STTS424 Memory module temperature sensor Data Brief Features ■ Temperature sensor compliant with JEDEC JC42.4 Temperature sensor ■ Temperature sensor resolution: 0.25°C (typ)/LSB ■ Temperature sensor accuracy: – ± 1°C from +75°C to +95°C – ± 2°C from +40°C to +125°C – ± 3°C from –40°C to +125°C ■ ADC conversion time: 125ms (max) ■ Supply voltage: 2.7V to 3.6 V ■ Maximum operating supply current: 200µA ■ Hysteresis selectable set points from: 0, 1.5, 3, 6.0°C ■ Ambient temperature sensing range: -40°C to 125°C DFN8 (DA) 2mm x 3mm Two-wire bus ■ 2-Wire SMBus/I2C -compatible serial interface ■ Supports up to 100kHz transfer rate TSSOP8 (DW) 4.4mm x 3mm Packages ■ 2mm x 3mm DFN8, height: 0.85mm (typ) ■ 4.4mm x 3mm TSSOP8(a) ■ Halogen-free, lead-free a. Contact local ST sales office for availability. August 2007 Rev 1 For further information contact your local STMicroelectronics sales office. 1/7 www.st.com 1 Description STTS424 Description The STTS424 is targeted for DIMM modules in Mobile Personal Computing Platforms (Laptops), Server Memory Modules, and other industrial applications. The thermal sensor (TS) in the STTS424 is fully compliant to the JEDEC 42.4 specification which defines Memory Module Thermal Sensors requirements for Mobile platforms. The TS provides space as well as cost savings for Mobile and Server Platform Dual Inline Memory Modules (DIMM) manufacturers, as it is packaged in the compact 2mm x 3mm 8lead DFN package which has a height that will not exceed 0.9mm. It is also available in the JEDEC compliant TSSOP8 package. The temperature sensor includes a band gap-based temperature sensor and 10-bit Analogto-Digital Converter (ADC) which monitor and digitize the temperature to a resolution of up to 0.25°C. The typical accuracies over these temperature ranges are: ● ±3°C (max) over the full temperature measurement range of –40°C to 125°C, ● ±2°C in the +40°C to +125°C temperature range, and ● ±1°C in the +75°C to +95°C temperature range. The temperature sensor in the STTS424 is specified for operating at supply voltages from 2.7V to 3.6V. Operating at 3.3V, the supply current is 100µA (typ). The on-board sigma delta ADC converts the measured temperature to a digital value that is calibrated in °C. For Fahrenheit applications, a lookup table or conversion routine is required. The STTS424 is factory-calibrated and requires no external components to measure temperature. The digital temperature sensor component has user-programmable registers that provide the capabilities for DIMM temperature-sensing applications. The open drain Event output pin is active when the monitoring temperature exceeds a programmable limit, or it falls above or below an alarm window. The user has the option to set the Event output as a critical temperature output. This pin can be configured to operate in either a comparator mode for thermostat operation or in interrupt mode. 2/7 STTS424 Description Figure 1. Logic diagram VDD SDA(1) EVENT(1) SCL A2 A1 A0 STTS424 VSS AI12947 1. SDA and EVENT are open drain. Table 1. Signal names Pin Symbol 1 A0 Serial Bus Address selection pin. Can be tied to VSS or VDD. Input 2 A1 Serial Bus Address selection pin. Can be tied to VSS or VDD. Input 3 A2 Serial Bus Address selection pin. Can be tied to VSS or VDD. Input 4 VSS Supply ground. 5 (1) SDA 6 SCL 7 EVENT(1) 8 VDD Description Direction Serial Data. Input/output Serial Clock. Input Event output pin. Open drain and active-low. Output Supply power (2.7V to 3.6V). 1. SDA and EVENT are open drain. 3/7 Description STTS424 Figure 2. Connections (DFN8 and TSSOP8) A0 A1 A2 GND 8 7 6 5 1 2 3 4 VDD EVENT(1) SCL SDA(1) AI12262 1. SDA and EVENT are open drain. Figure 3. Block diagram 8 VDD Temperature Sensor Logic Control Comparator Timing EVENT 7 ADC Capability Register Upper Register Configuration Register Lower Register Temperature Register Critical Register Manufacturer ID Address Pointer Register Device ID/ Revision 1 2 3 SCL A0 A1 A2 6 SMBus/I2C Interface SDA 5 VSS 4 AI12948 4/7 STTS424 Part numbering Part numbering Table 2. Ordering information scheme Example: STTS424 C DA 3 F Device type STTS424 Grade C: Maximum accuracy 75°C to 95°C = ± 2°C B: Maximum accuracy 75°C to 95°C = ± 1°C(1) Package DA = DFN8 (2mm x 3mm) DW = TSSOP8 (4.4mm x 3mm body size)(1) Temperature range 3 = –40°C to 125°C Shipping method F = ECOPACK package, tape & reel packing E = ECOPACK package, tube packing 1. Contact local ST sales office for availability For other options, or for more information on any aspect of this device, please contact the ST sales office nearest you. 5/7 Revision history STTS424 Revision history Table 3. 6/7 Revision history Date Revision 03-Aug-2007 1 Changes Initial release. STTS424 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. 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