{"id":8062,"date":"2026-06-28T08:48:34","date_gmt":"2026-06-28T08:48:34","guid":{"rendered":"https:\/\/materialparts.com\/ad594aq\/"},"modified":"2026-06-28T11:35:01","modified_gmt":"2026-06-28T11:35:01","slug":"ad594aq","status":"publish","type":"post","link":"https:\/\/materialparts.com\/ar\/ad594aq\/","title":{"rendered":"AD594AQ"},"content":{"rendered":"<h2>AD594AQ Overview<\/h2>\n<p>The AD594AQ is a monolithic thermocouple amplifier from Analog Devices designed for J-type thermocouples, with built-in cold junction compensation, 10mV\/C linear voltage output, supply voltage 5V-30V, in a DIP-14 package.<\/p>\n<h3>Key Features<\/h3>\n<ul>\n<li>Thermocouple type: J<\/li>\n<li>Built-in cold junction compensation<\/li>\n<li>Output: 10mV\/C<\/li>\n<li>Supply voltage: 5V-30V<\/li>\n<li>Supply current: 1mA<\/li>\n<li>Operating temperature: -55C to 125C<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>AD594AQ Overview The AD594AQ is a monolithic thermocouple amplifier from Analog Devices designed for J-type thermocouples, with built-in cold junction compensation, 10mV\/C linear voltage output, supply voltage 5V-30V, in a DIP-14 package. Key Features Thermocouple type: J Built-in cold junction compensation Output: 10mV\/C Supply voltage: 5V-30V Supply current: 1mA Operating temperature: -55C to 125C<\/p>","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19,13],"tags":[],"chip_brand":[165],"class_list":["post-8062","post","type-post","status-publish","format-standard","hentry","category-analog-linear-ics","category-integrated-circuits-ics","chip_brand-adi"],"acf":{"brief_explanation":"J-type thermocouple amplifier, 10mV\/degC output, cold junction compensation","date_code":"","package_case":"14-CERDIP (19.55 x 6.60 x 3.76 mm)","in_stock":10160,"datasheet":"https:\/\/www.analog.com\/media\/en\/technical-documentation\/data-sheets\/AD594_595.pdf","price":"$24.75 @ 1ku","product_introduction":"The AD594AQ is a monolithic thermocouple amplifier with cold junction compensation from Analog Devices, specifically designed for J-type (Iron-Constantan) thermocouples. It provides a low-impedance 10 mV per degree C output directly proportional to the thermocouple measurement temperature, eliminating the need for external signal conditioning. Packaged in a 14-lead CERDIP, it operates from a single +5 V supply or bipolar supplies up to +\/-15 V, and includes an on-chip ice-point reference, fault alarm, and retransmission capability. Note: This product is not recommended for new designs.","working_principle":"The AD594AQ integrates three functional blocks: (1) an ice-point compensation network that senses the cold junction temperature at the thermocouple connection point and generates a correction voltage equal to the thermocouple output at that temperature, (2) a precision differential amplifier with a fixed gain of 193.4 that scales the combined thermocouple and compensation voltage to 10 mV per degree C, and (3) an alarm comparator that detects thermocouple open-circuit or short-circuit faults, driving a TTL-compatible output. The compensation network uses a temperature-sensing transistor at the reference junction to track ambient temperature changes, ensuring measurement accuracy without manual ice-bath calibration.","pin_description":"<table><tr><th>Pin<\/th><th>Name<\/th><th>Description<\/th><\/tr><tr><td>1<\/td><td>+IN<\/td><td>Positive thermocouple input (Iron for J-type)<\/td><\/tr><tr><td>2<\/td><td>-IN<\/td><td>Negative thermocouple input (Constantan for J-type)<\/td><\/tr><tr><td>3<\/td><td>ALM+<\/td><td>Alarm output high-side (open-collector NPN)<\/td><\/tr><tr><td>4<\/td><td>ALM-<\/td><td>Alarm output low-side (open-collector NPN)<\/td><\/tr><tr><td>5<\/td><td>COM<\/td><td>Common ground for alarm circuit<\/td><\/tr><tr><td>6<\/td><td>V-<\/td><td>Negative supply (connect to GND for single-supply operation)<\/td><\/tr><tr><td>7<\/td><td>V+<\/td><td>Positive supply (+5 V to +15 V)<\/td><\/tr><tr><td>8<\/td><td>FB<\/td><td>Feedback node for gain adjustment<\/td><\/tr><tr><td>9<\/td><td>VO<\/td><td>Output (10 mV per degree C)<\/td><\/tr><tr><td>10<\/td><td>CSET<\/td><td>Compensation setpoint resistor connection<\/td><\/tr><tr><td>11<\/td><td>V+<\/td><td>Positive supply (duplicate)<\/td><\/tr><tr><td>12<\/td><td>V-<\/td><td>Negative supply (duplicate)<\/td><\/tr><tr><td>13<\/td><td>COM<\/td><td>Common (duplicate)<\/td><\/tr><tr><td>14<\/td><td>+IN<\/td><td>Positive input (duplicate, for star connection)<\/td><\/tr><\/table>","application_scenarios":"<ul><li><strong>Industrial Temperature Monitoring<\/strong>: Direct J-type thermocouple signal conditioning in furnaces, ovens, and process piping<\/li><li><strong>Laboratory Instrumentation<\/strong>: Precision temperature measurement in test equipment and calibration setups<\/li><li><strong>Food Processing<\/strong>: Temperature profiling and HACCP compliance monitoring in cooking and cold-chain systems<\/li><li><strong>Temperature Alarming<\/strong>: Built-in alarm output for over-temperature or sensor-fault detection in safety systems<\/li><li><strong>Setpoint Controller<\/strong>: Standalone temperature comparison using the compensation voltage as a reference<\/li><\/ul>","alternative_models":"<table><tr><th>Model<\/th><th>Manufacturer<\/th><th>TC Type<\/th><th>Output<\/th><th>Package<\/th><th>Notes<\/th><\/tr><tr><td>AD595AQ<\/td><td>Analog Devices<\/td><td>K-type<\/td><td>10 mV\/degC<\/td><td>14-CERDIP<\/td><td>K-type version of same family<\/td><\/tr><tr><td>AD8495<\/td><td>Analog Devices<\/td><td>J-type<\/td><td>5 mV\/degC<\/td><td>MSOP-8<\/td><td>Modern replacement, smaller package<\/td><\/tr><tr><td>MCP9600<\/td><td>Microchip<\/td><td>K\/J\/N\/T\/S\/E\/B\/R<\/td><td>I2C digital<\/td><td>DFN-8<\/td><td>Multi-type, digital output<\/td><\/tr><tr><td>MAX31855<\/td><td>Maxim Integrated<\/td><td>K\/J\/N\/T\/S\/E\/B\/R<\/td><td>SPI digital<\/td><td>SOIC-8<\/td><td>14-bit digital output thermocouple IC<\/td><\/tr><tr><td>LTC2983<\/td><td>Analog Devices<\/td><td>Universal<\/td><td>SPI digital<\/td><td>LQFP-48<\/td><td>High-accuracy multi-channel thermocouple system<\/td><\/tr><\/table>\n<p>AD594AQ is a J-type thermocouple amplifier with cold junction compensation in 14-CDIP. The AD595AQ provides the identical function for K-type thermocouples. For surface-mount alternatives, the AD8495ARMZ offers K-type amplification in MSOP-8 with 5mV\/\u00b0C output. The MAX6675 from Maxim provides a SPI-output K-type thermocouple-to-digital converter in SOIC-8 for direct microcontroller interface. The MCP9600 from Microchip offers I2C digital output with cold junction compensation for K\/J\/T\/N\/S\/E\/B\/R type thermocouples in MSOP-8.<\/p>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/posts\/8062","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/comments?post=8062"}],"version-history":[{"count":1,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/posts\/8062\/revisions"}],"predecessor-version":[{"id":8069,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/posts\/8062\/revisions\/8069"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/media?parent=8062"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/categories?post=8062"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/tags?post=8062"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/chip_brand?post=8062"}],"curies":[{"name":"\u062f\u0628\u0644\u064a\u0648 \u0628\u064a","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}