as: programmable conversion rate, shutdown mode, and turn off of unused channels. Features n Accurately senses die temperature of 4 remote ICs or diode junctions and local temperature n TruTherm technology accurately senses sub-micron process thermal diodes n Programmable digital filters and analog front end filter n 0.125˚C LSb temperature resolution n 0.03125˚C LSb remote temperature resolution with digital filter enabled n +127.875˚C/–128˚C and 0˚C/255˚C remote ranges n Remote diode fault detection, model selection and offset correction n Mask and status register support n 3 programmable TCRIT outputs with programmable shared hysteresis and Fault-Queue n Programmable conversion rate and shutdown mode one-shot conversion control n SMBus 2.0 compatible interface, supports TIMEOUT n Three-level address pin n 14-pin LLP package Key Specifications j Local Temperature Accuracy j Remote Diode Temperature Accuracy j Supply Voltage j Average Supply Current (1Hz ± 2.0 ˚C (max) ± 0.75 ˚C (max) 3.0 V to 3.6 V 0.5 mA (typ) conversion rate) Applications n Processor/Computer System Thermal Management (e.g. Laptop, Desktop, Workstations, Server) n Electronic Test Equipment n Office Electronics Connection Diagram LLP-14 20106301 TOP VIEW TruTherm™ is a trademark of National Semiconductor Corporation. © 2006 National Semiconductor Corporation DS201063 www.national.com LM95234 Quad Remote Diode and Local Temperature Sensor with SMBus Interface and TruTherm Technology ADVANCE INFORMATION LM95234 Ordering Information Package Marking NS Package Number Transport Media LM95234CISD 95234CI SDA14B (LLP-14) 1000 Units on Tape and Reel LM95234CISDX 95234CI SDA14B (LLP-14) 4500 Units on Tape and Reel Part Number Simplified Block Diagram 20106302 Pin Descriptions Label Pin # NC 1 No Connect Not connected. May be left floating, connected to GND or VDD. VDD 2 Positive Supply Voltage Input DC Voltage from 3.0 V to 3.6 V. VDD should be bypassed with a 0.1µF capacitor in parallel with 100pF. The 100pF capacitor should be placed as close as possible to the power supply pin. Noise should be kept below 200 mVp-p, a 10 µF capacitor may be required to achieve this. www.national.com Function Typical Connection 2 LM95234 Pin Descriptions (Continued) Label Pin # D4+ 3 Diode Current Source Function To fourth Diode Anode. Connected to remote discrete diode-connected transistor junction or to the diode-connected transistor junction on a remote IC whose die temperature is being sensed. A capacitor is not required between D4+ and D-. A 100 pF capacitor between D4+ and D- can be added and may improve perfomance in noisy systems. Float this pin if this thermal diode is not used. Typical Connection D3+ 4 Diode Current Source To third Diode Anode. Connected to remote discrete diode-connected transistor junction or to the diode-connected transistor junction on a remote IC whose die temperature is being sensed. A capacitor is not required between D3+ and D-. A 100 pF capacitor between D3+ and D- can be added and may improve perfomance in noisy systems. Float this pin if this thermal diode is not used. D− 5 Diode Return Current Sink To all Diode Cathodes. Common D- pin for all four remote diodes. D2+ 6 Diode Current Source To second Diode Anode. Connected to remote discrete diode-connected transistor junction or to the diode-connected transistor junction on a remote IC whose die temperature is being sensed. A capacitor is not required between D2+ and D-. A 100 pF capacitor between D2+ and D- can be added and may improve perfomance in noisy systems. Float this pin if this thermal diode is not used. D1+ 7 Diode Current Source To first Diode Anode. Connected to remote discrete diode-connected transistor junction or to the diode-connected transistor junction on a remote IC whose die temperature is being sensed. A capacitor is not required between D1+ and D-. A 100 pF capacitor between D1+ and D- can be added and may improve perfomance in noisy systems. Float this pin if this thermal diode is not used. GND 8 Power Supply Ground System low noise ground. A0 9 Dgital Input SMBus slave address select pin. Selects one of three addresses. Can be tied to VDD, GND, or to the middle of a resistor divider connected between VDD and GND. TCRIT1 10 Digital Output, Open-Drain Critical temperature output 1. Requires pull-up resistor. Active "LOW". TCRIT2 11 Digital Output, Open-Drain Critical temperature output 2. Requires pull-up resistor. Active "LOW". SMBDAT 12 SMBus Bi-Directional Data Line, Open-Drain Output From and to Controller; may require an external pull-up resistor SMBCLK 13 SMBus Clock Input From Controller; may require an external pull-up resistor TCRIT3 14 Digital Output, Open-Drain Critical temperature output 3. Requires pull-up resistor. Active "LOW". 3 www.national.com LM95234 Typical Application 20106303 www.national.com 4 inches (millimeters) 14-Lead Molded Leadless Leadframe Package (LLP), Order Number LM95234CISD or LM95234CISDX NS Package Number SDA14B National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information visit us at www.national.com. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. BANNED SUBSTANCE COMPLIANCE National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C2) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/quality/green. Lead free products are RoHS compliant. National Semiconductor Americas Customer Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: [email protected] National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: [email protected] Tel: 81-3-5639-7560 LM95234 Quad Remote Diode and Local Temperature Sensor with SMBus Interface and TruTherm Technology Physical Dimensions unless otherwise noted