芯美电子 Preliminary EUT1086 ±1°C, SMBus-Compatible Remote/Local Temperature Sensors with Overtemperature Alarms DESCRIPTION FEATURES The EUT1086 is precise, two channel digital temperature sensors. Each accurately measures the temperature of its own die and one remote PN junction, and reports the temperature in digital form on a 2-wire serial interface. The remote junction can be a diode-connected transistor like the low-cost 2N3904 NPN type or 2N3906 PNP type. The remote junction can also be a common-collector PNP, such as a substrate PNP of a microprocessor. z Dual Channel: Measures Remote and Local Temperature z 11-Bit, 0.125°C Resolution z High Accuracy ±1°C (max) from +60°C to +100°C (Remote) z Programmable Under/Overtemperature Alarms The 2-wire serial interface accepts standard System Management Bus (SMBus) commands such as Write Byte, Read Byte, Send Byte, and Receive Byte to read the temperature data and program the alarm thresholds and conversion rate. The EUT1086 can function autonomously with a programmable conversion rate, which allows the control of supply current and temperature update rate to match system needs. For conversion rates of 4Hz or less, the temperature is represented in extended mode as 10 bits + sign with a resolution of 0.125°C. When the conversion rate is faster than 4Hz, output data is 7 bits + sign with a resolution of 1°C. The EUT1086 also includes an SMBus timeout feature to enhance system reliability. z Programmable Conversion Rate (0.0625Hz to 16Hz) z SMBus/I2C-Compatible Interface z Two Alarm Outputs: ALERT and OVERT z SOP-8 Package Available z RoHS Compliant and 100% Lead (Pb)-Free APPLICATIONS z Notebook Computers z Workstations Remote accuracy is ±1°C between +60°C and +100°C with no calibration needed. The EUT1086 measures temperatures from 0°C to +125°C. Typical Application Circuit DS1086 Ver0.4 May. 2007 1 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 Preliminary EUT1086 Pin Configurations Part Number Pin Configurations EUT1086 SOP-8 Pin Description SOP-8 NAME DESCRIPTION 1 VCC Supply Voltage Input, +3V to +5.5V. Bypass to GND with a 0.1µF capacitor. A 200Ω series resistor is recommended but not required for additional noise filtering. See Typical Application Circuit. 2 DXP Combined Remote-Diode Current Source and A/D Positive Input for Remote-Diode Channel. DO NOT LEAVE DXP FLOATING; connect DXP to DXN if no remote diode is used. Place a 2200pF capacitor between DXP and DXN for noise filtering. 3 DXN 4 OVERT 5 GND 6 ALERT 7 SMBDATA 8 SMBCLK DS1086 Ver0.4 May. 2007 Combined Remote-Diode Current Sink and A/D Negative Input. DXN is internally biased to one diode drop above ground. Overtemperature Active-Low Output, Open-Drain. Output is logic low only when temperature is above the software programmed threshold. Ground SMBus Alert (Interrupt) Active-Low Output, Open-Drain. Asserts when temperature exceeds user-set limits (high or low temperature). Stays asserted until acknowledged by either reading the Status register or by successfully responding to an Alert Response address. See ALERT Interrupts. SMBus Serial-Data Input/Output, Open-Drain SMBus Serial-Clock Input 2 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 Preliminary EUT1086 Ordering Information Order Number Package Type EUT1086DIR1 SOP-8 Marking Operating Temperature range xxxxx EUT1086 A -55 °C to 125°C EUT1086- □ □ □ □ Lead Free Code 1: Lead Free 0: Lead Packing R: Tape& Reel Operating temperature range I: Industry Standard Package Type D: SOP Block Diagram DS1086 Ver0.4 May. 2007 3 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 EUT1086 Preliminary Absolute Maximum Ratings All Voltages Referenced to GND Vcc----------------------------------------------------------------------- -0.3V to +6V DXP------------------------------------------------------------------------------------------------------ -0.3V to VCC + 0.3V DXN------------------------------------------------------------------------------------------------------------ -0.3V to +0.8V SMBCLK, SMBDATA, ALERT , OVERT -------------------------------------------------------------- -0.3V to +6V SMBDATA, ALERT , OVERT Current -------------------------------------------------------------- -1mA to +50mA DXN Current ------------------------------------------------------------------------------------------------------------ ±1mA Thermal Resistance θJA (SOP-8) ------------------------------------------------------------------------------------------------------------ 42.3°C/W Junction Temperature------------------------------------------------------------------------------------------------- +150°C Storage Temperature Range------------------------------------------------------------------------------- -65°C to +150°C Lead Temperature (soldering, 10s) ----------------------------------------------------------------------------------+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability Electrical Characteristics (Circuit of Typical Operating Circuit, VCC = +3.0V to +5.5V, TA = 0°C to +125°C, unless otherwise specified. Typical values are at VCC = +3.3V and TA = +25°C.) Symbol Parameter Conditions Temperature Resolution, Legacy Mode Local Temperature Error Line Regulation VCC UVLO Max. Bits °C Bits TRJ = +60°C to +100°C, VCC = +3.3V (Note 1) -1.0 +1.0 TRJ = 0°C to +100°C, VCC = +3.3V (Note 1) -3.0 +3.0 TRJ = 0°C to +125°C, VCC = +3.3V (Note 1) -5.0 +5.0 TA = +60°C to +100°C, VCC = +3.3V -2.0 +2.0 TA = 0°C to +100°C, VCC = +3.3V -3.0 +3.0 TA = 0°C to +125°C, VCC = +3.3V -5.0 +5.0 2.60 2.80 1.5 5.5 V 2.95 V 2.0 mV 2.5 90 SMBus static °C m°C/V 90 VCC, falling edge °C 0.6 0.2 3.0 Falling edge of VCC disables ADC Units °C 11 3.0V ≤ VCC ≤ 5.5V Undervoltage Lockout Threshold Undervoltage Lockout Hysteresis Power-On Reset (POR) Threshold POR Threshold Hysteresis DS1086 Ver0.4 May. 2007 Typ. 0.125 Supply Voltage Range Standby Supply Current Min. 1 8 Temperature Resolution, Extended Mode Remote Temperature Error EUT1086 3 4 联系电话：１５９９９６４４５７９ ８３１５１７１５ V mV 10 µA 芯美电子 EUT1086 Preliminary Electrical Characteristics (Continued) (Circuit of Typical Operating Circuit, VCC = +3.0V to +5.5V, TA = 0°C to +125°C, unless otherwise specified. Typical values are at VCC = +3.3V and TA = +25°C.) Symbol tCONV Parameter Conditions Operating Current During conversion Conversion Time From stop bit to conversion completed (Note 4) EUT1086 Min. 95 Max. 0.5 1.0 mA 125 156 ms 25 % 100 nA Conversion Timing Error DXP and DXN Leakage Current IRJ In standby mode Remote-Diode Source Current Units Typ. High level 80 100 120 Low level 8 10 12 VOL = 0.4V 1 VOL = 0.6V 6 µA ALERT , OVERT Output Low Sink Current Output High Leakage Current mA VOH = 5.5V 1 µA 0.3VCC V SMBus-COMPATIBLE INTERFACE (SMBCLK, SMBDATA) VIL Logic Input Low Voltage VIH Logic Input High Voltage ILEAK 0.7VCC Input Leakage Current VIN = GND or VCC IOL Output Low Sin Current VOL = 0.6V CIN Input Capacitance V ±1 6 µA mA 5 pF SMBus-COMPATIBLE TIMING (Note 4) fSCL tBUF tSU:STA Serial Clock Frequency Bus Free Time Between STOP and START Condition START Condition Setup Time Repeat START Condition Setup Time (Note 5) 100 kHz 4.7 µs 4.7 µs 90% to 90% 50 ns tHD:STA START Condition Hold Time 10% of SMBDATA to 90% of SMBCLK 4 µs tSU:STO STOP Condition Setup Time 90% of SMBCLK to 90% of SMBDATA 4 µs DS1086 Ver0.4 May. 2007 5 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 EUT1086 Preliminary Electrical Characteristics (Continued) (Circuit of Typical Operating Circuit, VCC = +3.0V to +5.5V, TA = 0°C to +125°C, unless otherwise specified. Typical values are at VCC = +3.3V and TA = +25°C.) Symbol tLOW tHIGH tHD:DAT Parameter Clock Low Period Clock High Period Data Setup Time Conditions 10% to 10% 90% to 90% (Note 6) EUT1086 Min. 4.7 4 0 Typ. Max. Units µs µs µs tR Receive SCL/SDA Rise Time 1 µs tF Receive SCL/SDA Fall Time 300 ns tSP Pulse Width of Spike Suppressed 50 ns 45 ms SMBus Timeout 0 SMBDATA low period for interface reset 25 37 Note 1: TA = +25°C to +85°C. Note 2: If both the local and the remote junction are below TA = -20°C, then VCC > 3.15V. Note 3: For conversion rates of 4Hz or slower, the conversion time doubles. Note 4: Timing specifications guaranteed by design. Note 5: The serial interface resets when SMBCLK is low for more than tTIMEOUT. Note 6: A transition must internally provide at least a hold time to bridge the undefined region (300ns max) of SMBCLK's falling edge. DS1086 Ver0.4 May. 2007 6 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 EUT1086 Preliminary Typical Operating Characteristics (VCC=+3.3V, TA = +25°C, unless otherwise noted.) Remote Temperature Error VS Remote-diode Temperature Standby Supply Current VS Supply Voltage Temperature Error(℃) Standby Supply Current(μA) 3.5 3 2.5 2 1.5 1 0.5 0 3 3.5 4 4.5 5 Supply Voltage(V) 5.5 Temperature Error(℃) Temperature Error(℃) 3 2 1 0 -1 -2 20 45 70 2 1 0 -1 -2 -3 -55 -30 -5 20 45 70 95 120 Temperature(℃) Local Temperature Error VS DIE Temperature -3 -55 -30 -5 3 Temperature Error VS Power-Supply Noise Frequency 1 0 -1 -2 -3 10K 95 120 100K 1M 10M Frequency(Hz) Temperature(℃) Temperature Error VS Differential-Mode Noise Frequency 1 Temperature Error(℃) Temperature Error(℃) Temperature Error VS Common-Mode Noise Frequency 0 -1 -2 -3 0.01K 1K 100K 10M 1G Frequency(Hz) DS1086 Ver0.4 May. 2007 1 0.5 0 -0.5 -1 -1.5 -2 -2.5 -3 10K 100K 1M 10M Frequency(Hz) 100M 7 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 Preliminary Detailed Description EUT1086 Remote-Diode Selection The EUT1086 is temperature sensor designed to work in conjunction with a microprocessor or other intelligence in thermostatic, process-control, or monitoring applications. Communication with the EUT1086 occurs through the SMBus serial interface and dedicated alert pins. The overtemperature alarms ( ALERT ) is asserted if its software programmed temperature thresholds are exceeded. OVERT can be connected to fans, a system shutdown, or other thermal management circuitry. The EUT1086 converts temperatures to digital data either at a programmed rate or a single conversion. Conversions have a 0.125°C resolution (extended resolution) or 1°C resolution (legacy resolution). Extended resolution represents temperature as 10 bits + sign bit and is available for autonomous conversions that are 4Hz and slower and single-shot conversions. Legacy resolution represents temperature as 7 bits + sign bit and allows for faster autonomous conversion rates of 8Hz and 16Hz. The EUT1086 can directly measure the die temperature of CPUs and other ICs that have on-board temperaturesensing diodes (see Typical Application Circuit) or they can measure the temperature of a discrete diode-connected transistor. The type of remote diode used is set by bit 5 of the Configuration Byte. If bit 5 is set to zero, the remote sensor is a diode-connected transistor, and if bit 5 is set to 1, the remote sensor is a substrate or common collector PNP transistor. For best accuracy, the discrete transistor should be a small-signal device with its collector and base connected together. Accuracy has been experimentally verified for all the devices listed in Table 1. Table 1. Remote-Sensor Transistor Manufacturer Model Number Central Semiconductor (USA) CMPT3904 Fairchild Semiconductor (USA) 2N3904, 2N3906 On Semiconductor (USA) 2N3904, 2N3906 Rohm Semiconductor (USA) SST3904 Samsung (Korea) KST3904-TF Siemens (Germany) SMBT3904 Zetex (England) FMMT3904CT-ND Note: Transistors must be diode connected (base shorted to collector) ADC and Multiplexer The averaging ADC integrates over a 60ms period (each channel, typically, in the 7-bit + sign legacy mode). Using an averaging ADC attains excellent noise rejection. The multiplexer automatically steers bias currents through the remote and local diodes. The ADC and associated circuitry measure each diode’s forward voltage and compute the temperature based on this voltage. If the remote channel is not used, connect DXP to DXN. Do not leave DXP and DXN unconnected. When a conversion is initiated, both channels are converted whether they are used or not. The DXN input is biased at one VBE above ground by an internal diode to set up the ADC inputs for a differential measurement. Resistance in series with the remote diode causes about +1/2°C error per ohm. The transistor must be a small-signal type with a relatively high forward voltage; otherwise, the A/D input voltage range can be violated. The forward voltage at the highest expected temperature must be greater than 0.25V at 10µA, and at the lowest expected temperature, forward voltage must be less than 0.95V at 100µA. Large power transistors must not be used. Also, ensure that the base resistance is less than 100Ω. Tight specifications for forward current gain (50<β<150, for example) indicate that the manufacturer has good process controls and that the devices have consistent VBE characteristics. A/D Conversion Sequence A conversion sequence consists of a local temperature measurement and a remote temperature measurement. Each time a conversion begins, whether initiated automatically in the free-running autoconvert mode (RUN/STOP = 0) or by writing a “one-shot” command, both channels are converted, and the results of both measurements are available after the end of conversion. A BUSY status bit in the Status register shows that the device is actually performing a new conversion. The results of the previous conversion sequence are still available when the ADC is busy. DS1086 Ver0.4 May. 2007 8 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 Preliminary EUT1086 Thermal Mass and Self-Heating PC Board Layout When sensing local temperature, these devices are intended to measure the temperature of the PC board to which they are soldered. The leads provide a good thermal path between the PC board traces and the die. Thermal conductivity between the die and the ambient air is poor by comparison, making air temperature measurements impractical. Because the thermal mass of the PC board is far greater than that of the EUT1086, the devices follow temperature changes on the PC board with little or no perceivable delay. When measuring the temperature of a CPU or other IC with an on-chip sense junction, thermal mass has virtually no effect; the measured temperature of the junction tracks the actual temperature within a conversion cycle. When measuring temperature with discrete remote sensors, smaller packages (i.e., a SOT23) yield the best thermal response times. Take care to account for thermal gradients between the heat source and the sensor, and ensure that stray air currents across the sensor package do not interfere with measurement accuracy. Self-heating does not significantly affect measurement accuracy. Remote-sensor self-heating due to the diode current source is negligible. For the local diode, the worst-case error occurs when autoconverting at the fastest rate and simultaneously sinking maximum current at the ALERT output. For example, with VCC = +5.0V, a 16Hz Follow these guidelines to reduce the measurement error of the temperature sensors: 1) Place the EUT1086 as close as is practical to the remote diode. In noisy environments, such as a computer motherboard, this distance can be 4in to 8in (typ). This length can be increased if the worst noise sources are avoided. Noise sources include CRTs, clock generators, memory buses, and ISA/PCI buses. 2) Do not route the DXP-DXN lines next to the deflection coils of a CRT. Also, do not route the traces across fast digital signals, which can easily introduce +30°C error, even with good filtering. 3) Route the DXP and DXN traces in parallel and in close proximity to each other, away from any higher voltage traces, such as +12VDC. Leakage currents from PC board contamination must be dealt with carefully since a 20MΩleakage path from DXP to ground causes about +1°C error. If high-voltage traces are unavoidable, connect guard traces to GND on either side of the DXP-DXN traces (Figure 1). conversion rate and ALERT sinking 1mA, the typical power dissipation is: VCC × 450 µA + 0.4V × 1mA = 2.65mW θJ-A for the 8-pin SO package is about +170°C/W, so assuming no copper PC board heat sinking, the resulting temperature rise is: Figure 1. Recommended DXP-DXN PC Traces 4) Route through as few vias and crossunders as possible to minimize copper/solder thermocouple effects. 5) When introducing a thermocouple, make sure that both the DXP and the DXN paths have matching thermocouples. A copper-solder thermocouple exhibits 3µV/°C, and it takes about 200µV of voltage error at DXP-DXN to cause a +1°C measurement error. Adding a few thermocouples causes a negligible error. 6) Use wide traces. Narrow traces are more inductive and tend to pick up radiated noise. The 10mil widths and spacings that are recommended in Figure 1 are not absolutely necessary, as they offer only a minor improvement in leakage and noise over narrow traces. Use wider traces when practical. ∆T = 2.65mW × 170 o C / W = +0.45 o C Even under these engineered circumstances, it is difficult to introduce significant self-heating errors. ADC Noise Filtering The integrating ADC used has good noise rejection for low-frequency signals such as 60Hz/120Hz power-supply hum. In noisy environments, high-frequency noise reduction is needed for high-accuracy remote measurements. The noise can be reduced with careful PC board layout and proper external noise filtering. High-frequency EMI is best filtered at DXP and DXN with an external 2200pF capacitor. Larger capacitor values can be used for added filtering, but do not exceed 3300pF because it can introduce errors due to the rise time of the switched current source. DS1086 Ver0.4 May. 2007 7) Add a 200Ωresistor in series with VCC for best noise filtering (see Typical Application Circuit). 9 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 Preliminary EUT1086 When the conversion rate is 4Hz or less, the first 8 bits of temperature data can be read from the Read Internal Temperature (00h) and Read External Temperature (01h) registers, the same as for faster conversion rates. An additional 3 bits can be read from the Read External Extended Temperature (10h) and Read Internal Extended Temperature (11h) registers, which extends the data to 10 bits + sign and the resolution to +0.125°C per LSB (Table 3). Twisted-Pair and Shielded Cables Use a twisted-pair cable to connect the remote sensor for remote-sensor distances longer than 8in or in very noisy environments. Twisted-pair cable lengths can be between 6ft and 12ft before noise introduces excessive errors. For longer distances, the best solution is a shielded twisted pair like that used for audio microphones. For example, Belden #8451 works well for distances up to 100ft in a noisy environment. At the device, connect the twisted pair to DXP and DXN and the shield to GND. Leave the shield unconnected at the remote sensor. For very long cable runs, the cable’s parasitic capacitance often provides noise filtering, so the 2200Pf capacitor can often be removed or reduced in value. Cable resistance also affects remote-sensor accuracy. For every 1Ωof series resistance, the error is approximately +1/2°C. Table 3. Extended Resolution Register Fractional Contents of Temperature Extended Register 0.000 000X XXXX 0.125 001X XXXX 0.250 010X XXXX 0.375 011X XXXX 0.500 100X XXXX 0.625 101X XXXX 0.750 110X XXXX 0.875 111X XXXX SMBus Digital Interface From a software perspective, the EUT1086 appears as a series of 8-bit registers that contain temperature data, alarm threshold values, and control bits. A standard SMBuscompatible 2-wire serial interface is used to read Temperature Data and Write Control bits and alarm threshold data. The device responds to the same SMBus slave address for access to all functions. The EUT1086 employs four standard SMBus protocols: Write Byte, Read Byte, Send Byte, and Receive Byte (Figures 2, 3, and 4). The shorter Receive Byte protocol allows quicker transfers, provided that the correct data register was previously selected by a Read Byte instruction. Use caution with the shorter protocols in multimaster systems, since a second master could overwrite the command byte without informing the first master. When a conversion is complete, the Main register and the Extended register are updated almost simultaneously. Ensure that no conversions are completed between reading the Main and Extended registers so that when data that is read, both registers contain the result of the same conversion. To ensure valid extended data, read extended resolution temperature data using one of the following approaches: 1) Put the EUT1086 into standby mode by setting bit 6 of the Configuration register to 1. Initiate a one-shot conversion using Command Byte 0Fh. When this conversion is complete, read the contents of the Temperature Data registers. 2) If the EUT1086 is in run mode, read the Status register. If a conversion is in progress, the BUSY bit is set to 1. Wait for the conversion to complete as indicated by the BUSY bit being set to 0, and then read the Temperature Data registers. Note that the power-on reset sets the conversion rate to 16Hz, so no extended data is valid without reducing the conversion rate to 4Hz or less. Table 2. Data Format Temp (℃) Digital output 130.00 0 111 1111 127.00 0 111 1111 126.00 0 111 1111 25 0 001 1001 0.00 0 000 0000 -1 1 111 1111 -25 1 110 0111 -55 1 100 1001 Diode Fault 1 000 0000 (Short or Open) When the conversion rate is greater than 4Hz, temperature data can be read from the Read Internal Temperature (00h) and Read External Temperature (01h) registers. The temperature data format is 7 bits + sign in two's complement form for each channel, with the LSB representing 1°C (Table 2). The MSB is transmitted first. DS1086 Ver0.4 May. 2007 10 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 Preliminary EUT1086 Figure 2. SMBus Protocols Figure 3. SMBus Write Timing Diagram Figure 4. SMBus Read Timing Diagram DS1086 Ver0.4 May. 2007 11 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 Preliminary slave address (0001100). Then, any slave device that generated an interrupt attempts to identify itself by putting its own address on the bus (Table 8). The Alert Response can activate several different slave devices simultaneously, similar to the I2C General Call. If more than one slave attempts to respond, bus arbitration rules apply, and the device with the lower address code wins. The losing device does not generate an acknowledge and continues to hold the ALERT line low until cleared. (The conditions for clearing an alert vary, depending on the type of slave device.) Successful completion of the Alert Response protocol clears the interrupt latch, provided the condition that caused the alert no longer exists. If the condition still exists, the device reasserts the ALERT interrupt at the end of the next conversion. Diode Fault Alarm There is a continuity fault detector at DXP that detects an open circuit between DXP and DXN, or a DXP short to VCC, GND, or DXN. If an open or short circuit exists, the external temperature register is loaded with 1000 0000. Additionally, if the fault is an open circuit, bit 2 (OPEN) of the status byte is set to 1 and the ALERT condition is activated at the end of the conversion. Immediately after POR, the Status register indicates that no fault is present until the end of the first conversion. Alarm Threshold Registers Four registers store ALERT threshold values—one high-temperature (THIGH) and one low-temperature (TLOW) register each for the local and remote channels. If either measured temperature equals or exceeds the corresponding ALERT threshold value, the ALERT output is asserted. OVERT Overtemperature Alarm/Warning Outputs OVERT is asserted when the temperature rises to a value programmed in the appropriate threshold register. It is deasserted when the temperature drops below this threshold minus the hysteresis. An OVERT output can be used to activate a cooling fan, send a warning, or trigger a system shutdown to prevent component damage. The HYST byte sets the amount of hysteresis for both OVERT outputs. The data format for the HYST byte is the same for the other temperature registers (Table 2). The POR state of both ALERT THIGH registers is 0100 0110 or +70°C and the POR state of TLOW registers is 1100 1001 or -55°C. Four additional registers store remote and local alarm threshold data corresponding to the OVERT outputs. The values stored in these registers are high-temperature thresholds. If any one of the measured temperatures equals or exceeds the corresponding alarm threshold value, an OVERT output is asserted. The POR state of the OVERT threshold is 0101 0101 or +85°C. Command Byte Functions The 8-bit Command Byte register (Table 4) is the master index that points to the various other registers within the EUT1086. This register’s POR state is 0000 0000, so a Receive Byte transmission (a protocol that lacks the command byte) occurring immediately after POR returns the current local temperature data. ALERT Interrupts An ALERT interrupt occurs when the internal or external temperature reading exceeds a high or low temperature limit (user programmed) or when the remote diode is disconnected (for continuity fault detection). The ALERT interrupt output signal is latched and can be cleared only by either reading the Status register or by successfully responding to an Alert Response address. In both cases, the alert is cleared even if the fault condition still exists, but is reasserted at the end of the next conversion. The interrupt does not halt automatic conversions. The interrupt output pin is open-drain so that multiple devices can share a common interrupt line. The interrupt rate never exceeds the conversion rate. One-Shot The one-shot command immediately forces a new conversion cycle to begin. If the one-shot command is received when the EUT1086 is in software standby mode ( RUN /STOP bit = 1), a new conversion is begun, after which the device returns to standby mode. If a conversion is in progress when a one-shot command is received, the command is ignored. If a one-shot command is received in autoconvert mode （ RUN /STOP bit = 0 ） between conversions, a new conversion begins, the conversion rate timer is reset, and the next automatic conversion takes place after a full delay elapses. Alert Response Address The SMBus Alert Response interrupt pointer provides quick fault identification for simple slave devices that lack the complex, expensive logic needed to be a bus master. Upon receiving an ALERT interrupt signal, the host master can broadcast a Receive Byte transmission to the Alert Response DS1086 Ver0.4 May. 2007 EUT1086 12 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 EUT1086 Preliminary Configuration Byte Functions The Configuration Byte register (Table 5) is a Read-Write register with several functions. Bit 7 is used to mask (disable) interrupts. Bit 6 puts the device into software standby mode (STOP) or autonomous (RUN) mode. Bit 5 selects the type of external junction (set to 1 for a substrate PNP on an IC or set to 0 for a discrete diode-connected transistor) for optimized measurements. Bits 0 to 4 are reserved and return a zero when read. Status Byte Functions 7 (MSB) 6 5 The status byte (Table 6) indicates which (if any) temperature thresholds have been exceeded. This byte also indicates whether the ADC is converting and if there is an open-circuit fault detected with the external sense junction. After POR, the normal state of the MSB is 1 and all the other flag bits are 0, assuming no alert or overtemperature conditions are present. Bits 2 through 6 of the Status register are cleared by any successful read of the Status register, unless the fault persists. The ALERT output follows the status flag bit. Both are cleared when successfully read, but if the condition still exists, they reassert at the end of the next conversion. The bits indicating OVERT (bits 0 and 1) are cleared only when the condition no longer exists. Reading the status byte does not clear the OVERT outputs or fault bits. One way to eliminate the fault condition is for the measured temperature to drop below the temperature threshold minus the hysteresis value. Another way to eliminate the fault condition is by writing new values for the OVERT threshold or hysteresis so that a fault condition is no longer present. The EUT1086 incorporates collision avoidance so that completely asynchronous operation is allowed between SMBus operations and temperature conversions. When autoconverting, if the THIGH and TLOW limits are close together, it’s possible for both high-temp and low-temp status bits to be set, depending on the amount of time between status read operations. In these circumstances, it is best not to rely on the status bits to indicate reversals in long-term temperature changes. Instead, use a current temperature reading to establish the trend direction. DS1086 Ver0.4 May. 2007 BIT 4 to 0 Table 5. Configuration-Byte Bit POR FUNCTION NAME STATE MASK Masks ALERT interrupts 0 1 if a 1. Standby mode control bit; RUN / 0 if a 1, standby mode is STOP initiated. Set to 1 when the remote sensor is a substrate or common collector PNP. SPNP 1 Set to 0 when the remote sensor is a diodeconnected discrete transistor. RFU 0 Reserved Conversion Rate Byte The Conversion Rate register (Table 7) programs the time interval between conversions in free-running autonomous mode ( RUN /STOP = 0). This variable rate control can be used to reduce the supply current in portable-equipment applications. The conversion rate byte’s POR state is 08h (16Hz). The EUT1086 uses only the 4 least-significant bits (LSBs) of this register. The 4 most-significant bits (MSBs) are “don’t care” and should be set to zero when possible. The conversion rate tolerance is ±25% at any rate setting. Valid A/D conversion results for both channels are available one total conversion time (125ms nominal, 156ms maximum) after initiating a conversion, whether conversion is initiated through the RUN STOP bit, one-shot command, or initial power-up. Slave Addresses The EUT1086 has a fixed address of 1001100. The address pin state is checked at POR only, and the address data stays latched to reduce quiescent supply current due to the bias current needed for high-Z state detection. The EUT1086 also respond to the SMBus Alert Response slave address (see Alert Response Address section). 13 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 EUT1086 Preliminary Table 4. Command Byte Register Assignments FUNCTION ADDRESS POR STATE REGISTER RLTS RRTE RSL RCL RCRA RLHN RLLI RRHI RRLS WCA WCRW WLHO WLLM WRHA WRLN OSHT REET RIET RWOE RWOI HYST 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh 0Eh 0Fh 10h 11h 19h 20h 21h 0000 0000 0000 0000 1000 0000 0010 0000 0000 1000 0100 0110 1100 1001 0100 0110 1100 1001 0010 0000 0000 1000 0100 0110 1100 1001 0100 0110 1100 1001 N/A 0000 0000 0000 0000 0101 0101 0101 0101 0000 1010 — FEh 4Dh Read Internal Temperature Read External Temperature Read Status Register Read Configuration Byte Read Conversion Rate Byte Read Internal High Limit Read Internal Low Limit Read External High Limit Read External Low Limit Write Configuration Byte Write Conversion Rate Byte Write Internal High Limit Write Internal Low Limit Write External High Limit Write External Low Limit One Shot Read External Extended Temperature Read Internal Extended Temperature ——————— Read/Write External OVERT Limit ——————— Read/Write Internal OVERT Limit Overtemperature Hysteresis Read Manufacture ID Table 6. Status Register Bit Assignments BIT NAME POR STATE 7 (MSB) BUSY 1 A/D is busy converting when high. 6 LHIGH 0 Internal high-temperature alarm has tripped when high; cleared by POR or readout of the Status register if the fault condition no longer exists. 5 LLOW 0 Internal low-temperature alarm has tripped when high; cleared by POR or readout of the Status register if the fault condition no longer exists. 4 RHIGH 0 External high-temperature alarm has tripped when high; cleared by POR or readout of the Status register if the fault condition no longer exists. 3 RLOW 0 External low-temperature alarm has tripped when high; cleared by POR or readout of the Status register if the fault condition no longer exists. 2 OPEN 0 A high indicates an external diode open; cleared by POR or readout of the Status register if the fault condition no longer exists. 1 EOT 0 0 IOT 0 A high indicates the external junction temperature exceeds the external OVERT threshold. A high indicates the internal junction temperature exceeds the internal OVERT threshold. DS1086 Ver0.4 May. 2007 FUNCTION 14 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 EUT1086 Preliminary Table 7. Conversion-Rate Data Conversion Rate (hz) 00h 0.0625 01h 0.125 02h 0.25 03h 0.5 04h 1 05h 2 06h 4 07h 8 08h 16 09h 16 0Ah-FFh Reserved Note: Extended resolution applies only for conversion rates of 4Hz or slower. Power-Up Defaults Power-up defaults include: ADC begins autoconverting at a 16Hz rate (legacy resolution). THIGH and TLOW registers are set to default limits, respectively. Interrupt latch is cleared. Command register is set to 00h to facilitate quick internal Receive Byte queries. Hysteresis is set to 10°C. Transistor type is set to a substrate or common collector PNP. Table 8. Read Format for Alert Response POR and UVLO The EUT1086 has a volatile memory. To prevent unreliable power-supply conditions from corrupting the data in memory and causing erratic behavior, a POR voltage detector monitors VCC and clears the memory if VCC falls below 1.7V (typ, see Electrical Characteristics). When power is first applied and VCC rises above 2.0V (typ), the logic blocks begin operating, although reads and writes at VCC levels below 3.0V are not recommended. A second VCC comparator and the ADC undervoltage lockout (UVLO) comparator prevent the ADC from converting until there is sufficient headroom (VCC = +2.8V typ). DS1086 Ver0.4 May. 2007 BIT 7(MSB) 6 5 4 3 2 1 0(LSB) Address (000 1100) NAME FUNCTION ADD7 ADD6 ADD5 ADD4 Provide the current ADD3 ADD2 ADD1 1 Logic 1 15 联系电话：１５９９９６４４５７９ ８３１５１７１５ 芯美电子 EUT1086 Preliminary Package Information SOP-8 SYMBOLS MILLIMETERS INCHES MIN. MAX. MIN. MAX. A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.004 0.010 D E 4.90 5.80 E1 6.20 0.228 3.90 0.244 0.153 L 0.40 1.27 0.016 0.050 b 0.31 0.51 0.012 0.020 e DS1086 Ver0.4 May. 2007 0.193 1.27 0.050 16 联系电话：１５９９９６４４５７９ ８３１５１７１５