Linear Technology LTC2983 Manual

Multi-sensor high accuracy digital temperature measurement system

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FEATURES

Directly Digitize RTDs, Thermocouples, Thermistors

and Diodes

Single 2.85V to 5.25V Supply

Results Reported in °C or °F

20 Flexible Inputs Allow Interchanging Sensors

Automatic Thermocouple Cold Junction Compensation

Built-In Standard and User-Programmable Coefficients

for Thermocouples, RTDs and Thermistors

Configurable 2-, 3- or 4-Wire RTD Configurations

Measures Negative Thermocouple Voltages

Automatic Burn Out, Short-Circuit and Fault Detection

Buffered Inputs Allow External Protection

Simultaneous 50Hz/60Hz Rejection

Includes 15ppm/°C (Max) Reference (I-Grade)

APPLICATIONS

Direct Thermocouple Measurements

Direct RTD Measurements

Direct Thermistor Measurements

Custom Sensor Applications

TYPICAL APPLICATION

Thermocouple Measurement with Automatic Cold Junction Compensation

2.85V TO 5.25V

0.1µF

SENSE

PT-100

RTD

LTC2983

24-BIT

∆∑ ADC

LINEARIZATION/

FAULT DETECTION

24-BIT

∆∑ ADC

24-BIT

∆∑ ADC

(10ppm/°C)

REF

2983 TA01a

For more information

Multi-Sensor High Accuracy

Digital Temperature

Measurement System

DESCRIPTION

The

LTC

2983

measures a wide variety of temperature

sensors and digitally outputs the result, in °C or °F , with

0.1°C accuracy and 0.001°C resolution. The LTC2983 can

measure the temperature of virtually all standard (type B,

E, J, K, N, S, R, T) or custom thermocouples, automatically

compensate for cold junction temperatures and linearize

the results. The device can also measure temperature with

standard 2-, 3- or 4-wire RTDs, thermistors and diodes. It

has 20 reconfigurable analog inputs enabling many sen-

sor connections and configuration options. The LTC2983

includes excitation current sources and fault detection

circuitry appropriate for each type of temperature sensor.

The LTC2983 allows direct interfacing to ground referenced

sensors without the need for level shifters, negative supply

voltages, or external amplifiers. All signals are buffered and

simultaneously digitized with three high accuracy, 24-bit ∆∑

ADCs, driven by an internal 15ppm/°C (maximum) reference.

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Patents Pending

Typical Temperature Error Contribution

0.5

0.4

0.3

0.2

0.1

–0.1

SPI

–0.2

INTERFACE

–0.3

°C/°F

–0.4

–0.5

–200

www.linear.com/LTC2983

LTC2983

THERMISTOR

THERMOCOUPLE

3904 DIODE

RTD

200

400

600 800

1000

1200

1400

TEMPERATURE (°C)

2983 TA01b

2983fc

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Summary of Contents for Linear Technology LTC2983

Page 1: Features
ADCs, driven by an internal 15ppm/°C (maximum) reference. Direct RTD Measurements Direct Thermistor Measurements L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Custom Sensor Applications...
Page 2: Table Of Contents
LTC2983 TABLE OF CONTENTS Features ..........................1 Applications ........................1 Typical Application ....................... 1 Description......................... 1 Absolute Maximum Ratings ..................... 3 Order Information ......................... 3 Complete System Electrical Characteristics .................. 3 Pin Configuration ......................... 3 ADC Electrical Characteristics ....................4 Reference Electrical Characteristics ...................
Page 3: Absolute Maximum Ratings
LTC2983 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2) Supply Voltage (V ) ........–0.3V to 6V TOP VIEW Analog Input Pins (CH1 to CH20, COM) ......... –0.3V to (V + 0.3V) Input Current (CH1 to CH20, COM) ...... ±15mA Digital Inputs (CS, SDI, SCK, RESET) ........
Page 4: Adc Electrical Characteristics
LTC2983 COMPLETE SYSTEM ELECTRICAL CHARACTERISTICS denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C. PARAMETER CONDITIONS UNITS Input Normal Mode Rejection 50Hz (Notes 4, 8) Input Normal Mode Rejection 50Hz/60Hz (Notes 4, 6, 9) Power-On Reset Threshold 2.25...
Page 5: Digital Inputs And Digital Outputs
Note 15: Differential Input Range is ±V Note 10: The exact value of V is stored in the LTC2983 and used Note 16: RTD and thermistor measurements are made ratiometrically. As a for all measurement calculations. Temperature coefficient is measured result current source excitation variation does not affect absolute accuracy.
Page 6: Typical Performance Characteristics
LTC2983 TYPICAL PERFORMANCE CHARACTERISTICS Type J Thermocouple Error and Type K Thermocouple Error and Type N Thermocouple Error and RMS Noise vs Temperature RMS Noise vs Temperature RMS Noise vs Temperature –0.2 –0.2 –0.2 –0.4 –0.4 –0.4 –0.6 –0.6 –0.6...
Page 7 LTC2983 TYPICAL PERFORMANCE CHARACTERISTICS RTD PT-200 Error and RMS Noise RTD PT-100 Error and RMS Noise RTD NI-120 RTD Error and vs Temperature RMS Noise vs Temperature vs Temperature –0.2 –0.2 –0.2 –0.4 –0.4 –0.4 –0.6 –0.6 –0.6 RMS NOISE...
Page 8 –0.8 = 2.85V = 2.85V –1.0 –2.0 –40 –50 –25 –50 –25 DIODE TEMPERATURE (°C) LTC2983 TEMPERATURE (°C) LTC2983 TEMPERATURE (°C) 2983 G27 2983 G13 2983 G14 One Shot Conversion Current vs vs Temperature Temperature vs Temperature SLEEP REFOUT REFOUT 16.0...
Page 9: Pin Functions
LTC2983 PIN FUNCTIONS GND (Pins 1, 3, 5, 7, 9, 12, 15, 44): Ground. Connect cycle is in progress. This pin goes HIGH at the conclusion each of these pins to a common ground plane through a of the start-up state or conversion cycle.
Page 10: Block Diagram
LTC2983 BLOCK DIAGRAM REF_BYP REFP 1µF 0.1µF REFOUT 10ppm/°C REFERENCE 10µF CHARGE PUMP 10µF 10µF ADC1 CH1 TO CH20 21:6 MUX ADC2 INTERRUPT PROCESSOR ADC3 RESET EXCITATION CURRENT SOURCES 2983 BD 2983fc For more information www.linear.com/LTC2983...
Page 11: Test Circuits
LTC2983 TEST CIRCUITS 1.69k 1.69k = 20pF = 20pF LOAD LOAD Hi-Z TO V Hi-Z TO V TO V TO V TO Hi-Z TO Hi-Z 2983 TC01 TIMING DIAGRAM SPI Timing Diagram 2983 TD01 2983fc For more information www.linear.com/LTC2983...
Page 12: Overview
(up sensor element using a table lookup (RTDs) or solving to 14th order) must be solved. The LTC2983 has these Steinhart-Hart equations (thermistors). The LTC2983 auto- polynomials built in for virtually all standard thermocouples matically generates the excitation current, simultaneously (J, K, N, E, R, S, T, and B).
Page 13 LTC2983 OVERVIEW Table 1. LTC2983 Error Contribution and Peak Noise Errors SENSOR TYPE TEMPERATURE RANGE ERROR CONTRIBUTION PEAK-TO-PEAK NOISE Type K Thermocouple –200°C to 0°C ±(Temperature • 0.23% + 0.05)°C ±0.08°C 0°C to 1372°C ±(Temperature • 0.12% + 0.05)°C Type J Thermocouple –210°C to 0°C...
Page 14 Channel assign- ment data resides in memory locations 0x200 to 0x24F The LTC2983 channel assignment, configuration, conver- and can be programmed via the SPI interface as shown in sion start, and results are all accessible via the RAM (see Figure 2.
Page 15 LTC2983 OVERVIEW • • • RECEIVER SAMPLES TRANSMITTER TRANSITIONS DATA ON RISING EDGE DATA ON FALLING EDGE A11 A10 • • • SUBSEQUENT DATA BYTES MAY FOLLOW SPI INSTRUCTION BYTE 16-BIT ADDRESS FIELD FIRST DATA BYTE READ = 0x03 USER MEMORY READ TRANSACTION 2983 F01 Figure 1.
Page 16: Applications Information
State 1: Start-Up CONVERSION (OPTIONAL) The start-up state automatically occurs when power is ap- plied to the LTC2983. If the power drops below a threshold STATUS CHECK COMPLETE? of ≈2.6V and then returns to the normal operating voltage (2.85V to 5.25V), the LTC2983 resets and enters the power- READ RESULTS up state.
Page 17 LTC2983 APPLICATIONS INFORMATION Table 3. Channel Assignment Memory Map CHANNEL ASSIGNMENT CONFIGURATION CONFIGURATION CONFIGURATION CONFIGURATION SIZE (BYTES) NUMBER DATA START DATA DATA DATA END ADDRESS ADDRESS + 1 ADDRESS + 2 ADDRESS + 3 0x200 0x201 0x202 0x203 0x204 0x205...
Page 18 Separate detailed operation CH20 sections for thermocouples, RTDs, diodes, thermistors, and Sleep sense resistors describe the assignment data associated with All Other Combinations Reserved each sensor type in more detail. The LTC2983 demonstration 2983fc For more information www.linear.com/LTC2983...
Page 19 The measurement cycle starts after the initiate conversion CH12 0x03C 0x03F command is written into RAM location 0x000 (Table 6). CH13 0x040 0x043 The LTC2983 simultaneously measures the selected input CH14 0x044 0x047 sensor, sense resistors (RTDs and thermistors), and cold CH15 0x048 0x04B junction temperatures if applicable (thermocouples).
Page 20 LTC2983 APPLICATIONS INFORMATION Table 9A. Example Data Output Words (°C) START ADDRESS START ADDRESS + 1 START ADDRESS + 2 START ADDRESS + 3 (END ADDRESS) D31 D30 D29 D28 D27 D23 D22 D21 D20 D19 D18 D17 D16 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0...
Page 21: Thermocouple Measurements
(see Table 13). When a conversion is performed on a channel tied to a thermocouple, the For each thermocouple tied to the LTC2983, a 32-bit channel cold junction sensor is simultaneously and automatically assignment word is programmed into a memory location measured.
Page 22 LTC2983 APPLICATIONS INFORMATION (3) Sensor Configuration CHANNEL = CH (1≤ TC ≤ 20) ASSIGNMENT The sensor configuration field (see Table 14) is used 0.1µF SINGLE-ENDED to select single-ended (B21=1) or differential (B21=0) – input and allows selection of open circuit current if internal open-circuit detect is enabled (bit B20).
Page 23 LTC2983 APPLICATIONS INFORMATION Fault Reporting – Thermocouple sensor. A valid temperature is reported, but the accuracy may be compromised since the cold junction sensor is Each sensor type has a unique fault reporting mechanism operating outside its normal temperature range. Bits indicated in the upper byte of the data output word.
Page 24: Diode Measurements
Bit B24 enables a running average of the diode temperature reading. This reduces the noise when the diode is used For each diode tied to the LTC2983, a 32-bit channel as- as a cold junction temperature element on an isothermal signment word is programmed into a memory location block where temperatures change slowly.
Page 25 LTC2983 APPLICATIONS INFORMATION (4) Diode Ideality Factor hard error and –999°C or °F is reported. In the case of an excessive noise event, the device should recover and The last field in the channel assignment word (B21 to B0) the following conversions will be valid if the noise event sets the diode ideality factor within the range 0 to 4 with was a random, infrequent event.
Page 26 LTC2983 APPLICATIONS INFORMATION Example: Single-Ended Type K and Differential Type T shown in Tables 22 to 24. Thermocouple #1 (Type K) Thermocouples with Shared Diode Cold Junction sensor type and configuration data are assigned to CH1. Compensation 32-bits of binary configuration data are mapped directly into memory locations 0x200 to 0x203 (see Table 22).
Page 27 0x000. Both the Type K thermocouple a conversion can be initiated on CH4 by writing 10000100 and the diode are measured simultaneously. The LTC2983 into memory location 0x000. The results (in °C) can be calculates the cold junction compensation and determines read from memory locations 0x010 to 0x013 for CH1 and the temperature of the Type K thermocouple.
Page 28: Rtd Measurements
[5:0] [5:0] Channel Assignment – RTD (2) Sense Resistor Channel Pointer For each RTD tied to the LTC2983, a 32-bit channel as- RTD measurements are performed ratiometrically relative signment word is programmed into a memory location to a known R resistor.
Page 29 LTC2983 APPLICATIONS INFORMATION (3) Sensor Configuration sensor using a high impedance Kelvin sensing. 4-wire are useful in applica- measurements with Kelvin R The sensor configuration field is used to define various SENSE tions where sense resistor wiring parasitics can lead to RTD properties.
Page 30 In the case where an RTD not listed in Table 30 is used, resistor with a PT-100 RTD allows 500µA excitation for a custom RTD table may be entered into the LTC2983. any wiring configuration. See Custom RTD section near the end of this data sheet for more information.
Page 31 LTC2983 APPLICATIONS INFORMATION Fault Reporting – RTD is a hard error and –999°C or °F is reported. In the case of an excessive noise event, the device should recover and Each sensor type has unique fault reporting mechanism the following conversions will be valid if the noise was a indicated in the most significant byte of the data output random infrequent event.
Page 32 2-lead RTD elements. The disad- vantages of this topology are errors due to parasitic lead For each sense resistor tied to the LTC2983, a 32-bit resistance. If sharing is not selected (1 R per RTD),...
Page 33 RTD ties to CH17 and CH18 and an NI-120 RTD ties to A conversion is initiated on CH by writing 10010010 into CH19 and CH20. Using this configuration, the LTC2983 can digitize up to nine 2-wire RTDs with a single sense resistor. memory location 0x000. Once the conversion is complete,...
Page 34 LTC2983 APPLICATIONS INFORMATION Table 37. Channel Assignment Data for 2-Wire RTD #2 (NI-120, R on CH , 2-Wire, Shared R , 100µA Excitation Current) SENSE SENSE CONFIGURATION DESCRIPTION # BITS BINARY DATA MEMORY MEMORY MEMORY MEMORY FIELD ADDRESS 0x24C ADDRESS 0x24D...
Page 35 LTC2983 APPLICATIONS INFORMATION Figure 12 shows a typical temperature measurement sys- errors due to thermocouple effects or mismatched lead tem using a 3-wire RTD. In this example, a 3-wire RTD’s resistances. The RTD sensor type and configuration data terminals tie to CH...
Page 36 LTC2983 APPLICATIONS INFORMATION A conversion is initiated on CH by writing 10001001 into Sense resistor channel assignments follow the general convention shown in Figure 14. The sense resistor is tied memory location 0x000 . Once the conversion is complete, the INTERRUPT pin goes HIGH and memory location...
Page 37 LTC2983 APPLICATIONS INFORMATION Figure 15 shows a typical temperature measurement 32 bits of binary configuration data are mapped directly system using a 4-wire RTD. In this example, a 4-wire into memory locations 0x228 to 0x22B (see Table 42). RTD’s terminals tie to GND, CH...
Page 38 GND, as in the standard case. This data is mapped into a memory location corresponding to RTD+1 allows the LTC2983 to automatically change the direc- RSENSE tion of the current source without the need for additional external components.
Page 39 LTC2983 APPLICATIONS INFORMATION Figure 18 shows a typical temperature measurement The user programmable value of this resistor is 10.0102kΩ. system using a rotating 4-wire RTD. In this example 32 bits of binary configuration data are mapped directly a 4-wire RTD’s terminals tie to CH...
Page 40 Tables 45 to 47. system using two 4-wire RTDs with a shared R SENSE The LTC2983 can support up to six 4-wire RTDs with A conversion is initiated on CH by writing 10010000 into a single sense resistor. In this example, the first 4-wire memory location 0x000.
Page 41 LTC2983 APPLICATIONS INFORMATION Table 46. Channel Assignment Data for 4-Wire RTD #2 (PT-500, R on CH , 4-Wire, Rotated 50µA Excitation Current, SENSE α = 0.003911 Curve) CONFIGURATION DESCRIPTION # BITS BINARY DATA MEMORY MEMORY MEMORY MEMORY FIELD ADDRESS 0x248...
Page 42 LTC2983 APPLICATIONS INFORMATION Figure 21 shows a typical temperature measurement system configuration are not used then terminal 1 of the RTD is tied to using a 4-wire RTD with a Kelvin connected R . In this ground instead of CH , freeing up one input channel.
Page 43: Thermistor Measurements
Channel Assignment – Thermistor bits (B31 to B27) as shown in Table 51. Linearization coef- For each thermistor tied to the LTC2983, a 32-bit channel ficients based on Steinhart-Hart equation for commonly assignment word is programmed into a memory location...
Page 44 (see Table 52). current can be selected. In this case, the LTC2983 conver- The next sensor configuration bits (B19 and B20) deter- sion is performed in three cycles (instead of the standard mine the excitation current mode.
Page 45 LTC2983 APPLICATIONS INFORMATION Fault Reporting – Thermistor This is a hard error and –999°C is output. In the case of an excessive noise event, the device should recover and Each sensor type has unique fault reporting mechanism in- the following conversions will be valid if the noise event dicated in the upper byte of the data output word.
Page 46 LTC2983 APPLICATIONS INFORMATION Table 55. Thermistor Temperature/Resistance Range THERMISTOR TYPE MIN (Ω) MAX (Ω) LOW Temp Limit (°C) HIGH Temp Limit (°C) Thermistor 44004/44033 2.252kΩ at 25°C 41.9 75.79k –40 Thermistor 44005/44030 3kΩ at 25°C 55.6 101.0k –40 Thermistor 44007/44034 5kΩ at 25°C 92.7...
Page 47 LTC2983 APPLICATIONS INFORMATION Figure 24 shows a typical temperature measurement A conversion is initiated on CH by writing 10000101 into system using a single-ended thermistor. In this example memory location 0x000. Once the conversion is complete, a 10kΩ (44031 type) thermistor is tied to a 10.1kΩ sense the INTERRUPT pin goes HIGH and memory location resistor.
Page 48 LTC2983 APPLICATIONS INFORMATION Example: Differential Thermistor Sense resistor channel assignments follow the general convention shown in Figure 26. The sense resistor is tied The differential thermistor configuration allows separate between CH and CH , where CH RSENSE RSENSE-1 RSENSE ground sensing for each sensor. In this standard differ- tied to the 2nd terminal of the thermistor.
Page 49 LTC2983 APPLICATIONS INFORMATION Figure 27 shows a typical temperature measurement A conversion is initiated on CH by writing 10001101 into system using a differential thermistor. In this example a memory location 0x000. Once the conversion is complete, 30kΩ (44032 type) thermistor is tied to a 9.99kΩ sense the INTERRUPT pin goes HIGH and memory location resistor.
Page 50 LTC2983 APPLICATIONS INFORMATION Example: Shared/Rotated Differential Thermistor Sense resistor channel assignments follow the general convention shown in Figure 29. The sense resistor is tied The differential thermistor configuration allows separate between CH and CH , where CH is tied RSENSE...
Page 51 LTC2983 APPLICATIONS INFORMATION a 30kΩ (44032 Type) thermistor is tied to a 10.0kΩ sense A conversion is initiated on CH by writing 10010010 into resistor and configured as rotated/shared. The second memory location 0x000. Once the conversion is complete, thermistor a 2.25kΩ (44004 Type) is configured as a the INTERRUPT pin goes HIGH and memory location non-rotated/shared.
Page 52 LTC2983 APPLICATIONS INFORMATION Table 61. Channel Assignment Data Differential Thermistor (44004/44033 2.252kΩ at 25°C Type Thermistor, Differential Configuration with Sharing and No Rotation, R on CH , 10µA Excitation Current) SENSE Configuration Description # Bits Binary Data MEMORY MEMORY MEMORY...
Page 53 For example, the thermocouple tied to CH1 can use the diode tied to CH2 as a cold junction sensor. However, any The LTC2983 includes 20 fully configurable analog input thermocouple (CH1, CH3, CH5, CH6, CH9, CH10, or CH16) channels. Each input channel can be configured to accept can use any diode (CH2, CH4, or CH7), RTD (CH13, CH14), any sensor type.
Page 54 (CH1, CH2) is shared between a 4-wire RTD (CH4, CH3), a 2-wire RTD (CH7, CH6), two 3-wire RTDs (CH9, CH8 and The LTC2983 includes 20 fully configurable analog input CH11, CH10) and a thermistor (CH13, CH12). This can channels. Each input channel can be configured to accept be mixed with diode sensors (CH15) and thermocouples any sensor type.
Page 55: Direct Adc Measurements
0xF400 0000 for single-ended. The positive input channel ties to CH for both single-ended In addition to measuring temperature sensors, the LTC2983 and differential modes. For single-ended measurements can perform direct voltage measurements. Any channel the ADC negative input is COM while for differential mea-...
Page 56 Readings beyond ±1.125 • V /2 exceed the normal ac- differential input voltage (±V /2) and V /2 common curacy range of the LTC2983 and flag a soft error; these mode input voltage. results should be discarded. Readings beyond ±1.75 • –5 –5 –10...
Page 57: Fault Protection And Anti-Aliasing
Since LTC2983. The most common input circuitry is a low pass a thermistor’s resistance varies many orders of magni- filter with 1k to 10k resistance (limited by excitation current tude, the performance in the low resistance regions are for RTDs and thermistors) and a capacitor with 100pF-0.1µf...
Page 58: Running Conversions Consecutively On Multiple Channels
Entering/Exiting Sleep Mode Running Conversions Consecutively on Multiple Channels The LTC2983 can be placed into sleep mode by writing 0x97 to memory location 0x000. On the rising edge of Generally, during the Initiate Conversion state, a conver- sion measurement is started on a single input chan-...
Page 59: Global Configuration Register
(memory location 0x0F0, see Figure 37). This register is used to set the notch frequency of the digital filter and The mechanical stress of soldering the LTC2983 to a PC temperature results format (°C or °F). The default setting is board can cause the output voltage reference to shift and temperature coefficient to change.
Page 60 CUSTOM THERMOCOUPLES a slope determined by points P8 and P9 (the final two In order to program the LTC2983 with the custom ther- table entries). Voltage readings below point P1 are also mocouple table, both the mV data and the Kelvin data are reported as soft faults.
Page 61 Kelvin as an unsigned value, but the memory location 0x250 (starting address is 0). The start- final temperatures reported by the LTC2983 are reported ing address (offset from 0x250) is entered in the custom in °C or °F . The sensor temperature (Kelvin), follows the...
Page 62: Custom Rtds
LTC2983 CUSTOM RTDS In addition to digitizing standard RTDs, the LTC2983 Custom RTD Example can also digitize custom RTDs (RTD type=0b10010, see In this example, a simplified RTD curve is implemented (see Table 26). Custom sensor data (minimum of three, maxi- Figure 39).
Page 63 0x3CF . values are input in Kelvin as an unsigned value, but the In order to program the LTC2983 with the custom RTD final temperatures reported by the LTC2983 are reported table, both the resistance data and the Kelvin data are in °C or °F .
Page 64 LTC2983 CUSTOM RTDS convention shown in Table 75, where the first 14 bits at memory location 0x28C (starting address is 10). The are the integer part and the remaining 10 bits are the starting address (offset from 0x250) is entered in the fractional part.
Page 65: Custom Thermistors
In addition to digitizing standard thermistors, the P9 result in a soft fault and the reported temperature is LTC2983 can also digitize custom thermistors (thermistor a linear extrapolation using a slope determined by points type=0b11011, see Table 51). Custom sensor data (mini- P8 and P9 (the final two table entries).
Page 66 0x3CF . final temperatures reported by the LTC2983 are reported In order to program the LTC2983 with the custom therm- in °C or °F . The sensor temperature (Kelvin) follows the istor table, both the resistance data and the Kelvin data convention shown in Table 79, where the first 14 bits are converted to 24-bit binary values.
Page 67 LTC2983 CUSTOM THERMISTORS starting address (offset from 0x250) is entered in the In this example, a custom thermistor tied to CH5, with a custom thermistor data pointer field of the channel as- sense resistor on CH3/4, is programmed with the channel assignment data shown in Table 80 (refer to Figure 24 signment data.
Page 68 Steinhart-Hart data is stored sequentially in any memory possible to directly input Steinhart-Hart coefficients into location greater than or equal to 0x250 and below 0x3CF . the LTC2983 (thermistor type 11010, see Table 51). Each coefficient is represented by a standard, single- Steinhart-Hart coefficients are commonly specified precision, IEEE754 32-bit value (see Table 81).
Page 69 CONFIGURATION SEE TABLE measurement device. Up to four sets of universal inputs OPTIONS BITS can be applied to a single LTC2983. Each of these sets can 3-WIRE RTD Share B18 = 1, B19 = 0 Table 28 directly digitize a 3-wire RTD, 4-Wire RTD, Thermistor, or...
Page 70: Package Description
PACKAGE IN TRAY LOADING ORIENTATION 2983fc Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- For more information www.linear.com/LTC2983 tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
Page 71: Revision History
LTC2983 REVISION HISTORY DATE DESCRIPTION PAGE NUMBER 07/15 Removed Tape and Reel options Added Absolute Maximum Ratings for Q , LDO, V REFOUT REF_BYP Changed reference Output Voltage Temperature Coefficient Changed Error Contribution for thermocouples Changed filter capacitor values in Figures 9, 12, 15, 18, 19, 21...
Page 72: Typical Application
RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC2984 Multi-Sensor High Accuracy Digital Pin/Software Compatible Version of LTC2983 with Integrated EEPROM Temperature Measurement System with EEPROM LTC2990 Quad I C Temperature, Voltage and Remote and Internal Temperatures, 14-Bit Voltages and Current, Internal 10ppm/°C...

Linear Technology LTC2983 Manual

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FEATURES

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TYPICAL APPLICATION

DESCRIPTION

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