Rainbow-electronics LM87 Manual de usuario

LM87Serial Interface System Hardware Monitor with RemoteDiode Temperature SensingGeneral DescriptionThe LM87 is a highly integrated data acquisition s

Functional Description (Continued)2.0 INTERFACE10099507FIGURE 4. LM87 Register StructureLM87www.national.com 10

Functional Description (Continued)2.1 Internal Registers of the LM87TABLE 1. The internal registers and their corresponding internal LM87 addresses ar

Functional Description (Continued)2.2 Serial Bus InterfaceThe Serial Bus control lines consist of the SMBData (serialdata), SMBCLK (serial clock) and

Functional Description (Continued)power up. If ADD is tied to ground the value for XY is 10. IfADD is tied to Vcc XY will be set to 01. If ADD is notc

Functional Description (Continued)Bit 2 of the Channel Mode Register, when set to 0, config-ures pins 18 and 19 as +2.5V and VCCP2voltage inputs.When

Functional Description (Continued)The resistors were selected by setting R2 = 20 kΩ and thencalculating R1 using the following equation, ( VSis themax

Functional Description (Continued)Counts are based on 2 pulses per revolution tachometeroutputs.RPM Time per Revolution Counts for “Divide by 2” Comme

Functional Description (Continued)1 second) excursion to full operating voltage, then reducethe voltage. Most fans do not operate at all below 5 to 7v

Functional Description (Continued)η from part to part. As an example, assume a temperaturesensor has an accuracy specification of±3˚C at room tem-pera

Functional Description (Continued)9.0 WATCHDOG LIMIT COMPARISONS ANDINTERRUPT STRUCTUREFigure 10 depicts the Interrupt Structure of the LM87. TheLM87

Block Diagram10099501Pin DescriptionPinName(s)PinNumberNumberof PinsType DescriptionADD/NTEST_OUT 1 1 Digital I/0 This pin normally functions as a thr

Functional Description (Continued)•THERM# Input: This is an active low interrupt thatwould typically be generated by an external temperaturemonitoring

Functional Description (Continued)1 (40h) is written to re-Initialize the chip, or power is removedand reapplied. This feature is provided to prevent

Functional Description (Continued)input Interrupt Status Bit and will cause AOUT to go to fullscale, regardless of the state of the THERM# Input Inter

Functional Description (Continued)12.0 FAN MANUFACTURERSManufacturers of cooling fans with tachometer outputs arelisted below:NMB Tech9730 Independenc

Functional Description (Continued)13.0 REGISTERS AND RAM13.1 Address Pointer RegisterThe main register is the Address Pointer Register. The bitdesigna

Functional Description (Continued)13.3 Test Register — Address 15hPower on default –<7:0>= 00000000 binaryBit Name Read/Write Description0 Shutd

Functional Description (Continued)13.5 Configuration Register 1 — Address 40hPower on default –<7:0>= 00001000 binaryBit Name Read/Write Descrip

Functional Description (Continued)13.7 Interrupt Status Register 2 — Address 42hPower on default –<7:0>= 0000 0000 binaryBit Name Read/Write Des

Functional Description (Continued)Bit Name Read/Write Description4-5 FAN1 RPMControlRead/Write FAN1 Speed Control.<5:4>= 00 - divide by 1;<5:

Functional Description (Continued)Bit Name Read Only Description6 FAN1/AIN1 Read Only A one indicates the fan count limit has been exceeded or an AIN1

Pin Description (Continued)PinName(s)PinNumberNumberof PinsType DescriptionGND 8 1 GROUND The system ground pin. Internally connected to all circuitry

Functional Description (Continued)Address A6–A0 Description2Ah Reserved2Bh +2.5V High Limit/External Temperature 2 High Limit2Ch +2.5V Low Limit/Exter

Typical Application10099523FIGURE 13. In this PC application the LM87 monitors temperature, fan speed for 2 fans, and 6 powersupply voltages. It also

Physical Dimensions inches (millimeters) unless otherwise noted24-Lead TSSOPOrder Number LM87CIMTNS Package Number MTC24BLIFE SUPPORT POLICYNATIONAL’S

Absolute Maximum Ratings (Notes 1,2)If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distri

DC Electrical Characteristics (Continued)The following specifications apply for +2.8 VDC≤ V+≤ +3.8 VDC, Analog voltage inputs RS= 510 Ω, unless otherw

AC Electrical CharacteristicsThe following specifications apply for +2.8 VDC≤V+≤ +3.8 VDCon SMBCLK and SMBData, unless otherwise specified. Bold-face

Pin Name D1 D2 D3 R1 R2 R3 R4 Pin Name D1 D2 D3 R1 R2 R3 R4INT#xxx0∞100k 1M +12Vin x x R1+R2≈130k∞CI xxx0∞∞1M +5Vin x x R1+R2≈130k∞FAN1–FAN2 x x x 0∞∞

Test CircuitTypical Performance CharacteristicsDAC Power Supply Sensitivity10099536Functional Description1.0 GENERAL DESCRIPTIONThe LM87 provides 7 an

Functional Description (Continued)8800 RPM on FAN1 and FAN2. Schmitt-Trigger input cir-cuitry is included to accommodate slow rise and fall times.An 8