LTC2990 Quad I2C Voltage, Current and Temperature Monitor FEATURES DESCRIPTION Measures Voltage, Current and Temperature nn Measures Two Remote Diode Temperatures nn 0.5C Accuracy, 0.06C Resolution (Typ) nn 1C Internal Temperature Sensor (Typ) nn 14-Bit ADC Measures Voltage/Current nn 3V to 5.5V Supply Operating Voltage nn Four Selectable Addresses nn Internal 10ppm/C Voltage Reference nn 10-Lead MSOP Package nn The LTC(R)2990 is used to monitor system temperatures, voltages and currents. Through the I2C serial interface, the device can be configured to measure many combinations of internal temperature, remote temperature, remote voltage, remote current and internal VCC. The internal 10ppm/C reference minimizes the number of supporting components and area required. Selectable address and configurable functionality give the LTC2990 flexibility to be incorporated in various systems needing temperature, voltage or current data. The LTC2990 fits well in systems needing sub-millivolt voltage resolution, 1% current measurement and 1C temperature accuracy or any combination of the three. nn All registered trademarks and trademarks are the property of their respective owners. nn APPLICATIONS Temperature Measurement Supply Voltage Monitoring nn Current Measurement nn Remote Data Acquisition nn Environmental Monitoring TYPICAL APPLICATION Voltage, Current, Temperature Monitor Temperature Total Unadjusted Error RSENSE 2.5V 1.0 ILOAD 5V SDA SCL ADR0 ADR1 V1 0.5 V2 V3 LTC2990 TREMOTE TUE (C) VCC TREMOTE 0 V4 2990 TA01a GND -0.5 TINTERNAL MEASURES: TWO SUPPLY VOLTAGES, SUPPLY CURRENT, INTERNAL AND REMOTE TEMPERATURES -1.0 -50 -25 0 50 25 TAMB (C) 75 100 125 2990 TA01b Rev. F Document Feedback For more information www.analog.com 1 LTC2990 ABSOLUTE MAXIMUM RATINGS (Note 1) PIN CONFIGURATION Supply Voltage VCC.................................... -0.3V to 6.0V Input Voltages V1, V2, V3, V4, SDA, SCL, ADR1, ADR2...................................-0.3V to (VCC + 0.3V) Operating Temperature Range LTC2990C................................................. 0C to 70C LTC2990I..............................................-40C to 85C Storage Temperature Range................... -65C to 150C Lead Temperature (Soldering, 10 sec).................... 300C TOP VIEW V1 V2 V3 V4 GND 10 9 8 7 6 1 2 3 4 5 VCC ADR1 ADR0 SCL SDA MS PACKAGE 10-LEAD PLASTIC MSOP TJMAX = 125C, JA = 150C/W ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC2990CMS#PBF LTC2990CMS#TRPBF LTDSQ 10-Lead Plastic MSOP 0C to 70C LTC2990IMS#PBF LTC2990IMS#TRPBF LTDSQ 10-Lead Plastic MSOP -40C to 85C LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC2990CMS LTC2990CMS#TR LTDSQ 10-Lead Plastic MSOP 0C to 70C LTC2990IMS LTC2990IMS#TR LTDSQ 10-Lead Plastic MSOP -40C to 85C Consult the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Contact the factory for parts trimmed to ideality factors other than 1.004. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 3.3V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 5.5 V 1.1 1.8 mA General VCC Input Supply Range l ICC Input Supply Current During Conversion, I2C Inactive ISD Input Supply Current Shutdown Mode, I2C Inactive VCC(UVL) Input Supply Undervoltage Lockout l l 2.9 1 5 A 2.1 2.7 V 0.5 1 3 3.5 C C C l 0.5 1.5 C l 1.3 Measurement Accuracy TINT(TUE) Internal Temperature Total Unadjusted Error TRMT(TUE) Remote Diode Temperature Total Unadjusted Error VCC(TUE) VCC Voltage Total Unadjusted Error l 0.1 0.25 % Vn(TUE) V1 Through V4 Total Unadjusted Error l 0.1 0.25 % VDIFF(TUE) Differential Voltage Total Unadjusted Error -300mV VD 300mV V1 - V2 or V3 - V4 l 0.2 0.75 % VDIFF(MAX) Maximum Differential Voltage l 300 mV 2 TAMB = 0C to 85C TAMB = -40C to 0C = 1.004 (Note 4) -300 Rev. F For more information www.analog.com LTC2990 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 3.3V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX VOFFSET_DIFF Differential Offset V1 = V2 = VCC, V3 = V4 = 0V -12.5 0 12.5 LSB VOFFSET_SE Single-Ended Offset V1, V2, V3, V4 = 0V -6 0 6 LSB VDIFF(CMR) Differential Voltage Common Mode Range VLSB(DIFF) Differential Voltage LSB Weight l 0 VCC 19.42 VLSB(SINGLE-ENDED) Single-Ended Voltage LSB Weight VLSB(TEMP) Temperature LSB Weight Celsius or Kelvin TNOISE Temperature Noise Celsius or Kelvin TMEAS = 46ms (Note 2) Res Resolution (No Missing Codes) (Note 2) l INL Integral Nonlinearity 2.9V VCC 5.5V, VIN(CM) = 1.5V (Note 2) Single-Ended Differential l UNITS V V 305.18 V 0.0625 Deg 0.2 0.05 RMS /Hz 14 Bits -2 -2 2 2 LSB LSB CIN V1 Through V4 Input Sampling Capacitance (Note 2) 0.35 pF IIN(AVG) V1 Through V4 Input Average Sampling Current 0V VN 3V (Note 2) 0.6 A IDC_LEAK(VIN) V1 Through V4 Input Leakage Current 0V VN VCC l -10 l 37 10 nA 46 55 ms Measurement Delay TINT , TR1, TR2 Per Configured Temperature Measurement (Note 2) V1, V2, V3, V4 Single-Ended Voltage Measurement (Note 2) Per Voltage, Two Minimum l 1.2 1.5 1.8 ms V1 - V2, V3 - V4 Differential Voltage Measurement (Note 2) l 1.2 1.5 1.8 ms VCC VCC Measurement (Note 2) l 1.2 1.5 1.8 ms Max Delay Mode[4:0] = 11101, TINT , TR1, TR2, VCC (Note 2) l 167 ms Remote Diode Mode l 350 A VCC V 0.3 * VCC V 0.4 V 0.3 * VCC V V1, V3 Output (Remote Diode Mode Only) IOUT Output Current 260 VOUT Output Voltage l VADR(L) ADR0, ADR1 Input Low Threshold Voltage Falling l VADR(H) ADR0, ADR1 Input High Threshold Voltage Rising l VOL1 SDA Low Level Maximum Voltage IO = -3mA, VCC = 2.9V to 5.5V l VIL Maximum Low Level Input Voltage SDA and SCL Pins l VIH Minimum High Level Input Voltage SDA and SCL Pins l ISDAI,SCLI SDA, SCL Input Current 0 < VSDA,SCL < VCC l 1 A IADR(MAX) Maximum ADR0, ADR1 Input Current ADR0 or ADR1 Tied to VCC or GND l 1 A 0 I2C Interface 0.7 * VCC V 0.7 * VCC V I2C Timing (Note 2) fSCL(MAX) Maximum SCL Clock Frequency tLOW Minimum SCL Low Period 400 1.3 kHz s tHIGH Minimum SCL High Period 600 ns tBUF(MIN) Minimum Bus Free Time Between Stop/ Start Condition 1.3 s tHD,STA(MIN) Minimum Hold Time After (Repeated) Start Condition 600 ns Rev. F For more information www.analog.com 3 LTC2990 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 3.3V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS tSU,STA(MIN) Minimum Repeated Start Condition Set-Up Time 600 ns tSU,STO(MIN) Minimum Stop Condition Set-Up Time 600 ns tHD,DATI(MIN) Minimum Data Hold Time Input tHD,DATO(MIN) Minimum Data Hold Time Output tSU,DAT(MIN) Minimum Data Set-Up Time Input tSP(MAX) Maximum Suppressed Spike Pulse Width CX SCL, SDA Input Capacitance 300 Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Guaranteed by design and not subject to test. Note 3: Integral nonlinearity is defined as the deviation of a code from a straight line passing through the actual endpoints of the transfer curve. The deviation is measured from the center of the quantization band. 4 MIN 50 TYP MAX UNITS 0 ns 900 ns 100 ns 250 ns 10 pF Note 4: Trimmed to an ideality factor of 1.004 at 25C. Remote diode temperature drift (TUE) verified at diode voltages corresponding to the temperature extremes with the LTC2990 at 25C. Remote diode temperature drift (TUE) guaranteed by characterization over the LTC2990 operating temperature range. Rev. F For more information www.analog.com LTC2990 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25C, VCC = 3.3V unless otherwise noted 1200 3.5 4 MEASUREMENT DELAY VARIATION (%) VCC = 5V 3.0 1150 VCC = 5V 2.5 1100 2.0 ICC (A) ICC (A) Measurement Delay Variation vs T Normalized to 3.3V, 25C Supply Current vs Temperature Shutdown Current vs Temperature 1.5 1050 VCC = 3.3V 1.0 VCC = 3.3V 1000 0.5 0 -50 -25 0 25 50 75 TAMB (C) 950 -50 -25 100 125 150 0 25 50 75 TAMB (C) 3 VCC = 5V 2 1 -1 -50 -25 100 125 150 VCC TUE Single-Ended VX TUE 0.5 VDIFF TUE (%) 0.05 VX TUE (%) 0.05 0 -0.05 25 50 75 TAMB (C) 100 125 150 -0.10 -50 -25 0 25 50 75 TAMB (C) 4 LTC2990 TRX ERROR (C) TINTERNAL ERROR (DEG) 1 0 -1 0 25 50 75 TAMB (C) 100 125 150 2990 G07 25 50 75 TAMB (C) 100 125 150 Remote Diode Error with LTC2990 at 25C, 90C Remote Diode Error with LTC2990 at Same Temperature as Diode 1.00 0.75 LTC2990 AT 25C 0.2 LTC2990 AT 90C 0 0.50 0.25 -0.25 -0.2 0 -0.50 -0.4 -2 0 2990 G06 0.4 2 -3 -50 -25 -1.0 -50 -25 100 125 150 0.6 3 VCC = 3.3V 2990 G05 2990 G04 TINTERNAL Error VCC = 5V 0 -0.5 LTC2990 TRX ERROR (DEG) VCC TUE (%) 1.0 0 100 125 150 Differential Voltage TUE 0.10 -0.10 -50 -25 25 50 75 TAMB (C) 2990 G03 0.10 -0.05 0 2990 G02 2990 G01 0 VCC = 3.3V 0 -0.6 -50 -25 -0.75 0 25 50 75 100 125 150 BATH TEMPERATURE (C) 2990 G08 -1.00 -50 -25 0 25 50 75 TAMB (C) 100 125 150 2990 G09 Rev. F For more information www.analog.com 5 LTC2990 TYPICAL PERFORMANCE CHARACTERISTICS Single-Ended Noise Single-Ended Transfer Function 4800 READINGS 3500 LTC2990 VALUE (V) COUNTS 1.0 5 3000 2500 2000 1500 1000 VCC = 5V 4 0.5 VCC = 3.3V 3 2 1 0 VCC = 5V -0.5 -3 -2 2 1 0 LSBs (305.18V/LSB) -1 -1 3 -1 -0 1 3 2 VX (V) 5 4 2990 G10 -1.0 6 0 1 2 3 VX (V) 4 Differential Transfer Function Differential INL 2 0.4 800 READINGS 5 2990 G12 2990 G11 LTC2990 Differential Noise 500 VCC = 3.3V 0 500 0 Single-Ended INL 6 INL (LSBs) 4000 TA = 25C, VCC = 3.3V unless otherwise noted 0.3 1 0.2 300 200 0.1 INL (LSBs) LTC2990 V1-V2 (V) COUNTS 400 0 -0.1 -1 -0.2 100 0 -0.3 0 -4 -3 0 1 -2 -1 LSBs (19.42V/LSB) 2 -0.4 -0.4 -0.3 -0.2 -0.1 0 0.1 V1-V2 (V) 3 0.2 0.3 Remote Diode Noise 600 1000 READINGS POR Thresholds vs Temperature 1000 READINGS 2.4 THRESHOLD (V) COUNTS COUNTS 400 300 200 100 1.8 VCC FALLING 1.6 -0.75 -0.5 -0.25 0 0.25 (C) 0.5 0.75 0 1.2 -0.75 -0.5 -0.25 0 0.25 (C) 0.5 2990 G16 6 2.0 1.4 100 0 VCC RISING 2.2 200 0.4 2.6 500 400 0.2 2990 G15 2990 G14 TINT Noise 300 0 -0.2 VIN (V) 2990 G13 500 -2 -0.4 0.4 0.75 2990 G17 1.0 -50 -25 0 25 50 75 TAMB (C) 100 125 150 2990 G18 Rev. F For more information www.analog.com LTC2990 PIN FUNCTIONS V1 (Pin 1): First Monitor Input. This pin can be configured as a single-ended input or the positive input for a differential or remote diode temperature measurement (in combination with V2). When configured for remote diode temperature, this pin will source a current. V2 (Pin 2): Second Monitor Input. This pin can be configured as a single-ended input or the negative input for a differential or remote diode temperature measurement (in combination with V1). When configured for remote diode temperature, this pin will have an internal termination, while the measurement is active. V3 (Pin 3): Third Monitor Input. This pin can be configured as a single-ended input or the positive input for a differential or remote diode temperature measurement (in combination with V4). When configured for remote diode temperature, this pin will source a current. V4 (Pin 4): Fourth Monitor Input. This pin can be configured as a single-ended input or the negative input for a differential or remote diode temperature measurement (in combination with V3). When configured for remote diode temperature, this pin will have an internal termination, while the measurement is active. SDA (Pin 6): Serial Bus Data Input and Output. In the transmitter mode (Read), the conversion result is output through the SDA pin, while in the receiver mode (Write), the device configuration bits are input through the SDA pin. At data input mode, the pin is high impedance; while at data output mode, it is an open-drain N-channel driver and therefore an external pull-up resistor or current source to VCC is needed. SCL (Pin 7): Serial Bus Clock Input. The LTC2990 can only act as a slave and the SCL pin only accepts external serial clock. The LTC2990 does not implement clock stretching. ADR0 (Pin 8): Serial Bus Address Control Input. The ADR0 pin is an address control bit for the device I2C address. See Table 2. ADR1 (Pin 9): Serial Bus Address Control Input. The ADR1 pin is an address control bit for the device I2C address. See Table 2. VCC (Pin 10): Supply Voltage Input. GND (Pin 5): Device Circuit Ground. Connect this pin to a ground plane through a low impedance connection. Rev. F For more information www.analog.com 7 LTC2990 FUNCTIONAL DIAGRAM REMOTE DIODE SENSORS VCC 10 MODE 1 2 3 4 V1 GND 5 V2 SCL CONTROL LOGIC V3 MUX SDA ADC I2C V4 ADR0 ADR1 7 6 8 9 UV INTERNAL SENSOR VCC UNDERVOLTAGE DETECTOR REFERENCE 2990 FD TIMING DIAGRAM SDA tSU, DAT tHD, DATO, tHD, DATI tSU, STA tSP tHD, STA tSP tBUF tSU, STO 2990 TD SCL tHD, STA START CONDITION 8 REPEATED START CONDITION STOP CONDITION START CONDITION Rev. F For more information www.analog.com LTC2990 OPERATION The LTC2990 monitors voltage, current, internal and remote temperatures. It can be configured through an I2C interface to measure many combinations of these parameters. Single or repeated measurements are possible. Remote temperature measurements use a transistor as a temperature sensor, allowing the remote sensor to be a discrete NPN (ex. MMBT3904) or an embedded PNP device in a microprocessor or FPGA. The internal ADC reference minimizes the number of support components required. The Functional Diagram displays the main components of the device. The input signals are selected with an input MUX, controlled by the control logic block. The control logic uses the mode bits in the control register to manage the sequence and types of data acquisition. The control logic also controls the variable current sources during remote temperature acquisition. The order of acquisitions is fixed: TINTERNAL, V1, V2, V3, V4 then VCC. The ADC performs the necessary conversion(s) and supplies the data to the control logic for further processing in the case of temperature measurements, or routing to the appropriate data register for voltage and current measurements. Current and temperature measurements, V1 - V2 or V3 - V4, are sampled differentially by the internal ADC. The I2C interface supplies access to control, status and data registers. The ADR1 and ADR0 pins select one of four possible I2C addresses (see Table 2). The undervoltage detector inhibits I2C communication below the specified threshold. During an undervoltage condition, the part is in a reset state, and the data and control registers are placed in the default state of 00h. Remote diode measurements are conducted using multiple ADC conversions and source currents to compensate for sensor series resistance. During temperature measurements, the V2 or V4 terminal of the LTC2990 is terminated with a diode. The LTC2990 is calibrated to yield the correct temperature for a remote diode with an ideality factor of 1.004. See the applications section for compensation of sensor ideality factors other than the factory calibrated value of 1.004. The LTC2990 communicates through an I2C serial interface. The serial interface provides access to control, status and data registers. I2C defines a 2-wire open-drain interface supporting multiple slave devices and masters on a single bus. The LTC2990 supports 100kbits/s in the standard mode and up to 400kbit/s in fast mode. The four physical addresses supported are listed in Table 2. The I2C interface is used to trigger single conversions, or start repeated conversions by writing to a dedicated trigger register. The data registers contain a destructive-read status bit (data valid), which is used in repeated mode to determine if the register 's contents have been previously read. This bit is set when the register is updated with new data, and cleared when read. APPLICATIONS INFORMATION Figure 1 is the basic LTC2990 application circuit. 2.5V 5V RSENSE 15m ILOAD 0.1F 2-WIRE I2C INTERFACE VCC V1 MMBT3904 V2 SDA SCL LTC2990 ADR0 ADR1 GND V3 The VCC pin must exceed the undervoltage (UV) threshold of 2.5V to keep the LTC2990 out of power-on reset. Power-on reset will clear all of the data registers and the control register. Temperature Measurements 470pF V4 2990 F01 Figure 1. Power Up The LTC2990 can measure internal temperature and up to two external diode or transistor sensors. During temperature conversion, current is sourced through either the V1 or the V3 pin to forward bias the sensing diode. The Rev. F For more information www.analog.com 9 LTC2990 APPLICATIONS INFORMATION change in sensor voltage per degree temperature change is 275V/C, so environmental noise must be kept to a minimum. Recommended shielding and PCB trace considerations are illustrated in Figure 2. The diode equation: VBE = * I * ln C q IS k*T (1) can be solved for T, where T is Kelvin degrees, IS is a process dependent factor on the order of 1E-13, is the diode ideality factor, k is Boltzmann's constant and q is the electron charge. T= VBE * q I * k *In C IS (2) The LTC2990 makes differential measurements of diode voltage to calculate temperature. Proprietary techniques allow for cancellation of error due to series resistance. 0.1F GND SHIELD TRACE LTC2990 470pF NPN SENSOR V1 V2 V3 V4 VCC ADR1 ADR0 SCL GND SDA MANUFACTURER PART NUMBER PACKAGE Fairchild Semiconductor MMBT3904 FMMT3904 SOT-23 SOT-23 Central Semiconductor CMPT3904 CET3904E SOT-23 SOT-883L Diodes, Inc. MMBT3904 SOT-23 MMBT3904LT1 SOT-23 NXP MMBT3904 SOT-23 Infineon MMBT3904 SOT-23 UMT3904 SC-70 On Semiconductor Rohm ideality factor of the diode sensor can be considered a temperature scaling factor. The temperature error for a 1% accurate ideality factor error is 1% of the Kelvin temperature. Thus, at 25C, or 298K, a +1% accurate ideality factor error yields a +2.98 degree error. At 85C or 358K, a +1% error yields a 3.6 degree error. It is possible to scale the measured Kelvin or Celsius temperature measured using the LTC2990 with a sensor ideality factor other than 1.004, to the correct value. The scaling Equations (3) and (4) are simple, and can be implemented with sufficient precision using 16-bit fixed-point math in a microprocessor or microcontroller. Factory Ideality Calibration Value: CAL = 1.004 2990 F02 Actual Sensor Ideality Value: Figure 2. Recommended PCB Layout ACT Compensated Kelvin Temperature: Ideality Factor Scaling The LTC2990 is factory calibrated for an ideality factor of 1.004, which is typical of the popular MMBT3904 NPN transistor. The semiconductor purity and wafer-level processing limits device-to-device variation, making these devices interchangeable (typically <0.5C) for no additional cost. Several manufacturers supply suitable transistors, some recommended sources are listed in Table 1. Discrete 2-terminal diodes are not recommended as temperature sensors. While an ideality factor value of 1.004 is typical of target sensors, small deviations can yield significant temperature errors. Contact LTC Marketing for parts trimmed to ideality factors other than 1.004. The 10 Table 1. Recommended Transistors to Be Used as Temperature Sensors TK _ COMP = CAL * TK _ MEAS ACT (3) Compensated Celsius Temperature TC _ COMP = CAL * ( TC _ MEAS + 273 ) - 273 ACT (4) A 16-bit unsigned number is capable of representing the ratio CAL/ACT in a range of 0.00003 to 1.99997, by multiplying the fractional ratio by 215. The range of scaling encompasses every conceivable target sensor value. The ideality factor scaling granularity yields a worst-case Rev. F For more information www.analog.com LTC2990 APPLICATIONS INFORMATION temperature error of 0.01 at 125C. Multiplying this 16bit unsigned number and the measured Kelvin (unsigned) temperature represented as a 16-bit number, yields a 32bit unsigned result. To scale this number back to a 13bit temperature (9-bit integer part, and a 4-bit fractional part), divide the number by 215 per Equation (5). Similarly, Celsius coded temperature values can be scaled using 16-bit fixed-point arithmetic, using Equation (6). In both cases, the scaled result will have a 9-bit integer (d[12:4]) and the 4LSBs (d[3:0]) representing the 4-bit fractional part. To convert the corrected result to decimal, divide the final result by 24 or 16, as you would the register contents. If ideality factor scaling is implemented in the target application, it is beneficial to configure the LTC2990 for Kelvin coded results to limit the number of math operations required in the target processor. (Unsigned) CAL 215 TK _ MEAS ACT TK _ COMP = 215 CAL (5) 215 TC _ MEAS + 273.15 * 2 4 ACT 215 (Unsigned) TC _ COMP = ( ) (6) - 273.15 * 2 4 Sampling Currents Single-ended voltage measurements are directly sampled by the internal ADC. The average ADC input current is a function of the input applied voltage as follows: IIN(AVG) = (VIN - 1.49V) * 0.17[A/V] Inputs with source resistance less than 200 will yield full-scale gain errors due to source impedance of <1/2LSB for 14-bit conversions. The nominal conversion time is 1.5ms for single-ended conversions. Current Measurements The LTC2990 has the ability to perform 14-bit current measurements with the addition of a current sense resistor (see Figure 3). In order to achieve accurate current sensing a few details must be considered. Differential voltage or current measurements are directly sampled by the internal ADC. RSENSE 0V - VCC ILOAD V1 V2 LTC2990 2990 F03 Figure 3. Simplified Current Sense Schematic The average ADC input current for each leg of the differential input signal during a conversion is (VIN - 1.49V) * 0.34[A/V]. The maximum source impedance to yield 14-bit results with, 1/2LSB full-scale error is ~50. In order to achieve high accuracy 4-point, or Kelvin connected measurements of the sense resistor differential voltage are necessary. In the case of current measurements, the external sense resistor is typically small, and determined by the fullscale input voltage of the LTC2990. The full-scale differential voltage is 0.300V. The external sense resistance is then a function of the maximum measurable current, or REXT_MAX = 0.300V/IMAX. For example, if you wanted to measure a current range of 5A, the external shunt resistance would equal 0.300V/5A = 60m. There exists a way to improve the sense resistor's precision using the LTC2990. The LTC2990 measures both differential voltage and remote temperature. It is therefore, possible to compensate for the absolute resistance tolerance of the sense resistor and the temperature coefficient of the sense resistor in software. The resistance would be measured by running a calibrated test current through the discrete resistor. The LTC2990 would measure both the differential voltage across this resistor and the resistor temperature. From this measurement, RO and TO in the equation below would be known. Using the two equations, the host microprocessor could compensate for both the absolute tolerance and the TCR. RT = RO * [1 + (T - TO)] where: = +3930 ppm/C for copper trace = 2 to ~+200ppm/C for discrete R (7) I = (V1 - V2)/RT (8) Rev. F For more information www.analog.com 11 LTC2990 APPLICATIONS INFORMATION Device Configuration The LTC2990 is configured by writing the control register through the serial interface. Refer to Table 5 for control register bit definition. The device is capable of many application configurations including voltage, temperature and current measurements. It is possible to configure the device for single or repeated acquisitions. The device can make single measurements, or in continuous mode, repeated acquisitions. When the device is configured for multiple measurements, the order of the measurements is fixed. For repeated acquisitions, only an initial trigger is required after which data registers are continuously refreshed with new data. As each new data result is ready, the MSB of the corresponding data register is set, and the corresponding status register bit is set. These bits are cleared when the corresponding data register is addressed. The configuration register value at power-up causes the part to measure only the internal temperature sensor when triggered. The four input pins V1 through V4 will be in a high impedance state, until configured otherwise, and a measurement is triggered. The data registers are double-buffered in order to ensure upper and lower data bytes do not become out of sync. Read operations must be terminated in order to avoid an indefinitely paused wait state. Reading the STATUS register does not interrupt measurement data updates. In a polling system, it is recommended that the STATUS register be tested for new data, this prevents unnecessary delays updating the measurement registers. Data Format The data registers are broken into 8-bit upper and lower bytes. Voltage and current conversions are 14-bits. The upper bits in the MSB registers provide status on the resulting conversions. These status bits are different for temperature and voltage conversions: Temperature: Temperature conversions are reported as Celsius or Kelvin results described in Table 8 and Table 9, each with 0.0625 degree-weighted LSBs. The format is controlled by the control register, Bit 7. All temperature formats, TINT , TR1 and TR2 are controlled by this bit. The Temperature MSB result register most significant bit (Bit 7) is the DATA_VALID bit, which indicates whether the current register contents have been accessed since the result was written to the register. This bit will be set 12 when new data is written to the register, and cleared when accessed. Bit 6 of the register is a sensor-shorted alarm. This bit of the corresponding register will be high if the remote sensor diode differential voltage is below 0.14V. The LTC2990 internal bias circuitry maintains this voltage above this level during normal operating conditions. Bit 5 of the register is a sensor open alarm. This bit of the corresponding register will be high if the remote sensor diode differential voltage is above 1.0VDC. The LTC2990 internal bias circuitry maintains this voltage below this level during normal operating conditions. The two sensor alarms are only valid after a completed conversion indicated by the data_valid bit being high. Bit 4 through Bit 0 of the MSB register are the conversion result bits D[12:8], in two's compliment format. Note in Kelvin results, the result will always be positive. The LSB register contains temperature result bits D[7:0]. To convert the register contents to temperature, use the following equation: T = D[12:0]/16. See Table 10 for conversion value examples. Voltage/Current: Voltage results are reported in two respective registers, an MSB and LSB register. The Voltage MSB result register most significant bit (Bit 7) is the data_valid bit, which indicates whether the current register contents have been accessed since the result was written to the register. This bit will be set when the register contents are new, and cleared when accessed. Bit 6 of the MSB register is the sign bit, Bits 5 though 0 represent bits D[13:8] of the two's complement conversion result. The LSB register holds conversion bits D[7:0]. The LSB value is different for single-ended voltage measurements V1 through V4, and differential (current measurements) V1 - V2 and V3 - V4. Single-ended voltages are limited to positive values in the range 0V to 3.5V. Differential voltages can have input values in the range of -0.300V to 0.300V. Use the following equations to convert the register values (see Table 10 for examples): VSINGLE-ENDED = D[14:0] * 305.18V, if Sign = 0 VSINGLE-ENDED = (D[14:0] +1) * -305.18V, if Sign = 1 VDIFFERENTIAL = D[14:0] * 19.42V, if Sign = 0 VDIFFERENTIAL = (D[14:0] +1) * -19.42V, if Sign = 1 For more information www.analog.com Rev. F LTC2990 APPLICATIONS INFORMATION Current = D[14:0] * 19.42V/RSENSE, if Sign = 0 Current = (D[14:0] +1) * -19.42V/RSENSE, if Sign = 1 where RSENSE is the current sensing resistor, typically <1. VCC: The LTC2990 measures VCC. To convert the contents of the VCC register to voltage, use the following equation: VCC = 2.5 + D[13:0] * 305.18V Digital Interface The LTC2990 communicates with a bus master using a two-wire interface compatible with the I2C Bus and the SMBus, an I2C extension for low power devices. The LTC2990 is a read-write slave device and supports SMBus bus Read Byte Data and Write Byte Data, Read Word Data and Write Word Data commands. The data formats for these commands are shown in Table 3 throughTable 10. The connected devices can only pull the bus wires LOW and can never drive the bus HIGH. The bus wires are externally connected to a positive supply voltage via a current source or pull-up resistor. When the bus is free, both lines are HIGH. Data on the I2C bus can be transferred at rates of up to 100kbit/s in the standard mode and up to 400kbit/s in the fast mode. Each device on the I2C bus is recognized by a unique address stored in that device and can operate as either a transmitter or receiver, depending on the function of the device. In addition to transmitters and receivers, devices can also be considered as masters or slaves when performing data transfers. A master is the device which initiates a data transfer on the bus and generates the clock signals to permit that transfer. At the same time any device addressed is considered a slave. The LTC2990 can only be addressed as a slave. Once addressed, it can receive configuration bits or transmit the last conversion result. Therefore the serial clock line SCL is an input only and the data line SDA is bidirectional. The device supports the standard mode and the fast mode for data transfer speeds up to 400kbit/s. The Timing Diagram shows the definition of timing for fast/ standard mode devices on the I2C bus. The internal state machine cannot update internal data registers during an I2C read operation. The state machine pauses until the I2C read is complete. It is therefore, important not to leave the LTC2990 in this state for long durations, or increased conversion latency will be experienced. START and STOP Conditions When the bus is idle, both SCL and SDA must be high. A bus master signals the beginning of a transmission with a START condition by transitioning SDA from high to low while SCL is high. When the bus is in use, it stays busy if a repeated START (SR) is generated instead of a STOP condition. The repeated START (SR) conditions are functionally identical to the START (S). When the master has finished communicating with the slave, it issues a STOP condition by transitioning SDA from low to high while SCL is high. The bus is then free for another transmission. I2C Device Addressing Four distinct bus addresses are configurable using the ADR0-ADR1 pins. There is also one global sync address available at EEh which provides an easy way to synchronize multiple LTC2990s on the same I2C bus. This allows write only access to all 2990s on the bus for simultaneous triggering. Table 2 shows the correspondence between ADR0 and ADR1 pin states and addresses. Acknowledge The acknowledge signal is used for handshaking between the transmitter and the receiver to indicate that the last byte of data was received. The transmitter always releases the SDA line during the acknowledge clock pulse. When the slave is the receiver, it must pull down the SDA line so that it remains LOW during this pulse to acknowledge receipt of the data. If the slave fails to acknowledge by leaving SDA HIGH, then the master can abort the transmission by generating a STOP condition. When the master is receiving data from the slave, the master must pull down the SDA line during the clock pulse to indicate receipt of the data. After the last byte has been received the master will leave the SDA line HIGH (not acknowledge) and issue a STOP condition to terminate the transmission. Write Protocol The master begins communication with a START condition followed by the seven bit slave address and the R/W# For more information www.analog.com Rev. F 13 LTC2990 APPLICATIONS INFORMATION bit set to zero. The addressed LTC2990 acknowledges the address and then the master sends a command byte which indicates which internal register the master wishes to write. The LTC2990 acknowledges the command byte and then latches the lower four bits of the command byte into its internal Register Address pointer. The master then delivers the data byte and the LTC2990 acknowledges once more and latches the data into its internal register. The transmission is ended when the master sends a STOP condition. If the master continues sending a second data byte, as in a Write Word command, the second data byte will be acknowledged by the LTC2990 and written to the next register in sequence, if this register has write access. Read Protocol The master begins a read operation with a START condition followed by the seven bit slave address and the R/W# bit set to zero. The addressed LTC2990 acknowledges this and then the master sends a command byte which indicates which internal register the master wishes to read. The LTC2990 acknowledges this and then latches the lower four bits of the command byte into its internal Register Address pointer. The master then sends a repeated START condition followed by the same seven bit address with the R/W# bit now set to one. The LTC2990 acknowledges and sends the contents of the requested register. The transmission is ended when the master sends a STOP condition. The register pointer is automatically incremented after each byte is read. If the master acknowledges the transmitted data byte, as in a Read Word command, the LTC2990 will send the contents a6-a0 S START 1-7 ADDRESS of the next sequential register as the second data byte. The byte following register 0x0F is register 0x00, or the status register. Control Register The control register (Table 5) determines the selected measurement mode of the device. The LTC2990 can be configured to measure voltages, currents and temperatures. These measurements can be single-shot or repeated measurements. Temperatures can be set to report in Celsius or Kelvin temperature scales. The LTC2990 can be configured to run particular measurements, or all possible measurements per the configuration specified by the mode bits. The power-on default configuration of the control register is set to 0x00, which translates to a repeated measurement of the internal temperature sensor, when triggered. This mode prevents the application of remote diode test currents on pins V1 and V3, and remote diode terminations on pins V2 and V4 at power-up. Status Register The status register (Table 4) reports the status of a particular conversion result. When new data is written into a particular result register, the corresponding DATA_VALID bit is set. When the register is addressed by the I2C interface, the status bit (as well as the DATA_VALID bit in the respective register) is cleared. The host can then determine if the current available register data is new or stale. The busy bit, when high, indicates a single-shot conversion is in progress. The busy bit is always high during repeated mode, after the initial conversion is triggered. b7-b0 8 9 R/W ACK 1-7 b7-b0 8 DATA 9 1-7 ACK 8 DATA 9 ACK P STOP 2990 F04 Figure 4. Data Transfer Over I2C or SMBus S ADDRESS W# A COMMAND A DATA A 10011a1:a0 0 0 XXXXXb3:b0 0 b7:b0 0 FROM MASTER TO SLAVE FROM SLAVE TO MASTER A: ACKNOWLEDGE (LOW) A#: NOT ACKNOWLEDGE (HIGH) P R: READ BIT (HIGH) W#: WRITE BIT (LOW) S: START CONDITION P: STOP CONDITION 2990 F05 Figure 5. LTC2990 Serial Bus Write Byte Protocol 14 Rev. F For more information www.analog.com LTC2990 APPLICATIONS INFORMATION S ADDRESS W# A COMMAND A DATA A DATA A 10011a1:a0 0 0 XXXXXb3:b0 0 b7:b0 0 b7:b0 0 P 2990 F06 Figure 6. LTC2990 Serial Bus Repeated Write Byte Protocol S ADDRESS W# A COMMAND A 10011a1:a0 0 0 XXXXXb3:b0 0 S R A DATA A# 10011a1:a0 1 ADDRESS 0 b7:b0 1 P 2990 F07 Figure 7. LTC2990 Serial Bus Read Byte Protocol S ADDRESS W# A COMMAND A 10011a1:a0 0 0 XXXXXb3:b0 0 S R A DATA A DATA A# 10011a1:a0 1 0 b7:b0 0 b7:b0 1 ADDRESS P 2990 F08 Figure 8. LTC2990 Serial Bus Repeated Read Byte Protocol Table 2. I2C Base Address HEX I2C BASE ADDRESS BINARY I2C BASE ADDRESS ADR1 ADR0 98h 1001 100X* 0 0 9Ah 1001 101X* 0 1 9Ch 1001 110X* 1 0 9Eh 1001 111X* 1 1 EEh 1110 1110 Global Sync Address *X = R/W Bit Table 3. LTC2990 Register Address and Contents REGISTER ADDRESS* REGISTER NAME READ/WRITE DESCRIPTION 00h STATUS R 01h CONTROL R/W Indicates BUSY State, Conversion Status Controls Mode, Single/Repeat, Celsius/Kelvin R/W Triggers an Conversion 02h TRIGGER** 03h N/A 04h TINT (MSB) R Internal Temperature MSB 05h TINT (LSB) R Internal Temperature LSB 06h V1 (MSB) R V1, V1 - V2 or TR1 MSB 07h V1 (LSB) R V1, V1 - V2 or TR1 LSB 08h V2 (MSB) R V2, V1 - V2 or TR1 MSB 09h V2 (LSB) R V2, V1 - V2 or TR1 LSB 0Ah V3 (MSB) R V3, V3 - V4 or TR2 MSB 0Bh V3 (LSB) R V3, V3 - V4 or TR2 LSB 0Ch V4 (MSB) R V4, V3 - V4 or TR2 MSB Unused Address 0Dh V4 (LSB) R V4, V3 - V4 or TR2 LSB 0Eh VCC (MSB) R VCC MSB 0Fh VCC (LSB) R VCC LSB *Register Address MSBs b7-b4 are ignored. **Writing any value triggers a conversion. Data Returned reading this register address is the Status register. Power-on reset sets all registers to 00h. Rev. F For more information www.analog.com 15 LTC2990 APPLICATIONS INFORMATION Table 4. STATUS Register (Default 0x00) BIT NAME OPERATION b7 0 Always Zero b6 VCC Ready 1 = VCC Register Contains New Data, 0 = VCC Register Read b5 V4 Ready 1 = V4 Register Contains New Data, 0 = V4 Register Read b4 V3, TR2, V3 - V4 Ready 1 = V3 Register Contains New Data, 0 = V3 Register Data Old b3 V2 Ready 1 = V2 Register Contains New Data, 0 = V2 Register Data Old b2 V1, TR1, V1 - V2 Ready 1 = V1 Register Contains New Data, 0 = V1 Register Data Old b1 TINT Ready 1 = TINT Register Contains New Data, 0 = TINT Register Data Old b0 Busy* 1= Conversion In Process, 0 = Acquisition Cycle Complete *In Repeat mode, Busy = 1 always Table 5. CONTROL Register (Default 0x00) BIT NAME OPERATION b7 Temperature Format Temperature Reported In; Celsius = 0 (Default), Kelvin = 1 b6 Repeat/Single Repeated Acquisition = 0 (Default), Single Acquisition = 1 Reserved Reserved Mode [4:3] Mode Description b5 b[4:3] 0 b[2:0] Internal Temperature Only (Default) 0 1 TR1, V1 or V1 - V2 Only per Mode [2:0] 1 0 TR2, V3 or V3 - V4 Only per Mode [2:0] 1 1 All Measurements per Mode [2:0] Mode [2:0] 0 16 0 Mode Description 0 0 V1, V2, TR2 (Default) 0 0 1 V1 - V2, TR2 0 1 0 V1 - V2, V3, V4 0 1 1 TR1, V3, V4 1 0 0 TR1, V3 - V4 1 0 1 TR1, TR2 1 1 0 V1 - V2, V3 - V4 1 1 1 V1, V2, V3, V4 Rev. F For more information www.analog.com LTC2990 APPLICATIONS INFORMATION Table 6. Voltage/Current Measurement MSB Data Register Format BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 DV* Sign D13 D12 D11 D10 D9 D8 *Data Valid is set when a new result is written into the register. Data Valid is cleared when this register is addressed (read) by the I2C interface. Table 7. Voltage/Current Measurement LSB Data Register Format BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 D7 D6 D5 D4 D3 D2 D1 D0 Table 8. Temperature Measurement MSB Data Register Format BIT 7 DV* BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 SS** SO D12 D11 D10 D9 D8 *DATA_VALID is set when a new result is written into the register. DATA_VALID is cleared when this register is addressed (read) by the I2C interface. **Sensor Short is high if the voltage measured on V1 is too low during temperature measurements. This signal is always low for TINT measurements. Sensor Open is high if the voltage measured on V1 is excessive during temperature measurements. This signal is always low for TINT measurements. Table 9. Temperature Measurement LSB Data Register Format BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 D7 D6 D5 D4 D3 D2 D1 D0 Rev. F For more information www.analog.com 17 LTC2990 APPLICATIONS INFORMATION Table 10. Conversion Formats VOLTAGE FORMATS SIGN BINARY VALUE D[13:0] VOLTAGE Single-Ended 0 11111111111111 >5 LSB = 305.18V 0 10110011001101 3.500 0 01111111111111 2.500 0 00000000000000 0.000 1 11110000101001 -0.300 Differential 0 11111111111111 >0.318 LSB = 19.42V 0 11110001011000 +0.300 0 10000000000000 +0.159 0 00000000000000 0.000 1 10000000000000 -0.159 1 00001110101000 -0.300 1 00000000000000 <-0.318 VCC = Result + 2.5V 0 10110011001101 VCC = 6V LSB = 305.18V 0 10000000000000 VCC = 5V 0 00001010001111 VCC = 2.7V TEMPERATURE FORMATS FORMAT BINARY VALUE D[12:0] TEMPERATURE Temperature Internal, TR1 or TR2 Celsius 0011111010000 +125.0000 LSB = 0.0625 Degrees Celsius 0000110010001 +25.0625 Celsius 0000110010000 +25.0000 Celsius 1110110000000 -40.0000 Kelvin 1100011100010 398.1250 Kelvin 1000100010010 273.1250 Kelvin 0111010010010 233.1250 18 Rev. F For more information www.analog.com LTC2990 TYPICAL APPLICATIONS High Voltage/Current and Temperature Monitoring RSENSE 1m 1% 12V 5V ILOAD 0A TO 10A VIN 5V TO 105V RIN 20 1% +IN - 0.1F -INF V+ VREG V- 3.3V 0.1F -INS + Computer Voltage and Temperature Monitoring 10.0k 1% 30.1k 1% 10.0k 1% 10.0k 1% VCC V1 2-WIRE I2C INTERFACE SDA SCL ADR0 ADR1 V2 LTC2990 GND MICROPROCESSOR V3 470pF V4 OUT LTC6102HV 200k 1% 4.75k 1% 5V 2-WIRE I2C INTERFACE ROUT 4.99k 1% 2990 TA03 0.1F 0.1F VOLTAGE, CURRENT AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x58 REG 4, 5 0.0625C/LSB TAMB V1 (+5) REG 6, 7 0.61mVLSB V2(+12) REG 8, 9 1.22mV/LSB REG A, B 0.0625C/LSB TPROCESSOR REG E, F 2.5V + 305.18V/LSB VCC 0.1F VCC V1 V2 SDA SCL LTC2990 ADR0 ADR1 GND MMBT3904 V3 470pF V4 2990 TA02 ALL CAPACITORS 20% VOLTAGE, CURRENT AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x58 REG 4, 5 0.0625C/LSB TAMB REG 6, 7 13.2mVLSB VLOAD REG 8, 9 1.223mA/LSB V2(ILOAD) REG A, B 0.0625C/LSB TREMOTE REG E, F 2.5V + 305.18V/LSB VCC Rev. F For more information www.analog.com 19 LTC2990 TYPICAL APPLICATIONS Motor Protection/Regulation LOADPWR = I * V 0.1 1% MOTOR CONTROL VOLTAGE 0VDC TO 5VDC 0A TO 2.2A 5V 0.1F 2-WIRE I2C INTERFACE VCC V1 V2 SDA SCL LTC2990 ADR0 ADR1 GND MMBT3904 V3 470pF V4 TMOTOR 2990 TA04 TINTERNAL CURRENT AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x59 REG 4, 5 0.0625C/LSB TAMB REG 6, 7 194A/LSB IMOTOR REG A, B 0.0625C/LSB TMOTOR REG E, F 2.5V + 305.18V/LSB VCC MOTOR VOLTAGE AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x58 REG 4, 5 0.0625C/LSB TAMB REG 8, 9 305.18VLSB VMOTOR REG A, B 0.0625C/LSB TMOTOR REG E, F 2.5V + 305.18V/LSB VCC Large Motor Protection/Regulation LOADPWR = I * V 0.01 1W, 1% MOTOR CONTROL VOLTAGE 0V TO 40V 0A TO 10A 5V 2-WIRE I2C INTERFACE 71.5k 1% 71.5k 1% 10.2k 1% 10.2k 1% 0.1F VCC V1 V2 SDA SCL LTC2990 ADR0 ADR1 GND MMBT3904 V3 470pF V4 TMOTOR TINTERNAL VOLTAGE AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x58 REG 4, 5 0.0625C/LSB TAMB REG 8, 9 2.44mVLSB VMOTOR REG A, B 0.0625C/LSB TMOTOR REG E, F 2.5V + 305.18V/LSB VCC 20 MOTOR 2990 TA05 CURRENT AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x59 REG 4, 5 0.0625C/LSB TAMB REG 6, 7 15.54mA/LSB IMOTOR REG A, B 0.0625C/LSB TMOTOR REG E, F 2.5V + 305.18V/LSB VCC Rev. F For more information www.analog.com LTC2990 TYPICAL APPLICATIONS Fan/Air Filter/Temperature Alarm 3.3V MMBT3904 3.3V 22 0.125W 470pF FAN 0.1F VCC 2-WIRE I2C INTERFACE HEATER ENABLE V1 MMBT3904 V2 SDA SCL LTC2990 ADR0 ADR1 GND TEMPERATURE FOR: V3 22 0.125W 470pF V4 FAN GOOD FAN BAD FAN HEATER TINTERNAL NDS351AN HEATER ENABLE 2 SECOND PULSE CONTROL REGISTER: 0x5D REG 4, 5 TAMB REG 6, 7 TR1 REG A, B TR2 REG E, F VCC 2990 TA06 0.0625C/LSB 0.0625C/LSB 0.0625C/LSB 2.5V + 305.18V/LSB Battery Monitoring CHARGING CURRENT 5V 2-WIRE I2C INTERFACE BATTERY I AND V MONITOR 15m* 0.1F VCC V1 SDA SCL LTC2990 ADR0 ADR1 GND V2 MMBT3904 V3 *** 470pF V4 TINTERNAL + NiMH BATTERY TBATT T(t) V(t) 100% 100% I(t) 100% 2990 TA07 *IRC LRF3W01R015F VOLTAGE AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x58 REG 4, 5 0.0625C/LSB TAMB REG 8, 9 305.18VLSB VBAT REG A, B 0.0625C/LSB TBAT REG E, F 2.5V + 305.18V/LSB VCC CURRENT AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x59 REG 4, 5 0.0625C/LSB TAMB REG 6, 7 1.295mA/LSB IBAT REG A, B 0.0625C/LSB TBAT REG E, F 2.5V + 305.18V/LSB VCC Rev. F For more information www.analog.com 21 LTC2990 TYPICAL APPLICATIONS Wet-Bulb Psychrometer 5V 0.1F VCC C V1 MMBT3904 V2 SDA SCL LTC2990 ADR0 ADR1 GND T 470pF 470pF V4 2990 TA08 TWET TDRY TINTERNAL CONTROL REGISTER: 0x5D REG 4, 5 TAMB REG 6, 7 TWET REG A, B TDRY REG E, F VCC MMBT3904 V3 FAN: SUNON KDE0504PFB2 0.0625C/LSB 0.0625C/LSB 0.0625C/LSB 2.5V + 305.18V/LSB DAMP MUSLIN FAN WATER RESERVOIR 5V FAN ENABLE NDS351AN REFERENCES: http://en.wikipedia.org/wiki/Hygrometer http://en.wikipedia.org/wiki/Psychrometrics Wind Direction/Instrumentation 3.3V 0.1F VCC C V1 MMBT3904 3.3V V2 SDA SCL LTC2990 ADR0 ADR1 GND 22 470pF 470pF V4 2990 TA11 TINTERNAL CONTROL REGISTER: 0x5D REG 4, 5 TAMB REG 8, 9 TR1 REG A, B TR2 REG E, F VCC MMBT3904 V3 HEATER ENABLE 2 SECOND PULSE HEATER 75 0.125W 2N7002 0.0625C/LSB 0.0625C/LSB 0.0625C/LSB 2.5V + 305.18V/LSB Rev. F For more information www.analog.com LTC2990 TYPICAL APPLICATIONS Liquid-Level Indicator 3.3V 3.3V SENSOR HI* 0.1F HEATER ENABLE VCC C V1 SDA SCL LTC2990 ADR0 ADR1 GND 470pF V2 SENSOR HI SENSOR LO* V3 SENSOR LO 470pF V4 TINTERNAL HEATER ENABLE 2 SECOND PULSE CONTROL REGISTER: 0x5D REG 4, 5 0.0625C/LSB TAMB REG 6, 7 0.0625C/LSB THI REG A, B 0.0625C/LSB TLO REG E, F 2.5V + 305.18V/LSB VCC T = ~2.0C pp, SENSOR HI ~0.2C pp, SENSOR LO NDS351AN HEATER: 75 0.125W *SENSOR MMBT3904, DIODE CONNECTED 2290 TA09 Oscillator/Reference Oven Temperature Regulation HEATER VOLTAGE 5V 2-WIRE I2C INTERFACE HEATERPWR = I *V 0.1 STYROFOAM INSULATION 0.1F VCC V1 V2 SDA SCL LTC2990 ADR0 ADR1 GND MMBT3904 V3 20C AMBIENT HEATER 470pF V4 TOVEN TINTERNAL 70C OVEN 2990 TA10 HEATER CONSTRUCTION: HEATER POWER = * (TSET - TAMB) + * (TOVEN - TSET) dt 5FT COIL OF #34 ENAMEL WIRE FEED FEED ~1.6 AT 70C FORWARD BACK PHEATER = ~0.4W WITH TA = 20C = 0.004W, = 0.00005W/DEG-s VOLTAGE AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x58 REG 4, 5 0.0625C/LSB TAMB V1, V2 REG 8, 9 305.18VLSB REG A, B 0.0625C/LSB TOVEN REG E, F 2.5V + 305.18V/LSB VCC CURRENT AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x59 REG 4, 5 0.0625C/LSB TAMB REG 6, 7 269VLSB IHEATER REG A, B 0.0625C/LSB THEATER REG E, F 2.5V + 305.18V/LSB VCC Rev. F For more information www.analog.com 23 LTC2990 PACKAGE DESCRIPTION MS Package MS Package 10-Lead Plastic MSOP 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1661 Rev F) (Reference LTC DWG # 05-08-1661 Rev F) 0.889 0.127 (.035 .005) 5.10 (.201) MIN 3.20 - 3.45 (.126 - .136) 3.00 0.102 (.118 .004) (NOTE 3) 0.50 0.305 0.038 (.0197) (.0120 .0015) BSC TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 10 9 8 7 6 3.00 0.102 (.118 .004) (NOTE 4) 4.90 0.152 (.193 .006) DETAIL "A" 0.497 0.076 (.0196 .003) REF 0 - 6 TYP GAUGE PLANE 1 2 3 4 5 0.53 0.152 (.021 .006) DETAIL "A" 0.18 (.007) SEATING PLANE 0.86 (.034) REF 1.10 (.043) MAX 0.17 - 0.27 (.007 - .011) TYP 0.50 (.0197) BSC NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 24 0.1016 0.0508 (.004 .002) MSOP (MS) 0213 REV F Rev. F For more information www.analog.com LTC2990 REVISION HISTORY REV A DATE DESCRIPTION 6/11 Revised title of data sheet from "I2C Temperature, Voltage and Current Monitor" 1 Revised Conditions and Values under Measurement Accuracy in Electrical Characteristics section 2 Revised curve G05 labels in Typical Performance Characteristics section Revised Applications Information section and renumbered tables and table references B C 8/11 12/11 1 Updated Current Measurements section 10 Updated Related Parts 24 Removed conditions for VCC(TUE) in Electrical Characteristics 2 Updated Pin 8 description 6 Removed symbol in reference to Kelvin measurements 9 Applications Information Revised Typical Applications drawings TA05 and TA11 7/14 E 11/16 F 11/18 4 9 to 17 Updated Features section Revised Current Measurements, Voltage/Current, I2C Device Addressing, Table 2, Table 5, and Table 10 in D PAGE NUMBER 10, 11, 12, 14, 15, 17 19, 20 Revised Device Configuration section 11 Updated MSOP Package Description 22 Added VOFFSET_DIFF and VOFFSET_SE to the Electrical Characteristics section 3 Corrected current register equations 13 Corrected differential voltage = +0.300 binary value 18 Rev. F Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license For is granted implication or otherwise under any patent or patent rights of Analog Devices. more by information www.analog.com 25 LTC2990 TYPICAL APPLICATION High Voltage/Current and Temperature Monitoring RSENSE 1m 1% ILOAD 0A TO 10A VIN 5V TO 105V RIN 20 1% +IN 0.1F -INS - + -INF V+ VREG V- OUT LTC6102HV 200k 1% 4.75k 1% 5V ROUT 4.99k 1% 0.1F 0.1F 0.1F VCC 2-WIRE I2C INTERFACE V1 MMBT3904 V2 SDA SCL LTC2990 ADR0 ADR1 GND V3 470pF V4 2990 TA02 ALL CAPACITORS 20% VOLTAGE, CURRENT AND TEMPERATURE CONFIGURATION: CONTROL REGISTER: 0x58 REG 4, 5 0.0625C/LSB TAMB REG 6, 7 13.2mVLSB VLOAD REG 8, 9 1.223mA/LSB V2(ILOAD) REG A, B 0.0625C/LSB TREMOTE REG E, F 2.5V + 305.18V/LSB VCC RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC2991 Octal I2C Voltage, Current, Temperature Monitor Remote and Internal Temperatures, 14-Bit Voltages and Current, Internal 10ppm/C Reference LTC2997 Remote/Internal Temperature Sensor Temperature to Voltage with Integrated 1.8V Voltage Reference, 1C Accuracy LM134 Constant Current Source and Temperature Sensor Can Be Used as Linear Temperature Sensor LTC1392 Micropower Temperature, Power Supply and Differential Voltage Monitor Complete Ambient Temperature Sensor Onboard LTC2487 16-Bit, 2-/4-Channel Delta Sigma ADC with PGA, Easy DriveTM Internal Temperature Sensor and I2C Interface LTC6102/LTC6102HV Precision Zero Drift Current Sense Amplifier 5V to 100V, 105V Absolute Maximum (LTC6102HV) LTC2983 Multi-Sensor High Accuracy Digital Temperature Measurement System 20 Channels Measure Any Combination of Thermocouples, RTDs, Thermistors and Diodes LTC2984 Multi-Sensor High Accuracy Digital Temperature Measurement System with EEPROM 20 Channels Measure Any Combination of Thermocouples, RTDs, Thermistors and Diodes LTC2986 Multi-Sensor High Accuracy Digital Temperature Measurement System with EEPROM 10 Channels Measure Any Combination of Thermocouples, RTDs, Thermistors and Diodes 26 Rev. F 11/18 www.analog.com For more information www.analog.com ANALOG DEVICES, INC. 2010-2018