{"id":7406,"date":"2026-06-24T04:59:02","date_gmt":"2026-06-24T04:59:02","guid":{"rendered":"https:\/\/materialparts.com\/lp2951acmx\/"},"modified":"2026-06-24T04:59:02","modified_gmt":"2026-06-24T04:59:02","slug":"lp2951acmx","status":"publish","type":"post","link":"https:\/\/materialparts.com\/zh\/lp2951acmx\/","title":{"rendered":"LP2951ACMX"},"content":{"rendered":"

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

The LP2951ACMX from Texas Instruments (formerly National Semiconductor) is a micropower low-dropout voltage regulator with 100mA output, 380mV dropout at 100mA, programmable output (1.24-29V), and error flag in an 8-pin VSSOP package.<\/p>\n

\u4e3b\u8981\u89c4\u683c<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Output Voltage<\/td>\nAdjustable (1.24 V to 29 V)<\/td>\n<\/tr>\n
\u8f93\u51fa\u7535\u6d41<\/td>\n100 mA<\/td>\n<\/tr>\n
Dropout Voltage<\/td>\n380 mV @ 100mA<\/td>\n<\/tr>\n
\u9759\u6001\u7535\u6d41<\/td>\n75 uA typical (no load)<\/td>\n<\/tr>\n
Load Regulation<\/td>\n0.05% typical<\/td>\n<\/tr>\n
Line Regulation<\/td>\n0.03% typical<\/td>\n<\/tr>\n
Output Noise<\/td>\n100 uV RMS (10Hz-100kHz)<\/td>\n<\/tr>\n
Shutdown<\/td>\nYes (logic level)<\/td>\n<\/tr>\n
Error Flag<\/td>\nYes (output undervoltage)<\/td>\n<\/tr>\n
Reference Voltage<\/td>\n1.235V<\/td>\n<\/tr>\n
\u8f93\u5165\u7535\u538b<\/td>\n2.0 V to 30 V<\/td>\n<\/tr>\n
\u5de5\u4f5c\u6e29\u5ea6<\/td>\n-40\u00b0C to +125\u00b0C<\/td>\n<\/tr>\n
\u5305\u88c5<\/td>\nVSSOP-8 (3.0×3.0mm)<\/td>\n<\/tr>\n<\/table>\n

\u7279\u70b9<\/h2>\n
    \n
  • 100mA LDO with 380mV dropout and 75uA quiescent current<\/li>\n
  • Adjustable output from 1.24V to 29V with 1.235V internal reference<\/li>\n
  • Error flag output indicates output undervoltage condition<\/li>\n
  • Logic-level shutdown for power management control<\/li>\n<\/ul>\n

    \u5e94\u7528<\/h2>\n
      \n
    • Battery-powered instrumentation and portable electronics LDO<\/li>\n
    • High-efficiency post-regulation after switching converters<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"

      Product Overview The LP2951ACMX from Texas Instruments (formerly National Semiconductor) is a micropower low-dropout voltage regulator with 100mA output, 380mV dropout at 100mA, programmable output (1.24-29V), and error flag in an 8-pin VSSOP package. Key Specifications Output Voltage Adjustable (1.24 V to 29 V) Output Current 100 mA Dropout Voltage 380 mV @ 100mA Quiescent […]<\/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":[13,32],"tags":[],"chip_brand":[138],"class_list":["post-7406","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","category-low-dropout-regulators-ldo","chip_brand-ti"],"acf":{"brief_explanation":"100mA LDO, 380mV dropout, 75uA Iq, adj 1.24-29V, error flag, VSSOP-8","date_code":"","package_case":"VSSOP-8 (3.00 x 3.00 x 0.90 mm)","in_stock":9500,"datasheet":"https:\/\/www.ti.com\/lit\/ds\/symlink\/lp2951-n.pdf","price":"$0.55 @ 1ku","product_introduction":"The LP2951ACMX from Texas Instruments is a micropower low-dropout voltage regulator designed for battery-powered applications. The device provides up to 100mA output current with only 380mV dropout voltage at full load, enabling efficient operation from batteries down to end-of-life voltage. The quiescent current is a very low 75uA with no load, and the device maintains regulation with only 1uA load. The output voltage is adjustable from 1.24V to 29V using an external resistor divider, referenced to an internal 1.235V bandgap. An error flag output (open-collector) asserts when the output drops below approximately 92% of the nominal voltage, providing early warning of power failure or brownout. A logic-level shutdown pin reduces quiescent current to near zero when the regulator is disabled. The AC version provides tighter initial accuracy (+\/-0.5%) than the standard LP2951. The CMX suffix denotes the VSSOP-8 package on tape and reel.","working_principle":"The LP2951ACMX operates as a PNP-based low-dropout linear voltage regulator. (1) PNP Pass Transistor: Unlike NPN-based regulators that require the input voltage to be at least 1.5-2V above the output (VBE + VCE(sat) + Vdrop), the PNP pass transistor only requires VCE(sat) dropout, typically 380mV at 100mA. This allows operation with much smaller input-to-output voltage differential, critical for battery-powered applications. (2) Bandgap Reference: The internal 1.235V bandgap reference is compared with the feedback voltage from the output divider. The error amplifier adjusts the base drive of the PNP pass transistor to maintain regulation. (3) Error Flag: A voltage comparator monitors the output voltage. When the output drops below approximately 92% of the set value (due to overload, low input, or thermal shutdown), the error flag output pulls low through an open-collector NPN transistor. This provides an early warning for system power-fail detection. (4) Shutdown: The TTL\/CMOS-compatible shutdown pin controls the regulator. When the shutdown pin is pulled high, the PNP pass transistor is turned off, reducing the supply current to near zero.","pin_description":"
      Pin<\/th>Name<\/th>Function<\/th><\/tr>
      1<\/td>VOUT<\/td>Regulated output (up to 100mA)<\/td><\/tr>
      2<\/td>SENSE<\/td>Feedback sense (connect to VOUT)<\/td><\/tr>
      3<\/td>SHDN<\/td>Shutdown (high = off)<\/td><\/tr>
      4<\/td>GND<\/td>Ground<\/td><\/tr>
      5<\/td>ERR<\/td>Error flag output (open-collector)<\/td><\/tr>
      6<\/td>TAP<\/td>Output voltage tap (internal divider)<\/td><\/tr>
      7<\/td>FB<\/td>Feedback input (external divider)<\/td><\/tr>
      8<\/td>VIN<\/td>Input supply (2.0-30V)<\/td><\/tr><\/table>","application_scenarios":"
      • Battery-powered instrumentation LDO with 380mV dropout and error flag<\/li>
      • Post-regulation after switching converter with 75uA Iq<\/li><\/ul>","alternative_models":"
        Manufacturer<\/th>Part Number<\/th>Package<\/th>Notes<\/th><\/tr>
        TI<\/td>LP2951ACMX\/NOPB<\/td>VSSOP-8<\/td>NOPB = non-braided packaging<\/td><\/tr>
        TI<\/td>LP2950CDT-3.3RG4<\/td>SOT-223<\/td>Fixed 3.3V, 100mA, 3-pin<\/td><\/tr>
        Microchip<\/td>TC1185-3.3VCT713<\/td>SOT-23-5<\/td>150mA LDO, smaller<\/td><\/tr><\/table>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/7406","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=7406"}],"version-history":[{"count":0,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/7406\/revisions"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/media?parent=7406"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/categories?post=7406"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/tags?post=7406"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/chip_brand?post=7406"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}