{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"LM4040A20IDCKR","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"LM4040A20IDCKR","canonicalUrl":"https://icboms.com/texas-instruments/LM4040A20IDCKR","factsUrl":"https://icboms.com/api/mcp/products/LM4040A20IDCKR","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments LM4040A20IDCKR, precision shunt voltage reference, 2.048 V fixed output, ±0.1% tolerance, 35 µVrms noise, 100 ppm/°C drift, SC-70-5, -40°C to 85°C.","salesMarkdown":"## 2.048 V shunt reference — the ±0.1% tolerance that locks the ADC scale The Texas Instruments LM4040A20IDCKR is a precision shunt voltage reference with a fixed 2.048 V output and a ±0.1% initial tolerance. That tolerance grade is the tightest in the LM4040A family — the ±0.5% and ±1% siblings are cheaper but add a systematic gain error that a calibration technician will find on the first board-level verification. For a 12-bit ADC with a 4.096 V reference input, the 2.048 V output sets the full-scale range directly; the ±0.1% tolerance keeps the gain error below 2 mV, which is within the LSB budget for most 12-bit conversions without a trim step. The 35 µVrms noise over 10 Hz to 10 kHz is low enough that a 16-bit ADC reference input sees less than 0.5 LSB of noise contribution from the reference alone, assuming a 4.096 V reference span. For a lab-grade instrument that stays at 25°C, the drift is negligible; for an outdoor data logger, budget the drift into the system accuracy calculation. ## Shunt topology — the cathode current floor and output drive limit As a shunt reference, the LM4040A20IDCKR requires a series resistor from the supply to the cathode pin; the 80 µA minimum cathode current sets the resistor value so the reference always has enough bias to regulate. The 15 mA maximum output current limits how many ADC reference inputs or op-amp bias networks one reference can drive — driving more than one or two high-impedance loads is fine, but sourcing the reference input of a SAR ADC that draws a few mA during conversion needs a buffer or a separate reference per channel. ## SC-70-5 footprint — the layout constraint for the shunt resistor The SC-70-5 (SOT-353) package is a 5-pin surface-mount footprint with 0.65 mm pitch. The small body means the shunt resistor and bypass capacitor must sit close to the reference pin to keep the loop area small and avoid injecting noise into the reference node. ## Active lifecycle — no end-of-life watch for this BOM line","metaTitle":"TI LM4040A20IDCKR Shunt Voltage Reference, 2.048 V, ±0.1%","metaDescription":"Texas Instruments LM4040A20IDCKR precision shunt reference, 2.048 V fixed output, ±0.1% tolerance, 35 µVrms noise, SC-70-5.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Analog & Data Acquisition"],"specifications":{"Mfr":"Texas Instruments","Series":"-","Package":"Tape & Reel (TR); Cut Tape (CT)","Tolerance":"±0.1%","Output Type":"Fixed","Mounting Type":"Surface Mount","Package / Case":"5-TSSOP, SC-70-5, SOT-353","Product Status":"Active","Reference Type":"Shunt","Voltage - Input":"-","lifecycle_stage":"eol_hot","Current - Output":"15 mA","Current - Supply":"-","Current - Cathode":"80 µA","Base Product Number":"LM4040","Noise - 0.1Hz to 10Hz":"-","Noise - 10Hz to 10kHz":"35µVrms","Operating Temperature":"-40°C~85°C(TA)","Supplier Device Package":"SC-70-5","Temperature Coefficient":"100ppm/°C","Voltage - Output (Min/Fixed)":"2.048V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.8315","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/LM4040A20IDCKR/alternatives.json"},"ai":{"faq":[{"question":"What is the difference between LM4040A20IDCKR and LM4040A20IDBZR?","answer":"Both are the same LM4040A20 die with a 2.048 V output and ±0.1% tolerance. The difference is the package: the LM4040A20IDCKR is in an SC-70-5 (SOT-353) package, while the LM4040A20IDBZR is in an SOT-23-3 package. The SC-70-5 is smaller and has five pins (the extra pins are no-connects or a separate cathode sense), so the PCB footprint differs. Electrically they are identical, but the board layout must match the package."},{"question":"What is LM4040A20IDCKR's listed tolerance?","answer":"The listed tolerance is ±0.1% at 25°C. This is the tightest initial accuracy grade in the LM4040A family, making it suitable for precision analog designs where a 2 mV error on a 2.048 V reference is the maximum acceptable gain error."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/LM4040A20IDCKR","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/LM4040A20IDCKR when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-22T18:03:28.771Z","lastPublished":"2026-07-22T18:03:28.771Z","indexable":true}}