The SN74HC02DR from Texas Instruments is a quadruple 2-input positive NOR gate in a 14-pin SOIC package, operating from 2V to 6V with 5.2mA output drive and 10-50ns propagation delay.<\/p>\n
| Logic Function<\/td>\n | Quad 2-Input NOR Gate<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Number of Gates<\/td>\n | 4<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| \u7535\u6e90\u7535\u538b<\/td>\n | 2V to 6V<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Output Drive Current<\/td>\n | 5.2 mA (sink\/source)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| \u4f20\u64ad\u5ef6\u8fdf<\/td>\n | 10-50 ns (typ, VCC=4.5V)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| \u8f93\u5165\u7c7b\u578b<\/td>\n | \u6807\u51c6 CMOS<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| \u8f93\u51fa\u7c7b\u578b<\/td>\n | Push-Pull<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Logic Function (positive)<\/td>\n | Y = NOT(A OR B)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ESD Protection<\/td>\n | HBM >2000V, CDM >1000V<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| \u5305\u88c5<\/td>\n | SOIC-14 (8.65 x 3.90mm)<\/td>\n<\/tr>\n | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| \u5de5\u4f5c\u6e29\u5ea6<\/td>\n | -40 to +85 C<\/td>\n<\/tr>\n<\/table>\n\u7279\u70b9<\/h2>\n\u5e94\u7528<\/h2>\nProduct Overview The SN74HC02DR from Texas Instruments is a quadruple 2-input positive NOR gate in a 14-pin SOIC package, operating from 2V to 6V with 5.2mA output drive and 10-50ns propagation delay. Key Specifications Logic Function Quad 2-Input NOR Gate Number of Gates 4 Supply Voltage 2V to 6V Output Drive Current 5.2 mA (sink\/source) […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[13],"tags":[],"chip_brand":[138],"class_list":["post-3765","post","type-post","status-publish","format-standard","hentry","category-integrated-circuits-ics","chip_brand-ti"],"acf":{"brief_explanation":"Quad 2-input NOR gate, 2-6V, 5.2mA drive, 10-50ns tpd, SOIC-14","date_code":"","package_case":"SOIC-14 (8.65 x 3.90 x 1.58 mm, D package)","in_stock":11378,"datasheet":"https:\/\/www.ti.com\/lit\/ds\/symlink\/sn54hc02.pdf","price":"$0.186 @ 1ku","product_introduction":"The SN74HC02DR from Texas Instruments is a quadruple 2-input positive NOR gate from the 74HC (High-Speed CMOS) logic family. The device contains four independent NOR gates, each performing the Boolean function Y = NOT(A OR B) in positive logic, or equivalently Y = A NOR B. The NOR gate is one of the universal logic gates, meaning any combinational or sequential logic function can be implemented using only NOR gates. A common application is the SR (Set-Reset) latch, where two cross-coupled NOR gates form a basic memory element with Set and Reset inputs. The 74HC family operates from a wide supply voltage range of 2V to 6V, making it compatible with 3.3V and 5V logic systems. Buffered inputs provide improved noise immunity compared to unbuffered designs, with CMOS input thresholds at approximately 50% of VCC. The output can sink or source up to 5.2mA, sufficient to drive up to 10 LSTTL loads or multiple CMOS inputs. The propagation delay of 10-50ns (depending on supply voltage) supports data rates up to 28Mbps. The SOIC-14 surface-mount package (DR suffix) is suitable for automated PCB assembly. The device features latch-up immunity exceeding 100mA per JESD 78 Class II and ESD protection exceeding 2000V HBM and 1000V CDM.","working_principle":"The SN74HC02DR operates as four independent CMOS NOR gates. Key operating principles include: (1) NOR Gate Logic - each gate implements the function Y = NOT(A OR B); the output Y is LOW only when at least one input (A or B) is HIGH; the output Y is HIGH only when both inputs A and B are LOW; this truth table makes NOR gates useful for active-HO control signals and SR latch construction; (2) CMOS Complementary Output - each gate uses a PMOS\/NMOS complementary output stage that actively drives both HIGH and LOW levels; this push-pull output provides rail-to-rail swing (VCC to GND) with low output impedance; the 5.2mA drive capability is symmetric for sourcing and sinking; (3) Buffered Input - each gate input includes a buffer stage (two inverters in series) before the core NOR logic; buffering increases the input threshold sharpness and noise immunity; the CMOS input draws essentially zero DC current (only leakage), allowing large fanout to other CMOS devices; (4) SR Latch - two NOR gates can be cross-coupled (output of each feeds an input of the other) to form an SR latch; Set (S=1, R=0) makes Q=1; Reset (S=0, R=1) makes Q=0; S=R=0 holds the previous state; S=R=1 is an invalid condition (both Q and not-Q go LOW); (5) Power Consumption - static power consumption is near zero (only leakage current, typically <1uA); dynamic power consumption is P = CPD x VCC^2 x f, where CPD is the power dissipation capacitance; this makes HC logic much more power-efficient than bipolar LSTTL.","pin_description":"
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