74LS91 IC 8-Bit Shift Registers DIP-14
The 74LS91 IC 8-Bit Shift Registers DIP-14 is an 8-bit shift register integrated circuit housed in a 14-pin DIP (Dual In-line Package) configuration. It functions primarily as a decade counter, capable of dividing the input frequency by 10, providing binary-coded decimal outputs. This IC features serial-in and serial-out capabilities, enabling the shifting of data bits serially through the register. It supports synchronous operation with a clock input and carries a reset function to clear the count. The 74LS91 is useful in digital circuits for counting, frequency division, and data storage applications, making it a versatile component in timing and sequencing circuits. Its 14-pin package incorporates all necessary inputs and outputs for interfacing with other TTL logic devices, optimized for use in digital systems requiring stable and reliable 8-bit counting or shifting operations.
Features
- Monolithic 8-bit serial-in, serial-out shift register.
- Utilizes transistor-transistor logic (TTL) circuits.
- Packaged in a 14-pin DIP type for easy integration.
- Data on input pins is clocked into the first register on clock pulse.
- Previous data shifts serially to accommodate new input (FIFO buffer).
- Supports cascaded operation for longer shift registers.
- Operates at a supply voltage of 5 V typical.
- Plastic/Epoxy package body material for durability.
- Terminal pitch of 2.54 mm compatible with standard DIP sockets.
- Suitable for digital circuits requiring data storage, buffering, or serial-to-parallel data conversion.
- Can be used to form buffers, delay lines, or shift registers of varying lengths.
- TTL compatible signals ensure easy interfacing with other logic ICs.
Pinout Configuration
| Pin Number | Pin Name | Description |
|---|---|---|
| 1 | NC | No Connection |
| 2 | NC | No Connection |
| 3 | NC | No Connection |
| 4 | NC | No Connection |
| 5 | VCC | Positive Supply Voltage |
| 6 | NC | No Connection |
| 7 | NC | No Connection |
| 8 | NC | No Connection |
| 9 | CLK | Clock Input |
| 10 | GND | Ground |
| 11 | E | Input E |
| 12 | D | Input D |
| 13 | Q7 | Output Q7 |
| 14 | Q7‾\overline{Q7} | Output Q7 (Inverted) |
Specifications
| Parameters | Description |
|---|---|
| Technology Family | LS |
| Supply Voltage (Min) (V) | 4.75 |
| Supply Voltage (Max) (V) | 5.25 |
| High-level Output Current, I(OH) | -400 µA |
| Low-level Output Current, I(OL) | 8 mA |
| Operating Temperature Range | 0 to 70 °C |
| Typical Maximum Clock Frequency | 18 MHz |
| Typical Power Dissipation | 80 mW |
| Number of Bits | 8 bits |
| Package Type | 14-pin DIP |
| Operating Voltage (Nominal) | 5V |
Applications
- Used as a data buffer to store serial data for later conversion to parallel output in digital systems.
- Serial-in, serial-out data shift operations for timing and sequence control—commonly found in microprocessor circuits.
- Frequency division and pulse counting functions (acting as counter in digital clocks, timers, and event counters).
- Data-handling in control systems, such as state machines, control logic, or digital communication interfaces.
- Can be cascaded to create longer shift registers or FIFO buffers for data handling and delay operations.
- Utilized in digital computers, data acquisition systems, and register-based memory elements.
- Signal processing and data serialization/deserialization tasks.
Package Contents
- 1 x 74LS91 8-Bit Shift Registers IC DIP-14.
