SN74LS93N - 4-Bit Binary Counter | Texas Instruments
Référence : SN74LS93N ✓ ActifSN74LS93N Présentation
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.
Alternatives de remplacement direct pour SN74LS93N — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Aucune alternative de remplacement direct disponible pour ce produit.
Demander des alternativesSN74LS93N Valeurs maximales et caractéristiques électriques
| Counter Type | 4-bit binary counter and divider |
| Number of Counting Elements | 1 element |
| Output Width | 4 bits |
| Edge Triggering | Negative edge |
| Fréquence d'horloge maximale | 42 MHz |
| Supply Voltage Range | 4.75 V to 5.25 V |
| Logic Family | LS |
| Internal Flip-Flop Count | 4 master-slave flip-flops |
| Supported Count Functions | Binary, decade, and divide-by-twelve |
| Maximum Count Lengths | Divide-by-8, divide-by-10, and divide-by-12 |
| Boîtier | 14-PDIP |
| Lead Pitch | 0.300 in (7.62 mm) |
| Nombre de broches | 14 pins |
| Type de montage | Through-hole |
Guide de configuration des broches du SN74LS93N 14-pdip
Configuration des broches du SN74LS93N (boîtier 14-pdip). Ce circuit intégré numérique comprend des GPIO, des interfaces de communication (UART, SPI, I2C) et des broches d'alimentation. Consultez la fiche technique du fabricant pour les fonctions alternatives des broches et les options de configuration. Indispensable pour la conception de systèmes embarqués et la conception de circuits imprimés.
Aucune donnée de brochage détaillée disponible pour SN74LS93N.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
SN74LS93N convient pour 6 applications: Digital Frequency Divider, Pulse and Event Counter, Programmable Timer Reference, Industrial Control Sequencing, Digital Test and Measurement, Legacy Equipment Repair.
Digital Frequency Divider
The SN74LS93N is suitable for producing a divided clock from an external timing reference because it contains four master-slave flip-flops and advances on the negative clock edge. The verified maximum operating frequency is 42 MHz, giving designers substantial timing margin for a 5 V divide-by-2, divide-by-8, decade, or divide-by-12 arrangement. The appropriate output feedback must be selected carefully, and reset timing should be checked before enabling the divided clock in a system requiring deterministic startup. Clock-to-output propagation delay also has to be included when cascading counters or synchronizing the result with another digital circuit.
Pulse and Event Counter
The SN74LS93N can count recurring events presented as a clock signal when the design requires a compact 4-bit LS-family counter. Its negative-edge trigger gives the circuit a predictable state transition for each accepted input pulse, while four master-slave flip-flops provide a stable binary count between transitions. The verified 4.75 V to 5.25 V operating range supports conventional 5 V digital systems, and the 42 MHz maximum frequency is suitable for many industrial pulse-counting tasks. Designers should account for input pulse width, setup and hold requirements, and rollover behavior when an event count exceeds the selected count modulus.
Programmable Timer Reference
The SN74LS93N fits legacy timing systems that derive a repeatable slower reference from a master oscillator. By feeding back the appropriate output, the counter can implement a decade or divide-by-twelve sequence in addition to binary and divide-by-8 operation. Its verified 42 MHz ceiling makes it appropriate for clock division below the device's specified operating limit, while the 14-PDIP package simplifies repair and prototype work. Timing margin should be calculated using the counter's clock-to-output timing and the reset recovery requirements rather than frequency alone. The power rail also needs suitable bypassing to keep switching transients from disturbing other digital logic.
Industrial Control Sequencing
The SN74LS93N can support repeatable step sequencing in older industrial and machine-control logic where 5 V LS-family devices are already installed. A master clock divided through the counter produces deterministic state intervals, and the clear inputs allow the sequence to be restarted after a command or fault. The 14-pin through-hole package remains practical for legacy control boards with plated-through holes. Integration requires checking that the input thresholds, clock-edge convention, reset pulse, and output states match the surrounding controller. Because it is not presented as a modern safety-qualified controller, it should remain inside the properly separated functional portion of the control system.
Digital Test and Measurement
The SN74LS93N is useful as a low-level frequency-divider or repetitive stimulus element in educational and legacy test equipment. Its divide-by-2, divide-by-8, decade, and divide-by-twelve capabilities allow a single stable oscillator to create several related timing bases. The verified 42 MHz maximum operating frequency supports higher-rate test signals, and negative-edge counting provides a clearly defined sampling instant for downstream circuitry. Engineers should use the manufacturer timing diagram to establish setup, hold, reset, and propagation constraints. When the counter is used to generate a trigger, the clock source must have controlled rise and fall times to avoid double counting or metastability.
Legacy Equipment Repair
The SN74LS93N is particularly useful for maintaining older digital equipment built around through-hole 74LS logic. Its 14-PDIP package, 5 V supply range, negative-edge triggering, and four-bit counter architecture provide a direct functional match to the original counter role identified by Texas Instruments. Repair work should begin by confirming the physical pinout, clock source, clear-input connections, and feedback wiring against the manufacturer documentation. The supplied data does not include the detailed pin table or operating temperature limits, so technicians must obtain those before installation. A power-off continuity check and a post-repair logic-analyzer test can confirm the count sequence.
Données de référence d'ingénierie pour SN74LS93N — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit |
|---|---|
| Counter Width | 4 bits |
| Maximum Clock Frequency | 42 MHz |
| Supply Voltage Range | 4.75 V to 5.25 V |
| Counting Edge | Negative edge |
| Internal Architecture | 4 master-slave flip-flops |
| Count Functions | Binary, decade, and divide-by-twelve |
| Package | 14-PDIP, 0.300 in (7.62 mm) pitch |
| Brand | Texas Instruments |
Principaux différenciateurs
- Documented 42 MHz maximum operating frequency (vs 74LS93F)
- Negative-edge counting with four master-slave flip-flops (vs SN54LS93J)
- Configurable binary, decade, and divide-by-twelve operation (vs SN74LS293N)
Notes de conception
Do not treat every device named 74LS93 as a direct replacement for the SN74LS93N. The verified cross-reference material identifies related devices, but it does not establish identical packages, pin assignments, supply ranges, and timing. Before substitution, compare every connection on the 14-pin DIP footprint, confirm 4.75 V to 5.25 V operation, verify negative-edge triggering, and reproduce the original feedback connections for the required count modulus.
Keep the clock path short and provide a clean, low-jitter transition at the counting input. Because the device advances on the negative edge, excessive rise time, ringing, or a double transition can cause incorrect counting. Use the manufacturer timing requirements to establish input setup and hold margins, and terminate or damp clock lines if reflections are visible on an oscilloscope. Validate the first complete counting cycle with a logic analyzer after reset.
Place normal bypass capacitance close to the supply and ground pins of the 14-PDIP device, following the manufacturer recommendations and the switching characteristics of the surrounding circuit. The verified operating range is 4.75 V to 5.25 V, so do not power the SN74LS93N from an unregulated 5 V rail. Check the source tolerance and ripple at the IC, particularly when clock transitions cause simultaneous output changes in the attached logic.
Informations de conformité
The supplied product and distributor snippets do not state RoHS, REACH, lead-free, halogen-free, or conflict-minerals status. AEC-Q100 is not applicable because SN74LS93N is presented as a general-purpose logic counter rather than an automotive-qualified device.
