{"id":3301,"date":"2026-06-01T00:45:15","date_gmt":"2026-06-01T00:45:15","guid":{"rendered":"https:\/\/materialparts.com\/bss138\/"},"modified":"2026-06-01T00:45:15","modified_gmt":"2026-06-01T00:45:15","slug":"bss138","status":"publish","type":"post","link":"https:\/\/materialparts.com\/zh\/bss138\/","title":{"rendered":"BSS138"},"content":{"rendered":"

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

The BSS138 from onsemi (formerly Fairchild) is an N-channel logic-level enhancement-mode MOSFET in the industry-standard SOT-23-3 surface-mount package. Rated for 50V drain-source voltage and 220mA continuous drain current, it is specifically designed for low-voltage switching applications. With a gate threshold voltage of 0.8-1.5V and RDS(on) of 3.5 Ohm maximum at VGS=10V, the BSS138 can be driven directly from 3.3V and 5V microcontroller GPIOs, making it one of the most popular small-signal MOSFETs for logic-level interfacing.<\/p>\n

\u4e3b\u8981\u89c4\u683c<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n
VDS (Drain-Source Voltage)<\/td>\n50V<\/td>\n<\/tr>\n
ID (Continuous Drain Current)<\/td>\n220mA<\/td>\n<\/tr>\n
RDS(on) Max @ VGS=10V<\/td>\n3.5 Ohm<\/td>\n<\/tr>\n
RDS(on) Max @ VGS=4.5V<\/td>\n6.0 Ohm<\/td>\n<\/tr>\n
VGS(th) Range<\/td>\n0.8V to 1.5V<\/td>\n<\/tr>\n
Total Gate Charge (Qg)<\/td>\n2.4nC max @ 10V<\/td>\n<\/tr>\n
Input Capacitance (Ciss)<\/td>\n27pF @ 25V<\/td>\n<\/tr>\n
\u529f\u7387\u8017\u6563<\/td>\n360mW<\/td>\n<\/tr>\n
\u5de5\u4f5c\u6e29\u5ea6<\/td>\n-55 to +150\u00b0C<\/td>\n<\/tr>\n
\u5305\u88c5<\/td>\nSOT-23-3 (TO-236-3)<\/td>\n<\/tr>\n<\/table>\n

\u7279\u70b9<\/h2>\n
    \n
  • Logic-level gate drive: 0.8V min threshold enables 2.5V\/3.3V operation<\/li>\n
  • Low RDS(on): 3.5 Ohm max at VGS=10V<\/li>\n
  • Low gate charge (2.4nC) for fast switching<\/li>\n
  • High-density cell design for low on-resistance<\/li>\n
  • Pb-free and halogen-free construction<\/li>\n
  • Industry-standard SOT-23-3 package<\/li>\n
  • Low input capacitance (27pF) minimizes drive power<\/li>\n<\/ul>\n

    \u5e94\u7528<\/h2>\n
      \n
    • Logic-level signal switching and level shifting<\/li>\n
    • Load switching in battery-powered devices<\/li>\n
    • I2C and SPI bus voltage level translation<\/li>\n
    • Small servo motor control<\/li>\n
    • MOSFET gate driver pre-driver<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The BSS138 from onsemi (formerly Fairchild) is an N-channel logic-level enhancement-mode MOSFET in the industry-standard SOT-23-3 surface-mount package. Rated for 50V drain-source voltage and 220mA continuous drain current, it is specifically designed for low-voltage switching applications. With a gate threshold voltage of 0.8-1.5V and RDS(on) of 3.5 Ohm maximum at VGS=10V, the BSS138 […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[13,56],"tags":[],"chip_brand":[144],"class_list":["post-3301","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","category-mosfets","chip_brand-on"],"acf":{"brief_explanation":"N-Channel logic-level MOSFET, 50V, 220mA, RDS(on) 3.5 Ohm, SOT-23-3","date_code":"","package_case":"SOT-23-3 \/ TO-236-3 (2.9 x 1.3 x 1.0 mm)","in_stock":6506,"datasheet":"https:\/\/www.onsemi.com\/pdf\/datasheet\/bss138-d.pdf","price":"$0.04 @ 1ku","product_introduction":"The BSS138 from onsemi is a widely-used N-channel logic-level enhancement-mode MOSFET produced using proprietary high cell density DMOS technology. Engineered to minimize on-state resistance while providing rugged and reliable switching performance, the BSS138 has become an industry staple for low-voltage, low-current applications. Its low gate threshold voltage (0.8-1.5V) enables direct control from 3.3V and even 2.5V logic, making it the go-to choice for bidirectional level shifting circuits in I2C and SPI buses. The industry-standard SOT-23-3 package allows high-density PCB placement, and its extremely low cost makes it practical for high-volume consumer electronics.","working_principle":"The BSS138 operates as a voltage-controlled switch. When a gate-source voltage (VGS) exceeding the threshold voltage (VGS(th) = 0.8-1.5V) is applied, an inversion layer forms beneath the gate oxide, creating a conductive channel between drain and source. The channel resistance (RDS(on)) decreases with increasing VGS, reaching 3.5 Ohm maximum at VGS=10V and 6.0 Ohm at VGS=4.5V. As an enhancement-mode device, it is normally off when VGS=0, with leakage current below 0.5uA. The small gate charge (1.7-2.4nC) enables fast switching transitions with typical turn-on delay of 2.5ns and turn-off delay of 20ns. The body diode between source and drain provides a path for inductive kickback currents in switching applications.","pin_description":"
      Pin<\/th>Name<\/th>Type<\/th>Function<\/th><\/tr>
      1<\/td>G (Gate)<\/td>Input<\/td>Gate control terminal<\/td><\/tr>
      2<\/td>S (Source)<\/td>Source<\/td>Source terminal<\/td><\/tr>
      3<\/td>D (Drain)<\/td>Drain<\/td>Drain terminal<\/td><\/tr><\/table>","application_scenarios":"
      • Bidirectional voltage level translation for I2C, SPI, and UART buses (3.3V to 5V)<\/li>
      • Low-side load switching in battery-powered microcontroller circuits<\/li>
      • LED and relay driver controlled by GPIO pins<\/li>
      • Power gating for low-power sleep modes in portable devices<\/li>
      • Signal gating and analog switch replacement in sensor interfaces<\/li><\/ul>","alternative_models":"
        Manufacturer<\/th>Part Number<\/th>Package<\/th>Notes<\/th><\/tr>
        NXP<\/td>BSS138<\/td>SOT-23-3<\/td>60V version, pin compatible<\/td><\/tr>
        Diodes Inc<\/td>MMBF170<\/td>SOT-23-3<\/td>60V, 500mA, higher RDS(on)<\/td><\/tr>
        Infineon<\/td>BSR14<\/td>SOT-23-3<\/td>60V, 280mA, logic level<\/td><\/tr>
        Vishay<\/td>2N7002<\/td>SOT-23-3<\/td>60V, 300mA, popular alternative<\/td><\/tr>
        TI<\/td>2N7002K<\/td>SOT-23-3<\/td>60V, 350mA, ESD protected gate<\/td><\/tr><\/table>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/3301","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=3301"}],"version-history":[{"count":0,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/3301\/revisions"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/media?parent=3301"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/categories?post=3301"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/tags?post=3301"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/chip_brand?post=3301"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}