Rainbow-electronics LM40 Manual do Utilizador

LM40Hardware Monitor with Dual Thermal Diodes andSensorPath™BusGeneral DescriptionThe LM40 is a hardware monitor that measures 3 tempera-ture zones, 5

Typical Performance CharacteristicsRemote Diode Temperature Reading Sensitivity to DiodeFilter CapacitanceThermal Diode Capacitor or PCB Leakage Curre

1.0 Functional Description (Continued)that begin with the label Mout_ depict a drive by the master.Signal labels that begin with the label Slv_ depict

1.0 Functional Description (Continued)1.3.2 Read TransactionDuring a read transaction, the master reads data from aregister at a specified address wit

1.0 Functional Description (Continued)•Data Bits This is the data written to the LM40 register,are driven by the master. Data is transferred serially

1.0 Functional Description (Continued)All devices (master or slave) must monitor the bus for anAttention Request signal. The following notes clarify t

2.0 Register Set2.1 REGISTER SET SUMMARYReg AddRegisterNameR/WPORValBit15MSbBit14Bit13Bit12Bit11Bit10Bit9Bit8Bit7Bit6Bit5Bit4Bit3Bit2Bit1Bit0LSb000 00

2.0 Register Set (Continued)* Depends on state of ADD pins see Section 2.3 "Device Number".2.2 DEVICE RESET OPERATIONA Device Reset operatio

2.0 Register Set (Continued)2.5 DEVICE ID (Addr: 000 010; 02h)RegAddRegisterNameR/WPORValBit15MSbBit14Bit13Bit12Bit11Bit10Bit9Bit8Bit7Bit6Bit5Bit4Bit3

2.0 Register Set (Continued)Bit Type Description7ROBER (Bus Error) This bit is set when the device either generates, or receives an error indication i

2.0 Register Set (Continued)The minimum scan rate is recommended to be 4Hz (i.e. the measurement data is updated at least once in 250 ms), see Section

Connection DiagramTSSOP-1420068402Top ViewNational Package Number MTC14COrderNumberPackageMarkingNSPackageNumberTransportMediaLM40CIMT LM40CIMTMTC14C

2.0 Register Set (Continued)2.9.3 Temperature Data Readout (Addr: 001 001; 09h)RegAddRegisterNameR/WPORValBit15MSbBit14Bit13Bit12Bit11Bit10Bit9Bit8Bit

2.0 Register Set (Continued)Temperature Data Format (Continued)Temperature Binary Hex- 40 ˚C 11 1011 0000 2B0h-255.5 ˚C 10 0000 0001 201h-256 ˚C 10 00

2.0 Register Set (Continued)result is ready before the previous result has been read, the new results overwrites the previous result and the Error Fun

2.0 Register Set (Continued)Analog Input Voltage MappingSensorNumber(SNUM) Voltage InputInput Voltagefor NominalReading(code 384 or180h)MaximumInput V

2.0 Register Set (Continued)Bit Type Description7-2 RO Reserved. Will always read "0".Conversion Rate ControlLowPwr [CR1:CR0] Typical Conver

3.0 Application Hints (Continued)3.1 DIODE NON-IDEALITY3.1.1 Diode Non-Ideality Factor Effect on AccuracyWhen a transistor is connected as a diode, th

3.0 Application Hints (Continued)3. Ideally, the LM40 should be placed within 10cm of theProcessor diode pins with the traces being as straight,short

Physical Dimensions inches (millimeters)unless otherwise noted14-Lead Molded Thin Shrink Small Outline Package (TSSOP,JEDEC Registration Number MO-153

Block Diagram20068403LM40www.national.com3

Absolute Maximum Ratings(Notes 2, 1)Supply Voltage (V+) −0.5 V to 6.0 VVoltage at Any Digital Input orOutput Pin −0.5 V to 6.0 VVoltage on 12V Analog

TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICSParameter ConditionsTypical(Note 7)Limits(Note 8)Units(Limits)Diode Source Current(VD+−VD−) = +0.65 V;

AC Electrical Characteristics (Continued)The following specification apply for V+ = +3.0 VDCto +3.6 VDC, unless otherwise specified. Boldface limits a

PIN#PinNamePinCircuitAll Input Structure Circuits1NC ACircuit ACircuit CCircuit BCircuit D2 GND B3V+/3.3V SBB4 SWD A5 ADD A6 +1.2V C7 +2.5V C8 D1- D9

Timing Diagrams20068404FIGURE 1. Timing for Data Bits 0, 1 and Start Bit. See Section 1.2 "SensorPath BIT SIGNALING" for further details.LM4

Timing Diagrams (Continued)20068405FIGURE 2. Timing for Attention Request and Reset. See Section 1.2 "SensorPath BIT SIGNALING" for further