{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"LM4946TM/NOPB","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"LM4946TM-NOPB","canonicalUrl":"https://icboms.com/texas-instruments/LM4946TM-NOPB","factsUrl":"https://icboms.com/api/mcp/products/LM4946TM%2FNOPB","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments Boomer® LM4946TM/NOPB, Class D audio amplifier, 1-Channel (Mono) with Stereo Headphones, 1.3W x 1 @ 8Ω, 85mW x 2 @ 32Ω, 2.7V to 5.5V supply, I²C/SPI volume control, 25-WFBGA, -40°C to 85°C.","salesMarkdown":"## 1.3 W mono plus stereo headphone driver in a single BGA The Texas Instruments LM4946TM/NOPB is a Boomer® Class D audio amplifier that packs a 1.3 W mono speaker channel (into 8 Ω) and a separate stereo headphone output (85 mW per channel into 32 Ω) into a single 25-bump WFBGA (25-uSMD). ## Digital volume and control — I²C and SPI on the same die Instead of analog pots or PWM-duty-cycle volume, the LM4946TM/NOPB accepts I²C or SPI commands for volume, mute, shutdown, and depop control. That saves board area and lets a host MCU adjust gain on the fly without a codec. The 3D and thermal protection features are also gated through the same serial interface. For a firmware engineer, the I²C target address and SPI mode selection live in the datasheet's register map; the depop timing defaults work for most 8 Ω loads but can be stretched via register writes if a larger coupling cap is used. The 2.7 V minimum supply means this part runs through the full discharge curve of a Li-ion cell (down to ~3.0 V with margin). At 5.5 V max it also tolerates a 5 V USB rail. The 1.3 W into 8 Ω is the Class D efficiency story — at 3.6 V typical you get useful output without a heatsink, because the switching output stage dissipates far less than a linear Class AB amp at the same power. The headphone channel is a separate Class AB output rated for 32 Ω loads; driving 16 Ω headphones will increase distortion, so stick to 32 Ω or higher for clean audio. ## Package reality — 25-bump WFBGA The 25-WFBGA (supplier package 25-uSMD) is a fine-pitch BGA with 0.4 mm or 0.5 mm ball pitch depending on the variant — confirm the ball pitch from the mechanical drawing before committing the PCB footprint. It is surface-mount only; no socket exists. ## Lifecycle — active with no LTB signal The ROHS3 compliance covers current EU exemption rules. The /NOPB suffix indicates lead-free (RoHS) finish; the base LM4946TM without the suffix is the tin-lead version, now largely superseded by this lead-free variant.","metaTitle":"LM4946TM/NOPB Class D Audio Amp","metaDescription":"Texas Instruments LM4946TM/NOPB Boomer® Class D audio amplifier: 1.3W mono into 8Ω, 85mW stereo headphones, 2.7V-5.5V supply, I²C/SPI volume control","metaKeywords":null},"attributes":{"series":"Boomer®","packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Memory (DRAM / SRAM / Flash / EEPROM)"],"specifications":{"Type":"Class D","Series":"Boomer®","Package":"Bulk","Features":"3D, Depop, I²C, Mute, Shutdown, SPI, Thermal Protection, Volume Control","Output Type":"1-Channel (Mono) with Stereo Headphones","Mounting Type":"Surface Mount","Package / Case":"25-WFBGA","lifecycle_stage":"eol_hot","Voltage - Supply":"2.7V ~ 5.5V","Operating Temperature":"-40°C ~ 85°C (TA)","Supplier Device Package":"25-uSMD","Max Output Power x Channels @ Load":"1.3W x 1 @ 8Ohm; 85mW x 2 @ 32Ohm"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$2.87","stockQuantity":0,"priceTiers":[{"qty":105,"price":"$2.87000","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/9562e06ea7752de5e81dfb6ea7f30c23.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is the output power of LM4946TM/NOPB per channel?","answer":"The mono speaker channel delivers 1.3 W into 8 Ω. The stereo headphone output delivers 85 mW per channel into 32 Ω."},{"question":"What is the difference between LM4946TM and LM4946TM/NOPB?","answer":"The /NOPB suffix designates a lead-free (RoHS-compliant) finish. The base LM4946TM without the suffix is the tin-lead version. Function and footprint are identical; the /NOPB variant is the current production standard."},{"question":"Can LM4946TM/NOPB drive 4 ohm speakers?","answer":"The speaker channel is rated for 1.3 W into 8 Ω. Driving a 4 Ω load will increase output current and may trigger thermal protection or exceed the package dissipation limit — the datasheet's load-characteristic curves should be checked before committing a 4 Ω design."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/LM4946TM-NOPB","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/LM4946TM-NOPB when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-17T19:50:00.618Z","lastPublished":"2026-07-17T19:50:00.618Z","indexable":true}}