{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SN74LS21N","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"SN74LS21N","canonicalUrl":"https://icboms.com/texas-instruments/SN74LS21N","factsUrl":"https://icboms.com/api/mcp/products/SN74LS21N","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments 74LS series, AND Gate, SN74LS21N, 2 Circuits, 4 Inputs, 14-DIP (0.300\", 7.62mm), Through Hole, Tube.","salesMarkdown":"## Dual 4-input AND gate in a 14-pin DIP The SN74LS21N: It integrates two independent AND gates, each with four inputs, in a single 14-pin plastic DIP (0.300\" body width) for through-hole assembly. ## 20 ns propagation delay at 5 V, 15 pF Maximum propagation delay is 20 ns at 5 V supply and 15 pF load capacitance. This sets the timing floor for the signal path — at 5 V the gate toggles in under 20 ns, which is fast enough for most 5 V control logic but not for high-speed synchronous buses above 25 MHz. Output drive capability is 400 µA sourcing (logic high) and 8 mA sinking (logic low). The asymmetric drive means the gate can sink more current than it sources — common in TTL — so downstream loads should be designed to be driven low rather than high where possible. Input logic thresholds are 0.8 V maximum for a low and 2.0 V minimum for a high, compatible with standard 5 V TTL levels. The 0.8 V low threshold gives noise margin against ground bounce on a shared backplane. ## Active production, ROHS3 compliant ROHS3 compliant — no restricted substances above threshold limits. No additional compliance documentation (REACH, UL, IEC) is listed on the product record, so the standard TI declaration of conformity applies.","metaTitle":"TI SN74LS21N Dual 4-Input AND Gate, 74LS, 20ns, 14-DIP","metaDescription":"Texas Instruments SN74LS21N dual 4-input AND gate, 74LS family. 20ns propagation delay at 5V, 15pF. Commercial temp 0-70°C. Active production, ROHS3 compliant.","metaKeywords":null},"attributes":{"series":"74LS","packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Microcontrollers & Processors (MCU / MPU / DSP)"],"specifications":{"Series":"74LS","Package":"Tube","Logic Type":"AND Gate","Mounting Type":"Through Hole","Package / Case":"14-DIP (0.300\\\", 7.62mm)","lifecycle_stage":"eol_hot","Number of Inputs":"4","Voltage - Supply":"4.75V ~ 5.25V","Number of Circuits":"2","Operating Temperature":"0°C ~ 70°C","Input Logic Level - Low":"0.8V","Supplier Device Package":"14-PDIP","Input Logic Level - High":"2V","Current - Output High, Low":"400µA, 8mA","Max Propagation Delay @ V, Max CL":"20ns @ 5V, 15pF"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.91","priceTiers":[{"qty":1,"price":"$0.91000","currency":"USD"},{"qty":10,"price":"$0.80500","currency":"USD"},{"qty":25,"price":"$0.75640","currency":"USD"},{"qty":100,"price":"$0.61720","currency":"USD"},{"qty":250,"price":"$0.57324","currency":"USD"},{"qty":500,"price":"$0.48788","currency":"USD"},{"qty":1000,"price":"$0.39030","currency":"USD"},{"qty":2500,"price":"$0.35371","currency":"USD"},{"qty":5000,"price":"$0.34520","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/a8ad9313f2cd9a22f7a836fedec5f852.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/SN74LS21N/alternatives.json"},"ai":{"faq":[{"question":"What is the closest functional second-source to SN74LS21N?","answer":"It is not a pin-for-pin drop-in at 5 V because the HC family's input thresholds differ from TTL levels — at 5 V the HC low threshold is 1.5 V max vs 0.8 V for the LS part, so the HC gate may not recognise a TTL low signal correctly without a pull-up. The SN74ALS11ANS is a surface-mount 3-input AND gate in a different package and pinout, so it requires a board layout change."},{"question":"What compliance documentation does Texas Instruments provide for SN74LS21N?","answer":"Texas Instruments provides ROHS3 compliance for the SN74LS21N. No UL, IEC, or REACH documentation is listed on the product record. Standard TI declarations of conformity and material composition data are available upon request through the supply chain."},{"question":"Will SN74LS21N drop into a panel that was specified around SN74ALS11ANS without rewiring?","answer":"No. The SN74ALS11ANS is a surface-mount 14-pin SOIC package with a 3-input AND gate topology (three inputs per gate, three gates total), while the SN74LS21N is a through-hole 14-DIP with a 4-input AND gate (four inputs per gate, two gates total). The pinouts, package footprint, and logic function differ — a board spin is required."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/SN74LS21N","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/SN74LS21N 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}}