{"id":9599,"date":"2026-07-04T04:22:41","date_gmt":"2026-07-04T04:22:41","guid":{"rendered":"https:\/\/materialparts.com\/a4447sljtr-t\/"},"modified":"2026-07-04T04:22:41","modified_gmt":"2026-07-04T04:22:41","slug":"a4447sljtr-t","status":"publish","type":"post","link":"https:\/\/materialparts.com\/ar\/a4447sljtr-t\/","title":{"rendered":"A4447SLJTR-T"},"content":{"rendered":"

\u0646\u0638\u0631\u0629 \u0639\u0627\u0645\u0629 \u0639\u0644\u0649 \u0627\u0644\u0645\u0646\u062a\u062c<\/h2>\n

The A4447SLJTR-T is an Allegro MicroSystems high-voltage step-down buck regulator with integrated 450 mΩ DMOS switch. Operating from 8V to 50V input with adjustable output from 0.8V to 24V at up to 2A, it features fixed off-time current mode control, cycle-skipping light-load regulation, and soft start in an 8-pin SOIC-EP package.<\/p>\n

\u0627\u0644\u0645\u0648\u0627\u0635\u0641\u0627\u062a \u0627\u0644\u0631\u0626\u064a\u0633\u064a\u0629<\/h2>\n\n\n\n\n\n\n\n\n\n\n
\u062c\u0647\u062f \u0627\u0644\u0625\u062f\u062e\u0627\u0644<\/td>\n8V to 50V<\/td>\n<\/tr>\n
\u062c\u0647\u062f \u0627\u0644\u062e\u0631\u062c<\/td>\n0.8V to 24V (adjustable)<\/td>\n<\/tr>\n
\u062a\u064a\u0627\u0631 \u0627\u0644\u0625\u062e\u0631\u0627\u062c<\/td>\n2A continuous<\/td>\n<\/tr>\n
Switch On-Resistance<\/td>\n450 mΩ (25°C), 650 mΩ (125°C)<\/td>\n<\/tr>\n
Reference Voltage<\/td>\n0.8V ±2%<\/td>\n<\/tr>\n
\u062a\u064a\u0627\u0631 \u0627\u0644\u062a\u0647\u062f\u0626\u0629<\/td>\n0.9 mA (operating, VBIAS = VOUT)<\/td>\n<\/tr>\n
Soft Start<\/td>\n10 ms (internal)<\/td>\n<\/tr>\n
\u062f\u0631\u062c\u0629 \u062d\u0631\u0627\u0631\u0629 \u0627\u0644\u062a\u0634\u063a\u064a\u0644<\/td>\n-20°C to +85°C<\/td>\n<\/tr>\n
\u0627\u0644\u062d\u0632\u0645\u0629<\/td>\n8-SOIC-EP (4.9 x 3.9 x 1.55 mm)<\/td>\n<\/tr>\n<\/table>\n

\u0627\u0644\u0645\u064a\u0632\u0627\u062a<\/h2>\n
    \n
  • Wide 8V-50V input range supports industrial 24V\/36V bus and automotive battery applications<\/li>\n
  • Integrated 450 mΩ DMOS switch reduces external component count<\/li>\n
  • Fixed off-time current mode control with external resistor programming<\/li>\n
  • Cycle-skipping mode maintains regulation at light loads<\/li>\n
  • 10 ms internal soft start limits inrush current<\/li>\n
  • Thermal shutdown with automatic recovery for robust operation<\/li>\n<\/ul>\n

    \u0627\u0644\u062a\u0637\u0628\u064a\u0642\u0627\u062a<\/h2>\n
      \n
    • Industrial 24V bus step-down converter for 5V\/3.3V logic supply<\/li>\n
    • Point-of-sale (POS) thermal printer power supply<\/li>\n
    • Uninterruptible power supply (UPS) auxiliary power rail<\/li>\n
    • Automotive 12V\/24V battery step-down for MCU supply<\/li>\n
    • Motor drive housekeeping power supply from 48V bus<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The A4447SLJTR-T is an Allegro MicroSystems high-voltage step-down buck regulator with integrated 450 mΩ DMOS switch. Operating from 8V to 50V input with adjustable output from 0.8V to 24V at up to 2A, it features fixed off-time current mode control, cycle-skipping light-load regulation, and soft start in an 8-pin SOIC-EP package. Key Specifications […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[31,13],"tags":[847],"chip_brand":[176],"class_list":["post-9599","post","type-post","status-publish","format-standard","hentry","category-dc-dc-converters","category-integrated-circuits-ics","tag-a4447sljtr-t","chip_brand-allegro"],"acf":{"brief_explanation":"8-50V 2A buck regulator, integrated DMOS, adjustable output 0.8-24V, SOIC-8EP, for industrial 24V bus","date_code":"","package_case":"8-SOIC-EP (4.9 x 3.9 x 1.55 mm)","in_stock":7145,"datasheet":"https:\/\/www.allegromicro.com\/products\/regulate\/regulators\/single-output-regulators\/a4447","price":"$0.64 @ 3ku","product_introduction":"The A4447SLJTR-T is an Allegro MicroSystems high-voltage step-down buck regulator integrating a 450 m\u03a9 N-channel DMOS switch for 2A output current from 8V to 50V input. The output voltage is adjustable from 0.8V to 24V using an external resistor divider with a precision 0.8V \u00b12% reference. Fixed off-time current mode control, programmed by an external resistor (R_TSET), provides stable operation across varying input and output conditions. The device features cycle-skipping mode for light-load regulation, 10 ms internal soft start, enable control (ENB pin), undervoltage lockout, and thermal shutdown \u2014 all in a compact 8-pin SOIC with exposed thermal pad.","working_principle":"The A4447SLJTR-T uses fixed off-time current mode control where the off-time is set by an external resistor (R_TSET) connected to the TSET pin. During each switching cycle, the internal DMOS switch turns on and current ramps up through the external inductor. When the peak current reaches the threshold set by the error amplifier (proportional to VFB), the switch turns off for the programmed off-time, and the inductor current freewheels through the external Schottky clamp diode. At light loads, the device enters cycle-skipping mode where the switch minimum on-time creates more energy than needed, so the controller skips switching cycles to prevent output voltage rise. The VBIAS pin improves efficiency by powering the internal circuitry from the output voltage (when \u22653.3V) instead of the higher input voltage.","pin_description":"
      Pin<\/th>Function<\/th><\/tr>
      Pin 1 (VIN)<\/td>Input power supply (8-50V)<\/td><\/tr>
      Pin 2 (TSET)<\/td>Off-time programming resistor to GND<\/td><\/tr>
      Pin 3 (ENB)<\/td>Enable control (LOW = enabled, open = disabled)<\/td><\/tr>
      Pin 4 (FB)<\/td>Feedback voltage input (0.8V reference)<\/td><\/tr>
      Pin 5 (VBIAS)<\/td>Bias supply input (connect to VOUT for \u22653.3V output)<\/td><\/tr>
      Pin 6 (SW)<\/td>Switch node (DMOS drain, connect to inductor\/diode)<\/td><\/tr>
      Pin 7 (GND)<\/td>Power ground and signal ground<\/td><\/tr>
      Pad<\/td>Exposed thermal pad (connect to GND plane)<\/td><\/tr><\/table>","application_scenarios":"
      • Industrial 24V DC bus to 5V\/3.3V logic power supply at 2A for PLC and HMI<\/li>
      • POS thermal printer 24V to 12V motor and 5V logic supply<\/li>
      • UPS 36V\/48V battery to 12V auxiliary power rail<\/li>
      • Automotive 12V battery to 5V ECU microcontroller supply<\/li>
      • Motor drive 48V bus to 15V gate driver supply<\/li><\/ul>","alternative_models":"
        Model<\/th>Manufacturer<\/th>Key Difference<\/th><\/tr>
        A8447SLJTR-T<\/td>Allegro<\/td>3A version in same package<\/td><\/tr>
        LM5012AMH\/NOPB<\/td>Texas Instruments<\/td>1A, 100V buck in SOT-6<\/td><\/tr>
        LMR16006XDDCR<\/td>Texas Instruments<\/td>600mA 60V buck in SOT-6<\/td><\/tr>
        TNY287DG<\/td>Power Integrations<\/td>Flyback topology alternative<\/td><\/tr>
        A4407SLJTR-T<\/td>Allegro<\/td>1.5A lower-current variant<\/td><\/tr><\/table>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/posts\/9599","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=9599"}],"version-history":[{"count":0,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/posts\/9599\/revisions"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/media?parent=9599"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/categories?post=9599"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/tags?post=9599"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/ar\/wp-json\/wp\/v2\/chip_brand?post=9599"}],"curies":[{"name":"\u062f\u0628\u0644\u064a\u0648 \u0628\u064a","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}