Digital Temperature Sensor with SST Interface ADT7484/ADT7486 Preliminary Technical Data FEATURES GENERAL DESCRIPTION 1 on-chip temperature sensor 1 or 2 remote temperature sensors Simple Serial TransportTM (SSTTM) interface Rev 1 compliant The ADT7484/ADT7486 are simple digital temperature sensors for use in PC applications with a Simple Serial Transport (SST) interface. These devices can monitor their own temperature as well as the temperature of one (ADT7484) or two (ADT7486) remote sensor diodes. The ADT7484/ADT7486 are controlled by a single SST bidirectional data line. The devices are fixedaddress SST clients where the target address is chosen by the state of the two address pins, ADD0 and ADD1. APPLICATIONS Personal computers Portable personal devices Industrial sensor nets FUNCTIONAL BLOCK DIAGRAM ON-CHIP TEMPERATURE SENSOR A/D CONVERTER D1+ ANALOG MUX D2+ (ADT7486 ONLY) SST INTERFACE SST REMOTE TEMPERATURE VALUE REGISTER D2- ADT7484/ ADT7486 VDD OFFSET REGISTERS GND RESERVED ADDRESS SELECTION ADD1 ADD0 05198-001 D1- DIGITAL MUX LOCAL TEMPERATURE VALUE REGISTER Figure 1. Rev. PrA Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 (c)2006 Analog Devices, Inc. All rights reserved. ADT7484/ADT7486 Preliminary Technical Data TABLE OF CONTENTS Features .............................................................................................. 1 SST Interface ..................................................................................8 Applications....................................................................................... 1 Temperature Measurement ........................................................... 11 General Description ......................................................................... 1 Temperature Measurement Method ........................................ 11 Functional Block Diagram .............................................................. 1 Reading Temperature Measurements...................................... 11 Revision History ............................................................................... 2 SST Temperature Sensor Data Format .................................... 12 Specifications..................................................................................... 3 Using Discrete Transistors ........................................................ 12 Absolute Maximum Ratings............................................................ 4 Layout Considerations............................................................... 12 Thermal Resistance ...................................................................... 4 Temperature Offset .................................................................... 13 ESD Caution.................................................................................. 4 Application Schematics ............................................................. 13 Pin Configurations And Functional Descriptions ....................... 5 Outline Dimensions ....................................................................... 14 Typical Performance Characteristics ............................................. 6 Ordering Guide .......................................................................... 14 Product Description ......................................................................... 8 REVISION HISTORY 4/06--Revision PrA: Preliminary Version Rev. PrA | Page 2 of 16 Preliminary Technical Data ADT7484/ADT7486 SPECIFICATIONS TA = TMIN to TMAX, VCC = VMIN to VMAX, unless otherwise noted. Table 1. Parameter POWER SUPPLY Supply Voltage, VCC Undervoltage Lockout Threshold Average Operating Supply Current, IDD TEMPERATURE-TO-DIGITAL CONVERTER Local Sensor Accuracy Min Typ Max Unit Test Conditions/Comments 3.0 3.3 2.8 1.4 3.6 V V mA Continuous conversions Remote Sensor Accuracy Remote Sensor Source Current Resolution Conversion Time (Local Temperature)1 Conversion Time (Remote Temperature)1 Total Monitoring Cycle Time1 DIGITAL INPUTS (ADD0, ADD1) Input High Voltage, VIH Input Low Voltage, VIL Input High Current, IIH Input Low Current, IIL Pin Capacitance DIGITAL I/O (SST Pin) Input High Voltage , VIH Input Low Voltage, VIL Hysteresis1 Output High Voltage, VOH High Impedance State Leakage, ILEAK SST TIMING Bitwise Period, tBIT High Level Time for Logic 1, tH1 2 High Level Time for Logic 0, tH0 2 Time to Assert SST High for Logic 1, tSU, HIGH Hold Time, tHOLD3 Stop Time, tSTOP Time to Respond After a Reset, tRESET Response Time to Speed Negotiation After Power-Up C C C 3 C A A A C ms ms ms 6 36 96 0.016 12 38 50 2.1 0.8 -1 1 5 1.1 1.9 1 10 A 150 1.1 V V A A pF V V mV V A 0.4 High Impedance State Leakage, ILEAK Signal Noise Immunity, VNOISE 1 3 1 300 mV p-p 0.495 0.65 x tBIT 0.2 x tBIT 0.75 x tBIT 0.25 x tBIT 1.25 x tBIT 2 x tBIT 500 0.8 x tBIT 0.4 x tBIT 0.2 x tBIT 0.5 x tBIT-M 2 x tBIT s s s s s s 0.4 ms s 500 1 Guaranteed by design, not production tested. Minimum and maximum bit times are relative to tBIT defined in the timing negotiation pulse. 3 Devices compatible with hold time specification as driven by SST originator. 2 Rev. PrA | Page 3 of 16 40 TA 70C, VCC = 3.3 V -40 TA +125C -40 TD +125C; -40 TA 70C, VCC = 3.3 V -40 TD +125C; -40 TA +125C Low level Mid level High level Averaging enabled Averaging enabled Averaging enabled VIN = VCC VIN = 0 Between input switching levels ISOURCE = 6 mA (maximum) Device powered on SST bus; VSST = 1.1 V, VCC = 3.3 V Device unpowered on SST bus; VSST = 1.1 V, VCC = 0 V Noise glitches from 10 MHz to 100 MHz; width up to 50 ns tBIT defined in speed negotiation See SST Specification Rev 1.0 Device responding to a constant low level driven by originator Time after power-up when device can participate in speed negotiation ADT7484/ADT7486 Preliminary Technical Data ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Supply Voltage (VCC) Voltage on Any Other Pin (Including SST Pin) Input Current at Any Pin Package Input Current Maximum Junction Temperature (TJ max) Storage Temperature Range Lead Temperature, Soldering IR Peak Reflow Temperature Lead Temperature (10 sec) ESD Rating Rating 3.6 V 3.6 V 5 mA 20 mA 150C -65C to +150C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. THERMAL RESISTANCE 260C 300C 2000 V JA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Table 3. Thermal Resistance Package Type 8-Lead MSOP (ADT7484) 10-Lead MSOP (ADT7486) JA 206 206 ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. Rev. PrA | Page 4 of 16 JC 44 44 Unit C/W C/W Preliminary Technical Data ADT7484/ADT7486 GND 2 D1+ 3 ADT7484 TOP VIEW (Not to Scale) D1- 4 8 SST 7 ADD0 6 RESERVED 5 ADD1 VCC 1 10 SST GND 2 ADT7486 9 ADD0 D1+ 3 TOP VIEW (Not to Scale) 8 RESERVED 7 ADD1 6 D2- D1- 4 D2+ 5 Figure 2. ADT7484 8-Lead MSOP Figure 3. ADT7486 10-Lead MSOP Table 4. ADT7484 Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 10 Mnemonic VCC GND D1+ D1- ADD1 RESERVED ADD0 SST Type Power supply Ground Analog input Analog input Digital input Reserved Digital input Digital input/output Description 3.3 V 10%. Ground Pin. Positive Connection to Remote Temperature Sensor. Negative Connection to Remote Temperature Sensor. SST Address Select. Connect to Ground. SST Address Select. SST Bidirectional Data Line. Table 5. ADT7486 Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 8 9 10 Mnemonic VCC GND D1+ D1- D2+ D2- ADD1 RESERVED ADD0 SST Type Power supply Ground Analog input Analog input Analog input Analog input Analog input Analog input Digital input Digital input/output Description 3.3 V 10%. Ground Pin. Positive Connection to Remote 1 Temperature Sensor. Negative Connection to Remote 1 Temperature Sensor. Positive Connection to Remote 2 Temperature Sensor. Negative Connection to Remote 2 Temperature Sensor. SST Address Select. Connect to Ground. SST Address Select. SST Bidirectional Data Line. Rev. PrA | Page 5 of 16 05198-003 VCC 1 05198-002 PIN CONFIGURATIONS AND FUNCTIONAL DESCRIPTIONS ADT7484/ADT7486 Preliminary Technical Data TYPICAL PERFORMANCE CHARACTERISTICS Figure 4. SST O/P Level vs. Supply Voltage Figure 7. SST O/P Level vs. Pull Down(?) Figure 5. Supply Current vs. Temperature Figure 8. Supply Current vs. Voltage Figure 6. Local Temperature Error Figure 9. Remote Temperature Error Rev. PrA | Page 6 of 16 Preliminary Technical Data ADT7484/ADT7486 Figure 10. Remote Temperature Error vs. PCB Resistance Figure 13. Remote Temperature Error vs. Capacitance Between D1+ and D1- Figure 11. Temperature Error vs. Common-Mode Noise Frequency Figure 14. Temperature Error vs. Differential Mode Noise Frequency Figure 12. Temperature Error vs. Power Supply Noise Rev. PrA | Page 7 of 16 ADT7484/ADT7486 Preliminary Technical Data PRODUCT DESCRIPTION The ADT7484 is a single remote temperature sensor, and the ADT7486 is a dual temperature sensor for use in PC applications. The ADT7484/ADT7486 accurately measure local and remote temperature and communicate over a one-wire Simple Serial Transport (SST) bus interface. SST INTERFACE Simple Serial Transport (SST) is a one-wire serial bus and a communications protocol between components intended for use in personal computers, personal handheld devices, or other industrial sensor nets. The ADT7484/ADT7486 support SST specification Rev 1. SST is a licensable bus technology from Analog Devices, Inc., and Intel Corporation. To inquire about obtaining a copy of the Simple Serial Transport Specification or an SST technology license, please email Analog Devices, Inc., at sst_licensing@analog.com or write to Analog Devices, Inc., 3550 North First Street, San Jose, CA 95134, Attention: SST Licensing, M/S B7-24. ADT7486 Client Address The client address for the ADT7484/ADT7486 is selected using the address pin. The address pin is connected to a float detection circuit, which allows the ADT7484/ADT7486 to distinguish between three input states: high, low (GND), and floating. The address range for fixed address, discoverable devices is 0x48 to 0x50. Table 6. ADT7484/ADT7486 Selectable Addresses ADD1 Low (GND) Low (GND) Low (GND) Float Float Float High High High Rev. PrA | Page 8 of 16 ADD0 Low (GND) Float High Low (GND) Float High Low (GND) Float High Address Selected 0x48 0x49 0x4A 0x4B 0x4C 0x4D 0x4E 0x4F 0x50 Preliminary Technical Data ADT7484/ADT7486 Command Summary Table 7 summarizes the commands supported by the ADT7484/ADT7486 devices when directed at the target address selected by the fixed address pins. It contains the command name, command code (CC), write data length (WL), read data length (RL), and a brief description. Table 7. Command Code Summary Command Ping() Command Code, CC 0x00 Write Length, WL 0x00 Read Length, RL 0x00 Description Shows a nonzero FCS over the header if present. GetIntTemp() 0x00 0x01 0x02 GetExt1Temp() 0x01 0x01 0x02 Shows the temperature of the device's internal thermal diode. Shows the temperature of External Thermal Diode 1. GetExt2Temp() 0x02 0x01 0x02 GetAllTemps() 0x00 0x01 0x04 (ADT7484) 0x06 (ADT7486) SetExt1Offset() 0xe0 0x03 0x00 GetExt1Offset() 0xe0 0x01 0x02 SetExt2Offset() 0xe1 0x03 0x00 GetExt2Offset() 0xe1 0x01 0x02 ResetDevice() 0xf6 0x01 0x00 GetDIB() 0xf7 0xf7 0x01 0x01 0x08 0x10 Rev. PrA | Page 9 of 16 Shows the temperature of External Thermal Diode 2 (ADT7486 only). Shows a 4- or 6-byte block of data (ADT7484: GetIntTemp, GetExt1Temp; ADT7486: GetIntTemp, GetExt1Temp, GetExt2Temp). Sets the offset used to correct errors in External Diode 1. Shows the offset that the device is using to correct errors in External Diode 1. Sets the offset used to correct errors in External Diode 2 (ADT7486 only). Shows the offset that the device is using to correct errors in External Diode 2 (ADT7486 only). Functional reset. The ADT7484/ADT7486 also respond to this command when directed to the Target Address 0x00. Shows information used by SW to identify the device's capabilities. Can be in 8- or 16-byte format. ADT7484/ADT7486 Preliminary Technical Data Command Code Details ADT7484/ADT7486 Device Identifier Block GetIntTemp() The GetDIB() command retrieves the device identifier block (DIB), which provides information to identify the capabilities of the ADT7484/ADT7486. The data returned can be in 8- or 16byte format. The full 16 bytes of DIB is detailed in Table 8. The 8-byte format involves the first eight bytes described in this table. Byte-sized data is returned in the respective fields as it appears in Table 8. Word-sized data, including vendor ID, device ID, and data values use little endian format, that is, the LSB is returned first, followed by the MSB. Table 8. DIB Byte Details Value 0xc0 0x10 Vendor ID 00x11d4 Device ID 0x7484 or 0x7486 0x01 0x00 0x00 0x00 0x00 0x48 to 0x50 The ADT7484 shows the local and remote temperatures in a 4-byte block of data (internal temperature first, followed by External Temperature 1) in response to a GetAllTemps() command. The ADT7486 shows the local and remote temperatures in a 6-byte block of data (internal temperature first, followed by External Temperature 1 and External Temperature 2) in response to this command. SST device Reserved Reserved Reserved Reserved Dependent on the state of the address pins. This command sets the offset that the ADT7484/ADT7486 will use to correct errors in the external diode. The offset is set in little endian, 16-bit, twos compliment format. The maximum offset is 128C with +0.25C resolution. The Ping() command verifies if a device is responding at a particular address. The ADT7484/ADT7486 show a valid nonzero FCS in response to the Ping() command when correctly addressed. Write Length 0x00 Read Length 0x00 FCS ResetDevice() This command resets the register map and conversion controller. The reset command can be global or directed at the client address of the ADT7484/ADT7486. Table 10. ResetDevice() Command Write Length 0x01 Read Length 0x00 Reset command 0xf6 SetExtOffset() GetExtOffset() This command causes the ADT7484/ADT7486 to show the offset that they are using to correct errors in the external diode. The offset value is returned in little endian format, that is, LSB before MSB. ADT7484/ADT7486 Response to Unsupported Commands Table 9. Ping() Command Target Address Device Address Prompted by the GetExtTemp() command, the ADT7484/ADT7486 show the temperature of the remote diode in little endian, 16-bit, twos compliment format. The ADT7484/ADT7486 show 0x8000 in response to this command if the external diode is an open or short circuit. Description Fixed address device. Meets Version 1 of the SST specification Contains company ID number in little endian format Contains device ID number in little endian format Ping() Target Address Device Address GetExtTemp() GetAllTemps() Name Device Capabilities Version/Revision Device Interface Function Interface Reserved Reserved Vendor Specific ID Client Device Address The ADT7484/ADT7486 show the local temperature of the device in response to the GetIntTemp() command. The data has a little endian, 16-bit, twos compliment format. A full list of command codes supported by the ADT7484/ ADT7486 is given in Table 7. The offset registers (Command Codes 0xe0 and 0xe1) are the only registers that the user can write to. The other defined registers are read only. Writing to Register Addresses 0x03 to 0xdf shows a valid FSC, but no action is taken by the ADT7484/ADT7486. The ADT7484/ADT7486 show an invalid FSC if the user attempts to write to the devices between Command Codes 0xe2 to 0xee and no data is written to the device. These registers are reserved for the manufacturer's use only, and no data can be written to the device via these addresses. FCS Rev. PrA | Page 10 of 16 Preliminary Technical Data ADT7484/ADT7486 TEMPERATURE MEASUREMENT The ADT7484/ADT7486 each have two dedicated temperature measurement channels: one for measuring the temperature of an on-chip band gap temperature sensor, and one for measuring the temperature of a remote diode, usually located in the CPU or GPU. The ADT7484 monitors one local and one remote temperature channel, whereas the ADT7486 monitors one local and two remote temperature channels. Monitoring of each of the channels is done in a round-robin sequence. The monitoring sequence is in the order shown in Table 11. Table 11. Temperature Monitoring Sequence Channel Number 0 1 2 Measurement Local temperature Remote Temperature 1 Remote Temperature 2 (ADT7486 only) Conversion Time (ms) 52 52 52 To measure VBE, the operating current through the sensor is switched between three related currents. Figure 15 shows N1 x I and N2 x I as different multiples of the current I. The currents through the temperature diode are switched between I and N1 x I, giving VBE1, and then between I and N2 x I, giving VBE2. The temperature can then be calculated using the two VBE measurements. This method can also cancel the effect of series resistance on the temperature measurement. The resulting VBE waveforms are passed through a 65 kHz low-pass filter to remove noise and then through a chopper-stabilized amplifier to amplify and rectify the waveform, producing a dc voltage proportional to VBE. The ADC digitizes this voltage, and a temperature measurement is produced. To reduce the effects of noise, digital filtering is performed by averaging the results of 16 measurement cycles for low conversion rates. Signal conditioning and measurement of the internal temperature sensor is performed in the same manner. VDD I A simple method for measuring temperature is to exploit the negative temperature coefficient of a diode by measuring the base-emitter voltage (VBE) of a transistor operated at constant current. Unfortunately, this technique requires calibration to null the effect of the absolute value of VBE, which varies from device to device. The technique used in the ADT7484/ADT7486 measures the change in VBE when the device is operated at three different currents. Figure 15 shows the input signal conditioning used to measure the output of a remote temperature sensor. This figure shows the remote sensor as a substrate transistor, which is provided for temperature monitoring on some microprocessors, but it could also be a discrete transistor. If a discrete transistor is used, the collector is not grounded and should be linked to the base. To prevent ground noise from interfering with the measurement, the more negative terminal of the sensor is not referenced to ground, but is biased above ground by an internal diode at the D1- input. If the sensor is operating in an extremely noisy environment, C1 can be added as a noise filter. Its value should not exceed 1000 pF. REMOTE SENSING TRANSISTOR N1 x I N2 x I IBIAS D+ VOUT+ C1* TO ADC D- BIAS DIODE VOUT- LOW-PASS FILTER fC = 65kHz *CAPACITOR C1 IS OPTIONAL. IT SHOULD ONLY BE USED IN NOISY ENVIRONMENTS. 05198-004 TEMPERATURE MEASUREMENT METHOD Figure 15. Signal Conditioning for Remote Diode Temperature Sensors READING TEMPERATURE MEASUREMENTS The temperature measurement command codes are detailed in Table 10. The temperature data returned is two bytes in little endian format, that is, LSB before MSB. All temperatures can be read together by using Command Code 0x00 with a read length of 0x04. The command codes and returned data are described in Table 12. Table 12. Temperature Channel Command Codes Temp Channel Internal External 1 External 2 All Temps Rev. PrA | Page 11 of 16 Command Code 0x00 0x01 0x02 0x00 Returned data LSB, MSB LSB, MSB LSB, MSB Internal LSB, Internal MSB; External 1 LSB, External 1 MSB; External 2 LSB, External 2 MSB ADT7484/ADT7486 Preliminary Technical Data SST TEMPERATURE SENSOR DATA FORMAT LAYOUT CONSIDERATIONS The data for temperature is structured to allow values in the range of 512C to be reported. Thus, the temperature sensor format uses a twos complement, 16-bit binary value to represent values in this range. This format allows temperatures to be represented with approximately a 0.016C resolution. Digital boards can be electrically noisy environments. Take the following precautions to protect the analog inputs from noise, particularly when measuring the very small voltages from a remote diode sensor: * Table 13. SST Temperature Data Format Twos Compliment MSB LSB 1110 0000 1100 0000 1110 1100 0000 0000 1111 0110 0000 0000 1111 1011 0011 1110 1111 1110 1100 0000 1111 1111 1100 0000 0000 0000 0000 0000 0000 0000 0100 0000 0000 0001 0100 0000 0000 0100 1100 0010 0000 1010 0000 0000 0001 0100 0000 0000 0001 1111 0100 0000 * * 5MIL GND 5MIL D+ 5MIL 5MIL 5MIL D- 5MIL GND USING DISCRETE TRANSISTORS If a discrete transistor is used, the collector is not grounded and should be linked to the base. If a PNP transistor is used, the base is connected to the D1- input and the emitter is connected to the D1+ input. If an NPN transistor is used, the emitter is connected to the D1- input and the base is connected to the D1+ input. Figure 15 shows how to connect the ADT7484/ADT7486 to an NPN or PNP transistor for temperature measurement. To prevent ground noise from interfering with the measurement, the more negative terminal of the sensor is not referenced to ground, but is biased above ground by an internal diode at the D1- input. D+ D- ADT7484/ ADT7486 D+ 2N3906 PNP * * * * ADT7484/ ADT7486 D- Figure 17. Arrangements of Signal Tracks 05198-005 2N3904 NPN * Figure 16. Connections for NPN and PNP Transistors The ADT7484/ADT7486 show an external temperature value of 0x8000 if the external diode is an open or short circuit. 5MIL 05198-006 Temperature (C) -125 -80 -40 -20 -5 -1 0 +1 +5 +20 +40 +80 +125 Place the device as close as possible to the remote sensing diode. Provided that the worst noise sources, such as clock generators, data/address buses, and CRTs, are avoided, this distance can be four to eight inches. Route the D1+ and D1- tracks close together in parallel with grounded guard tracks on each side. Provide a ground plane under the tracks if possible. Use wide tracks to minimize inductance and reduce noise pickup. A 5 mil track minimum width and spacing is recommended. Try to minimize the number of copper/solder joints, which can cause thermocouple effects. Where copper/solder joints are used, make sure that they are in both the D1+ and D1- paths and are at the same temperature. Thermocouple effects should not be a major problem because 1C corresponds to about 240 V, and thermocouple voltages are about 3 V/C of the temperature difference. Unless there are two thermocouples with a big temperature differential between them, thermocouple voltages should be much less than 200 mV. Place a 0.1 F bypass capacitor close to the device. If the distance to the remote sensor is more than eight inches, the use of a twisted-pair cable is recommended. This works for distances of about six to 12 feet. For very long distances (up to 100 feet), use shielded twistedpair cables, such as Belden #8451 microphone cables. Connect the twisted-pair cable to D1+ and D1- and the shield to GND, close to the device. Leave the remote end of the shield unconnected to avoid ground loops. Because the measurement technique uses switched current sources, excessive cable and/or filter capacitance can affect the measurement. When using long cables, the filter capacitor can be reduced or removed. Cable resistance can also introduce errors. A 1 series resistance introduces about 0.5C error. Rev. PrA | Page 12 of 16 Preliminary Technical Data ADT7484/ADT7486 APPLICATION SCHEMATICS VCC 2N3904 OR CPU THERMAL DIODE Rev. PrA | Page 13 of 16 ADT7484 1 VCC SST 8 2 GND ADD0 7 3 D1+ RESERVED 6 4 D1- 5 ADD1 SST 05198-007 As CPUs run faster, it is more difficult to avoid high frequency clocks when routing the D1+ and D1- tracks around a system board. Even when the recommended layout guidelines are followed, there may still be temperature errors, attributed to noise being coupled on to the D1+ and D1- lines. High frequency noise generally has the effect of producing temperature measurements that are consistently too high by a specific amount. The ADT7484/ADT7486 have a temperature offset command code of 0xe0 through which a desired offset can be set. By doing a one-time calibration of the system, the offset caused by system board noise can be calculated and nulled by specifying it in the ADT7484/ADT7486. The offset is automatically added to every temperature measurement. The maximum offset is 128C with 0.25C resolution. The offset format is the same as the temperature data format--16-bit, twos compliment notation, as shown in Table 13. The offset should be programmed in little endian format, that is, LSB before MSB. The offset value is also returned in little endian format when read. Figure 18. ADT7484 Typical Application Schematic VCC 2N3904 NPN ADT7486 1 VCC 2 GND ADD0 SST 10 9 3 D1+ RESERVED 8 4 D1- ADD1 7 5 D2+ D2- 6 SST CPU THERMAL DIODE Figure 19. ADT7486 Typical Application Schematic 05198-008 TEMPERATURE OFFSET ADT7484/ADT7486 Preliminary Technical Data OUTLINE DIMENSIONS Figure 20. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters 3.10 3.00 2.90 10 3.10 3.00 2.90 1 6 5.15 4.90 4.65 5 PIN 1 0.50 BSC 0.95 0.85 0.75 0.15 0.05 1.10 MAX 0.33 0.17 SEATING PLANE 0.23 0.08 8 0 0.80 0.60 0.40 COPLANARITY 0.10 COMPLIANT TO JEDEC STANDARDS MO-187-BA Figure 21. 10-Lead Mini Small Outline Package [MSOP] (RM-10) Dimensions shown in millimeters ORDERING GUIDE Model ADT7484ARMZ1 ADT7484ARMZ-REEL1 ADT7484ARMZ-REEL71 ADT7486ARMZ1 ADT7486ARMZ-REEL1 ADT7486ARMZ-REEL71 1 Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package Description 8-Lead MSOP 8-Lead MSOP 8-Lead MSOP 10-Lead MSOP 10-Lead MSOP 10-Lead MSOP Z = Pb-free part. Rev. PrA | Page 14 of 16 Package Option RM-8 RM-8 RM-8 RM-10 RM-10 RM-10 Preliminary Technical Data ADT7484/ADT7486 NOTES Rev. PrA | Page 15 of 16 ADT7484/ADT7486 Preliminary Technical Data NOTES (c)2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. PR05198-0-4/06(PrA) Rev. PrA | Page 16 of 16