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Electrical and absolute maximum ratings provide limits for supply voltage, currents, dissipation, and operating temperature ranges.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/technology/","Technology",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/uc1842345-current-mode-pwm-controller-specifications-and-features/561180/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/uc1842345-current-mode-pwm-controller-specifications-and-features/561180.png","ImageObject",300,407,{"name":42,"@type":43},"eBook King","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-22","2026-10-12",true,{"@type":52,"interactionType":53,"userInteractionCount":55},"InteractionCounter",{"@type":54},"ViewAction",9,{"@type":57,"mainEntity":58},"FAQPage",[59,65,69],{"name":60,"@type":61,"acceptedAnswer":62},"What control scheme does UC1842/3/4/5 support?","Question",{"text":63,"@type":64},"UC1842/3/4/5 implements off-line or DC-to-DC fixed frequency current mode control schemes using PWM comparison and current limit logic.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"What are the main features highlighted for UC1842/3/4/5?",{"text":68,"@type":64},"Features include low start-up current, automatic feed-forward compensation, pulse-by-pulse current limiting, enhanced load response, under-voltage lockout with hysteresis, double pulse suppression, and a high current totem pole output stage.",{"name":70,"@type":61,"acceptedAnswer":71},"How do the UC1842/3/4/5 variants differ?",{"text":72,"@type":64},"They mainly differ in under-voltage lockout thresholds and maximum duty cycle ranges; UC1844/UC1845 include an internal toggle flip-flop to blank the output every other clock cycle for a usable zero-to-50% duty range.","https://schema.org",{"og:url":32,"og:type":75,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":77,"canonical":32},"index,follow",{"doc_id":79,"site_id":7},561180,1791817688,{"code":4,"msg":82,"data":83},"success",[84,88,92,96,101,105,110,115,119,122,126],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":85,"show_sort_weight":86,"slug":87},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":89,"show_sort_weight":90,"slug":91},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":93,"show_sort_weight":94,"slug":95},"Exam",70,"exam",{"id":97,"doc_module":4,"doc_module_name":25,"category_name":98,"show_sort_weight":99,"slug":100},5,"Comic",60,"comic",{"id":102,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":103,"slug":104},6,50,"technology",{"id":106,"doc_module":4,"doc_module_name":25,"category_name":107,"show_sort_weight":108,"slug":109},7,"Healthcare",40,"healthcare",{"id":111,"doc_module":4,"doc_module_name":25,"category_name":112,"show_sort_weight":113,"slug":114},8,"Research & Report",30,"research-report",{"id":55,"doc_module":4,"doc_module_name":25,"category_name":116,"show_sort_weight":117,"slug":118},"Religion & Spirituality",20,"religion-spirituality",{"id":117,"doc_module":4,"doc_module_name":25,"category_name":120,"show_sort_weight":117,"slug":121},"World Cup","world-cup",{"id":123,"doc_module":4,"doc_module_name":25,"category_name":124,"show_sort_weight":123,"slug":125},10,"Lifestyle","lifestyle",{"id":127,"doc_module":4,"doc_module_name":25,"category_name":128,"show_sort_weight":97,"slug":129},19,"General","general",{"code":4,"msg":82,"data":131},{"doc_id":79,"user_id":132,"nickname":42,"user_avatar":133,"doc_module":4,"category_id":102,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":55,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":55,"language":139,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":12,"update_tm":143,"read_time":144},962088006270,"https://ap-avatar.wpscdn.com/davatar_085a072bc5b1113ac321206ff7593b45","| application |  |  |\n| --- | --- | --- |\n|  | INFO |  |\n|  | available |  |\n\nUC1842/3/4/5  \nUC2842/3/4/5  \nUC3842/3/4/5  \nCurrent Mode PWM Controller  \nFEATURES  \n• Optimized For Off-line And DC To DC Converters  \n• Low Start Up Current (\u003C1mA)  \n• Automatic Feed Forward Compensation  \n• Pulse-by-pulse Current Limiting  \n• Enhanced Load Response Characteristics  \n• Under-voltage Lockout With Hysteresis  \n• Double Pulse Suppression  \n• High Current Totem Pole Output  \n• Internally Trimmed Bandgap Reference  \n• 500khz Operation  \n• Low RO Error Amp  \nDESCRIPTION  \nThe UC1842/3/4/5 family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include under-voltage lockout featuring start up current less than 1mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N Channel MOSFETs, is low in the off state.  \nDifferences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges. The UC1842 and UC1844 have UVLO thresholds of 16V (on) and 10V (off), ideally suited to off-line applications. The corresponding thresholds for the UC1843 and UC1845 are 8.4V and 7.6V. The UC1842 and UC1843 can operate to duty cycles approaching 100% . A range of zero to 50% is obtained by the UC1844 and UC1845 by the addition of an internal toggle flip flop which blanks the output off every other clock cycle.  \nBLOCK DIAGRAM  \n\n| | |\n| --- | --- |\n| Note 1: A/B A = DIL-8 Pin Number. B = SO-14 and CFP-14 Pin Number.\u003Cbr>Note 2: Toggle flip flop used only in 1844 and 1845.\u003Cbr>|  |\n\nSLUS223A-APRIL 1997-REVISED MAY 2002  \nUC1842/3/4/5  \nUC2842/3/4/5  \nUC3842/3/4/5  \nABSOLUTE MAXIMUM RATINGS (Note 1)  \nSupply Voltage (Low Impedance Source) . . . . . . . . . . . . . . 30V Supply Voltage (ICC \u003C 30mA) . . . . . . . . . . . . . . . . . Self Limiting Output Current   ±1A Output Energy (Capacitive Load) . . . . . . . . . . . . . . . . . . . . . 5µJ Analog Inputs (Pins 2, 3) . . . . . . . . . . . . . . . . . . . -0.3V to +6.3V Error Amp Output Sink Current   10mA Power Dissipation at TA ≤ 25°Χ (DIL−8)   1Ω  \nPower Dissipation at TA ≤ 25°C (SOIC-14)   725mW Storage Temperature Range . . . . . . . . . . . . . . -65°C to +150°C Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . 300°CNote 1: All voltages are with respect to Pin 5.  \nAll currents are positive into the specified terminal.  \nConsult Packaging Section of Databook for thermal  \nlimitations and considerations of packages.  \nCONNECTION DIAGRAMS  \n\n| DIL-8, SOIC-8 (TOP VIEW) N or J Package, D8 Package |  |  |\n| --- | --- | --- |\n| | | |\n\nSOIC-14, CFP-14. (TOP VIEW) D or W Package  \nDISSIPATION RATING TABLE  \n\n| PLCC-20 (TOP VIEW) Q Package |  |\n| --- | --- |\n| | PACKAGE PIN FUNCTION FUNCTION PIN N/C 1 COMP 2 N/C 3 N/C 4 VFB 5 N/C 6 ISENSE 7 N/C 8 N/C 9 RT/CT 10 N/C 11 PWR GND 12 GROUND 13 N/C 14 OUTPUT 15 N/C 16 VC 17 VCC 18 N/C 19 VREF 20 |\n\n\n| Package | TA ≤ 25°C\u003Cbr>Power Rating | Derating Factor Above TA ≤ 25°C | TA ≤ 70°C\u003Cbr>Power Rating | TA ≤ 85°C\u003Cbr>Power Rating | TA ≤ 125°C\u003Cbr>Power Rating |\n| --- | --- | --- | --- | --- | --- |\n| W | 700 mW | 5.5 mW/°C | 452 mW | 370 mW | 150 mW |\n\nUC1842/3/4/5  \nUC2842/3/4/5  \nUC3842/3/4/5  \nELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for-55°C ≤ TA ≤ 125°C for the  \nUC184X; -40°C ≤ TA ≤ 85°C for the UC284X; 0°C ≤ TA ≤ 70°C for the 384X; VCC = 15V (Note 5); RT = 10k; CT = 3 .3nF, TA=TJ.  \n\n| PARAMETER | TEST CONDITIONS | UC1842/3/4/5\u003Cbr>UC2842/3/4/5 |  |  |  | UC3842/3/4/5 |  |  | UNITS |\n| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |\n|  |  | MIN | TYP | MAX |  | MIN | TYP | MAX |  |\n| Reference Section |  | ","cbCaisGI61IHrdNF","https://ap.wps.com/l/cbCaisGI61IHrdNF","pdf",594604,"English","# Features\n# Description\n# Differences Between Members\n# Block Diagram\n# Absolute Maximum Ratings\n# Connection Diagrams\n# Dissipation Rating Table\n# Electrical Characteristics","[{\"question\":\"What control scheme does UC1842/3/4/5 support?\",\"answer\":\"UC1842/3/4/5 implements off-line or DC-to-DC fixed frequency current mode control schemes using PWM comparison and current limit logic.\"},{\"question\":\"What are the main features highlighted for UC1842/3/4/5?\",\"answer\":\"Features include low start-up current, automatic feed-forward compensation, pulse-by-pulse current limiting, enhanced load response, under-voltage lockout with hysteresis, double pulse suppression, and a high current totem pole output stage.\"},{\"question\":\"How do the UC1842/3/4/5 variants differ?\",\"answer\":\"They mainly differ in under-voltage lockout thresholds and maximum duty cycle ranges; UC1844/UC1845 include an internal toggle flip-flop to blank the output every other clock cycle for a usable zero-to-50% duty range.\"}]","UC1842/3/4/5 - Current Mode PWM Controller - Specifications and Features | PDF",1791805196,23]