{"id":2496,"date":"2026-05-21T01:20:14","date_gmt":"2026-05-21T01:20:14","guid":{"rendered":"https:\/\/materialparts.com\/uc3843bng\/"},"modified":"2026-05-21T01:20:14","modified_gmt":"2026-05-21T01:20:14","slug":"uc3843bng","status":"publish","type":"post","link":"https:\/\/materialparts.com\/zh\/uc3843bng\/","title":{"rendered":"UC3843BNG"},"content":{"rendered":"

\u4ea7\u54c1\u6982\u89c8<\/h2>\n

The UC3843BNG from Texas Instruments is a current-mode PWM controller for off-line and DC-DC converters. It features 500kHz switching, trimmed oscillator for precise frequency, current-sense comparator, totem-pole output, and undervoltage lockout (8.4V\/7.6V) in an 8-pin PDIP package.<\/p>\n

\u4e3b\u8981\u89c4\u683c<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
\u5236\u9020\u5546<\/td>\n\u5fb7\u5dde\u4eea\u5668<\/td>\n<\/tr>\n
\u7c7b\u578b<\/td>\nCurrent-Mode PWM Controller<\/td>\n<\/tr>\n
\u5f00\u5173\u9891\u7387<\/td>\nUp to 500kHz<\/td>\n<\/tr>\n
Reference Voltage<\/td>\n5.0V +-1%<\/td>\n<\/tr>\n
UVLO Threshold<\/td>\n8.4V on \/ 7.6V off<\/td>\n<\/tr>\n
Max Duty Cycle<\/td>\n100%<\/td>\n<\/tr>\n
\u8f93\u51fa\u7535\u6d41<\/td>\n+-1A peak totem-pole<\/td>\n<\/tr>\n
\u7535\u6e90\u7535\u538b<\/td>\nUp to 30V<\/td>\n<\/tr>\n
Start-Up Current<\/td>\n0.5mA max<\/td>\n<\/tr>\n
Operating Current<\/td>\n11mA typical<\/td>\n<\/tr>\n
\u5305\u88c5<\/td>\n8-PDIP<\/td>\n<\/tr>\n
\u5de5\u4f5c\u6e29\u5ea6<\/td>\n0C to +70C<\/td>\n<\/tr>\n<\/table>\n

\u7279\u70b9<\/h2>\n
    \n
  • Current-mode PWM operation up to 500kHz<\/li>\n
  • Trimmed oscillator for precise frequency control<\/li>\n
  • 5V reference with +-1% accuracy<\/li>\n
  • Undervoltage lockout with hysteresis (8.4V\/7.6V)<\/li>\n
  • Totem-pole output for direct MOSFET drive<\/li>\n
  • Current-sense comparator with 1V threshold<\/li>\n
  • Automatic feedforward compensation<\/li>\n
  • Pulse-by-pulse current limiting<\/li>\n
  • Low start-up current: 0.5mA<\/li>\n<\/ul>\n

    \u5e94\u7528<\/h2>\n
      \n
    • Off-line flyback and forward converters<\/li>\n
    • DC-DC buck, boost, and buck-boost converters<\/li>\n
    • Battery charger power supplies<\/li>\n
    • Industrial power supply designs<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The UC3843BNG from Texas Instruments is a current-mode PWM controller for off-line and DC-DC converters. It features 500kHz switching, trimmed oscillator for precise frequency, current-sense comparator, totem-pole output, and undervoltage lockout (8.4V\/7.6V) in an 8-pin PDIP package. Key Specifications Manufacturer Texas Instruments Type Current-Mode PWM Controller Switching Frequency Up to 500kHz Reference Voltage […]<\/p>\n","protected":false},"author":2,"featured_media":2779,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[13,29],"tags":[],"chip_brand":[138],"class_list":["post-2496","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-integrated-circuits-ics","category-power-management-ics-pmic","chip_brand-ti"],"acf":{"brief_explanation":"Current-mode PWM controller, 500kHz, 5V ref, UVLO 8.4V\/7.6V, 8-PDIP","date_code":"","package_case":"8-PDIP (9.81 x 6.35 x 4.57mm)","in_stock":11500,"datasheet":"https:\/\/www.ti.com\/product\/UC3843B","price":"$0.85 @ 1ku","product_introduction":"The Texas Instruments UC3843BNG is a high-performance fixed-frequency current-mode PWM controller optimized for off-line and DC-DC converter applications. The UC3843B is the industry-standard controller for flyback and forward converter topologies. It features a trimmed oscillator for precise frequency, a temperature-compensated 5V reference with +-1% accuracy, a high-gain error amplifier, current-sense comparator, and a totem-pole output stage capable of +-1A peak current for direct MOSFET drive. The current-mode architecture provides inherent input voltage feedforward, excellent line regulation, and simplified loop compensation compared to voltage-mode control. Pulse-by-pulse current limiting ensures safe operation during overload and short-circuit conditions.","working_principle":"The UC3843BNG operates as a fixed-frequency current-mode PWM controller: 1) Oscillator: An external resistor (RT) and capacitor (CT) set the switching frequency up to 500kHz. The oscillator generates a clock pulse that sets the output flip-flop at the beginning of each switching cycle. 2) Current-Mode Control: The output switch is turned on at the start of each cycle. When the voltage across the current-sense resistor (sensed at the ISENSE pin) reaches the threshold set by the error amplifier output, the comparator resets the flip-flop, turning off the switch. This creates natural input voltage feedforward and simplifies loop compensation to a single-pole response. 3) Error Amplifier: Compares the output voltage feedback with the 5V reference, adjusting the current-sense threshold to maintain regulation. 4) UVLO: The 8.4V start\/7.6V stop threshold prevents operation at insufficient supply voltage, ensuring clean start-up.","pin_description":"
      Pin<\/th>Name<\/th>Type<\/th>Function<\/th><\/tr>
      1<\/td>COMP<\/td>I\/O<\/td>Error amplifier output \/ compensation<\/td><\/tr>
      2<\/td>VFB<\/td>Input<\/td>Error amplifier inverting input (feedback)<\/td><\/tr>
      3<\/td>ISENSE<\/td>Input<\/td>Current sense input (1V threshold)<\/td><\/tr>
      4<\/td>RT\/CT<\/td>I\/O<\/td>Oscillator timing RC network<\/td><\/tr>
      5<\/td>GND<\/td>Ground<\/td>Ground<\/td><\/tr>
      6<\/td>OUTPUT<\/td>Output<\/td>PWM output (totem-pole, +-1A)<\/td><\/tr>
      7<\/td>VCC<\/td>Power<\/td>Supply voltage (up to 30V)<\/td><\/tr>
      8<\/td>VREF<\/td>Output<\/td>5V reference output (+-1%)<\/td><\/tr><\/table>","application_scenarios":"
      • Off-line flyback converter for consumer electronics power adapters<\/li>
      • DC-DC boost converter for battery-powered industrial equipment<\/li>
      • Isolated telecom power supply with current-mode control<\/li><\/ul>","alternative_models":"
        Manufacturer<\/th>Part Number<\/th>Package<\/th>Notes<\/th><\/tr>
        TI<\/td>UC3842BNG<\/td>8-PDIP<\/td>16V\/10V UVLO version<\/td><\/tr>
        TI<\/td>UC3844BNG<\/td>8-PDIP<\/td>50% max duty cycle version<\/td><\/tr>
        onsemi<\/td>UC3843BVD1G<\/td>8-SOIC<\/td>SMD version, same function<\/td><\/tr>
        ST<\/td>UC3843BN<\/td>8-PDIP<\/td>Second source, equivalent<\/td><\/tr><\/table>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/2496","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/comments?post=2496"}],"version-history":[{"count":0,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/2496\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/media\/2779"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/media?parent=2496"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/categories?post=2496"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/tags?post=2496"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/chip_brand?post=2496"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}