74LS91 8-Bit Shift Register
Series 74LS
74LS91 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. 74LS91 serial-in, serial-out, and 8-bit shift registers utilize transistor-transistor logic (TTL) circuits and are composed of eight R.S master-slave flip-flops, input gating, and a clock driver. Single-rail data and input control are gated through inputs A and B and an internal inverter to form the complementary inputs to the first bit of the shift register.
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
91.pdf
74LS91 features
- Use In Digital Computer Systems
- Use In Data-Handling Systems
- Use In Control Systems
74LS91 pinout
| Pin | Name | Description |
|---|---|---|
| 1 | NC | Not Connected |
| 2 | NC | Not Connected |
| 3 | NC | Not Connected |
| 4 | NC | Not Connected |
| 5 | VCC | NAND Gate 2 Input 2 |
| 6 | NC | Not Connected |
| 7 | NC | Not Connected |
| 8 | NC | Not Connected |
| 9 | CLK | Clock Pin |
| 10 | GND | Ground Pin |
| 11 | B | Input Pin B |
| 12 | A | Input Pin A |
| 13 | QH | Output Pin |
| 14 | (Q') H | Invert Output Pin |
74LS91 applications
- The shift registers are used for temporary data storage.
- The shift registers are also used for data transfer and data manipulation.
Application circuit
More about 74LS91
74LS91 Circuit
Here is a simple circuit of 4 Bit Shift Register using DQ Flip Flops.
74LS91 Alternative Equivalent
74LS164, 74LS165
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