The main specifications of the function

The mold temperature of the accurate induction remote control

Remote temperature accuracy ± 0.75 ° C (maximum)

IC or diode knot local Temperature accuracy ± 3.0 ° C (maximum)

Use Trutherm technology to achieve accuracy power supply voltage 3.0V to 3.6V

""Thermal diode"" temperature measurement

Power supply Current 402 μA (typical value)

The input level of thermal diodes with analog diode

Heat diode digital filter

processor/computer system thermal thermal heat

Intel Pentium 4 processor adopts 90nm process or manages 2N3904 non -ideal choice -such as laptop, desktop machine, workstation, server)

Remote diodes fault detection

Electronic testing Equipment

The local temperature sensing of the car office electronic equipment

Number of remote temperature reads

Filter: Description

- 0.125 ° C LSB LM95231 is a precision double remote diode -Trutherm technology of 10 -bit or 11 -bit programmable temperature sensor (RDTS) resolution instruments using Texas. The interface of 2 line serial LM95231 is compatible with SMBUS -11 -bit parsing temperature higher than 2.0. LM95231 can sensorize three temperatures of 127 ° C. It can measure the temperature of the temperature of its mold with a number and the remote temperature reading of the two diode connecting the transistor. This filter: LM95231 includes digital filtering and high-level simulation filtering and -0.03125 ° C LSB. It uses filtering Trutherm technology to reduce the processor to the-12-bit plus or 13-bit programmable processor non-ideal extension. The diode connection resolution transistor can be a ""thermal diode"". As the temperature found in Intel -13, the temperature is higher than the AMD processor, or it can be a diode 127 ° C connecting the MMBT3904 transistor. Trusham Technology allows accurate measurement of ""local temperature reading:"" diode ""in small geometric processes, 90nm – 0.25 ° C and below. LM95231 supports user selection -9 -bit plus -sensitive diode processor of Pentium 4 uses 90nm using 90nm Craft or 2N3904.

Status register supports

The programmable conversion rate allows users to remotely use LM95231 resolution format

The best temperature reading can be programmed as power consumption 11 [123

]

Digital filtering position with symbols or unsigned

The transition control of the closing mode is disabled. After the filter is enabled, the resolution SMBUS 2.0 compatible interface is supported, supporting the increase of 13 digits or unsigned. The remote diode reading of the timeout non -symbolic mode LM95231 can solve the temperature above 127 ° C. Local 8 -needle VSSOP packaging temperature reading is more than 9 digits

(1) Absolute maximum rated value indicates the limit of damage to the device. The work rated value indicates that the equipment function is normal, but it does not guarantee specific performance restrictions. Ensure the standards and test conditions, see electrical characteristics. The ensuring specifications are only applicable to the test conditions listed. Some performances may degenerate when the device does not run under the test conditions. The device is not recommended to use the maximum work rated value.

(2) When the input voltage (VI) of any pin exceeds the power supply (VI LT; GND or Vi GT; VDD), the current of the pin should be limited to 5. The parasitic elements and/or ESD protection circuits of the LM95231 pin are shown in Figure 2 and Table 1. Be careful about the parasitic diode on the bias pin D1: D1+, D2+, D1-, D2-. More than 50 MVs may damage temperature measurement.

(3) When connected to a printing circuit board with 1 ounce and no airflow, connect to the thermal resistance of the environment: -vssop-8 u003d 210 ° C/W

(123] ( 4) Human model, 100pf passes through the 1.5kΩ resistor. Machine model, 200pf discharge directly to each pin.

(5) For the packaging of lead (PB), the return welding temperature curve is different from the packaging without lead.

Temperature-Digital Converter Features

Unless otherwise explained, these specifications are suitable for VDD u003d+3.0VDC to 3.6VDC. Black body limit is suitable for TA u003d TJ u003d Tmin ≤ TA ≤TMAX; all other limit TA u003d TJ u003d+25 ° C, unless otherwise explained. TJ is the knot temperature of LM95231. TD is a remote heat diode knot temperature

(1) The typical value is TA u003d 25 ° C, which represents the most likely parameter specification when the product characteristic description. Typical specifications are not guaranteed.

(2) Specifying AOQL (the average shipment quality level) is specified.

(3) Local temperature accuracy does not include the effects of self -heating. The temperature caused by heating is the internal power consumption and thermal resistance of LM95231. See the annotation 2 in the running rated table for the resistance of self -heating calculations.

(4) When connected to a printing circuit board with 1 ounce and no airflow, connect to the thermal resistance of the environment: -vssop-8 u003d 210 ° C/W

(5) When using the thermal diode of the Pentium 4 processor on the 90nm process or the MMBT3904 type, you can ensure that the accuracy of the LM95231 is selected in the remote diode model selection.

(6) The temperature data that is usually provided only shows how to update. LM95231 does not need to be transformed (and the final conversion result will be generated).

(7) When SMBUS is in a state of activity, the static current will not significantly increase

Logical electrical characteristics

Digital DC characteristics

Otherwise, these specifications are suitable for VDD u003d+3.0 to 3.6 VDC. The thick body limit is suitable for TA u003d TJ u003d TMINTMAX; all other limit ta u003d TJ u003d+25 ° C, unless there is another explanation.

(1) The typical value is TA u003d 25 ° C, which represents the most likely parameter specifications when describing product characteristics. Typical specifications are not guaranteed.

(2) Specifying AOQL (the average shipment quality level) is specified.

Logic electrical characteristics

Digital switch characteristics

Unless otherwise explained, these specifications are applicable to VDD u003d+3.0 VDC to +3.6 VDC, CL (load capacitance) Output line u003d 80 Patriotic Front. Black body restrictions are suitable for TA u003d TJ u003d TMIN to TMAX; all other limit ta u003d TJ u003d+25 ° C, unless there is another explanation. The exchange characteristics of LM95231 fully meet or exceed the release specifications of version 2.0. The following parameters are the timing between SMBCLK and SMBDAT signals related to LM95231. They follow but not necessarily the SMBUS bus specification.

(1) The typical value is TA u003d 25 ° C, which represents the most likely parameter specifications when describing product characteristics. Typical specifications are not guaranteed.

(2) Specifying AOQL (the average shipment quality level) is specified.

(3) output rising time from (VIN (0) maximum value+0.15V) to (VIN (1) minimum value 0.15V).

(4) The output drop time from (1) min-0.15v) to (VIN (1) min+0.15V).

(5) Keeping the SMBDAT and/or SMBCLK line at a low time interval is greater than that of TTIMEOUT, which will reset the SMBUS state machine of LM95231.

LM95231 is a digital sensor that can use the Sigma-Delta modulus converter to sensorize the temperature of 3 thermal areas. It can measure the temperature of its local modulus and the temperature of the two external transistors. LM95231 can support two types of external transistors, namely the 90nm process thermal diode on the Pentium 4 processor or the transistor connected to the 2N3904 diode. The crystal type is programmable for register, and no software intervention is required after initialization. LM95231 has a advanced input stage using Trutherm technology of Texas instruments, reducing the non -ideal transmission in the 90nm process of the Pentium 4 processor. The thermal diode contains the internal simulation filter input level, thereby minimizing the demand for the external thermal diode filter capacitor. In addition, digital filters have been added. The improvement of these antipitrimating degrees in the analog input level and digital filtering will allow longer tracking trajectories or cables to the thermal diode compared with the previous thermal diode sensor equipment. LM95231's 2 -line serial interface is compatible with SMBUS 2.0 and I2C. See detailed description specifications between SMBUS 2.0i2C bus and SMBU.

The temperature conversion rate is programmable to allow users to optimize the requirements of the LM95231 system. LM95231 can be placed in a shutdown state at a minimum power consumption without temperature data. When closed, the single conversion mode allows the system to control the final flexibility conversion rate. The temperature resolution of the remote diode is variable, depending on whether the digital filter is activated. when? Digital filter activation, the resolution is 13 digits, and the programm can be programmed as 13 unprecedented or 12 -digit plus symbols. When the digital filter is not active, the minimum valid position (LSB) weight of the two resolution is 0.03125 ° C resolution resolution It is 11 digits, programmable to 11 unsprovisal or 10 -bit plus numbers, and the minimum valid bit (LSB) weight of the two resolution is 0.125 ° C. The non -symbol resolution allows the remote diode sensing temperature to be higher than 127 ° C. The local temperature resolution is not programmable, and it is always 9 -bit plus numbers and minimum temperatures of 0.25 ° C. The temperature accuracy of the LM95231 remote control diode will be adjusted for the thermal diode of the Pentium 4 processor on the 90nm process or the 2N3904 transistor. Only when any of these diode can be used to ensure that the accuracy is properly selected. When measuring the Pentium 4 processor above, the Trutherm mode should be enabled. When the 2N3904 transistors are measured, the 90nm process is disabled. Use 2N3904 to enable the transistor connected to the Trutherm mode may produce unexpected temperature reading. The diode fault detection circuit in LM95231 can detect the existence of remote diode: whether D+is short-circuit to VDD, D-or ground, or whether D+floats. LM95231 register group has 8 -bit data structures, including:

1. The highest effective byte (MSB) Local temperature register

2 minimum effective byte (LSB) Local temperature register

3. MSB remote temperature 1 register

] 4.LSB remote temperature 1 register

5.MSB remote temperature 2 register

6.LSB remote temperature 2 register

123]

8. Configuration register: resolution control, conversion rate control, standby control

9. Remote diodes filter settings

10. ]11.远程二极管TruTherm模式控制

12.单发寄存器

13.制造商ID

转换序列

在通电默认状态下， LM95231 requires up to 77.5 milliseconds to convert local temperatures, remotely and update all its registers. Only during the conversion process, the line (D7) is high in the state register (02H). These conversions are processed in a circular order. The conversion rate can be modified by the conversion rate in the configuration register (03H). When the conversion modification rate is inserted between conversion, the actual maximum conversion time is maintained at 87.7ms. Different conversion rates will cause LM95231 to absorb different numbers of power currents, as shown in Figure 6.

The default status of the boot

lm95231 is always powered on these known default status. LM95231 is still in these states until the first conversion.

1. The command register is set to 00h

2. The local temperature is set to 0 ° C until the end of the first conversion

3. The temperature setting of the remote diode is 0 ° to 0 ° C, until the end of the first conversion

4. The remote diode digital filter is opened.

5. In the case of enabling Trutherm mode, the Pentium 4 processor of the remote diode 1 is set to the 90nm process. The remote diode 2 model is set to 2N3904, and the Trutherm mode is disabled.

6. Status register depends on the state of the heat diode input

7. Configure the register set to 00h; continuous conversion, typical time u003d 85.8 ms, when Trutherm mode is only for remote 1 SMBUS SMBUS The interface LM95231 is operated on the SMBUS, so the SMBCLK line is an input, and the SMBDAT line is two -way. LM95231 never drives the SMBCLK line, alsoDo not support the clock stretch. According to SMBUS specifications, LM95231 has a 7 -bit port address. All bits A6 to A0 are internal programming that cannot be changed with software or hardware. SMBUS subordinate address depends on the number of LM95231 parts ordering:

The remote temperature data with digital filter is 13 digits and two supplements with one 13 digits, two supplements Code or non -symbols indicate binary characters with LSB (minimum effective position) equal to 0.03125 ° C (1/32 ° C). The data format is the use of the left pair 16- two 8-bit registers. Unused bit will always report ""0"".

SMBDAT drain -opening output

SMBDAT output is an open drain output without internal pulling. The ""high"" level will not be

Before a pull -up current (usually a pull -up resistor) is provided by the external power supply, it will be observed on the pin. Select

The resistance value depends on many system factors, but generally speaking, the upper pull resistance should not affect the data rate required by SMBUS. This will minimize any internal temperature reading

LM95231 internal heating errors. The maximum resistance of pulling can provide 2.1V high

According to the LM95231 specification, the level of the high level output current when the power supply voltage is 3.0V is 82kΩ

(5%) or 88.7kΩ (1%).

1.6 Diodes fault detection

LM95231 is equipped with operating circuits for detecting the diode related to the fault conditions related to the remote control. If the D+pin is detected short-circuit, D negative electrode, VDD, or D+floating, the remote range If there is a symbol format, the temperature reading is -128.000 ° C; if the unsigned format is selected, the temperature read is +255.875. In addition, set an appropriate state storage position RD1M or RD2M (D1 or D0). When the Trutherm mode is activated, the diode is not detected to the D+short circuit. The activation of 2N3904 transistor and Trutherm connection mode may cause detection of diode faults.

The data register in the LM95231 communication LM95231 is selected by the command register. The command register is set to ""00"" when power is power, and the location of the local temperature register is read. The command register locks the last settings. Each data register in LM95231 is divided into one of the four user accessable types:

1. Read only

2. Two

3. Read/write The same address

4. Write/read different addresses

The writing of LM95231 always contains address bytes and command bytes. The writing of any register requires a data byte. Reading LM95231 can be performed in two ways:

1. If the position locked in the command register is correct (in most cases, the command register will point to one of the read temperature registers because this will be this will be The most frequent data is read from LM95231), then reading can be simply composed of an address byte, and then retrieved data bytes.

2. If the command register is needed, one address byte, command byte, repeated startup and another address byte will be completed. Data bytes are first of all effective positions. At the end of the reading, LM95231 can accept any confirmation or confirmation from the main device (without response, it is usually used as the last byte from the device). When all 11 places are retrieved from the previous remote diode temperature measurement, all 11 hosts must ensure that all 11 bits come from the same temperature conversion. This can be achieved by reading. The first is MSB register. After reading MSB, LSB will be locked. LSB will be unlocked after reading. If the user reads MSB continuously, each time you read the MSB, the LSB associated with the temperature will be locking and covering the previous lock LSB value.

Serial interface reset

When transmitted on the SMBDAT line on LM95231, if the SMBUS host reset, LM95231 then LM95231 The known state of the communication protocol must be returned. This can be completed with one of the two methods:

1. When SMBDAT is low, the LM95231 SMBUS state machine will be reset to SMBUS idle state, if SMB's data is maintained for more than 35 minutes. Please note that when the SMBUS specification 2.0 is maintained by SMBCLK or the SMBDAT line, all devices will time out -35ms. Therefore, in order to ensure the timeout of all equipment on the bus, SMBCLK or SMBDAT lines must be kept at least 35 milliseconds.

In noisy environments, such as processor motherboards, the layout consideration is very important. Caused by noise on the recording channel between the remote temperature diode sensor and the LM95231 may cause temperature conversion errors. Keep in mind that the signal level that LM95231 tries to measure is based on the units. This should follow the following guidelines:

1.vdd should use the 0.1 μF capacitor with 100PF with 100PF. 100PF capacitors should be placed as close to the power as possible. Need to be close to LM95231.

2. It is recommended to use 100PF diode bypass capacitors to filter high -frequency noise, but it may not be neededEssence Make sure the trajectory matching of 100pf capacitors. Close the filter capacitor near LM95231.

3. Ideally, LM95231 should be placed in the range of the processor diode pins of 10cm, the trace line is straight, short, and the same as possible. The tracking resistance of 1Ω can cause an error of up to 0.62 ° C. This uses simple software compensation can compensate the error.

4. If possible, there should be an grounded protection ring in any side, above and below of the diode. This grounding protective cover should not be between D+and D-wires. If the noise does be coupled to the diode, it is ideal if it is coupled. This is the same as D+and D-line.

5. Avoid wiring diode near the power switch or filter induction.

6. Avoid the diode trajectory from approaching or parallel to high -speed numbers and bus lines. The diode trajectory should be kept at a distance of at least 2 cm from high -speed digital records.

7. If you need to cross high -speed digital trace lines, the diode traces and high -speed digital traces should be crossed at 90 degrees.

8. The ideal position of the GND pins connecting LM95231 is that the GND of the processor as close to the processor is related to the induction diode.

The leakage current between 9.D+and GND and between D+and D-should remain at the minimum value. Thirteen milliam leaks can lead to the temperature reading of the diode up to 0.2 ° C. Keeping the printing circuit board as clean as possible will minimize the leak current. The noise coupling to the digital line is greater than 400mvp-P (typical lag) and lower than 500mV lower than GND, which may prevent the successful communication between SMBUS and LM95231. SMBUS is not responding to the most common symptoms, causing unnecessary traffic jams. Although SMBUS's maximum frequency communication is quite low (maximum 100kHz), it is still necessary to pay attention to ensure that there are multiple components and long printing circuit board traces on the bus. A 3DB RC low -pass filter LM95231's SMBCLK input contains about 40MHz corner frequency. The additional resistance can be added with SMBDAT and SMBCLK lines to further help filter noise and bell. Reduce noise by maintaining a high -speed data communications with SMBDAT and SMBCLK lines with the coupling area of u200bu200bthe digital line from the switching power supply area and ensuring that the digital lines are coupled.