\n| \u5305\u88c5<\/td>\n | SOT-223 (3-pin surface-mount)<\/td>\n<\/tr>\n<\/table>\n\u7279\u70b9<\/h2>\n\n- Adjustable negative output from -1.2V to -37V<\/li>\n
- 1.5A output current with internal current limiting<\/li>\n
- Excellent line and load regulation (0.01%\/V, 0.1%)<\/li>\n
- 77dB ripple rejection at 120Hz<\/li>\n
- Internal thermal shutdown and safe-area compensation<\/li>\n
- Only 2 external resistors needed to set output voltage<\/li>\n
- Complement to LM317 positive regulator<\/li>\n
- SOT-223 surface-mount package for compact designs<\/li>\n<\/ul>\n
\u5e94\u7528<\/h2>\n\n- Negative supply rails for op-amps<\/li>\n
- Dual-tracking regulators (with LM317)<\/li>\n
- Analog and instrumentation power supplies<\/li>\n
- Audio amplifier split supplies<\/li>\n
- Battery charger negative rails<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"
Product Overview The LM337IMP\/NOPB is a 1.5A adjustable negative voltage regulator from Texas Instruments with -1.2V to -37V output, 0.1%\/V line regulation, and thermal shutdown in a SOT-223 surface-mount package. Key Specifications Output Voltage -1.2V to -37V (adjustable) Output Current 1.5A (with adequate heatsinking) Input-Output Differential -3V to -40V (max |VIN-VOUT|) Line Regulation 0.01%\/V typical […]<\/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-7871","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","category-low-dropout-regulators-ldo","chip_brand-ti"],"acf":{"brief_explanation":"1.5A adj negative regulator, -1.2V to -37V, SOT-223, complement to LM317","date_code":"","package_case":"SOT-223 (6.5 x 3.5 x 1.8mm, 3-pin with tab)","in_stock":6700,"datasheet":"https:\/\/www.ti.com\/lit\/ds\/symlink\/lm337.pdf","price":"$1.85 @ 1ku","product_introduction":"The LM337IMP\/NOPB is the negative-output complement to the LM317, providing an adjustable negative voltage from -1.2V to -37V at up to 1.5A. The output voltage is set by two external resistors: one from the output to the ADJ pin and one from the ADJ pin to ground. The device features excellent line regulation (0.01%\/V), load regulation (0.1%), and 77dB ripple rejection at 120Hz. Internal protection includes current limiting, thermal shutdown, and safe-area compensation for the pass transistor. The SOT-223 package provides surface-mount capability with adequate power dissipation for moderate input-output differentials. The IMP suffix denotes the SOT-223 package, and the NOPB suffix indicates lead-free RoHS compliance.","working_principle":"The LM337IMP\/NOPB uses a floating design where the ADJ pin is the reference point rather than ground. The internal bandgap reference maintains 1.25V between the output (VOUT) and ADJ pins. This reference voltage drives a constant current through the external resistor R1 (VOUT to ADJ), and the ADJ pin current (typically 50\u00b5A) flows through the second resistor R2 (ADJ to ground). The output voltage is VOUT = -1.25 \u00d7 (1 + R2\/R1) - 50\u00b5A \u00d7 R2. Since the 50\u00b5A adjustment pin current is small and stable, the output voltage is primarily determined by the resistor ratio. The error amplifier compares the VOUT-ADJ voltage with the 1.25V reference and drives the series pass transistor to maintain regulation. The current-limiting circuit monitors output current and reduces the drive when it exceeds approximately 2.2A. The thermal shutdown disables the pass transistor when the junction temperature exceeds approximately 170\u00b0C. Safe-area protection reduces the current limit as the input-output voltage differential increases, protecting the pass transistor from secondary breakdown.","pin_description":" \n| Pin<\/th> | Name<\/th> | Type<\/th> | Description<\/th><\/tr>\n |
|---|
| 1<\/td> | ADJ<\/td> | Adjustment<\/td> | Adjustment pin sets output voltage via external resistor divider. Maintained at 1.25V above VOUT by internal reference. Connect R1 from VOUT to ADJ (typically 120\u03a9), and R2 from ADJ to GND. Output = -1.25V \u00d7 (1 + R2\/R1). Adjustment pin current is typically 65\u00b5A. For fixed output, connect ADJ to the junction of two resistors between VOUT and GND.<\/td><\/tr>\n | | 2<\/td> | VOUT<\/td> | Power Output<\/td> | Negative regulated output voltage from -1.25V to -37V at up to 1.5A. In SOT-223-4 package, the tab (Pin 4) is electrically connected to VOUT. Bypass with 1\u00b5F solid tantalum or 10\u00b5F electrolytic to GND for stability. Output noise is typically 0.003% of VOUT.<\/td><\/tr>\n | | 3<\/td> | VIN<\/td> | Power Input<\/td> | Negative unregulated input voltage. Must be more negative than Vout - Vdropout (typ 2.5V at 1.5A). Maximum -40V input-to-output differential. Bypass with 0.1\u00b5F ceramic to GND when supply is remote. Ensure input does not exceed 0.7V above ground to avoid forward biasing internal diodes.<\/td><\/tr>\n | | 4<\/td> | TAB<\/td> | Thermal<\/td> | Thermal\/heatsink tab electrically connected to VOUT (Pin 2). Solder to PCB copper pour for heat dissipation. On FR-4 with 1oz copper, thermal resistance is approximately 50\u00b0C\/W. For higher current, use thermal vias to internal ground plane.<\/td><\/tr>\n<\/table>\n LM337IMP\/NOPB uses SOT-223-4 (DCY) package. Pin 1 = ADJ, Pin 2 = VOUT, Pin 3 = VIN, Pin 4 (Tab) = VOUT. Note that ADJ is Pin 1 (leftmost) unlike the LM337T TO-220 version. The tab is connected to VOUT, NOT GND. For safe operation, add protection diodes: D1 from ADJ to VOUT and D2 from VIN to VOUT to discharge capacitors during fault conditions.<\/p>","application_scenarios":" \n- Split Supplies:<\/strong> Paired with LM317 creates adjustable \u00b1 supplies for op-amp circuits with matched regulation performance<\/li>\n
- Audio Amplifiers:<\/strong> 77dB ripple rejection and 0.01%\/V line regulation ensure clean negative rail for Class-AB output stages<\/li>\n
- Instrumentation:<\/strong> 0.0004%\/\u00b0C temperature stability maintains precision negative reference for measurement circuits<\/li>\n
- Lab Supplies:<\/strong> Adjustable -1.2V to -37V output covers all common negative rail requirements<\/li>\n
- Compact Designs:<\/strong> SOT-223 package enables surface-mount negative regulation in space-constrained PCBs<\/li>\n<\/ul>","alternative_models":"
\n| Model<\/th> | Manufacturer<\/th> | Key Difference<\/th> | Package<\/th> | Output<\/th><\/tr>\n |
|---|
| LM337T\/NOPB<\/td> | TI<\/td> | TO-220 through-hole version for higher power dissipation with heatsink mounting<\/td> | TO-220-3<\/td> | -1.25V to -37V adj<\/td><\/tr>\n | | LM337K STEEL\/NOPB<\/td> | TI<\/td> | TO-3 steel can for high-reliability and military applications with superior thermal performance<\/td> | TO-3<\/td> | -1.25V to -37V adj<\/td><\/tr>\n | | KA337MTF<\/td> | onsemi<\/td> | SOT-223 surface-mount equivalent with 1.5A output and internal current limiting<\/td> | SOT-223-4<\/td> | -1.25V to -37V adj<\/td><\/tr>\n | | MC337MP<\/td> | onsemi<\/td> | SOT-223 equivalent with identical electrical specifications and RoHS compliance<\/td> | SOT-223-4<\/td> | -1.25V to -37V adj<\/td><\/tr>\n | | LT337MP#PBF<\/td> | ADI<\/td> | Higher performance version with improved load regulation and lower noise output<\/td> | DDPAK-3<\/td> | -1.25V to -37V adj<\/td><\/tr>\n | | LM337EMP\/NOPB<\/td> | TI<\/td> | SOT-223-4 version for space-constrained designs with 1A output current rating<\/td> | SOT-223-4<\/td> | -1.25V to -37V adj<\/td><\/tr>\n<\/table>\n The LM337IMP\/NOPB uses SOT-223-4 (DCY) package. For through-hole designs with heatsinks, use LM337T\/NOPB (TO-220). All LM337 variants are pin-compatible (ADJ-OUT-IN) and require only two external resistors to set the output voltage.<\/p>"},"_links":{"self":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/7871","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=7871"}],"version-history":[{"count":1,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/7871\/revisions"}],"predecessor-version":[{"id":8117,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/posts\/7871\/revisions\/8117"}],"wp:attachment":[{"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/media?parent=7871"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/categories?post=7871"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/tags?post=7871"},{"taxonomy":"chip_brand","embeddable":true,"href":"https:\/\/materialparts.com\/zh\/wp-json\/wp\/v2\/chip_brand?post=7871"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}} | | |