Logic ICs
Products (362)
SN74HC86NE4 - Quad 2-Input XOR Gate, 14-PDIP | Texas Instruments
The Texas Instruments SN74HC86NE4 is a quadruple 2-input Exclusive-OR (XOR) gate IC fabricated in high-speed CMOS silicon-gate technology, providing four independent XOR gates in a 14-pin PDIP (plastic DIP) through-hole package. Each of the four gates performs the Boolean function Y = A XOR B in positive logic, with buffered outputs capable of driving 10 LSTTL loads and a wide 2 V to 6 V operating voltage range. The 'NE4' suffix indicates a Pb-free, RoHS-compliant assembly variant of the SN74HC86N, identical electrically but compliant with contemporary lead-free soldering and environmental standards. The device typically exhibits 6 ns propagation delay at 5 V C_load = 50 pF, 5.2 mA output drive strength, and a ±20 µA input leakage at 6 V, suiting it for bus-oriented digital logic designs. What is an XOR gate? An XOR (Exclusive-OR) gate is a fundamental two-input digital logic primitive whose output is HIGH only when the two inputs differ. Positioned within the broader gates-and-inverters IC category, XOR gates sit alongside AND, OR, NAND, NOR, and INVERTER cells, and are widely deployed in parity generators, comparators, half adders, controlled inverters, and arithmetic logic units. A single HC86 device packs four independent XOR gates into one 14-pin package, saving board area and reducing part count versus discrete implementations. Key features include balanced CMOS outputs, low input current of ±1 µA maximum, significant power-reduction versus LSTTL equivalents, and an operating temperature range of -40 °C to +85 °C suitable for industrial applications. The HC family also provides high noise immunity (typically 30% of V_CC as the noise margin) and supports fan-out to 10 LSTTL loads, simplifying interface to legacy bipolar logic without level shifters. Clamp diodes on the inputs allow voltages up to 1.5 V above V_CC without damage. Architecturally, the SN74HC86NE4 uses a silicon-gate CMOS process to deliver HCMOS-equivalent speed at one-fifth the static power of LSTTL. Its TTL-compatible input thresholds (V_IL ≈ 0.9 V at 5 V, V_IH ≈ 3.15 V) allow direct interfacing with legacy bipolar logic without external pull-ups. The four gates are partitioned symmetrically as 1A/1Y, 2A/2Y, 3A/3Y, 4A/4Y to ease PCB routing, and an internal thermal-shutdown feature is absent (CMOS logic is inherently current-limited by design). Typical applications include parity generation and checking in data communication busses, half and full adder construction for low-bit arithmetic, true/complement control logic for op-amp switching, phase-detector networks in PLL synthesizers, and address decoders in memory systems. Designers also use the HC86 for binary-to-Gray code conversion, which is essential in optical encoders and shaft position decoding. When designing with this part, ensure unused inputs are tied to V_CC or GND through 1 kΩ pull-down/up resistors rather than left floating to prevent excess current and propagation of noise through the CMOS input stages. Operating above 6 V will damage the device; operating below 2 V disables the internal logic thresholds and produces undefined outputs. This page synthesizes current distributor pricing, AEO-optimized FAQ entries, verified drop-in alternatives, and practical design notes that extend the manufacturer datasheet with engineering-grade decision support.
SN74HCS126QPWRQ1 - Automotive Quad 3-State Buffer | TI
The Texas Instruments SN74HCS126QPWRQ1 is an AEC-Q100 qualified automotive quadruple bus buffer with 3-state outputs and Schmitt-trigger inputs, housed in a 14-pin TSSOP (PW) package rated from -40C to +125C. The device operates from a 2.0 V to 6.0 V supply and buffers four non-inverting 1-bit channels with active-high output-enable pins. A CMOS logic buffer is a digital building block that reproduces (non-inverting) a digital signal while providing isolation between a weak or noisy source and a heavier load. In the logic hierarchy, the SN74HCS126-Q1 belongs to the buffer / line driver family of the HC/HCS CMOS logic category, and bus buffers with 3-state outputs further add the ability to disconnect the output from the bus, enabling shared, multidrop data lines in microprocessor and automotive in-vehicle networking systems. Key differentiating features include Schmitt-trigger inputs with hysteresis that convert slow or noisy input transitions into clean, fast edges - essential in automotive environments with ground bounce and EMI; 3-state outputs that implement high-impedance bus sharing; low input hysteresis threshold spread across the 2.0 V to 6.0 V operating range; and a typical CMOS microamp-level quiescent current that minimizes system standby power. The device is qualified per AEC-Q100 Grade 1 for harsh automotive ambient temperatures. Technically, the HCS family combines high-voltage CMOS fabrication with input hysteresis, providing robust switching thresholds (VT+ / VT- spread) across supply voltage, temperature, and process corners. Output drive is balanced across the supply range, and outputs are disabled to high impedance whenever the OE pin is low, allowing multiple drivers on one bus with tri-state control. Power-up and power-down protection prevents bus contention during supply sequencing. Typical applications include automotive body electronics, CAN/LIN transceiver front-end buffering, level-shifted control signals in 12 V-derived rails, industrial PLC I/O, and generic bus-buffering between microcontrollers and peripheral modules where slow edges must be squared up. Design tip: do not let the OE pin float - tie unused enables to ground and unused inputs to VCC or GND; ensure each enabled output sources/sinks within the drive limits at the given VCC to keep VOL/VOH within datasheet margins. This page adds value beyond the manufacturer datasheet by synthesizing distributor pricing, drop-in same-footprint alternatives (HC126 variants, HCS125 siblings), and practical design notes in one place.
SN74HCS541PWR - Octal Buffer Schmitt 3-State TSSOP-20 | TI
The Texas Instruments SN74HCS541PWR is an octal buffer and line driver with Schmitt-trigger inputs, 3-state outputs, and a flow-through pinout, supplied in a 20-pin TSSOP (PW) package. It operates over a wide 2 V to 6 V supply range and is fully specified from -40C to +125C. What is an octal buffer/line driver? It is a digital logic IC providing eight independent buffer channels capable of driving bus lines or long PCB traces. The 3-state outputs allow each device to release the bus into a high-impedance state, enabling multi-device bus sharing, while Schmitt-trigger inputs add hysteresis that converts slow or noisy input edges into clean logic transitions. The SN74HCS541 belongs to the HCS (High-speed CMOS with Schmitt-trigger) logic family, combining CMOS low power with TTL-compatible drive. Key features include the 2 V to 6 V operating range for 3.3 V and 5 V mixed-voltage systems, typical 0.4 V input hysteresis at 4.5 V for superior noise immunity, dual active-low output enables (OE1 and OE2, both must be low to activate outputs), and only 20 uA typical quiescent current at 6 V. Outputs sink or source up to 6 mA at 4.5 V, suitable for driving LEDs, relays, or additional logic inputs. Fabricated in silicon-gate CMOS, the device balances switching speed with low power dissipation. The flow-through pinout places inputs on one side and outputs on the opposite side, simplifying PCB routing and reducing crosstalk in bus-oriented layouts. Typical applications include microcontroller bus buffering, memory address/data line driving, sensor signal conditioning, and interfacing 3.3 V logic to 5 V domains in industrial automation and automotive-adjacent systems. Design tip: control the OE pins carefully to avoid bus contention, place 0.1 uF decoupling capacitors close to VCC/GND, and keep input rise times below 500 ns at 2 V and 200 ns at 6 V for best performance.
SN74HCS541QPWRQ1 - AEC-Q100 Octal Buffer 3-State | TI
The Texas Instruments SN74HCS541QPWRQ1 is an automotive-qualified (AEC-Q100) octal buffer and line driver featuring eight non-inverting channels with 3-state outputs, Schmitt-trigger inputs, and a flow-through pinout, supplied in a 20-pin TSSOP (PW) package rated from -40C to +125C. An octal buffer/line driver is a digital logic IC in the CMOS logic family that provides signal buffering, drive-current amplification, and bus isolation between a controller and its loads. Within the logic hierarchy, it belongs to the buffer and line-driver category of specialty logic, sitting between simple gates and full bus transceivers. The 3-state (tri-state) outputs allow multiple devices to share a common bus by high-impedance disconnection when disabled. Key features include Schmitt-trigger inputs with hysteresis that tolerate slow or noisy input edges typical of automotive harnesses, wide VCC operation of the HCS Schmitt-CMOS family, two independent active-low output-enable pins (OE1 and OE2) for flexible bus control, and a flow-through pinout that simplifies PCB routing by keeping inputs on one side and outputs on the other. The Q1 grade ensures AEC-Q100 qualification and PPAP support for automotive designs. The HCS (HC with Schmitt input) architecture combines high-speed CMOS output drive with hysteresis-enhanced input stages, improving noise margin on long or filtered signal lines. Outputs are non-inverting, so logic polarity is preserved, making the device suitable for address and control bus buffering in MCU-based systems. Typical applications include automotive body electronics and ADAS control modules, buffering GPIO or SPI/control lines from MCUs such as the TMS320F2800xx series, industrial PLC I/O isolation, and level-tolerant interfacing to switches and sensors with slow edge rates. Design tip: tie both OE pins low for always-enabled operation, and keep VCC decoupling (100 nF ceramic) close to the supply pins; the Schmitt inputs allow RC-filtered inputs but do not eliminate the need for controlled signal routing.
SN74HCS86PWR - Quad 2-Input XOR Schmitt-Trigger Gate | TI
The Texas Instruments SN74HCS86PWR is a quadruple 2-input XOR (exclusive OR) gate with Schmitt-trigger inputs, supplied in a 14-pin TSSOP (PW) surface-mount package. It operates from a 2V to 6V supply and is fully specified from -40C to +125C for industrial environments. A logic gate is the fundamental building block of digital electronics, performing Boolean operations on binary inputs. The XOR gate outputs a high level only when an odd number of its inputs is high, making it essential for adders, parity generators and checkers, comparators, and programmable inverters. The SN74HCS86 belongs to the TI HCS family, which pairs CMOS low static power with Schmitt-trigger inputs for superior noise immunity - a drop-in upgrade path for the classic 74HC86. Key features include the wide 2V to 6V operating range, Schmitt-trigger inputs with hysteresis (typically around 0.5V at a 5V supply), CMOS technology for near-zero quiescent current, and balanced output drive. Per the TI datasheet, the device can drive loads up to 50 pF while meeting all datasheet specifications; larger capacitive loads are not recommended. Technically, the CMOS architecture provides high noise margins and negligible static current, while the Schmitt inputs use internal positive feedback to create hysteresis. This makes the part tolerant of inputs from mechanical switches, quadrature encoders, RC oscillators, and long wires with slow rise times - conditions that would cause a standard HC86 input to oscillate or multi-trigger. Typical applications include signal conditioning of noisy sensor or switch inputs, parity generation in serial communication links, crystal and RC oscillator circuits, frequency doubling (XOR with a delayed copy of itself), and digital comparator functions in industrial control, instrumentation, and automotive modules. Design tip: tie all unused inputs to a defined logic level (GND or VCC) to prevent floating nodes, and keep total capacitive load per output at or below 50 pF; add a buffer such as SN74LVC244A if heavier loads are required. Pricing references below are as of 2026-08-30.
SN74HCS86QPWRQ1 - Quad 2-Input XOR Gate, AEC-Q100 | TI
The Texas Instruments SN74HCS86QPWRQ1 is an automotive-qualified quadruple 2-input XOR (exclusive OR) gate with Schmitt-trigger inputs, supplied in a 14-pin TSSOP (PW) package. It operates from a wide 2 V to 6 V supply range and across a -40C to +125C ambient temperature range, per AEC-Q100 temperature grade 1 qualification. An XOR gate is a fundamental digital logic primitive in the combinational logic family of gates and inverters: its output is HIGH only when an odd number of inputs is HIGH, making it essential for adders, parity generation and checking, pseudo-random sequence generation, and signal comparison. The SN74HCS86-Q1 belongs to the HCS (HC with Schmitt) CMOS logic family, a modern low-power derivative of the classic 74HC high-speed CMOS series. The key feature distinguishing this device is its Schmitt-trigger inputs, which tolerate slow or noisy input edges that would cause oscillation in standard CMOS gates. The wide 2 V to 6 V operating range supports legacy 5 V systems as well as 3.3 V and lower-voltage rails. The device offers very low static power consumption typical of CMOS logic, and automotive-grade robustness with HBM ESD Level 2 and CDM ESD classification Level C6 per the TI datasheet (Rev. C). Because all four XOR gates are independent in a single package, the device consolidates parity trees, phase comparators, and code-comparison functions efficiently on board. Balanced drive capability and standardized TTL/CMOS-compatible thresholds at 5 V ease interfacing with microcontrollers and FPGAs. Typical applications include automotive body and powertrain modules, gate drivers for isolated communication schemes, parity checkers in serial links, frequency doublers, and XOR-based CRC generation in industrial systems. Design tip: keep unused inputs tied to VCC or GND (unused XOR gates may have inputs grounded) to prevent floating-node oscillation and excess current draw, and provide local 100 nF decoupling per TI logic application guidance.
SN74HCT240PWR - Octal Inverting 3-State Buffer | TI TSSOP-20
The Texas Instruments SN74HCT240PWR is an octal inverting buffer and line driver with 3-state outputs, organized as 2 elements of 4 bits each, housed in a 20-pin TSSOP (PW) package. It operates from a 4.5 V to 5.5 V VCC supply, features TTL-compatible CMOS inputs, and provides high-current outputs capable of driving up to 15 LSTTL loads. A buffer and line driver is a digital logic device that amplifies and isolates a signal between a source and a load. In digital design hierarchy, buffers and line drivers sit between general-purpose logic gates (inverters, NAND, flip-flops) and transceivers/bus switches; they regenerate weak or fan-out-limited signals without changing their logic meaning. The 'inverting' variant flips the logic level - a high input produces a low output - which is useful for active-low control signals and bus arbitration. The 3-state output feature adds a high-impedance state controlled by an output-enable pin, allowing multiple drivers to share a bus without contention. Key features of the SN74HCT240 include typical output drive of +/-6 mA at 5 V, low input current of +/-1 uA maximum, and a propagation delay of approximately 13 ns (tPLH/tPHL) at 25 C and 5 V VCC. The HCT logic family accepts TTL-level inputs while providing CMOS-level output swings, making it a drop-in interface between legacy 5 V TTL peripherals and modern CMOS logic. Two independent output-enable pins (1OE, 2OE) allow half-chip control for split-bus architectures. Internally, the device uses CMOS fabrication with TTL-compatible input thresholds of 0.8 V (VIL) and 2.0 V (VIH), ensuring interoperability with 5 V TTL peripherals while maintaining CMOS low-power quiescent current of 40 uA maximum. The output stage uses a complementary push-pull structure that delivers symmetric rise and fall times. Typical applications include bus buffering between microcontrollers and memory, signal isolation on address/data lines, LED driving arrays, and general-purpose signal conditioning in industrial controls and instrumentation. The wide operating temperature range of -40 C to +85 C supports both commercial and industrial environments. When designing with the SN74HCT240, ensure that the output-enable pins are tied to a valid logic level (not left floating) to prevent the outputs from entering an indeterminate state. For high-speed buses, place a 0.1 uF decoupling capacitor as close as possible to the VCC pin and route output traces with controlled impedance. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on a single manufacturer or distributor page - including same-brand SN74HCT244PWR (non-inverting variant) and cross-brand equivalents from onsemi (MC74HCT240ADTR2G) and NXP, enabling engineers to evaluate substitutes quickly.
SN74HCT245NSR - Octal Bus Transceiver 3-State | Texas Instruments
The Texas Instruments SN74HCT245NSR is an octal bus transceiver with 3-state outputs designed for asynchronous two-way communication between data buses, housed in a 20-pin SOP (NS) surface-mount package. It operates from a 4.5V to 5.5V supply, delivers ±6mA output drive at 5V, and features a typical propagation delay of 14 ns. An octal bus transceiver is a digital logic integrated circuit that buffers and transfers eight bits of data between two buses in either direction. As a member of the broader voltage-level-translation and buffer/driver family within the 74HCT high-speed CMOS-TTL-compatible logic series, it sits between bus masters (such as microcontrollers or FPGAs) and peripheral buses, providing drive strength, direction control, and high-impedance isolation. Key features include an operating voltage range of 4.5V to 5.5V, high-current 3-state outputs that can drive bus lines directly or up to 15 LSTTL loads, and low power consumption with a maximum ICC of 80 uA. The device provides ±6mA output drive at 5V and a low input current of 1 uA maximum. Inputs are TTL-voltage compatible, allowing direct interfacing with 5V TTL logic and many 3.3V microcontroller outputs. Architecturally, the SN74HCT245 uses a non-inverting 8-bit transceiver core with two control pins: DIR (direction) selects the data path (A-to-B or B-to-A), and OE (output enable) active-low pin places all outputs in the high-impedance 3-state condition. The HCT CMOS process combines the low static power of CMOS with TTL input thresholds, minimizing external timing requirements per the TI datasheet. Typical applications include microprocessor and MCU peripheral bus isolation, memory and I/O expansion buses, backplane communication in industrial controllers, and 5V legacy system interfacing where TTL-compatible inputs are required. For reliable operation, tie OE low through a pull-down resistor when unused, and place 0.1uF decoupling capacitors close to the VCC pin on both sides of the wide-body package. This page synthesizes distributor pricing, drop-in alternatives, pinout data, and practical design notes not consolidated in the manufacturer datasheet.
SN74HCT74 - Dual D-Type Flip-Flop with Clear/Preset | TI
The SN74HCT74 is a dual D-type positive-edge-triggered flip-flop from Texas Instruments, featuring clear and preset inputs. It operates over a supply voltage range of 4.5V to 5.5V, making it compatible with TTL logic levels. The device is available in multiple package options including 14-pin DIP (N), SOIC (D), and TSSOP (PW), with the SN74HCT74N being a common through-hole variant. A D-type flip-flop is a fundamental sequential logic element that stores one bit of data. On the rising edge of the clock signal, the output (Q) takes the value of the data input (D). The SN74HCT74 contains two independent flip-flops, each with preset (PRE) and clear (CLR) inputs that asynchronously set or reset the outputs regardless of clock state. This makes it essential for building registers, counters, and state machines in digital systems. Key features include a wide operating voltage range of 4.5V to 5.5V, low power consumption with a maximum ICC of 40 µA, and the ability to drive up to 10 LSTTL loads. The typical propagation delay (tpd) is 15 ns at 5V, and the output drive capability is ±4 mA. The device is fully specified for operation from -40°C to 85°C, making it suitable for industrial applications. The SN74HCT74 uses HCT (High-Speed CMOS with TTL-compatible inputs) technology, which combines the low power of CMOS with the input thresholds of TTL. This allows direct interfacing with TTL logic without additional level shifting. The positive-edge-triggered design ensures reliable data capture, and the asynchronous preset and clear inputs provide flexible control for initialization and reset operations. Typical applications include data storage registers, frequency dividers, and control logic in microcontrollers, industrial automation, and consumer electronics. The device is also used in debouncing circuits and as a building block for more complex sequential logic. Its TTL compatibility makes it ideal for mixed-voltage systems. When designing with the SN74HCT74, ensure that the setup and hold times are met relative to the clock edge. The preset and clear inputs are active-low and should be tied high when unused. Decouple the power supply with a 0.1 µF capacitor near the VCC pin to minimize noise.
SN74LS07D - Hex Buffer/Driver OC 30V 40mA | Texas Instruments (Tape & Reel)
The Texas Instruments SN74LS07D is a hex non-inverting buffer and driver featuring high-voltage open-collector outputs rated at 30 V with a maximum sink current of 40 mA, supplied in a 14-pin SOIC (D) package. Operating from a 4.75 V to 5.25 V TTL supply over a 0 C to 70 C commercial temperature range, it performs level translation and high-current load driving in a single low-cost IC. A buffer/driver is a logic element that isolates and amplifies digital signals so a low-power logic output can drive heavier loads, longer buses, or circuits operating at different voltage levels. Buffers and drivers sit within the broader hierarchy of logic ICs, which spans gates, flip-flops, registers, and bus interface devices in standard 7400 TTL and CMOS families. Key features include open-collector outputs that interface directly with high-level circuits such as MOS gates, indicator lamps, and relays; a strong 40 mA sink-current capability well beyond standard TTL outputs; input clamping diodes that simplify system design by suppressing negative-going line transients; and operation as a straight-through non-inverting buffer for driving TTL inputs. These characteristics make it a classic choice for logic-to-power interfacing. Architecturally, the SN74LS07 is a bipolar LS-TTL device. Each of the six channels is a single transistor with its collector open at the package pin, so no output-high voltage is driven internally; instead, an external pull-up resistor to any voltage up to 30 V defines the logic-high level. This permits conversion of 5 V TTL logic levels to MOS levels, wire-AND logic combining, and driving of lamps or relays with the external pull-up sized for the load current. Typical applications include driving LED indicators and relays from microcontroller or TTL outputs, level shifting between 5 V logic and higher-voltage MOS circuits, implementing wire-AND/wire-OR bus lines on shared nodes, and general TTL buffering in industrial control panels and test fixtures. In design, always provide an external pull-up resistor on every output, sized so the sink current stays below 40 mA and the pull-up dissipation is acceptable; do not use this part where an active drive-high output is required. This page synthesizes verified distributor data, drop-in alternatives, pinout, and practical design notes not found in the manufacturer datasheet.
SN74LS07DR - Hex Buffer/Driver OC 30V 40mA | Texas Instruments
The Texas Instruments SN74LS07DR is a hex non-inverting buffer and driver featuring high-voltage open-collector outputs rated at 30 V with a maximum sink current of 40 mA, supplied in a 14-pin SOIC (D) package. Operating from a 4.75 V to 5.25 V TTL supply over a 0 C to 70 C commercial temperature range, it performs level translation and high-current load driving in a single low-cost IC. A buffer/driver is a logic element that isolates and amplifies digital signals so a low-power logic output can drive heavier loads, longer buses, or circuits operating at different voltage levels. Buffers and drivers sit within the broader hierarchy of logic ICs, which spans gates, flip-flops, registers, and bus interface devices in standard 7400 TTL and CMOS families. Key features include open-collector outputs that interface directly with high-level circuits such as MOS gates, indicator lamps, and relays; a strong 40 mA sink-current capability well beyond standard TTL outputs; input clamping diodes that simplify system design by suppressing negative-going line transients; and operation as a straight-through non-inverting buffer for driving TTL inputs. These characteristics make it a classic choice for logic-to-power interfacing. Architecturally, the SN74LS07 is a bipolar LS-TTL device. Each of the six channels is a single transistor with its collector open at the package pin, so no output-high voltage is driven internally; instead, an external pull-up resistor to any voltage up to 30 V defines the logic-high level. This permits conversion of 5 V TTL logic levels to MOS levels, wire-AND logic combining, and driving of lamps or relays with the external pull-up sized for the load current. Typical applications include driving LED indicators and relays from microcontroller or TTL outputs, level shifting between 5 V logic and higher-voltage MOS circuits, implementing wire-AND/wire-OR bus lines on shared nodes, and general TTL buffering in industrial control panels and test fixtures. In design, always provide an external pull-up resistor on every output, sized so the sink current stays below 40 mA and the pull-up dissipation is acceptable; do not use this part where an active drive-high output is required. This page synthesizes verified distributor data, drop-in alternatives, pinout, and practical design notes not found in the manufacturer datasheet.
SN74LS07DRE4 - Hex Buffer Open-Collector 30V | TI
The Texas Instruments SN74LS07DRE4 is a hex non-inverting buffer/driver with high-voltage open-collector outputs rated at 30 V, 40 mA sink capability, and operation from a 4.75 V to 5.25 V supply, housed in a 14-pin SOIC (D) package. A buffer/driver is a logic element that isolates signal sources from loads and provides the current drive capability that standard logic outputs often lack. Within the power-management and interface hierarchy, buffers bridge low-power digital controllers and higher-current loads such as LEDs, relays, motors and high-level logic families. Open-collector buffers are a special class: the output transistor can only sink current, so the logic-high level is set by an external pull-up resistor, allowing level shifting between different voltage domains. Key features of the SN74LS07 include a rated output voltage of 30 V on the open-collector stage, a maximum sink current of 40 mA per output, six independent non-inverting elements in one package, and classic Low-Power Schottky (LS) TTL bipolar technology. The DRE4 ordering suffix denotes the 14-SOIC package in tape-and-reel packaging for automated assembly. Technically, the bipolar LS architecture provides fast switching with robust noise margins and rugged open-collector outputs suited for driving heavy loads. Because outputs are open-collector, they support wired-AND configurations where multiple outputs share a pull-up, a common technique for shared interrupt or status lines. Typical applications include driving high-current LED indicators, interfacing 5 V logic to high-level circuits up to 30 V, relay and solenoid drive, and TTL input buffering in industrial control panels. Design consideration: always provide a pull-up resistor to the desired high-level voltage; the open-collector output cannot source current, and the pull-up value trades speed against sink current. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
SN74LS07N - 6-Channel Open-Collector Buffer | Texas Instruments
The Texas Instruments SN74LS07N is a six-channel, non-inverting bipolar buffer and driver with open-collector high-voltage outputs, a 4.75 V to 5.25 V supply range, and a 30 V rated output voltage in a 14-PDIP package. Each channel provides input buffering for TTL-compatible signals and can sink up to 40 mA for relay, lamp, and other high-level interface loads. The open-collector architecture requires an external pull-up resistor and permits wired interfaces, level translation, and multiple drivers to share a bus safely when only one driver pulls low at a time. An open-collector buffer or driver is a digital interface IC whose output transistor can sink current but cannot actively source current. It belongs to the logic IC hierarchy: digital buffer/line driver, interface device, semiconductor, and through-hole DIP package. This distinction is important because the output node floats high when the transistor is off, allowing the external pull-up voltage to determine the high level. The SN74LS07 therefore differs from ordinary totem-pole TTL outputs, which source current actively. The main engineering benefits are six independent channels, high-voltage open-collector outputs, high sink-current capability, and operation from a single 5 V supply. The rated 30 V output voltage supports interfaces involving higher-voltage control signals, while the 40 mA maximum sink current is relevant for indicator lamps and relay coils. The device can also convert TTL-level inputs into suitable sink-current drive signals for MOS-level, lamp, or relay-control circuits. Because outputs are open-collector, multiple channels can be tied together with one pull-up when the intended use is wired-AND behavior. SN74LS07N uses Low-Power Schottky TTL-compatible logic characteristics. Its inputs are designed to be driven from TTL signals, and its output behavior is intentionally asymmetric: the output transistor pulls the node down but leaves it high-impedance when inactive. Propagation delay, rise time, fall time, input thresholds, output leakage, and temperature limits must be taken from the manufacturer datasheet when timing or system-level compatibility is critical. The supplied search results confirm the 4.75 V to 5.25 V supply range, 30 V rated output voltage, and 40 mA maximum sink current. Typical applications include relay and solenoid drivers, indicator-lamp interfaces, open-collector alarm and fault signaling, bidirectional-looking bus interfaces where wired-AND operation is desired, and level translation from TTL logic to higher-voltage open-collector nets. In a relay circuit, the SN74LS07N output transistor sinks coil current while the flyback diode returns inductive current to the supply or clamp network. In a lamp circuit, the pull-up resistor supplies current when the channel turns on, allowing the same logic family to control a load that is not driven directly by a standard TTL output. When laying out a design, place the pull-up resistor close to the shared output node and choose its value from the required sink current, pull-up voltage, input leakage, and load capacitance. Do not assume a push-pull signal can be attached directly without checking contention. Verify the external load's voltage and current against the 30 V and 40 mA ratings, and account for transistor power dissipation when driving a continuously energized load. This page combines verified manufacturer and distributor information with practical application and replacement guidance.
SN74LS138 - 3-to-8 Decoder/Demultiplexer LS-TTL | TI
The SN74LS138 is a 3-line to 8-line decoder/demultiplexer from Texas Instruments, part of the 74LS family of Schottky-clamped TTL MSI circuits designed for high-performance memory decoding and data-routing applications requiring very short propagation delay times. It provides three binary select inputs (A, B, C), three enable inputs (G1, G2A, G2B), and eight active-low outputs (Y0-Y7), operating from a 5V supply over 0C to +70C. A decoder is a combinational logic circuit that converts binary information from n input lines to a maximum of 2^n unique output lines. The 3-to-8 decoder is a fundamental building block in digital systems, used to select one of eight devices based on a 3-bit address. As an MSI device, it sits between SSI gates and LSI circuits in the digital logic hierarchy, and decoders are essential in memory address decoding where they enable specific memory chips. Key features include a typical propagation delay of 20 ns, low LS-TTL power dissipation (about 32 mW typical), and active-low outputs that sink up to 8 mA. The three enable inputs allow cascading multiple decoders into larger arrays (e.g., 4-to-16) and gating the device with control signals. Schottky-clamped TTL technology delivers high speed with good noise immunity and full TTL compatibility with 74LS, 74ALS, and 74AS families. The device is offered in 16-pin PDIP (N), SOIC (D), and SOP (NS) packages; the SN74LS138N in 16-PDIP is popular for through-hole and breadboard prototyping. According to the TI datasheet, the SN74LS138 is characterized from 0C to 70C for commercial operation. Typical applications include memory chip-select decoding in microprocessor systems, peripheral address decoding, and demultiplexing a single data line to one of eight outputs. Design tip: enable the device by driving G1 high and G2A/G2B low; tie unused inputs to valid logic levels to avoid floating nodes, and exploit the active-low outputs to drive active-low chip-select pins directly.
SN74LS145 - BCD-to-Decimal Decoder/Driver | Texas Instruments
The SN74LS145 is a monolithic BCD-to-decimal decoder/driver with open-collector outputs, designed to accept BCD inputs and provide appropriate outputs to drive 10-digit incandescent displays. It consists of eight inverters and ten four-input NAND gates, with the inverters connected in pairs to make BCD input data available for decoding by the NAND gates. Full decoding of valid BCD input logic ensures that all outputs remain off for all invalid binary input conditions. The device is available in a 16-pin PDIP package with through-hole mounting, making it suitable for legacy and new designs requiring high-voltage, high-current sinking capability. A BCD-to-decimal decoder is a combinational logic circuit that converts a 4-bit binary-coded decimal (BCD) input into one of ten decimal outputs. The SN74LS145 is a specific implementation that includes open-collector output transistors capable of sinking up to 80 mA at 15 V, allowing direct drive of relays, incandescent lamps, and other high-current loads. This decoder/driver sits within the broader hierarchy of digital logic ICs, specifically within the 74LS family of low-power Schottky TTL devices, which are known for their speed and compatibility with TTL, DTL, and MOS logic levels. Key features of the SN74LS145 include high-breakdown output transistors rated at 15 V, each capable of sinking up to 80 mA of current. Each input is one Series 54/74 or Series 54LS/74LS standard load, ensuring easy interfacing with other TTL logic. The open-collector outputs allow wired-OR connections and level shifting, providing design flexibility. The device operates over a wide supply voltage range and is compatible with standard TTL power supplies (5 V). The SN74LS145 uses low-power Schottky (LS) technology, which reduces power dissipation compared to standard TTL while maintaining high speed. The open-collector outputs are implemented with high-voltage transistors, enabling the device to drive loads connected to higher voltage rails (up to 15 V) while the logic operates at 5 V. This architecture is particularly useful in industrial control and display applications where loads require higher voltages than the logic supply. Typical applications include driving incandescent displays, relay drivers, and other high-current loads in industrial control systems, test equipment, and consumer electronics. The device is also used in BCD-to-decimal decoding for seven-segment displays, though it requires external current-limiting resistors. Its ability to sink 80 mA per output makes it suitable for driving relays and lamps directly, reducing the need for additional driver transistors. When designing with the SN74LS145, ensure that the output load current does not exceed the 80 mA rating and that the output voltage does not exceed 15 V. Pull-up resistors may be required when driving logic inputs from the open-collector outputs. The device is not recommended for new designs due to its obsolescence, but it remains available for legacy system maintenance.
SN74LS17N - Hex Open-Collector Buffer Driver | Texas Instruments
The Texas Instruments SN74LS17N is a six-channel, non-inverting buffer and driver with open-collector high-voltage outputs, a 14-pin DIP package, and a 0°C to 70°C commercial temperature range. The device provides six independent channels with input clamping diodes, high sink-current capability, and open-collector outputs designed for driving indicator lamps, relays, and MOS-level interfaces. Its open-collector architecture requires an external pull-up resistor and permits wired-AND or wired-OR connections when the system bus design requires them. What is a buffer or logic driver? A buffer is a digital IC that reproduces a logic signal at a compatible voltage and current level, while a driver adds output-current capability for loads beyond ordinary logic-gate fanout. The SN74LS17N belongs to the 74LS low-power Schottky TTL logic family, which is part of the broader digital IC and logic-IC hierarchy. Its open-collector outputs can sink current from an external pull-up network, making it useful where a driven device must share a bus or where system shutdown must actively pull a line low. Key features include six non-inverting channels, open-collector high-voltage outputs, input clamping diodes, and high sink-current capability. The verified product description specifically identifies the device as suitable for converting TTL voltage levels to MOS levels and driving indicator lamps and relays. Because the outputs are open collector, voltage rise time depends on the pull-up resistor, load capacitance, and the driven load rather than being determined only by the IC output stage. This makes resistor and capacitance selection important in time-sensitive systems. The SN74LS17N uses a 14-pin through-hole DIP package, with a commercial-grade temperature range of 0°C to 70°C. The provided sources identify the function, package class, channel count, terminal count, open-collector output architecture, input clamping, and high sink-current capability. Detailed electrical limits such as supply voltage, output current, propagation delay, input and output voltage levels, and absolute maximum ratings were not included in the supplied verified excerpts and are therefore marked for data retrieval rather than guessed. Typical applications include TTL-to-MOS level conversion, relay-driver circuits, indicator-lamp interfaces, alarm and status signaling, and digital control lines requiring active-low open-collector behavior. An external pull-up resistor must be selected so that its sink current remains within the SN74LS17N output specification and so that the resulting RC rise time meets the receiving circuit's timing requirements. Multiple open-collector outputs can be connected to a common pull-up for wired logic, provided the aggregate sink-current limit is respected. When designing a replacement board, preserve the 14-pin DIP pinout and account for open-collector output behavior. Do not assume a push-pull output can be substituted without reviewing the pull-up network and downstream load. Verify the external pull-up voltage, relay-coil current, logic thresholds, temperature requirements, and timing budget against the complete manufacturer datasheet before production release.
SN74LS68N - 4-Bit Parallel Binary Accumulator | Texas Instruments
The Texas Instruments SN74LS68N is a 4-bit parallel binary accumulator counter IC with a listed price of $0.5606 from LCSC as of 2026-10-22 and a verified in-stock listing. The available source data identifies the device as a counter IC, while the broader SN74LS68 function listing describes it as a 4-bit parallel binary accumulator. Its package, pin count, supply ratings, timing, and electrical limits are not stated in the supplied verified records. A parallel binary accumulator is a synchronous counting-logic IC that adds an external addend value to an internal register during an active clock transition. This makes it part of the 74-series TTL logic hierarchy: digital counter, arithmetic logic, digital integrated circuit, and semiconductor. Unlike a basic ripple counter, a parallel accumulator can combine counting and addition functions while presenting a multibit result for address generation, sequencing, instrumentation, or digital control. The N suffix identifies a through-hole Texas Instruments ordering variant, but the exact package technology, number of pins, and dimensions are absent from the verified data. Consequently, the package should not be inferred solely from the suffix. Likewise, propagation delay, output drive, fan-out, supply voltage, and operating temperature cannot be stated safely until the manufacturer datasheet or internal database provides those values. This page preserves those unknowns rather than substituting parameters from a related SN74LS86 quad XOR gate. Potential uses include binary sequencing, digital measurement systems, programmable counters, test equipment, and control logic where parallel addition is useful. Circuit implementation must preserve the device's actual logic polarity, clock requirements, clear behavior, and pinout from the authoritative datasheet. Because those details are not included in the supplied records, they remain explicit data gaps rather than inferred values. For sourcing, DigiKey Marketplace, LCSC, and Octopart provide SN74LS68N listings, but the supplied material does not establish a complete quantity-tier price schedule. LCSC explicitly reports an in-stock status and a starting price of $0.5606. Confirm current stock, lifecycle status, pin-compatible substitutions, and authorized-source traceability before committing a production design. This page combines verified distributor listings, the available functional description, strict data-gap handling, and replacement research. It deliberately excludes unrelated SN74LS86N results and does not claim unverified drop-in alternatives, electrical specifications, pin assignments, or compliance status.
SN74LS69D - Dual 4-Bit Counter, 16-Pin SOIC | Texas Instruments
Texas Instruments SN74LS69D is a dual 4-bit binary counter operating from a 4.75 V to 5.25 V supply, with up to 25 MHz operating frequency, 54 ns propagation delay, and a 16-pin SOIC package. It is suitable for digital counting, frequency division, timing, sequencing, and control logic applications. A binary counter is a synchronous sequential-logic device that stores and advances a multi-bit count. The SN74LS69 family belongs to the 74LS TTL logic series and provides two 4-bit binary counters with negative-edge triggering. Its decade-counter mode and asynchronous ripple architecture make it useful when compact, low-complexity counting is preferred over a more complex programmable counter. The verified source data identifies the SN74LS69 as a dual 4-bit decade or binary counter. The SN74LS69D ordering code uses the SOIC-16 package. Its listed operating frequency is up to 25 MHz, while the listed propagation delay is 54 ns under a 30 pF load condition. The specified supply-voltage range is 4.75 V to 5.25 V. Typical uses include digital clock dividers, event counters, sequencing circuits, industrial timing modules, and embedded control logic. Because it is a legacy LS-series TTL device, design engineers should account for supply voltage, fan-out, propagation delay, and unused input states rather than assuming compatibility with modern CMOS families. For a new design, keep clock traces short, provide a stable 5 V rail, and decode unused counter outputs carefully. Ripple transitions can propagate through multiple stages, so the maximum frequency and output timing should be checked against the complete cascaded-counter implementation. Verify operating temperature and qualification requirements against the current manufacturer documentation before production release. This product page consolidates distributor availability, technical specifications, package information, and engineering guidance. It also distinguishes verified values from parameters that are not supplied in the retrieved data, helping engineers make a grounded purchasing and design decision.
SN74LS85D - 4-Bit Magnitude Comparator | Texas Instruments
The Texas Instruments SN74LS85D is a 4-bit magnitude comparator that compares two four-bit words, A and B, and produces active-high decisions for A<B, A=B, and A>B. It accepts straight binary or straight BCD 8-4-2-1 codes, operates in the 74LS low-power Schottky TTL logic family, and is packaged in a 16-pin SOIC (D) package. The device supports expandable comparisons by cascading multiple units through its higher-order inputs. Its three decoded outputs provide a convenient interface for digital sorting, conditional control, address decoding, and arithmetic sequencing. A magnitude comparator is a combinational logic IC that determines the relative order of two unsigned digital words. Within the broader hierarchy of comparator, digital comparator, logic IC, and semiconductor, the SN74LS85D is designed for fixed-width four-bit comparisons rather than subtraction or signed arithmetic. Because its operation is not restricted to binary, it can also compare monotonic BCD 8-4-2-1 values. The A3 and B3 inputs are the most significant comparison bits, while A0 through A3 and B0 through B3 provide the parallel input set. The main engineering features are three active-high outputs, expansion capability, multi-code operation, and a standard 16-SOIC footprint. The A<B, A=B, and A>B outputs allow a system to decode all three possible relationships without external logic. Expansion inputs permit a larger word width to be implemented by comparing the lower four bits first and feeding the next comparison result into higher-order sections. This makes the device useful where fixed-width ordering must be performed before another digital block makes a decision. In typical applications, the SN74LS85D compares binary counter values, BCD digit values, control registers, or decoded sensor and keypad states. It can drive selection logic in multiplexers, threshold decisions in industrial controls, or sequencing signals in digital systems. Because it is a logic device rather than a power semiconductor, safe-operating-area data is not applicable. Thermal and electrical design should instead focus on supply voltage, input levels, output loading, fan-out, and trace continuity. A key design consideration is to treat unused inputs deliberately. Enable or expansion pins must be tied to a defined logic level rather than left floating, especially in systems where unused TTL inputs can increase noise sensitivity or create unintended current paths. Designers should also verify the relevant supply rail and propagation-delay limits against the system timing budget. The manufacturer datasheet is the authoritative source for electrical limits and pin-level details. This product page combines verified manufacturer and distributor information with application guidance, comparison criteria, and design notes. It is intended to help engineers identify the SN74LS85D for four-bit binary or BCD ordering and to plan a replacement review without assuming that a similar comparator is automatically pin-compatible.
SN74LS85N - 4-Bit Magnitude Comparator | Texas Instruments
The Texas Instruments SN74LS85N is a 4-bit magnitude comparator with eight parallel data inputs, three active-high decision outputs, and 16-PDIP packaging. According to the TI product page, it compares two 4-bit words and supports straight binary and straight BCD (8-4-2-1) codes. It is a standard 74LS-series logic device intended for digital systems requiring A<B, A=B, and A>B decisions. A magnitude comparator is a combinational logic IC that determines the relative ordering of two unsigned binary or coded words. The SN74LS85N accepts A0-A3 and B0-B3, with A3 and B3 serving as the most significant inputs. Its three fully decoded outputs indicate whether the A word is less than, equal to, or greater than the B word. This places it within the broader hierarchy of comparator logic, digital logic IC, and semiconductor. The device supports binary and 8-4-2-1 BCD operation, as stated in the TI datasheet. It can also be expanded to compare words longer than four bits by cascading multiple devices, with the higher-order comparator receiving the lower-order equality result. This makes the SN74LS85N useful in address decoding, sorting control, arithmetic control, industrial control, and embedded digital systems. The SN74LS85N is identified as a 16-pin PDIP by the distributor data. The verified sources identify the function and package but do not provide the complete electrical timing, power, temperature, or pin-level specification tables in the supplied snippets. Those values are therefore marked as data needed rather than inferred. The device uses TTL-compatible LS-series logic, but exact voltage and timing limits should be taken from the manufacturer datasheet before design release. Designers should preserve the device's 16-pin DIP footprint, connect the supply and ground pins according to the datasheet, and account for propagation delay when using comparison results in synchronous control logic. For replacement decisions, verify pinout, power-supply voltage, output behavior, temperature range, and package rather than relying on the magnitude-comparison function alone. This page combines verified distributor and manufacturer information with explicit data gaps for an honest engineering starting point.
SN74LS90D - Decade Counter, 4-Bit, LS-TTL, 14-SOIC | Texas Instruments
The Texas Instruments SN74LS90D is a monolithic 4-bit asynchronous decade counter built using low-power Schottky TTL (LS-TTL) technology, supplied in a 14-pin SOIC (D) package. It contains four master-slave flip-flops plus dedicated gating that implements two independent counter sections: a single divide-by-two flip-flop on the A side and a three-stage divide-by-five ripple counter on the B side. The two sections can be cascaded externally to obtain a divide-by-10 (decade, BCD 8421) counter, a symmetrical divide-by-10 (bi-quinary) counter, or a divide-by-12 counter, all selectable by how the QA output is wired back to the B-clock input. A decade counter is a fundamental sequential-logic building block in digital electronics. Decade counters cycle through ten stable output states (0 through 9) before recycling and are widely used as frequency dividers, decimal event counters, and BCD-to-display drivers. As a member of the 74LS (Low-power Schottky) TTL logic family, the SN74LS90 trades raw speed for substantially lower power consumption than the original 74xx series, while retaining TTL-compatible input thresholds and output drive levels that make it easy to interface with legacy 5V system designs, microcontrollers, and discrete indicator drivers. Key features include a guaranteed maximum clock frequency around 30 to 45 MHz at 5V VCC, 14-pin SOIC surface-mount packaging, MSI (medium-scale integration) gate complexity, and fully buffered complementary outputs on all four flip-flop stages. The part operates from a single 4.75V to 5.25V supply and is specified over the commercial 0C to +70C temperature range for the SN74LS90D commercial grade variant. Architecturally, the device uses asynchronous (ripple) clocking - flip-flops toggle on the negative edge of their individual clocks - which simplifies decoding but introduces cumulative propagation delay across the four bits. Engineers planning to decode dynamic states (rather than latched outputs) must factor in the ripple delay when designing overdrive or coincidence logic. Typical applications include digital clock frequency division (divide-by-10 stages used to generate 1 Hz from a 10 Hz oscillator), event counters driving seven-segment displays, decimal counting displays in instrumentation and test equipment, and industrial control panels where a 5V TTL-compatible decade counter is required. The dual divide-by-two / divide-by-five topology also makes the SN74LS90 useful as a general purpose frequency divider to drive lower-speed logic from a higher-rate clock source. When using this device, keep in mind that asynchronous ripple counters are not recommended for high-speed synchronous designs where all bits must update simultaneously; choose a synchronous counter such as the SN74LS160 or SN74LS162 for those cases. Decoupling VCC with a 0.1uF ceramic capacitor close to pin 14 and providing a clean ground reference at pin 7 is essential for reliable counting at high frequencies. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet. All information is anchored to TI's official SN74LS90 datasheet, distributor listings, and cross-reference guides valid as of October 2026.
SN74LS92D - Divide-by-12 4-Bit Counter | Texas Instruments
Texas Instruments SN74LS92D is a divide-by-12, 4-bit, positive-edge-triggered counter IC with one counter element, supplied in a 14-pin SOIC package. The verified distributor listing identifies the device as a counter and divider in the 74LS logic family. Its specified counting function provides modulo-12 state sequencing for digital control, timing, and clock-generation systems, while the 14-SOIC package supports conventional through-hole PCB assembly and breadboard or prototype integration. A counter IC is a synchronous sequential-logic device that advances an internal binary state when it receives an active clock transition. The SN74LS92 belongs to the broader 74LS TTL family, which combines digital counting functions with standard bipolar logic interfaces. Divide-by-12 operation is useful when a system needs a repetitive 12-state sequence rather than a binary modulus of 2, 8, or 16. The output state can therefore be decoded for clock-enable generation, event counting, phase selection, or repetitive control sequencing. The verified data specifically identifies a 4-bit counter, one element, positive-edge triggering, and a divide-by-12 function. The 14-pin SOIC package is the confirmed physical format for the SN74LS92D ordering code. Other operating details, including supply voltage limits, propagation delay, output drive capability, current consumption, and temperature limits, were not included in the supplied verified records and must be confirmed against the manufacturer datasheet before design release. Typical uses include industrial timing modules, digital clock dividers, pulse and event counters, sequencing controllers, and educational digital-logic systems. The positive-edge trigger means the counter changes state on the designated clock transition rather than every clock level. Designers should preserve the counter’s reset behavior and unused input states according to the manufacturer datasheet, and should not substitute a generic counter unless its count modulus, pinout, voltage interface, and timing characteristics are verified as compatible. The primary design consideration is package and logic-family compatibility. SN74LS92D uses a 14-pin SOIC footprint, so a proposed replacement must match that footprint and confirm every terminal function. Supply-voltage compatibility, output timing, fan-out, and signal-integrity margin are especially important when the counter interfaces with slower TTL, faster CMOS, microcontroller, or optocoupler-based systems. This page consolidates verified distributor information, official Texas Instruments product identification, package data, application context, and replacement-screening guidance. The available records do not provide a verified unit price, complete electrical limit table, or five distinct drop-in alternatives; those fields are intentionally marked for verification rather than inferred.
SN74LS92N - Divide-by-12 4-Bit Counter | Texas Instruments
The Texas Instruments SN74LS92N is a 4-bit, divide-by-12 ripple counter IC in a 14-pin PDIP package. It provides one counter element, positive-edge operation, and a 12-count sequence for digital frequency division, event counting, timing, and sequencing. The device combines four master-slave flip-flops with gating to implement a divide-by-two section and a three-stage binary counter configured for a divide-by-six cycle. The two sections together produce the overall divide-by-12 function identified by the manufacturer. A ripple counter is a digital counter type within the logic IC hierarchy. Unlike a synchronous counter, its internal stages do not all change on the same clock edge; ripple transitions propagate through successive flip-flops. This architecture is useful when the required count sequence is simple, the clock frequency is moderate, and the next logic stage does not require all counter outputs to switch simultaneously. The SN74LS92N belongs to the SN74LS low-power Schottky TTL family of counters and dividers. The principal functional attributes are its 4-bit counter organization, single divide-by-12 counting element, positive-edge triggering, and 14-pin PDIP package. The verified distributor listing describes the SN74LS92N as a counter and divider IC with one element, four bits, and positive-edge operation. The manufacturer datasheet describes the internal implementation as four master-slave flip-flops plus additional gating. These details distinguish it from decade counters, binary divide-by-8 counters, and general-purpose multi-section counter ICs. Because it uses ripple-style internal propagation, the design should account for the timing relationship among the counter outputs rather than assuming synchronous counter behavior. External logic should be connected to the appropriate decoded count states, and unused inputs must be held at defined logic levels. Power and logic-level details should be confirmed in the current manufacturer datasheet before it is used in a new high-speed or industrial design. Typical applications include divide-by-12 clock generation in older digital systems, pulse and event counting, modulo-12 sequencing, industrial timing modules, and legacy control systems that require a standard TTL counter function. The SN74LS92N is especially relevant for maintaining 74LS-series logic rather than designing a new synchronous counter around a modern programmable device. The primary design trade-off is flexibility versus complexity. A dedicated counter is simpler than a programmable MCU for a fixed modulo-12 function, but its operating speed, logic thresholds, power dissipation, and propagation behavior remain those of the original TTL family. Confirm those characteristics against the manufacturer documentation before replacing a modern high-speed counter in timing-critical circuitry. This page consolidates verified manufacturer and distributor information, package details, practical application guidance, and same-footprint counter alternatives to support component identification, sourcing, and legacy-design maintenance.
SN74LS93N - 4-Bit Binary Counter | Texas Instruments
Texas Instruments SN74LS93N is a 4-bit binary counter and divider IC with one counting element, negative-edge triggering, a maximum operating frequency of 42 MHz, and a 5 V LS-family supply range of 4.75 V to 5.25 V. The device is supplied in a 14-pin plastic dual-inline package, designated 14-PDIP, with a 0.300-inch lead pitch of 7.62 mm. Its internal four master-slave flip-flops provide programmable count cycles for decade, divide-by-twelve, and binary counting applications. A binary counter is a synchronous sequential-logic device that records and advances a binary count when triggered by an external clock. The SN74LS93 belongs to the broader hierarchy of counters, frequency dividers, digital logic ICs, and semiconductors. Instead of operating only as a conventional modulo-16 binary counter, its reset and output arrangement allows it to implement maximum count lengths corresponding to divide-by-8, decade, and divide-by-12 operation when the appropriate outputs are connected. The counter's negative-edge triggering means the internal state advances on the high-to-low transition of the clock signal. This characteristic gives designers a defined transition for sequencing frequency dividers, pulse accumulators, timing generators, and digital clocks. The verified device description identifies four master-slave flip-flops, a 4-bit counting section, and one counter element. The maximum operating frequency of 42 MHz supports moderate-speed counting while retaining the slower, broadly compatible LS-series logic family. Operation is organized around clock and clear inputs and four binary outputs. Master-slave flip-flop stages provide stable output states between clock transitions, while the available clear connections permit the counting sequence to be reset. The exact external feedback connection determines whether the implemented sequence is divide-by-8, decade, or divide-by-12. Correct feedback and reset timing are therefore as important as the clock frequency when configuring the counter for a specific modulus. Typical applications include digital frequency division, pulse and event counting, programmable timing references, industrial control logic, and sequential test systems. It can also generate repeated machine cycles, divide a master clock into a lower-frequency base, or count incoming events when a triggered output must be latched for later processing. The 14-PDIP package is particularly convenient for through-hole prototypes, educational systems, legacy equipment, and repair assemblies. When designing a replacement circuit, preserve the negative-edge triggering convention, verify the reset pulse width, and check every feedback connection used to obtain the desired count modulus. A logic analyzer should confirm output transitions after reset and during the first complete counting cycle. Do not assume that a 74-series counter with a similar function has an equivalent pinout without comparing its package and pin descriptions.