Makes a Measurement Function Pack Design Guide Devices for use with Sensors

Transcription

1 Analog and Interface Product Solutions Makes a Measurement Function Pack Design Guide Devices for use with Sensors Design ideas in this guide are based on many of the devices featured in Microchip Technology's Makes a Measurement Function Pack. A complete device list and corresponding data sheets for these products can be found at Design ideas in this guide use the following devices. Devices in BOLD type are also included in the funpack : Programmable Gain Amplifier Operational Amplifiers MCP6S2x family (MCP6S21, MCP602, MCP606/7/8/9, MCP6S22, MCP6S26, MCP6S28) MCP607, MCP617, MCP619, MCP6022, MCP6024, MCP6042, TC7650/7652, TC913A/B Analog-to-Digital Converters MCP3002, MCP3301 Temperature Sensors TC1047A Comparators MCP6541 Voltage References MCP1525, MCP1541 Digital Potentiometers MCP42010 MCP42050 MCP42100 This guide is a companion to the Makes a Measurement functional sample pack ( funpack ). Contact your local Microchip sales person for additional information.

2 Measurement Overview Microchip Technology has integrated analog technology, peripherals and features to meet today's demanding measurement design requirements. Microchip s extensive analog portfolio includes operational amplifiers and programmable gain amplifiers, voltage references, digital potentiometers, analog-to-digital converters, and silicon IC temperature sensors. These innovative products are combined with time saving application notes and design software to ease the integration of these products into your sensing systems. Programmable Gain Amplifier (PGA) with Built-in Analog Multiplexer The MCP6S21, MCP6S22, MCP6S26 and MCP6S28 Programmable Gain Amplifiers offer 1, 2, 6 or 8 input channels respectively and eight steps of gain. These devices are programmable over an SPI bus and thus add gain control and input channel selection to the embedded control system. This is all achieved in one simple integration that allows for considerable greater bandwidth at a low supply current. Product Overviews Operational Amplifiers Microchip Technology offers a broad portfolio of Operational Amplifiers (Op Amps), Comparators and Integrated Op Amp/Comparators. The Op Amp families include devices that operate with I Q as low as 0.6 µa and others with Gain Bandwidth Product (GBWP) up to 10 MHz. These Op Amp families offer some of the lowest I Q for a given GBWP in the industry. Additionally, all of Microchip s Op Amps operate on a single supply up to 5.5V, and depending on the family, as low as 1.4V. All Microchip Op Amps offer rail-to-rail output with most also offering rail-to-rail input. Some of the families have been designed to minimize V OS resulting in offsets as low as 5 µv. This design guide includes Op Amps from the following product families: the MCP60x, MCP61x, MCP602x, MCP604x, MCP62xx, MCP765x, TC913A/B and TC10xx. These families offer single, dual or quad amplifiers in space-saving packages with low operating currents, and advanced CMOS technology. These amplifiers were designed with the embedded control system in mind. The typical complexity of multiple sensor systems is reduced to one amplifier that the microcontroller (MCU) or processor can control. This reduces the demand on the I/O of the MCU and allows control over the level of gain. One superior amplifier can be used to perform the functions of multiple amplifiers at a lower cost and with less space. Voltage References Microchip offers the MCP15xx family of low power and low dropout precision Voltage References. The family includes the MCP1525 with an output voltage of 2.5V and the MCP1541 with an output voltage of 4.096V. Microchip s voltage references are offered in SOT23-3 and TO-92 packages. Digital Potentiometers (SPI Controlled) The MCP41xxx and MCP42xxx family of digital potentiometers combine high performance and low power consumption in a small package, making them ideal for embedded control applications. Analog-to-Digital Converters (ADC) Microchip offers a broad portfolio of high-precision SAR, Sigma-Delta and Dual Slope A/D Converters. The MCP300x (10-bit), MCP320x (12-bit) and MCP330x (13-bit) SAR ADCs combine high performance and low power consumption in a small package, making them ideal for embedded control applications. The TC34xx Sigma Delta ADCs are optimized for use with a microcontroller in low cost, battery-operated systems. The TC5xx Dual Slope ADC devices offer another alternative with up to 17-bits of conversion resolution. 2

3 Devices for both Local and Remote Sensing Applications Microchip has a wide variety of Op Amps to meet your sensing requirements for both remote and local sensing applications. The definition of a remote or local sensor is arbitrary and in high noise environments all sensors should be considered as remote sensors. A good design rule is to consider any sensor that is not located on the same PCB as the signal conditioning circuitry as a remote sensor. Remote sensing applications typically use a differential amplifier or an instrumentation amplifier, while local sensing can use a non-inverting or inverting amplifier. Remote Sensing Pressure Sensors Strain Gauges Key Amplifier Specifications Differential Input Large CMRR Small V OS Microchip products: MCP616/7/8/9 TC913A/B TC7650/7652 Sensors and Applications Thermocouples for stoves, engines and process control Wheatstone Bridge Pressure Sensors for automotive and industrial control Strain gauges for engines Low side current monitors for motors and batteries Local Sensing Key Amplifier Specifications Single-ended Input Rail-to-Rail Input/Output Amplifier Gain Bandwidth Product Microchip products: MCP6001/2/4 MCP6271/2/3/4 MCP601/2/3/4 MCP6281/2/3/4 MCP6021/2/3/4 MCP6291/2/3/4 MCP6041/2/3/4 MCP6141/2/3/4 MCP606/7/8/9 MCP6S21/2/6/8 Sensors and Applications Thermistors for battery chargers and power supply over temperature protection Humidity Sensors for process control Pyroelectric infrared intrusion alarms, motion detection and garage door openers Smoke and fire sensors for home and office Charge amplifier for Piezoelectric transducers 3

4 Amplifier: Example Designs for use with Local Sensors Local sensors are located relatively close to their signal conditioning circuits; therefore, the noise environment is not usually as severe as with remote sensors. In local sensing applications, non-inverting amplifiers are a good choice because they require a minimal amount of discrete components. New Product - Programmable Gain Amplifier This is a common sensor amplifier implementation and could be used in many sensor applications. MCP60x, MCP600x, MCP602x, MCP604x, MCP627x, MCP628x, MCP629x, MCP614x Input MUX 1, 2, 6, and 8 Channel Versions Low Bias Current Low Input Capacitance MCP42010 MCP42050 MCP42100 Amplifier High performance Constant BW (~ 2 to 12 MHz) Gain Accuracy < ±1% Input Offset Voltage < ±150 µv Applications Multiple local sensor applications Thermopiles which require a thermocouple and thermistor interface circuit Dew point sensors that require a humidity and temperature measurement MCP6S21/2/6/8 Programmable Gain Amplifier Features: SPI bus Programmable Gain Amplifiers Built-in analog Multiplexer 1, 2, 6 or 8 input channels, and eight steps of gain Since these devices are programmable over an SPI bus, they add gain control and input channel selection to the embedded control system in one simple integration that allows for considerably greater bandwidth at a low supply current. Product specifications can be found on page 10 4 Infrared Motion Detector Temperature Intolerant Gain Amplifier Amplifier Selection Criteria Rail-to-Rail Input / Output Swing Industrial Temperature Control Precision Instrumentation MCP60x, MCP600x, MCP602x, MCP604x, MCP627x, MCP628x, MCP629x, MCP6S2x Applications Thermistor for battery chargers and home thermostats LVDT position and rotation sensors for industrial control Hall effect sensors for engine speed sensing and door openers Photoelectric infrared detector Photoelectric motion detectors, flame detectors, intrusion alarms MCP6021/2/3/4 Operational Amplifier Features: Rail-to-Rail Input/Output, GBWP 10 MHz (typical) Low Noise: 8.7 nv/rthz, at 10 khz (typical) Low Offset Voltage: 500 µv (max.), at 25 C MCP6041/2/3/4 Operational Amplifier Features: Low Quiescent Current: 600 na/amplifier (typical) Rail-to-Rail Input: -0.3V to V DD +0.3V (max.) Rail-to-Rail Output: V SS +10mV to V DD -10mV (max.)

5 Amplifier: Example Design for Temperature Sensors Remote Temperature Measurement: Thermocouple Circuit The most widely measured phenomena in the process control environment is temperature. Common elements, such as Resistance Temperature Detectors (RTDs), thermistors, thermocouples or silicon IC sensors are used to sense absolute temperatures, as well as changes in temperature. Remote sensors are connected to the amplifier via long wires, which often introduce noise into the electronics. The Common Mode Rejection Ratio (CMRR) of a differential amplifier is used to minimize the noise signal that is induced and common to both sensor inputs. Attributes Good Noise Immunity Built In Test (BIT) Sensor Fault Identification Applications Engine Control Industrial Temperature Process Control MCP617 Dual Operational Amplifier Features: Low Power: I DD = 25 µa, max. Low Offset Voltage: 150 µv, max. Rail-to-Rail Swing at Output Low Input Offset Current: 0.3 na, typical Specifications rated for 2.3V to 5.5V Supplies Unity Gain Stable CMRR: 100 db, typical TC913A/TC913B Dual Auto-Zeroed Features: First Monolithic Dual Auto-Zeroed Op Amp Chopper Amplifier Performance without External Capacitors V OS : 15 µv max. V OS : Drift; 0.15 µv/ C max. Saves Cost of External Capacitors SOIC Packages Available High DC Gain; 120 db Low Supply Current; 650 µa Product specifications can be found on page 10 Low Input Voltage Noise 0.65 mv PP (0.1 Hz to 10 Hz) High CMRR: 116 db, typical MCP3002 Analog-to-Digital Converter Features: 2.7V Dual Channel 10-Bit A/D Converter with SPI Serial Interface ±1 LSB max. DNL; ±1 LSB max. INL Analog inputs programmable as single-ended or pseudo-differential pairs Single supply operation: 2.7V - 5.5V Low power CMOS technology: 5 na typical standby current, 2 µa max.; 550 µa max. active current at 5V TC1047A Temperature-to-Voltage Converter Features: Output voltage is directly proportional to measured temperature Accurately measures temperature from -40 C to +125 C High temperature converter accuracy: ±2 C max., at 25 C Linear temperature slope: 10mV/ C (typical) Available in space saving 3-pin SOT-23B packages 5

6 Amplifier: Example Designs with Oscillators for Resistive and Capacitive Sensors RC Operational Amplifier Oscillators for Sensor Applications Op Amp oscillators can be used to accurately measure resistive and capacitive sensors. Oscillators do not require an analog-to-digital converter and provide a sensor measurement whose accuracy is only limited by the accuracy of the reference clock signal. In addition, temperature correction can easily be provided with a silicon temperature sensor. State Variable Oscillator Attributes Precision circuit for either resistive or capacitive sensors Reliable oscillator start-up Circuit topology is relatively immune from stray capacitance, thus circuit can be used to accurately sense small valued capacitive sensors located off the PCB Product specifications can be found on page 10 6 Related Application Note AN866 Designing Operational Amplifier Oscillator Circuits For Sensor Applications (available for download from Microchip products: MCP6001/2/4 MCP6021/2/3/4 MCP6271/2/3/4 MCP6281/2/3/4 MCP6291/2/3/4

7 Amplifier: Example Designs Wheatstone Bridge Sensor Circuit Microchip produces complete solutions for your system sensor requirements. The instrumentation amplifier shown below, provides a low cost circuit to amplify the sensor signal. Next, an anti-aliasing low pass filter is provided to form a data acquisition system with the ADC. The digital potentiometer can be used to bias the signal, which is especially useful in single supply systems. Finally, the voltage reference provides a low cost accurate voltage signal for the Wheatstone bridge sensor. Pressure Sensors Strain Gauge Applications Barometric altitude pressure sensors Engine turbine fan blade strain gauges TC913 Dual Chopper Stabilized Operational Amplifier: V OS : 15 µv (max.) 6.5V to 16V single supply CMOS Op Amp Low power I DD = 850 µa max. 1.5 MHz GBWP Unity gain stable MCP606 Dual Single Supply Operational Amplifier: 2.5V to 5.5V micropower CMOS Op Amp Low power Low offset voltage Product specifications can be found on page 10 MCP1541 Voltage Reference Features: Low-cost voltage reference MCP3201 Analog-to-Digital Converter Features: 12-bit ADC SPI interface MCP41010 Digital Potentiometer Features: 10k digital potentiometer SPI serial interface Related Application Note AN695 Interfacing Pressure Sensors to Microchip s Analog Peripherals (available for download from 7

8 Operational Amplifier Filters FilterLab Screen Captures FilterLab Active Filter Design Software Tool FilterLab is an innovative software tool that simplifies active filter design. Available at no cost from Microchip's web site ( the FilterLab active filter software design tool provides full schematic diagrams of the filter circuit with component values. In addition, FilterLab software provides plots of the frequency, group delay and phase response of the filter. V/V FilterLab allows the design of low pass, band pass and high pass filters up to an 8th order filter with Chebyshev, Bessel or Butterworth responses from frequencies of 0.1 Hz to 1 MHz. Users can select a flat passband or sharp transition from passband to stopband. Options, such as minimum ripple factor, sharp transition and linear phase delay, are available. Once the filter response has been identified, FilterLab software generates the frequency response and the circuit. For maximum design flexibility, changes in capacitor values can be implemented to fit the demands of the application. FilterLab will recalculate all values to meet the desired response, allowing real-world values to be substituted or changed as part of the design process. FilterLab also generates a SPICE model of the designed filter. Extraction of this model will allow time domain analysis in spice simulations, streamlining the design process. The FilterLab software can be downloaded free from the Microchip web site at 8

9 Data Acquisition Design Software MXLAB Software Tool MXLAB Screen Captures MXLAB software provides data acquisition, analysis and display in a Windows environment. Additionally, analysis can be made of the digital potentiometer shutdown, reset and daisy chain operations. MXLAB software can determine digital potentiometer settings based on gain inputs (db or V/V), filter cutoff frequencies and offset voltage levels. The MXLAB software can be downloaded free from the Microchip web site at The MXLAB Windows software contains a variety of tools to interface to the MXDEV Analog Evaluation System. These tools provide different methods of troubleshooting the analog circuit in either the time or frequency domain: Fast Fourier Transform (FFT) Histogram Oscilloscope Real time numeric Real time stripchart Data List MXDEV Analog Evaluation System The MXDEV Analog Evaluation System is a versatile and easy-to-use system for evaluating Microchip s MCP mixedsignal products. The system is used with a PC and consists of two parts: the DVMCPA Driver Board with associated MXLAB software which provides data acquisition, analysis and display in a Windows environment; and the DVxxxxx Evaluation Board, which contains the device to be evaluated. Evaluation boards are currently available for the MCP3001/02 and MCP3004/08 10-bit ADCs, and the MCP3201/02 and MCP3204/08 12-bit ADCs, and the MCP42XXX digital potentiometers. For the DV320x A/D converter evaluation boards, the input signal is either from from an on-board potentiometer or from an external source. In addition, low pass filters can be inserted into the signal path for further flexibility. A prototype area allows the addition of custom circuitry to make a powerful for evaluation and development. The DV42xxx digital potentiometer evaluation board shows the MCP42xxx being used in many popular digital applications. These circuits include programmable gain circuits, a programmable filter circuit, and a programmable circuit. Digital potentiometer tools within MXLAB system calculate wiper values for these circuits based on user inputs of gain (in db or V/V), filter cutoff frequency and approximation method, and offset voltage. In addition, an ADC is on board that allows analysis of these circuits using the time and frequency domain tools of the MXLAB software. Microchip Ordering Part Numbers; DVMCPA MXDEV Analog Evaluation Driver Board Version 1 DV3201A MCP3001/3002 & MCP3201/02 A/D Converter Evaluation Board DV3204A MCP3004/3008 & MCP3204/08 A/D Converter Evaluation Board DV42xxx MCP42xxx Digital Potentiometer 9

10 10 Selected Product Specifications See Microchip Product Line Card for complete product selection and specifications Programmable Gain Amplifiers -3dB (BW) I Q V os Supply Temp. Part # Channels (MHz) Typical (µv) Voltage (V) Range ( C) Features Packages MCP6S to ma to to 85 SPI, 8 Gain Steps, software shutdown 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP6S to ma to to 85 SPI, 8 Gain Steps, software shutdown 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP6S to ma to to 85 SPI, 8 Gain Steps, software shutdown 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP6S to ma to to 85 SPI, 8 Gain Steps, software shutdown 16-Pin PDIP, 16-Pin SOIC Operational Amplifiers # per I Q Typical V os Max Supply Temp. Part # Package GBWP (µa) (mv) Voltage (V) Range ( C) Features Packages MCP6041(3) 1 14 khz to to +85 Rail-to-Rail Input/Output 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP, 5-Pin SOT23 MCP khz to to +85 Rail-to-Rail Input/Output 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP khz to to +85 Rail-to-Rail Input/Output 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP6141(3) khz to to +85 Rail-to-Rail Input/Output, G 10 stable 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP khz to to +85 Rail-to-Rail Input/Output, G 10 stable 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP khz to to +85 Rail-to-Rail Input/Output, G 10 stable 14-pin PDIP, 14-pin SOIC, 14-pin TSSOP MCP606(8) khz to to +85 Rail-to-Rail output 8-Pin PDIP, 8-Pin SN, 8-Pin TSSOP, 5-Pin SOT23 MCP khz to to +85 Rail-to-Rail output 8-Pin PDIP, 8-Pin SOIC, 8-Pin TSSOP MCP khz to to +85 Rail-to-Rail output 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP616(8) khz to to +85 Rail-to-Rail output 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP khz to to +85 Rail-to-Rail output 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP khz to to +85 Rail-to-Rail output 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP MHz to to +85 Rail-to-Rail Input/Output 5-Pin SOT23, 5-Pin SC-70 MCP MHz to to +85 Rail-to-Rail Input/Output 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP MHz to to +85 Rail-to-Rail Input/Output 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP601(3) MHz to to +85 Rail-to-Rail output 8-Pin PDIP, 8-Pin SOIC, 8-Pin TSSOP, 5-Pin SOT-23 MCP MHz to to +85 Rail-to-Rail output 8-Pin PDIP, 8-Pin SOIC, 8-Pin TSSOP MCP MHz to to +85 Rail-to-Rail output 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP6021(3) 1 10 MHz to to +85 Rail-to-Rail Input/Output 8-Pin PDIP, 8-Pin SOIC, 8-Pin TSSOP MCP MHz to to +85 Rail-to-Rail Input/Output 8-Pin PDIP, 8-Pin SOIC, 8-Pin TSSOP MCP MHz to to +85 Rail-to-Rail Input/Output 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP6271(3) 1 2 MHz to to +125 Rail-to-Rail Input/Output, extended temp. 8-Pin PDIP, 8-Pin SOIC, 8-pin MSOP MCP MHz to to +125 Rail-to-Rail Input/Output, extended temp. 8-Pin PDIP, 8-Pin SOIC, 8-pin MSOP MCP MHz to to +125 Rail-to-Rail Input/Output, extended temp. 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP6281(3) 1 2 MHz to to +125 Rail-to-Rail Input/Output, extended temp. 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP MHz to to +125 Rail-to-Rail Input/Output, extended temp. 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP MHz to to +125 Rail-to-Rail Input/Output, extended temp. 14-Pin PDIP, 14-Pin SOIC, 14-pin TSSOP MCP6291(3) 1 10 MHz to to +125 Rail-to-Rail Input/Output, extended temp. 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP MHz to to +125 Rail-to-Rail Input/Output, extended temp. 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP MHz to to +125 Rail-to-Rail Input/Output, extended temp. 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP TC khz to to +85 Rail-to-Rail Input/Output 8-Pin PDIP, 8-Pin MSOP, 8-Pin SOIC TC khz to to +85 Rail-to-Rail Input/Output, Shutdown pins 16-Pin QSOP TC khz to to +85 Rail-to-Rail Input/Output 5-Pin SOT-23A TC khz to to +85 Rail-to-Rail Input/Output, Shutdown pins 6-Pin SOT-23A TC MHz to 16 0 to +70 Auto-zero, single & split supply 8-Pin PDIP TC MHz to 16 0 to +70 Chopper stabilized 8-Pin PDIP, 14-Pin PDIP TC MHz to 16 0 to +70 Chopper stabilized, low noise 8-Pin PDIP, 14-Pin PDIP Analog-to-Digital Converters (SAR) Resolution Max. Samp. Rate # of Input Input Input Volt. Max. Supply Max. Part # (bits) (ksamples/sec) Channels Type Interface Range (V) Current (µa) INL Packages MCP Single-ended SPI 2.7 to ±1 LSB 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP, 8-Pin TSSOP MCP Single-ended SPI 2.7 to ±1 LSB 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP, 8-Pin TSSOP MCP Single-ended SPI 2.7 to ±1 LSB 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP Single-ended SPI 2.7 to ±1 LSB 16-Pin PDIP, 16-Pin SOIC MCP Single-ended SPI 2.7 to ±1 LSB 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP, 8-Pin TSSOP MCP Single-ended SPI 2.7 to ±1 LSB 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP, 8-Pin TSSOP MCP Single-ended SPI 2.7 to ±1 LSB 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP Single-ended SPI 2.7 to ±1 LSB 16-Pin PDIP, 16-Pin SOIC MCP Differential SPI 2.7 to ±1 LSB 8-Pin PDIP, 8-Pin SOIC, 8-Pin MSOP MCP Differential SPI 2.7 to ±1 LSB 14-Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP Differential SPI 2.7 to ±1 LSB 16-Pin PDIP, 16-Pin SOIC MCP Single-ended I2C 2.7 to ±1 LSB 5-Pin SOT-23A MCP Single-ended I2C 2.7 to ±2 LSB 5-Pin SOT-23A Microchip also carries a broad portfolio of Sigma-Delta and Dual Slope Analog-to-Digital Converters. See website for complete product offerings Voltage Output Temperature Sensors Typical Max. Accuracy Max. Temp. Vcc Max. Supply Part # Accuracy ( 25 C ( C) Range ( C) Range (V) Current (µa) Features Packages TC1046 ±0.5 ±2-40 to to High precision temperature-to-voltage converter, 6.25 mv/ C 3-Pin SOT-23B TC1047 ±0.5 ±2-40 to to High precision temperature-to-voltage converter, 10 mv/ C 3-Pin SOT-23B TC1047A ±0.5 ±2-40 to to High precision temperature-to-voltage converter, 10 mv/ C 3-Pin SOT-23B Voltage References Vcc Output Max. Load Initial Temperature Max. Supply Part # Range (V) Voltage (V) Current (ma) Accuracy (max.%) Coefficient (ppm/ C) Current 25 C) Packages MCP to ±2 ± Pin TO-92, 3-Pin SOT-23B MCP to ±2 ± Pin TO-92, 3-Pin SOT-23B Digital Potentiometers Part # # of Taps # per package Interface Resistance (ohms) INL (max) DNL(max) Temp. Range ( C) Packages MCP SPI 10K ±1 LSB ±1 LSB -40 to Pin PDIP, 8-Pin SOIC MCP SPI 50K ±1 LSB ±1 LSB -40 to Pin PDIP, 8-Pin SOIC MCP SPI 100K ±1 LSB ±1 LSB -40 to Pin PDIP, 8-Pin SOIC MCP SPI 10K ±1 LSB ±1 LSB -40 to Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP SPI 50K ±1 LSB ±1 LSB -40 to Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP MCP SPI 100K ±1 LSB ±1 LSB -40 to Pin PDIP, 14-Pin SOIC, 14-Pin TSSOP

11 Related Application Notes Complete Application Note library is available on the Microchip website: Op Amps AN679: Temperature Sensing Technologies. This application note covers the most popular temperature sensor technologies to a level of detail that will give the reader insight into how to determine which sensor is most appropriate for the application. This note is written from the perspective of catering to the complex issues of the sensing environment and required accuracy. AN681: Reading and Using Fast Fourier Transformation (FFT). If there is an Analog-to-Digital converter in the signal path, there are three fundamental issues that can be examined when assessing the circuit s performance. This application note discusses the three areas of concern that encompass the use of frequency analysis (FFTs), time analysis, and DC analysis techniques. AN684: Single Supply Temperature Sensing with Thermocouples. This application note focuses on circuit solutions that use thermocouples in the design. The signal conditioning path for the thermocouple system is discussed in this application note followed by complete application circuits. AN685: Thermistors in Single Supply Temperature Sensing. Circuits. There are a variety of temperature sensors on the market all of which meet specific application needs. This application note discusses the most common sensors that are used to solve these application problems including the thermocouple, Resistive Temperature Detector (RTD) thermistor, and silicon-based sensors. AN687: Precision Temperature Sensing with RTD Circuits. Temperature is one of the most widely measured phenomena in the process control environment. This application note discusses how common elements such as Resistance Temperature Detectors (RTDs), thermistors, thermocouples or diodes are used to sense absolute temperatures as well as changes in temperature. AN695: Interfacing Pressure Sensors to Microchip's Analog Peripherals. This application note concentrates on the signal conditioning path of the piezoresistive sensing element from sensor to microcontroller. It shows how the electrical output of this sensor can be gained, filtered and digitized in order to ready it for the microcontroller s calibration routines. AN699: Anti-Aliasing, Analog Filters for Data Acquisition Systems Analog filters can be found in almost every electronic circuit. Audio systems use them for preamplification, equalization, and tone control. In communication systems, filters are used for tuning in specific frequencies and eliminating others. Digital signal processing systems use filters to prevent the aliasing of out-of-band noise and interference. AN722: Operational Amplifier Topologies and DC Specifications This application note defines the DC specifications of op amps and presents circuit applications where optimization of a particular specification is critical. AN723: Operational Amplifier AC Specifications and Applications. This application note defines the ac specifications of voltage feedback operational amplifiers (Op Amps). Directly following these definitions, related amplifier circuits are given where the ramifications of the particular specifications causes less than optimum circuit performance. AN866: Designing Operational Amplifier Oscillator Circuits For Sensor Applications. Operational amplifier (op amp) oscillators can be used to accurately measure resistive and capacitive sensors. This application note will show you procedures to simplify oscillator design. Operational amplifier (op amp) oscillators can be used to accurately measure resistive and capacitive sensors. Digital Pots AN691: Optimizing the Digital Potentiometer in Precision Circuits In this application note, circuit ideas are presented that use the necessary design techniques to mitigate errors, consequently optimizing the performance of the digital potentiometer. AN692: Using a Digital Potentiometer to Optimize a Precision Single Supply Photo Detect. This application note shows how the adjustability of the digital potentiometer can be used to an advantage in photosensing circuits. SAR ADC AN246: Driving the Analog Inputs of a SAR A/D Converter. This application note delves into the issues surrounding the SAR Converter s input and conversion nuances to insure that the converter is handled properly from the beginning of the design phase. AN688: Layout Tips for 12-Bit A/D Converter Application. This application note provides basic 12-bit layout guidelines, ending with a review of issues to be aware of. Examples of good layout and bad layout implementations are presented throughout. AN693: Understanding A/D Converter Performance Specifications. This application note describes the specifications used to quantify the performance of A/D converters and give the reader a better understanding of the significance of those specifications in an application. AN842: Differential ADC Biasing Techniques, Tips and Tricks. True differential converters can offer many advantages over single-ended input A/D Converters (ADC). In addition to their common mode rejection ability, these converters can also be used to overcome many DC biasing limitations of common signal conditioning circuits. AN845: Communicating With The MCP3221 Using PICmicro Microcontrollers. This application note will cover communications between the MCP bit A/D Converter and a PICmicro microcontroller. The code supplied with this application note is written as relocatable assembly code. Dual Slope ADC AN780: 15-Kilogram Scale Using the TC520 (TC500/A, TC520). This project takes into account all aspects of a functional scale: Dynamic Range, Strain Gauge Compensation, Zeroing, Oversampling, Units Conversion (kilograms to pounds). AN789: Integrating Converter Analog Processor (TC500A). Today, design engineers rely more on microprocessors and microcontrollers to support their applications. Compatible analog-to- digital (A/D) and digital-to-analog (A/D) converters have greatly increased the flexibility of interface and control circuits. Programmable Gain Amplifier (PGA) AN248: Interfacing MCP6S2X PGAs to PICmicro Microcontroller. This application note shows how to program the six channel MCP6S26 PGA gains, channels and shutdown registers using the PIC16C505 microcontroller. AN251: Bridge Sensing with the MCP6S2X PGAs. Describes how an external A/D converter and a PGA can easily be used to convert the difference voltage from resistor bridge sensors to usable digital words for manipulation by the microcontroller. AN865: Sensing Light with a Programmable Gain Amplifier. This application notes discusses how Microchip s Programmable Gain Amplifiers (PGAs) can be effectively used in position photo sensing applications minus the headaches of amplifier stability. TB065: Linear Circuit Devices for Applications in Battery Powered Wireless Systems. This technical brief introduces the reader to Microchip broad portfolio of linear circuit devices. 11

12 Microchip Technology s Analog & Interface Product Families Microchip Technology Inc. is a leading provider of microcontroller, analog and memory products that provide risk-free product development, lower total system cost and faster time to market for thousands of diverse customer applications worldwide. Microchip s commitment to quality and innovation coupled with world-class development tools, dependable delivery and outstanding technical support sets us apart. Analog & Interface Attributes Robustness MOSFET Drivers lead the industry in latch-up immunity/ stability Low Power/Low Voltage Op Amp family with the lowest power for a given gain bandwidth 600nA/1.4V/10kHz bandwidth Op Amps 1.8V charge pumps and comparators Lowest power 12-bit ADC in SOT-23 package Integration One of the first to market with integrated LDO with Reset, and Fan Controller with temperature sensor PGA integrates MUX, resistive ladder, gain switches, high-performance amplifier, SPI interface Space Savings Resets and LDOs in SC70, ADCs in 5-lead SOT-23 CAN and IrDA Standard protocol stack embedded in an 18-pin package Accuracy Offset trimmed after packaging using non-volatile memory Innovation Low pincount embedded IrDA Standard stack, FanSense technology SelectMode operation For more information, visit the Microchip website at A Leading Provider of Microcontroller and Analog Products Microchip Technology Inc W. Chandler Blvd. Chandler, AZ (480) Fax (480) Information subject to change. The Microchip name and logo, PIC, are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. FanSense and SelectMode are trademarks of Microchip Technology in the U.S.A. and other countries. IrDA is a registered trademark of Infrared Data Association. All other trademarks mentioned herein are the property of their respective companies. 2003, Microchip Technology Inc. All rights reserved. DS21825A 9/2003