{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SN74LS688DW","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"SN74LS688DW","canonicalUrl":"https://icboms.com/texas-instruments/SN74LS688DW","factsUrl":"https://icboms.com/api/mcp/products/SN74LS688DW","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments 74LS series, SN74LS688DW, 8-bit Identity Comparator, Active Low output, 4.85V~5.25V supply, 0°C~70°C, 23ns propagation delay, 20-SOIC wide body.","salesMarkdown":"It compares two 8-bit words and asserts a single active-low output (A=B) when the words match. The output function is A=B, and the output is active low — meaning the pin goes low on a match, which is the convention for cascading in wide-word compare trees or driving an interrupt line. With a maximum propagation delay of 23 ns at 5 V into a 45 pF load, this part is fast enough for most 5 V backplane address decoding, memory-mapped I/O select generation, and bus-matching tasks running at clock rates up to about 20 MHz. The supply range is 4.85 V to 5.25 V, so it expects a regulated 5 V rail — not suitable for 3.3 V or mixed-voltage domains without level translation. The package is a 20-SOIC wide body (7.50 mm width), surface-mount only. No DIP option exists for this specific order code. ## Output drive and fanout The output can source 400 µA and sink 24 mA. That sink current is the important number: it can drive up to 10 standard 74LS loads (each rated at 360 µA input low current) plus a few more, so fanout is comfortable for typical bus interfaces. The source side is weak — 400 µA means it cannot drive a TTL input high directly without a pull-up resistor; in practice, the active-low output is usually wire-OR'd or pulled up externally.","metaTitle":"SN74LS688DW 8-bit Identity Comparator, 23ns, 20-SOIC","metaDescription":"Texas Instruments SN74LS688DW 8-bit identity comparator, active-low output, 23ns propagation delay at 5V. 20-SOIC wide body. Active lifecycle.","metaKeywords":null},"attributes":{"series":"74LS","packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Analog & Data Acquisition"],"specifications":{"Type":"Identity Comparator","Output":"Active Low","Series":"74LS","Package":"Tube","Mounting Type":"Surface Mount","Number of Bits":"8","Package / Case":"20-SOIC (0.295\\\", 7.50mm Width)","Output Function":"A=B","lifecycle_stage":"eol_hot","Voltage - Supply":"4.85V ~ 5.25V","Operating Temperature":"0°C ~ 70°C","Supplier Device Package":"20-SOIC","Current - Output High, Low":"400µA, 24mA","Max Propagation Delay @ V, Max CL":"23ns @ 5V, 45pF"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$2.93","priceTiers":[{"qty":1,"price":"$2.93000","currency":"USD"},{"qty":10,"price":"$2.63100","currency":"USD"},{"qty":25,"price":"$2.48760","currency":"USD"},{"qty":100,"price":"$2.15590","currency":"USD"},{"qty":250,"price":"$2.04532","currency":"USD"},{"qty":500,"price":"$1.83526","currency":"USD"},{"qty":1000,"price":"$1.56450","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/bd548aefa4303a6053821930dcb2e4a0.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/SN74LS688DW/alternatives.json"},"ai":{"faq":[{"question":"What is the replacement or equivalent for SN74LS688DW?","answer":"No official replacement is listed for this active part. The TLV9032DDFR is a different device class (dual comparator, push-pull output, 1.65 V supply) and is not a functional equivalent. For a true 8-bit identity comparator in 5 V logic, the 74LS688 family is the standard; the SN74LS688DW is the surface-mount SOIC variant."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/SN74LS688DW","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/SN74LS688DW when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:49:49.435Z","lastPublished":"2026-08-11T15:49:49.435Z","indexable":true}}