74LS161 Synch 4-bit Counter
Series 74LS
74LS161 overview
The 74LS series of integrated circuits (ICs) was one of the most popular logic families of transistor-transistor logic (TTL) logic chips. 74LS series is a bipolar, low-power Schottky IC.74LS161 synchronous, presettable counters feature an internal carry look-ahead for application in high-speed counting designs. The 161 is a 4-bit binary counter. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when structured by the count-enable inputs and internal gating.
Key specifications
Supply Voltage
4.75 - 5.25Vdc
Maximum Clock Frequency
40Mhz
Power Dissipation
2mW/gate @100kHz
Minimum Output Current
8mA
Propagation Delay
10nS
Fan Out (TTL Loads)
20
Datasheet
sn74ls161a.pdf
74LS161 features
- Edge Triggered High-Speed 4-bit Synchronous (Binary) Counters
- Asynchronous Master Reset
- Count Rate of 35MHz
- Operating Temperature up to 70°C
- Standard TTL Switching Voltages
74LS161 pinout
| Pin | Name | Description |
|---|---|---|
| 1 | CLR' | Clear Pin |
| 2 | CLK | Clock Pin |
| 3 | A | Data Input Of Counter A |
| 4 | B | Data Input Of Counter B |
| 5 | C | Data Input Of Counter C |
| 6 | D | Data Input Of Counter D |
| 7 | ENP | Enable Pin |
| 8 | GND | Ground |
| 9 | LOAD' | Load Pin |
| 10 | ENT | Enable Pin T |
| 11 | QD | Output Of Counter QD |
| 12 | QC | Output Of Counter QC |
| 13 | QB | Output Of Counter QB |
| 14 | QA | Output Of Counter QA |
| 15 | RCO | Ripple Carry Output |
| 16 | VCC | Positive Supply |
74LS161 applications
- Frequency counters
- Digital clocks
- Analog to digital converters
- With some changes in their design, counters can be used as frequency divider circuits
- In time measurement
More about 74LS161
74LS161 Alternative Equivalent
74LS163
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