{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SN74LS33N","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"SN74LS33N","canonicalUrl":"https://icboms.com/texas-instruments/SN74LS33N","factsUrl":"https://icboms.com/api/mcp/products/SN74LS33N","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments 74LS series, SN74LS33N, Logic Type NOR Gate, Open Collector, 4 Circuits, 2 Inputs, 4.75V ~ 5.25V Supply, Through Hole, 14-DIP (0.300\", 7.62mm), 0°C ~ 70°C.","salesMarkdown":"## Quad 2-input NOR gate with open-collector outputs — what the ratings mean for the bus The Texas Instruments SN74LS33N is a quad 2-input NOR gate from the 74LS Schottky family, with open-collector outputs. It packages four independent NOR gates in a through-hole 14-pin DIP (0.300\" body), operating from a 4.75 V to 5.25 V supply over the commercial temperature range of 0°C to 70°C. The open-collector output is the defining feature: each output can sink up to 24 mA (the 'low' state) but cannot source current — it relies on an external pull-up resistor to pull the output high. This makes the part suited for wired-OR bus structures, level translation (pulling up to a different voltage than Vcc), and driving loads like relays or LEDs where the load connects between the output and a positive supply. Propagation delay is specified at 32 ns maximum into a 45 pF load at 5 V — a typical figure for the 74LS family. When budgeting timing on a backplane or shared interrupt line, that 32 ns window includes the time from any input crossing the 0.8 V (low) / 2 V (high) thresholds to the output sinking current. The quiescent supply current is 3.6 mA max for all four gates. ## Open-collector output: sizing the pull-up resistor Because the SN74LS33N output only sinks, not sources, the pull-up resistor value determines both the rise time and the high-level voltage. The 24 mA sink rating sets the minimum pull-up: at 5 V supply, a 220 Ω resistor would draw about 23 mA when the output is low — right at the limit. In practice, a 1 kΩ to 4.7 kΩ pull-up is typical for TTL-level buses, trading off speed (lower resistance = faster rise) against power (higher current when low). For a wired-OR interrupt line with several gates, the combined low-level current of all driving gates must stay under 24 mA per output. The open-collector structure allows the output high voltage to be set by the pull-up supply, which can be different from Vcc. ## Lifecycle and supply posture The SN74LS33N is listed as Active in production and ROHS3 compliant.","metaTitle":"SN74LS33N 74LS Quad 2-Input NOR Gate, Open Collector, 14-DIP","metaDescription":"SN74LS33N active 74LS quad 2-input NOR gate with open-collector outputs. 24 mA sink, 32 ns delay at 5V/45pF. 4.75V–5.25V supply, 0°C–70°C. Through-hole 14-DIP.","metaKeywords":null},"attributes":{"series":"74LS","packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["DC-DC Power Modules"],"specifications":{"Series":"74LS","Package":"Tube","Features":"Open Collector","Logic Type":"NOR Gate","Mounting Type":"Through Hole","Package / Case":"14-DIP (0.300\\\", 7.62mm)","lifecycle_stage":"eol_hot","Number of Inputs":"2","Voltage - Supply":"4.75V ~ 5.25V","Number of Circuits":"4","Operating Temperature":"0°C ~ 70°C","Input Logic Level - Low":"0.8V","Supplier Device Package":"14-PDIP","Input Logic Level - High":"2V","Current - Quiescent (Max)":"3.6 mA","Current - Output High, Low":"-, 24mA","Max Propagation Delay @ V, Max CL":"32ns @ 5V, 45pF"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.87","stockQuantity":0,"priceTiers":[{"qty":1,"price":"$1.87000","currency":"USD"},{"qty":10,"price":"$1.68300","currency":"USD"},{"qty":25,"price":"$1.58720","currency":"USD"},{"qty":100,"price":"$1.35240","currency":"USD"},{"qty":250,"price":"$1.26988","currency":"USD"},{"qty":500,"price":"$1.11114","currency":"USD"},{"qty":1000,"price":"$0.92066","currency":"USD"},{"qty":2500,"price":"$0.89850","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/4c2e979bc971f29421ab561ab2de933e.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What are the alternatives for SN74LS33N?","answer":"The closest functional alternative within the 74LS family is the SN74LS03, which is also a quad 2-input NAND gate with open-collector outputs in the same 14-DIP package and supply range. The key difference is logic function: the SN74LS33N is a NOR gate, while the SN74LS03 is a NAND gate. For a NOR-gate replacement, stay with the SN74LS33N or its surface-mount sibling SN74LS33D. The 74F27 (triple 3-input NOR) and 74ALS11 (triple 3-input AND) are different logic functions and not direct substitutes."},{"question":"Can SN74LS33N work with a 3.3V supply?","answer":"No. The SN74LS33N is specified for a 4.75 V to 5.25 V supply. Operating it at 3.3 V is outside the guaranteed operating range — the input thresholds (0.8 V low, 2 V high) and output drive characteristics are not characterized below 4.75 V. For 3.3 V logic, use a 74LVC or 74AHC family gate instead."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/SN74LS33N","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/SN74LS33N 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}}