SX8733/SX8743/SX8744 DATASHEET ADVANCED COMMUNICATIONS & SENSING Precision Diode Digital Temperature For Up To 3 External Sensors SX8733 P1 1 AL1 AL2 6 P2 5 VDD 4 SMBCLK ALARM 2 D2+ D2- SMBDAT VDD SX8743 1 + + - MUX VSS D1+ D1- 3 8 + ADC - SMBUS SMBCLK VDD SX8744 1 AL1 AL2 P3 2 P1 4 +- + ADC - SMBUS 7 SMBDAT P1 2 6 P4 P2 3 5 VSS NC 4 ALARM D1+ D1- +- D2+ D2- + - MUX 3 ++- MUX P2 ALARM D1+ D1D2+ D2D3+ D3- 8 SMBCLK 7 SMBDAT 6 P4 5 VSS AL1 AL2 + ADC - SMBUS General Description Key Product Features The SX8733, SX8743 and SX8744 are digital temperature sensors with a 2-wire SMBus interface. It provides a lowcost solution to monitor the temperature of remote diodes as well as its own temperature with an on-chip PN junction sensor. 1 Internal and Up To 3 External Sensors 2 Temp. Output Formats: 0°C to 127°C and -40°C to 140°C With 0.125°C Resolution Depending on the device version, 2, 3 or 4 programmable ports are included. They offer the possibility to trig under- / over- temperature alarms which can be used as an interrupt or to connect up to 3 external sensors in single-ended mode or 2 external sensors in differential mode. Parasitic Series Resistance Cancellation: Algorithmic, 3point and Kelvin (4-wire) Under-/ Over- Temp. Alarms With Programmable Thresholds Programmable Conversion Rate For Optimal Power Consumption 250 uA Active Current @ 10Hz Sampling Rate V The parasitic resistances in series with the temperature monitoring diode can be cancelled by an algorithmic, a 3point or a Kelvin (4-wire) method. The SX8744 is pin-to-pin compatible with the LM86 part. The SX8733 (2 programmable ports) is available in MLPD6 package. The SX8743 (4 programmable ports) and SX8744 (3 programmable ports) are available in MSOP-8 package. Applications Printer Server Set Top Box Projector Remote Diode Temp. Accuracy of ±0.5°C on the Temp. Range 25°C to 100°C SMBus v2.0 Interface Supports TIMEOUT Pb-Free, Halogen Free, RoHS/WEEE Compliant Product Ordering Information Part Number Feature Package SX8733EWLTRT 2 Programmable ports MLPD-6 SX8743EMSTRT 4 Programmable ports MSOP-8 SX8744EMSTRT 3 Programmable ports MSOP-8 Batteries charger monitoring ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 1 www.semtech.com SX8733/SX8743/SX8744 ADVANCED COMMUNICATIONS & SENSING DATASHEET Table of contents Section Page 1. Electrical Characteristics ......................................................................................................................................... 3 2. 3. 4. 1.1. Sensor Temperature Definition ........................................................................................................................ 3 1.2. Absolute Maximum Ratings ............................................................................................................................. 3 1.3. Electrical Specification ..................................................................................................................................... 4 1.4. SMBus Timing Characteristics......................................................................................................................... 5 1.5. SMBus Timing Waveforms .............................................................................................................................. 5 Pin Configuration ..................................................................................................................................................... 6 2.1. Pinout............................................................................................................................................................... 6 2.2. Pin Description................................................................................................................................................. 6 Configuration ........................................................................................................................................................... 7 3.1. General Presentation ....................................................................................................................................... 7 3.2. Modes .............................................................................................................................................................. 7 3.3. Differential and Single-Ended External Sensor.............................................................................................. 10 3.4. Measurement Principle .................................................................................................................................. 10 3.5. Parasitic Track Resistance Cancellation........................................................................................................ 10 3.5.1. Algorithmic Track Resistance Cancellation............................................................................................ 10 3.5.2. 3-Point Track Resistance Cancellation ................................................................................................... 10 3.5.3. The Kelvin (4-wire) Track Resistance Cancellation ................................................................................ 11 3.6. Temperature Acquisition Sequence............................................................................................................... 11 3.7. Alarm.............................................................................................................................................................. 12 3.8. Temperature Data Format ............................................................................................................................. 12 3.9. Continuous Time Vs. Single Shot .................................................................................................................. 13 Application Note .................................................................................................................................................... 13 4.1. Typical Temperature Sensing System With A SX8743.................................................................................. 13 5. Power-Up Sequence and Standby Mode .............................................................................................................. 14 6. Serial Interface ...................................................................................................................................................... 14 7. 8. 6.1. Register Write - Combined Format ................................................................................................................ 14 6.2. Register Write - Direct Format ....................................................................................................................... 14 6.3. Register Read - Combined Format ................................................................................................................ 15 6.4. Register Read - Direct Format ....................................................................................................................... 15 6.5. Soft Reset ...................................................................................................................................................... 15 Register / Memory Map ......................................................................................................................................... 16 7.1. Memory Map .................................................................................................................................................. 16 7.2. Registers Description..................................................................................................................................... 16 Packaging Information ........................................................................................................................................... 20 8.1. MLPD-W6-EP2 Package Outline Drawing..................................................................................................... 20 8.2. MLPD-W6-EP2 Land Pattern Drawing........................................................................................................... 21 8.3. Package Outline Drawing: MSOP-8............................................................................................................... 22 8.4. Land Pattern Drawing: MSOP-8 .................................................................................................................... 23 ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 2 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 1. Electrical Characteristics 1.1. Sensor Temperature Definition Parameter Symbol Local sensor diode temperature (chip junction temperature) TJ External diode temperature (remote diode junction temperature) TD 1.2. Absolute Maximum Ratings Stresses above the values listed below may cause permanent device failure. Exposure to absolute maximum ratings for extended periods may affect device reliability. Operation outside the parameters specified in the Electrical Characteristics section is not implied. Parameter Symbol Conditions Min Max Unit Power supply to VSS VDD,ABSMAX -0.5 5.75 V Storage temperature TJ,STORE -50 150 °C Ambient operating temperature TJ,ABSMAX -40 140 °C Input voltage on programmable pin VPIN,ABSMAX P1, P2, P3, P4 -0.5 VDD + 0.25 V Input voltage on SMBUS pin VPIN,SMBUS SMBCLK, SMBDAT -0.5 5.75 V Input current on any pin IPIN,ABSMAX -10 10 mA Peak reflow temperature TPKG 260 °C Latchup ILUP 100 mA 2 kV ESD ACS Revision 2.91/February 2010 ©2010 Semtech Corp. -100 HBM Human Body Model MM Machine Model 200 V CDM Charged Device Model 500 V Page 3 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 1.3. Electrical Specification All values valid within the operating conditions unless otherwise specified. Parameter Symbol Conditions Min Typ Max Unit 2.7 3.3 5.5 V 125 °C 250 400 uA 40 uA Operating Conditions Power supply VDD TJ Operating temperature = Junction temperature Active current IVDD,ACTIVE 10 Hz sampling rate No track cancellation mode Current in standby mode IVDD,STDBY 10 TRESOL 0.125 Operating temperature -40 Current Consumption Temperature to Digital Converter Temperature resolution °C TD,ERR1 TJ = 25°C to 85°C TD = 25°C to 100°C -1.5 ±0.5 1.5 °C TD,ERR2 TJ = 25°C to 85°C TD = - 40°C to 125°C -3 ±1.5 3 °C TJ,ERR1 TJ = 25°C to 85°C -2 ±0.75 2 °C TJ,ERR2 TJ = - 40°C to 125°C ±1.5 °C tCONV 10Hz sampling rate 100 ms I2 High level 100 uA I1 Low level 10 uA Alarm output low voltage VOL,AL IOL< 4mA Leakage current ID,LEAK Standby mode Remote temperature error1 Local temperature error1 Conversion time Remote-diode source current -1 0.4 V 1 uA SMBus - Compatible Interface SMBCLK & SMBDAT Input logic high VIH Input logic low VIL Output logic low VOL Current leakage on SMBCLK/ SMBDAT ILEAK,SMB Capacitive load on SMBCLK/ SMBDAT CBUS 2.1 V IOL< 4mA -1 5 0.8 V 0.4 V 1 uA pF 1. Specification with VDD=3.0V to 3.6V and track resistance cancellation disabled. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 4 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 1.4. SMBus Timing Characteristics Parameter Symbol Conditions Min Typ Max Unit 400 kHz SMBus clock frequency fSMB 10 SMBus clock low time tLOW 1.3 us SMBus clock high time tHIGH 0.6 us SMBus rise time tR,SMB 300 ns SMBus fall time tF,SMB 300 ns 35 ms SMBDAT and SMBCLK time low for reset of serial interface tTIMEOUT 25 Data setup time tSU,DAT 100 ns Data hold time1 tHD,DAT 0 ns Start condition hold time (SMBDAT low to SMBCLK low) tHD,STA 0.6 us Stop condition hold time (SMBCLK high to SMBDAT high) tSU,STO 0.6 us Repeated start-condition setup time (SMBCLK high to SMBDAT low) tSU,STA 0.6 us tBUF 1.3 us SMBus free time between stop and start conditions 1. The device provides a hold time of at least 300ns for the SMBDAT signal to bridge the undefined region of the falling edge of SMBCLK. 1.5. SMBus Timing Waveforms SMBDAT SMBCLK tSU,STA tHD,STA tLOW tHIGH tHD,DAT Start tSU,DAT tSU,STO tBUF Stop Figure 1. SMBUS Timing ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 5 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 2. Pin Configuration 2.1. Pinout SX8743 SX87331 P1 VSS SMBDAT SMBCLK VDD P2 - Pin # 1 2 3 4 5 6 7 8 SX8744 VDD P1 P2 NC VSS P4 SMBDAT SMBCLK VDD P3 P2 P1 VSS P4 SMBDAT SMBCLK 1. MLPD exposed pad is not connected internally. It is connected to ground plane for thermal dissipation Table 1 Pinout 2.2. Pin Description Pin Type SMBCLK SMBDAT VDD VSS DIGITAL DIGITAL POWER POWER Description SMBus serial clock input, open drain SMBus serial data input/output, open drain Positive power supply Negative power supply Table 2 Power and SMBus Pin Description Pin P1 P2 P3 P4 VSS Type Description ANALOG DIGITAL ANALOG Ext. diode current source Alarm output, pseudo-open drain Ext. diode current source ANALOG Ext. diode return current sink DIGITAL ANALOG Alarm output, pseudo-open drain Ext. diode current source ANALOG Ext. diode return current sink DIGITAL ANALOG Alarm output, pseudo-open drain Ext. diode return current sink DIGITAL POWER 0 2 1 D1+ D1+ 3 Mode 4 6 8 11 13 16 10 15 18 20 5 7 9 12 14 17 D1+ D1+ D1+ D1+ D1+ D1+ D1+ D1+ D1+ D1+ AL1 D2+ D2+ D2+ D2+ D1- D1- D1AL2 D1- D1- D2+ D2+ D3+ D3+ D1+ D1D2- AL1 AL1 D2- Alarm output, pseudo-open drain Ext. diode return current sink D1- AL1 AL2 AL2 D1- D1D2- D1- D1- D1D1AL1 AL1 D2D3D1- D1D1- D1D2- D2D2- D2D3- D3- Table 3 Programmable Pin Description ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 6 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 3. Configuration 3.1. General Presentation SX8733 / SX8743 / SX8744 include an onchip PN junction to measure local temperaAL1 ture TJ. AL2 4 3 1 6 P1 P2 P3 2 DECODER 3 2 D1+ D1D2+ 6 + + - P4 D3+ D3- MUX D2- 6 The device has a 2-level current source and an ADC to measure each diode’s forward voltage to compute the temperature. The input multiplexer allows 3 external and 1 internal sensors to be connected to the ADC. ALARM + ADC - + SMBUS SMBCLK 4 8 SMBDAT 3 7 VDD 5 1 VSS 2 5 SX8733 SX8744 SX8743 Two alarms can provide to the system the information that a sensor temperature has reached the programmable threshold. The chip is configured with a 2-wire SMBUS serial line. The functional Figure 2. diagram is shown in Figure 2. Functional Diagram 3.2. Modes The mode set in RegConfig allows numerous circuit configurations described in Figure 3 and Figure 4. Up to 3 external sensors can be connected. Theses are configured with differential or single-ended connections. Some modes provide a track resistance cancellation feature to decrease temperature inaccuracy linked to long PCB traces connecting the external sensor to the chip. This is set in RegControl (bits Point3 or Algo). Table 4 presents the mode for the SX8743. Mode External sensor Differential Single-ended Algorithmic track resistance cancellation 3-point track resistance cancellation Kelvin (4-wire) track resistance cancellation Alarm # 0 1 x 1 1 x 2 1 3 0 x 4 2 5 2 6 1 7 1 x x x x x x 0 1 x 8 1 x 9 1 x x x 0 0 0 2 0 1 2 2 10 11 12 13 14 15 16 17 18 20 1 2 2 2 2 2 3 3 3 1 x x x x x x x x x x x x x x x x x 2 0 0 2 2 1 1 1 0 0 Table 4 Features Available With SX8743 Due to their limited number of ports, SX8733 and SX8744 do not offer all theses features. SX8733 does not provide ports P3 and P4 so modes 8 to 20 should not be used. Also port P3 is not available on SX8744 and this typically reduces the number of alarm or the number of external sensors. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 7 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING P1 P1 TD1 P2 TD1 P2 Mode 0, Mode 1 Mode 2 VDD P1 TD1 P1 P2 ALARM1 TD2 P2 VSS ALARM2 Mode 3 Mode 4, Mode 5 P1 P1 TD1 VSS P2 TD1 VDD VDD P2 P3 ALARM1 P4 ALARM2 ALARM1 Mode 8, Mode 9 Mode 6, Mode 7 P1 P1 TD1 P2 P2 VDD TD1 P3 P3 ALARM1 P4 ALARM2 P4 Mode 10 TD2 Mode 11, Mode 12 Figure 3. Mode Connection Diagrams (Modes 0 to 12) ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 8 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING P1 P1 TD1 P2 TD1 P2 VDD TD2 TD2 P3 VSS VDD P3 ALARM1 P4 P4 ALARM2 Mode 13, Mode 14 Mode 15 P1 P1 TD1 P2 P2 TD2 P3 P3 TD3 VSS ALARM1 P4 VDD P4 TD1 TD2 TD3 ALARM1 Mode 18 Mode 16, Mode 17 P1 TD1 P2 P3 P4 Mode 20 Figure 4. Mode Connection Diagrams (Modes 13 to 18 and 20) ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 9 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor ADVANCED COMMUNICATIONS & SENSING DATASHEET 3.3. Differential and Single-Ended External Sensor Table 4 indicates whether the external sensors are connected differentially or in single-ended configuration with grounded cathode. Differential modes have better common-mode rejection of external noise pickup. The external noise pickup is present equally on the anode and the cathode therefore differential noise is minimized. Single-ended modes allow more sensors to be connected to the chip but they are more prone to noise pickup since the cathode is connected to a common VSS and, therefore, any external noise pickup tends to be developed mainly across the anode which will be measured as temperature noise. A filtering capacitor is recommended to decrease measurement noise especially if the external sensor is connected to the chip by a long trace. A capacitor with a value of 100 pF should be placed as close as possible to the chip pins. 3.4. Measurement Principle The circuit uses the intrinsic thermal property of a diode to measure temperature. Temperature is calculated by measuring the base-emitter voltage of a transistor. Two different currents are sourced to the diodes. The base-emitter voltage is measured in each case. With a fixed current ratio, temperature is accurately calculated by measuring the difference in the base-emitter voltage at the two currents. The excitation current I2 of 100uA is passed through the diode first. The base-emitter voltage of the transistor is measured by the ADC. The measurement is then repeated using the excitation current divided by a fixed value. This current I1 has a value of 10uA. The following equation relates the VBE difference voltage with current and temperature T where: k is the Boltzmann’s constant (1.381 x 10-23 J/K) q is the charge on the electron (1.602 x 10-19 Cb). Tabs is the absolute temperature in Kelvins. (Tabs=273.15 + T where T is the temperature in Celsius). n is the pn junction ideality factor (1.00 for an ideal diode) For a current ratio I2/I1=10 and an ideality factor n=1.010, this gives a fixed relationship between ∆VBE and temperature of 200uV/ºC. The voltage is then converted to digital with an ADC. kT abs I 2 ∆V BE = V BE2 – V BE1 = n ⋅ ------------- ln ---- q I1 3.5. Parasitic Track Resistance Cancellation The temperature measurement method described previously assumes a very low series impedance in the sensor path.With a typical ∆VBE around 200uV/ºC and the ∆I=I2-I1=90uA, 1 ohm of parasitic resistance in the sensor path gives approximately 0.45ºC of temperature error. This may result in a significant error if the external sensor is located some distance away from the chip. Track resistance cancellation schemes decrease temperature error due to high resistance in the tracks from the device to the sensors. I2 – I1 ∆T Rtrack = R Track ⋅ -----------------------200uV ⁄ C 3.5.1. Algorithmic Track Resistance Cancellation The use of the algorithmic track resistance cancellation allows automatic cancellation of resistances in series with the temperature diode by using current modulation to bias the external diode. This is done transparently to the user. This method may cancel up to 1 kOhm of series resistance. The best accuracy is in the TD range 20ºC to 70ºC. 3.5.2. 3-Point Track Resistance Cancellation The 3-point track resistance cancellation requires one additional connection to the external PN junction so that an additional current source can be used to cancel out the error voltage due to the track resistance. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 10 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor ADVANCED COMMUNICATIONS & SENSING DATASHEET Track resistances up to 1 kOhm may be cancelled. It is important that the track resistance values in the cathode or anode path of the external sensor are made equal. Care must be taken during PCB layout to match track resistances between the device and the sensor. Any resistance difference will lead to cancellation errors. In this mode, VSS is used for the current return path from the cathode. This connection must be placed close to the diode’s cathode. One port supply the current modulation to the anode and another port supply the cancellation current to the cathode. The resulting junction voltage modulation is measured between the 2 used ports. Figure 5 explains the method: I P1 V1 V2 I P2 V1 2I VSS Assume sensor Q1 is being measured in mode 2 with 3-point track resistance cancellation enabled. The PCB trace linking the device to the external sensor must be matched which means the PCB track resistance are the same. The same current is forced out of P1 and P2. The voltages developed on P1 and P2 traces are the same therefore the differential voltage seen on P1-P2 is not impacted by the track resistance. Figure 5. 3-Point Track Resistance Cancellation 3.5.3. The Kelvin (4-wire) Track Resistance Cancellation P1 P2 P3 The sensor is connected to the chip via 4 wires. Two comes from the current source (force : P3, P4) and two are used for the voltage measurement (sense : P1, P2). Sense (+) Sense (-) Force (+) The Kelvin connection avoids the measurement error caused by the voltage drop in the force path. I I P4 Sense leads are attached directly accross the external sensor. The P1 and P2 connections must be as close as possible to sensor anode and cathode respectively. Force (-) Figure 6. Kelvin (4-wire) Track Resistance Cancellation 3.6. Temperature Acquisition Sequence The SX8743 monitors up to 4 sensors (3 remote and 1 internal). Theses can be scanned in sequence to make an automatic reading of the sensors one after the other. The result of each conversion is stored in the temperature registers (see Table 6). The register RegSensor defines which sensors are scanned in the sequence. When all the sensors are selected, the sequence is the following: Int→ Ext1→ Ext2→ Ext3→Int→etc. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 11 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 3.7. Alarm VDD ALARM VSS Alarm threshold registers (RegAlarm1 and RegAlarm2) contain the value the user wishes the alarms to trip on. The alarm data format is the same as the temperature data format which is set in RegControl (bit TempOffsetMode). In other words, in binary mode alarm value is set in degree; in offset binary mode alarm is set in with an offset of 64. The alarm calculation is performed at the end of the temperature sensing cycle. Therefore, if TempOffsetMode bit or alarm values are changed, a temperature sensor measurement must be run to update the alarm outputs. Depending on the selected mode, the chip can have two alarm outputs: Alarm1 and Alarm2. If the external or internal temperature exceeds or goes under a programmed temperature threshold, the alarm is activated. Any remote or local sensor may be selected to trigger Alarm1 and Alarm2. Figure 7. Alarm Output Internal Simplified Schematics The pseudo-open drain output shown in Figure 7 requires a pull-up resistor connected to VDD. It allows connection to a GPIO, a system shutdown or other thermal management circuitry. The alarm polarity can be set active low or high and, the over or under temperature can also be set with RegAlarmSet register. Temperature Alarm threshold Hysteresis Remote or local temperature Alarm(1 or 2) To prevent alarm outputs to trig constantly when the limit temperature is reached, the RegAlarmHyst register holds a hysteresis value. The alarm remains active while the temperature is superior to the alarm threshold minus the value programmed in the RegAlarmHyst register (for a trig on over-temperature) as described on Figure 8. Over-temperature Time Figure 8. Alarm Output 3.8. Temperature Data Format Temperature output code from the internal and external sensors are made of 2 bytes. The temperature high byte has an LSB representing 1ºC and contains the integer part of the temperature while the low byte contains the fractional value with a resolution of 0.125ºC. The SX8733 has 2 temperature data formats. By default, the format is binary and the measurement range is from 0ºC to 127ºC. To extend the measurement range to -40ºC to +140ºC, an offset of 64ºC is added to the binary code. When a conversion is complete, the main temperature register and the extended temperature register are updated simultaneously. Ensure that no conversions are completed between reading the main register and the extended register, so that both registers contain the result of the same conversion. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 12 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING Temperature High Byte Temperature (ºC) Offset Binary 0001 1000 1 Temperature (ºC) Binary or Offset Binary 0000 0000 0 0000 00002 0000 0000 0100 0000 x.000 1 0000 0001 0100 0001 x.125 0000 0001 50 0011 0010 0111 0010 x.250 0000 0010 -40 or less 1. 2. 3. 4. Temperature Low Byte Binary 64 0100 0000 0000 0000 x.375 0000 0011 100 0110 0100 1010 0100 x.500 0000 0100 127 0111 1111 1011 1111 x.625 0000 0101 140 or more 0111 11113 1100 1100 x.750 0000 0110 Diode fault 1111 11114 1111 11114 x.875 0000 0111 Offset binary scale temperature values are offset by 64ºC Binary scale returns 0ºC for all temperatures <0ºC Binary scale returns 127ºC for all temperatures >127ºC A diode fault is detected when the temperature ADC hard limits at 0% or 100% pulse density 3.9. Continuous Time Vs. Single Shot The chip can be operated in 2 distinct modes: continuous time or one-shot. The one-shot mode performs one temperature measurement of all sensors selected in RegSensor. After completion, it returns to standby. In continuous temperature sampling, temperature measurements are taken at regular intervals and the result held in internal registers accessible by SMBUS. The RegADCRate register controls the sampling time period. 4. Application Note 4.1. Typical Temperature Sensing System With A SX8743 VBUS 10k 3.3V 1 10k 7 SMBus Interface 8 100nF VDD SMBDAT SMBCLK P1 4 SX8743 HOST 10k GPIO 100pF P2 3 10k ALARM1 2 ALARM2 6 MMBT3906 P3 P4 VSS 5 VSS Figure 9. SX8743 Performs Remote Temperature Measurement In Mode 8 When the remote-sensing diode is a discrete transistor, its collector and base should be connected together. An external capacitor of 100pF across the PN junction smoothes out external noise interference. The capacitor must be located very close to the pins. The ideality factor is a measure of the deviation of the thermal diode from ideal behavior. The chips are trimmed for the PNP device described in Table 5. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 13 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING A different ideality factor causes a change in the slope of the linear equation ∆VBE=f(T). n nom ∆T nfact = --------------- – 1 ⋅ ( T D + 273.15 ) n actual Gain and offset can be adjusted with the registers RegExtGain and RegExtOffset to compensate for small variations in n. Large power transistors must not be used. Part Number Manufacturer Package MMBT3906 Fairchild SOT23-3 Table 5 Recommended device 5. Power-Up Sequence and Standby Mode At power-up, the device is in one-shot mode waiting for an SMBUS command to start conversion. The measurement interval and the alarm thresholds will default to a set value at power-up but may be reconfigured to different values with SMBUS command. Between temperature measurements, to decrease power consumption, the chip will shut down into its low-power standby state with most functions disabled. 6. Serial Interface 6.1. Register Write - Combined Format Write to single register (combined format) SA SA SA 2 1 0 Slave address 0x4C WD WD WD WD WD WD WD WD 7 6 5 4 3 2 1 0 R/ W Write Data Stop by Master Register Address SA SA 4 3 Slave ACK driven by SX8733 R/ W Slave address 0x4C SA SA 6 5 Slave ACK driven by SX8733 RA RA RA RA RA RA RA RA 7 6 5 4 3 2 1 0 Restart by Master SA SA 1 0 Slave ACK driven by SX8733 SA SA 3 2 Slave ACK driven by SX8733 Start by Master SA SA SA 6 5 4 6.2. Register Write - Direct Format Write to single register (direct format) SA2 SA1 Slave address 0x4C ACS Revision 2.91/February 2010 ©2010 Semtech Corp. SA0 RA7 R/W RA6 RA5 RA4 RA3 RA2 Register Address Page 14 RA1 RA0 WD7 WD6 WD5 WD4 WD3 WD2 WD1 WD0 Write Data Stop by Master SA3 Slave ACK driven by SX8733 SA4 Slave ACK driven by SX8733 SA5 Slave ACK driven by SX8733 Start by Master SA6 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 6.3. Register Read - Combined Format Read from single register (combined format) Register Address SA 4 SA 3 SA 2 SA 1 SA 0 RD RD RD RD RD RD RD RD 7 6 5 4 3 2 1 0 R/ W Slave address 0x4C Read data driven by SX8733 Stop by Master R/ W Slave address 0x4C SA SA 6 5 NACK driven by master RA RA RA RA RA RA RA RA 7 6 5 4 3 2 1 0 Slave ACK driven by SX8733 SA 0 Restart by Master SA SA 2 1 Slave ACK driven by SX8733 SA SA 4 3 Slave ACK driven by SX8733 Start by Master SA SA 6 5 6.4. Register Read - Direct Format Read from single register (short format) Read data driven by SX8733 Stop by Master R/ W Slave address 0x4C NACK driven by master RD RD RD RD RD RD RD RD 7 6 5 4 3 2 1 0 Slave ACK driven by SX8733 Start by Master SA SA SA SA SA SA SA 6 5 4 3 2 1 0 6.5. Soft Reset The user may reset the circuit via SMBus by sending a general call address at slave address 0x00 followed by the reset command 0x06. In other words, as illustrated in the figure below, a soft reset can be generated by sending a command at slave address 0x00 (rather than the regular 0x4C slave address) to IC register address 0x06 with any data (0xXX). The soft reset command sets the circuit and registers in the same state as after a power-up. Reset SA2 SA1 Slave address 0x00 ACS Revision 2.91/February 2010 ©2010 Semtech Corp. SA0 RA7 R/W RA6 RA5 RA4 RA3 RA2 Register Address 0x06 Page 15 RA1 RA0 WD7 WD6 WD5 WD4 WD3 WD2 WD1 WD0 Write Data 0xXX Stop by Master SA3 Slave ACK driven by SX8733 SA4 Slave ACK driven by SX8733 SA5 Slave ACK driven by SX8733 Start by Master SA6 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor ADVANCED COMMUNICATIONS & SENSING DATASHEET 7. Register / Memory Map Each register is described in the following register memory map. These are identified by a Register Name and corresponding hexadecimal register address. 7.1. Memory Map 0x00 0x06 0x07 0x20 0x21 RegConfig RegExtGain RegExtOffset RegDeviceID RegDeviceVersion 0x22 0x23 0x24 RegSensor RegAlarm1 RegAlarm2 0x25 RegAlarmSet 0x26 0x27 RegAlarmHyst RegADCRate 0x28 RegIntTempMSB Identification Registers Determines the chip variant and the communication interface (I2C or SMBus) Sets the calibration gain for remote temperature measurement Sets the calibration offset for remote temperature measurement Read-only ID = 0x33 Read-only circuit revision Configuration Registers Defines which sensors are scanned in sequence Alarm1 threshold Alarm2 threshold Defines which sensors control alarms 1 and 2, and whether over-/under- temperature triggers for each alarm Alarm hysteresis Temperature conversion rate Temperature Registers TJ temperature reading for internal sensor, integer part, LSB = 1ºC 0x29 RegIntTempLSB TJ temperature reading for internal sensor, fractional part, LSB = 0.125ºC 0x2A RegExtTemp1MSB TD1 temperature reading for external sensor 1, integer part, LSB = 1ºC 0x2B RegExtTemp1LSB TD1 temperature reading for external sensor 1, fractional part, LSB = 0.125ºC 0x2C RegExtTemp2MSB TD2 temperature reading for external sensor 2, integer part, LSB = 1ºC 0x2D RegExtTemp2LSB TD2 temperature reading for external sensor 2, fractional part, LSB = 0.125ºC 0x2E RegExtTemp3MSB TD3 temperature reading for external sensor 3, integer part, LSB = 1ºC 0x2F RegExtTemp3LSB TD3 temperature reading for external sensor 3, fractional part, LSB = 0.125ºC 0x30 0x31 RegControl RegStatus General Registers General Control register General Status register Table 6 Memory map 7.2. Registers Description Addr: 0x00 RegConfig Bits Name Mode Reset 7:6 Reserved rw 00 5 SetInterface rw 1 4:0 Mode rw 00000 ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Description Write to 00 Select between I2C or SMBus interface 0: I2C (Time Out Disabled) 1: SMBUS Select the configuration mode 00000: Mode 0 00001: Mode 1 ... 10010: Mode 18 10100: Mode 20 Page 16 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor ADVANCED COMMUNICATIONS & SENSING DATASHEET Addr: 0x06 RegExtGain Bits Name Mode Reset Description 7:6 Reserved rw 00 5:0 ExtGain rw xxxxxx Bits Name Mode Reset 7:0 ExtOffset rw xxxxxxxx Bits Name Mode Reset Description 7:4 Reserved rw 0000 Write to 0000 3 SelExt3 rw 0 2 SelExt2 rw 0 1 SelExt1 rw 0 0 SelInt rw 1 Bits Name Mode Reset 7:0 Threshold1 rw 01000000 Bits Name Mode Reset 7:0 Threshold2 rw 01000000 Bits Name Mode Reset 7 Reserved rw 0 Write to 00 Gain adjustement for external temperature measurement Do not write to avoid production calibration altering Addr: 0x07 RegExtOffset Description Offset adjustement for external temperature measurement. Do not write to avoid production calibration altering Addr: 0x22 RegSensor 0: External sensor 3 not in temp. scan sequence 1: Enable external sensor 3 to be in temp. scan sequence 0: External sensor 2 not in temp. scan sequence 1: Enable external sensor 2 to be in temp. scan sequence 0: External sensor 1 not in temp. scan sequence 1: Enable external sensor 1 to be in temp. scan sequence 0: Internal sensor not in temp. scan sequence 1: Enable internal sensor to be in temp. scan sequence Addr: 0x23 RegAlarm1 Description Alarm1 temperature threshold. The data is coherent with the binary and offset format. 1LSB=1ºC Addr: 0x24 RegAlarm2 Description Alarm2 temperature threshold. The data is coherent with the binary and offset format. 1LSB=1ºC Addr: 0x25 RegAlarmSet 6 AlarmPolarity rw 0 5 Direction2 rw 0 4 Direction1 rw 0 Description Write to 0 0: Alarm1, Alarm2 outputs active high 1: Alarm1, Alarm2 outputs active low 0: Trigger on over-temperature for Alarm2 1: Trigger on under-temperature for Alarm2 0: Trigger on over-temperature for Alarm1 1: Trigger on under-temperature for Alarm1 3:2 Select2 rw 00 00: External 1 sensor controls Alarm2 01: External 2 sensor controls Alarm2 10: External 3 sensor controls Alarm2 11: Internal sensor controls Alarm2 1:0 Select1 rw 11 00: External 1 sensor controls Alarm1 01: External 2 sensor controls Alarm1 10: External 3 sensor controls Alarm1 11: Internal sensor controls Alarm1 Bits Name Mode Reset Description 7:4 Hysteresis2 rw 0100 Defines Alarm2 hysteresis with 1ºC resolution. (0 to 15ºC) 3:0 Hysteresis1 rw 0100 Defines Alarm1 hysteresis with 1ºC resolution. (0 to 15ºC) Addr: 0x26 RegAlarmHyst ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 17 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor ADVANCED COMMUNICATIONS & SENSING DATASHEET Addr: 0x27 RegADCRate Bits Name Mode Reset Description 7:5 Reserved rw 000 Write to 000 4 OneShot rw 0 3 Regular rw 0 2:0 Rate rw 0: Standby 1: Perform one temperature measurement 0: Disable continuous temperature sampling 1: Enable continuous temperature sampling Temperature sampling rate 000: 0.1 second (continuous sampling) 001: 0.25 second 010: 0.50 second 011: 1 second 100: 2 seconds 101: 4 seconds 110: 8 seconds 111: 16 seconds 000 Addr: 0x28 RegIntTempMSB Bits Name Mode Reset 7:0 IntTempMSB r 00000000 Bits Name Mode Reset 7:3 Reserved r 00000 2:0 IntTempLSB r 000 Bits Name Mode Reset 7:0 ExtTemp1MSB r 00000000 Bits Name Mode Reset 7:3 Reserved r 00000 2:0 ExtTemp1LSB r 000 Bits Name Mode Reset 7:0 ExtTemp2MSB r 00000000 Description MSB of Internal Temperature TJ. LSB=1ºC Addr: 0x29 RegIntTempLSB Description LSB of Internal Temperature TJ. LSB=0.125ºC Addr: 0x2A RegExtTemp1MSB Description MSB of External Temperature TD1. LSB=1ºC Addr: 0x2B RegExtTemp1LSB Description LSB of External Temperature TD1. LSB=0.125ºC Addr: 0x2C RegExtTemp2MSB Description MSB of External Temperature TD2. LSB=1ºC Addr: 0x2D RegExtTemp2LSB Bits Name Mode Reset 7:3 Reserved r 00000 Description 2:0 ExtTemp2LSB r 000 Bits Name Mode Reset 7:0 ExtTemp3MSB r 00000000 Bits Name Mode Reset 7:3 Reserved r 00000 2:0 ExtTemp3LSB r 000 LSB of External Temperature TD2. LSB=0.125ºC Addr: 0x2E RegExtTemp3MSB Description MSB of External Temperature TD3. LSB=1ºC Addr: 0x2F RegExtTemp3LSB ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Description LSB of External Temperature TD3. LSB=0.125ºC Page 18 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor ADVANCED COMMUNICATIONS & SENSING DATASHEET Addr: 0x30 RegControl Bits Name Mode Reset 7:5 Reserved rw 000 Description Write to 000 0: No clock stretching 1: Enable clock stretching 0: Binary mode 1: Offset binary mode 0: Disable 3-point track resistance cancellation 1: Enable 3-point track resistance cancellation 0: Disable algorithmic track cancellation 1: Enable algorithmic track cancellation 4 ClockStretching rw 1 3 TempOffsetMode rw 0 2 Point3 rw 0 1 Algo rw 0 0 Bit0 rw 1 Bits Name Mode Reset Description 7:4 Reserved w 0000 Write to 0000 3 ExtTemp3End 0 1: External temperature 3 conversion complete 2 ExtTemp2End w1 w1 0 1: External temperature 2 conversion complete 1 ExtTemp1End w 1 0 1: External temperature 1 conversion complete 0 IntTempEnd w 1 0 1: Internal temperature conversion complete This bit must be set to 1 Addr: 0x31 RegStatus 1. write logic 1 to register bit to clear ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 19 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 8. Packaging Information 8.1. MLPD-W6-EP2 Package Outline Drawing A D DIMENSIONS B DIM A A1 A2 b D E D1 E1 e L N aaa bbb E PIN 1 INDICATOR (LASER MARK) A aaa C A1 1 SEATING PLANE C A2 D1 MILLIMETERS MIN NOM MAX 0.70 0.75 0.80 0.00 0.02 0.05 (0.20) 0.30 0.40 0.45 2.90 3.00 3.10 2.90 3.00 3.10 2.23 2.38 2.48 1.50 1.65 1.75 0.95 BSC 0.30 0.40 0.50 6 0.08 0.10 2 LxN E/2 E1 N bxN e bbb C A B D/2 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS TERMINALS. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 20 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 8.2. MLPD-W6-EP2 Land Pattern Drawing R K DIMENSIONS DIM (C) G H C G H K P R X Y Z Z Y X P MILLIMETERS (2.95) 2.20 1.65 2.38 0.95 0.225 0.45 0.75 3.70 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 3. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 21 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 8.3. Package Outline Drawing: MSOP-8 DIMENSIONS INCHES MILLIMETERS DIM MIN NOM MAX MIN NOM MAX e/2 A A A1 A2 b c D E1 E e L L1 N 01 aaa bbb ccc D N 2X E/2 E1 E PIN 1 INDICATOR ccc C 2X N/2 TIPS 1 2 e B aaa C D C 1.10 0.00 0.15 0.75 0.95 0.22 0.38 0.08 0.23 2.90 3.00 3.10 2.90 3.00 3.10 4.90 BSC 0.65 BSC 0.40 0.60 0.80 (.95) 8 0° 8° 0.10 0.13 0.25 H A2 SEATING PLANE .043 .000 .006 .030 .037 .009 .015 .003 .009 .114 .118 .122 .114 .118 .122 .193 BSC .026 BSC .016 .024 .032 (.037) 8 0° 8° .004 .005 .010 A c GAGE PLANE A1 bxN bbb C A-B D 0.25 L DETAIL SIDE VIEW 01 (L1) SEE DETAIL A A NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. 4. REFERENCE JEDEC STD MO-187, VARIATION AA. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 22 www.semtech.com SX8733/SX8743/SX8744 Digital temperature sensor DATASHEET ADVANCED COMMUNICATIONS & SENSING 8.4. Land Pattern Drawing: MSOP-8 X DIM (C) G Y Z C G P X Y Z DIMENSIONS INCHES MILLIMETERS (.161) .098 .026 .016 .063 .224 (4.10) 2.50 0.65 0.40 1.60 5.70 P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. ACS Revision 2.91/February 2010 ©2010 Semtech Corp. Page 23 www.semtech.com SX8733/SX8743/SX8744 DATASHEET ADVANCED COMMUNICATIONS & SENSING © Semtech 2009* All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. 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