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LINEAR Data Acquisition Circuit Collection Application Note 62

Summary

This detailed technical application note serves as a comprehensive guide for designing high-precision data acquisition and measurement systems. It features various circuit configurations, including 8-, 10-, and 12-bit analog processing for highly specialized applications. The coverage includes advanced battery monitoring circuits, accurate temperature sensing using RTDs and thermistors across extreme ranges, isolated communication interfaces, and diverse signal conditioning methods. This resource is essential for electrical engineers and designers developing demanding remote monitoring equipment or scientific measurement devices requiring robust data logging capabilities.

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Application Note 62 October 1994

Data Acquisition Circuit Collection Kevin R. Hoskins

INTRODUCTION

This application note features 8-, 10-, and 12-bit data Additional circuit information is located in the information acquisition components in various circuit configurations. references listed in the Circuit Index. Each information The circuits include battery monitoring, temperature sens- reference refers to either an application note (example: ing, isolated serial interfaces, and microprocessor and AN42 = Application Note 42), a data sheet (example: microcontroller serial and parallel interfaces. Also in- LTC®1292 DS = LTC1292 Data Sheet), or a design note cluded are voltage reference circuits (Application Note 42 (example: DN66 = Design Note 66).

contains more voltage reference circuits).

and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation.

CIRCUIT INDEX

INFORMATION

FIGURE TITLE FIGURE NO. PAGE REFERENCE/SOURCE General Analog-to-Digital Application Circuits Two-Quadrant 150k Hz Bandwidth Analog Multiplier Figure 1 AN62-3 LTC1099 DS Infinite Hold-Time Sample-and-Hold (t ACQ = 240ns) Figure 2 AN62-3 LTC1099 DS Four-Quadrant 250k Hz Bandwidth Analog Multiplier Figure 3 AN62-4 Demodulating a Signal Using Undersampling Figure 4 AN62-4 LTC1257 DS Complete 100ps Resolution ∆Time Circuit with “Bow” Correction Figure 5 AN62-5 LTC1282 DS Single 5V 12-Bit Temperature Control System with Shutdown........................................ Figure 6 AN62-6 LTC1257 DS Weight Scale Figure 7 AN62-6 LTC1091/2/3/4 DS Auto-Ranging 8-Channel 12-Bit Data Acquisition System with Shutdown Figure 8 AN62-7 LTC1257 DS Analog-to-Digital Battery Monitoring Application Circuits Micropower Battery Voltage Monitor Figure 9 AN62-8 LTC1096/8 DS 0A to 2A Battery Current Monitor Draws Only 70µA Figure 10 AN62-8 LTC1096/8 DS LTC1297 Data Acquisition System Micropower Battery Current Monitor Figure 11 AN62-9 Temperature Sensing and Conversion Current Output Silicon Sensor Thermometer Driving 10-Bit Analog-to-Digital Converter Covers –55°C to 125°C with 0.2°C Resolution Figure 12 AN62-9 LTC1091/2/3/4 DS Thermistor-Based Temperature Measurement System Covers 20°C to 40°C and 0°C to 100°C with 0.25°C Accuracy Figure 13 AN62-10 LTC1091/2/3/4 DS Digitally Linearized Platinum RTD Signal Conditioner Figure 14 AN62-10 LTC1091/2/3/4 DS Furnace Exhaust Gas Temperature Monitor Covers 0°C to 500°C and Has Low Supply Detection Figure 15 AN62-11 LTC1091/2/3/4/DS Isolated Interfaces Floating Analog-to-Digital Conversion System Powered by Capacitor Charge Pump Figure 16 AN62-11 LTC1096/8 DS Micropower Serial 10-Bit Data Acquisition System with 500V Opto-Isolated Communication Figure 17 AN62-12 LTC1091/2/3/4 DS Opto-Isolated Temperature Monitor Figure 18 AN62-13 LTC1292 DS Battery-Powered Digital Thermometer Transmits Over RF-Link Figure 19 AN62-13 LTC1092 10-Bit Analog-to-Digital Converter Receives Power and Transmits Data Over Two Transformer-Isolated Lines Figure 20 AN62-14 DN19

AN62-1

Page Summary Contents For LINEAR Data Acquisition Circuit Collection Application Note 62

Page 1 Application Note 62 October 1994 Data Acquisition Circuit Collection Kevin R. Hoskins INTRODUCTION This application note features 8-, 10-, and 12-bit data Additional circuit information is located in ...
Page 2 Application Note 62 INFORMATION FIGURE TITLE FIGURE NO. PAGE REFERENCE/SOURCE Miscellaneous Circuits Two LTC1390s Cascadable Serially Programmed 8-Channel Multiplexers Provide the Single Channel LTC10...
Page 3 Application Note 62 INFORMATION FIGURE TITLE FIGURE NO. PAGE REFERENCE/SOURCE Appendices Analog-to-Digital/Digital-to-Analog Converter Selection Guides Appendix A AN62-24 Voltage Reference Selection G...
Page 4 Application Note 62 –5V ≤ VIN1 ≤ 5V –10V ≤ VIN2 ≤ 5V AIN D11 D11 VREF VREF D10 D10 IOUT1 SAMPLE CLOCK CONVST D9 D9 IOUT2 LT1122 VOUT (f SAMPLE ≤ 500k Hz) BUSY D8 D8 RFB SHDN D7 D7 GND RD D6 D6 XFER DA...
Page 5 Application Note 62 ∆T IM LI NE AR IT ER RO (n s) REFOUT VDD 12-BIT LM134 AIN LTC1282 DATA 250p F OUTPUT 45.3Ω POLYSTYRENE CS VSS GND RD BUSY 74HC03 1N457 74HC74 START↑ CLK CLR 1N4148 1k 10k DATA 3.3V...
Page 6 Application Note 62 VCC–IN CS/ CS POWER DOWN DOUT CLK VIN +IN CLK DATA µP LTC1297 LT1025A DAC LOAD GND COMM VREF GND LTC1050 VCCVREF DIN CLK CONTROL LTC1257 1k VOUT OUTPUT DAC LOAD DOUT GND AN62 F06 F...
Page 7 Application Note 62 5V 22µF VCCCH0 LTC1296 8 ANALOG INPUT CHANNELS CH7 CLK COM DIN REF+ SSO REF– 74HC04 VREFVCC DIN 100Ω DAC1 CLK VOUT LTC1257 0.1µF DOUT VREFVCC DIN 100Ω CLK VOUT LTC1257 0.1µF DOUT N...
Page 8 Application Note 62 ANALOG-TO-DIGITAL BATTERY MONITORING APPLICATION CIRCUITS BATTERY MONITOR INPUT 8V TO 16V +IN 0.1µF LTC1096 CLOCK VREF GND LT1004-1.2 AN62 F09 Figure 9. Micropower Battery Voltage ...
Page 9 Application Note 62 IN OUT LT1121 GND SHDN 6V TO 0.1µF CS VCC TO µP– 0.005Ω 10Ω TANT 2A FULL +IN CLK LTC1047 LTC1297 SCALE –IN DOUT LO BATTERY GND VREF LT1004-2.5 LTC1047 AN62 F11 Figure 11. LTC1297 D...
Page 10 Application Note 62 YSI 44201 CHO VCC CH1 ACLK 0°C TO 100°C CH2 SCLK CH3 DIN LTC1090 YSI 44201 CH4 DOUT MCU 5k AT 25°C CH5 CS 20°C TO 40°C CH6 REF+ CH7 REF– 2954Ω COM V– LT1006 DGND AGND *YSI 44007 OR...
Page 11 Application Note 62 LT1019A-5 0.1µF GND 10µF LT1025A J TYPE 1N4148 GND COMMON CS VCC TO 47Ω MCU 1µF LTC1052 CH0 CLK LTC1091A CH1 DOUT GND DIN AN62 F15 Figure 15. Furnace Exhaust Gas Temperature Monito...
Page 12 Application Note 62 NC NC VIN NC 51k 150Ω LT1021-5 NC VOUT GND TRIM 1Ω 10k SCK CHO DVCC CH1 AVCC 4N28 CH2 CLK 10k C0 ANALOG CH3 CS INPUTS CH4 DOUT TO 0V TO 5V LTC1094 68HC05** RANGE CH5 DIN CH6 REF+ 4...
Page 13 Application Note 62 ISOLATED 5V 0.1% 0.1% 0.1% LT1019-2.5 10k 1k CLK IN LTC1292 0.1µF CS VCC LTC1050 +IN CLK +– –IN DOUT GND VREF LT1025A 5V RGND 1 F 1µF TYPE J 4N28 DATA 0°C TO 500°C TEMPERATURE RANG...
Page 14 Application Note 62 74HC132 LT1021-5 CS VCC +IN CLK LTC1092 –IN DOUT GND VREF 750p F 10k 74HC04 74HC00 74HC132 74HC04 CLR RIPPLE 74HC04 CARRY CLK VCC QA 75k 74HC00 74HC161 QB QC 1N4148 QD 74HC04 ENABL...
Page 15 Application Note 62 MISCELLANEOUS CIRCUITS CH0 S0 V+ LTC1390 5V CH1 S1 0.1µF S2 V– CS VCC S3 DATA2 +IN CLK LTC1096 S4 DATA1 –IN DOUT S5 CS GND VREF OPTIONAL ADC CH6 S6 CLK INPUT FILTER CH7 S7 GND CH8 ...
Page 16 Application Note 62 RB 5.1k R2 74HC04 1.2M CH0 VCC 5V R1 1/4 LT1014 CH1 SSO CH2 CLK CH3 CS 350Ω STRAIN MPU GAUGE BRIDGE CH4 DOUT LTC1296 1N4148 CH5 DIN C2 CH6 REF+ AN62 F23 CH7 REF– COM AGND DGND V–TH...
Page 17 Application Note 62 VREF VCC P1.4 +IN CLK P1.3 DIFFERENTIAL INPUTS (e.g. 8051) COMMON-MODE RANGE LTC1286 0V TO 5V –IN P1.2 SERIAL DATA LINK GND CS/SHDN AN62 F27 OUT IN 100k TRIM HEATER NC LT1019-2.5 0...
Page 18 Application Note 62 CS P1.4 CS C0 CH0 CLK P1.3 CH0 SCLK SCK LTC1091 LTC1091 MC68HC05C4 CH1 DOUT P1.2 CH1 DIN MOSI MUX ADDRESS DIN DOUT MISO A/D RESULT AN62 F32 AN62 F33 Figure 32. LTC1091* to Intel 80...
Page 19 Application Note 62 3-WIRE SERIAL INTERFACE TO OTHER PERIPHERALS OR LTC1290s OUTPUT PORT SERIAL DATA CS CS LTC1290 LTC1290 AN62 F37 8 CHANNELS 8 CHANNELS Figure 37. Multiple LTC1290s Sharing One Three...
Page 20 Application Note 62 9V LT1201-5 10µF 2MHz CLOCK CHO VCC CH1 ACLK MC68HC05C4 OTHER CHANNELS CH2 SCLK SCK OR SNEAK-A-BIT CH3 DIN MOSI INPUTS LTC1090 MISO CH4 DOUT CH5 CS C0 CH6 REF+ –5V TO 5V CH7 REF– C...
Page 21 Application Note 62 INPUT 7.2V TO 40V (UNREGULATED) f0SC ≅ 300k Hz 14, 13, 12, 11, 10, 4 LT1021-5 RS232 C2 POWERED OPTION (LTC1090 C4 ONLY) GND CHO VCC CLR CH1 ACLK CH2 SCLK CH3 DIN ANALOG INPUTS CH4 ...
Page 22 Application Note 62 A16 PA2 ADDRESS BUS PORT ADDRESS BUS A1 PA0 ADDRESS ADDRESS IS DEN DECODEEN DECODEEN TMS320C25 TMS32010 CS CS READY LTC1272 LTC1273 LTC1275 R/W RD LTC1282 RD LTC1276 DATA BUS DATA ...
Page 23 Application Note 62 RL RL VIN VIN VOUT VOUT 2.500V ±10m V 2.500V ±10m V TC (TYP) = 50ppm/°C TC (TYP) = 30ppm/°C CATHODE V+ COLL 8-BIT (±1LSB) INITIAL ACCURACY 8-BIT (±1LSB) INITIAL ACCURACY REF REF 9-...
Page 24 Application Note 62 APPENDIX A 8-BIT 10-BIT 12-BIT MULTIPLEXED LT574A µPOWER SO-8 COMPLETE MULTIPLEXED WITH SECOND 3V OR 5V HIGH SPEED SHUTDOWN SOURCE LTC1096 – 1 CHANNEL LTC1098 – 2 CHANNEL 5V 5V 5V ...
Page 25 Application Note 62 TOTAL MAXIMUM PART RESOLU- UNADJUSTED SAMPLE VOLTAGE SUPPLY PKGS. IMPORTANT NUMBER DESCRIPTION TION ERROR RATE SUPPLY CURRENT AVAIL. FEATURES LTC1094C,M 10-Bit, Serial I/O. A/D 10 ...
Page 26 Application Note 62 TOTAL MAXIMUM PART RESOLU- UNADJUSTED SAMPLE VOLTAGE SUPPLY PKGS. IMPORTANT NUMBER DESCRIPTION TION ERROR RATE SUPPLY CURRENT AVAIL. FEATURES LTC1276C 12-Bit, 2.7µs, 300ksps 12 Bit...
Page 27 Application Note 62 TOTAL MAXIMUM PART RESOLU- UNADJUSTED SAMPLE VOLTAGE SUPPLY PKGS. IMPORTANT NUMBER DESCRIPTION TION ERROR RATE SUPPLY CURRENT AVAIL. FEATURES LLTC1288C 12-Bit, 8-Pin, Serial I/O, 1...
Page 28 Application Note 62 Digital-to-Analog Converter Selection Guide TOTAL MAXIMUM PART RESOLU- UNADJUSTED SETTLING VOLTAGE SUPPLY PKGS. IMPORTANT NUMBER DESCRIPTION TION ERROR TIME SUPPLY CURRENT AVAIL. F...

Manual Details

Brand Linear
Pages 28
File Size 340.53 KB
Published June 18, 2026
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Frequently Asked Questions

What type of circuits are covered by Application Note 62?

The note features various data acquisition circuits using 8-, 10-, and 12-bit resolution components for applications like battery monitoring, temperature sensing, and measurement multipliers.

Can the LTC1390 multiplexers be cascaded?

Yes, two LTC1390s can be cascadable serially programmed to provide single channel selection from a larger array, such as connecting an LTC1096 with 16 analog inputs.

What is the temperature range covered by the AN62-9 system?

Figure 12 covers -55°C to 125°C with 0.2°C resolution, while Figure 13 offers measurement systems covering specific ranges like 20°C to 40°C or 0°C to 100°C.

What is the supply voltage range for the LTC1257C,I?

The LTC1257C,I supports a wide supply range from 5V to 15.5V.

Are there dedicated circuits for battery monitoring and current sensing?

Yes, the manual details several sections (AN62-8 and AN62-9) covering micropower battery voltage and current monitors, using parts like LTC1096/8.