74LS164 Parallel-Out Shift Register IC: Datasheet, Schematic and Pinout

74LS164 Pinout

The 74LS164 is an 8-bit Serial-In Parallel-Out Shift Register with excellent speed. Serial data is inputted via a two-input AND gate that is timed to the clock's LOW to HIGH transition. The device has an asynchronous Master Reset feature that clears the register and sets all outputs to LOW regardless of the clock. It achieves high speeds by using a Schottky diode clamped method and is completely compatible with all Motorola TTL products.

The 74LS164 shift register IC's logic diagram is represented in the diagram below. It has eight flip-flops, one AND gate, and two Not gates on the inside.

74LS164 Logic Diagram 

• Operating Voltage: 3V to 18V

• Supply Voltage – Max: 5.25 V

• Propagation Delay Time: 25 ns

• Max. Clock Frequency: 36 MHz

• Operating Temperature Range: 0C to + 70 C

• Fully Buffered Clock

• Available in 16-pin PDIP, GDIP, PDSO packages

• Arithmetic-unit registers

• Sequence generators

• Control circuits

• Digital up to and down counters

• Shift-left — shift right registers

• Serial-to-parallel/parallel-to-serial conversions

• Sequence generation

• ~MR is a low-input active master reset pin. The output will be in a low state until its state is low, regardless of what is at input A or B. As a result, it's also known as the Reset or Clear mode of operation. MR must be set to a high value to complete the procedure.

• Serial data can be sent by either of the two input pins while using another pin as an active high allows data to be entered into other input pins. Any input pin that isn't in use needs to be set to high. Connecting two input pins is also conceivable.

• When a clock transitions from low to high, Data moves one position to the right, and Q0 is filled with the AND of two data inputs at A and B.

The 74LS164 Shift Register is an 8-bit serial-in, parallel-out device. It can receive (input), obtain data serially, and control output pins in parallel, which means it can receive (input), get data serially and control output pins in parallel. This is useful when our MCU/MPU does not have enough GPIO pins to control the needed number of outputs. It's frequently used in projects where a huge number of LEDs must be controlled by a microcontroller. Because it may operate as the data bit for LCDs, it can also be utilized to interface an LCD panel.

To extend GIPO functionality, the 74LS164 shift register is typically utilized with microcontrollers or microprocessors. The 74LS164 is a 14-pin integrated circuit with four inputs, eight outputs, power, and ground. A microcontroller with four lines is required for the 74LS164. There are three input pins: one for the clock, one for the clear, and two for the input (A & B). Input Pins A and B function as a logical AND gate, meaning it will read 1 if both pins are logic high (5 volts). To clear the full register at once, use the clear pin.

74LS164 Circuit

74LS164 Package

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