DM74LS164N

Shift Registers Overview

The DM74LS164N is an 8-bit serial-in parallel-out shift register manufactured by onsemi. It operates within a supply voltage range of 4.75V to 5.25V and supports a maximum clock frequency of 25 MHz. The device features gated serial inputs, fully buffered clock and data lines, and an asynchronous clear function. Propagation delays from clock to output range from 27 ns to 40 ns depending on the transition direction. It is housed in a 14-lead Plastic Dual-In-Line Package (PDIP) suitable for through-hole mounting.

Shift Registers Feature Summary

• Features gated serial inputs that allow complete control over incoming data entry via enable/disable logic.
• Includes an asynchronous clear function that resets all flip-flops to a low level independently of the clock signal.
• Utilizes fully buffered clock and serial inputs to minimize transmission-line effects and ensure signal integrity.

Shift Registers Applications

• Data storage applications requiring serial-to-parallel conversion
• Pulse generation circuits utilizing shifted bit patterns
• Digital display driving systems for sequential segment activation

Shift Registers Procurement Notes

Verify component authenticity as this part may be sourced from legacy inventory or third-party distributors. Confirm package markings match the 14-lead PDIP specification. Check RoHS compliance status if required for modern assembly processes, as original datasheets indicate standard leaded construction. Ensure operating conditions remain within the specified 0°C to +70°C temperature range during deployment.

Shift Registers Selection Notes

Select this component when an 8-bit shift register with parallel outputs is required for TTL-compatible logic levels. The DM74LS164N is appropriate for designs needing asynchronous clearing and gated serial input functionality. Consider the 25 MHz maximum clock speed limit when designing high-frequency timing circuits. Verify that the 14-pin DIP footprint aligns with the target PCB layout constraints.

Shift Registers Part Context

This device belongs to the 74LS series of logic integrated circuits, characterized by Low-power Schottky technology. It serves as a fundamental building block for sequential logic design within digital systems. The DM74LS164N provides a reliable solution for basic data shifting operations where moderate speed and standard drive capabilities are sufficient for the application requirements.

Shift Registers Replacement Considerations

Direct substitutes include the SN74LS164N from Texas Instruments and the MC74LS164N from ON Semiconductor. These alternatives maintain pin compatibility and electrical specifications. Verify package dimensions and marking codes to ensure physical interchangeability without modifying the existing circuit board layout.

Shift Registers FAQ

How does the asynchronous clear function operate?

The asynchronous clear input overrides all other inputs. When driven to a low logic level, it immediately resets all eight flip-flops to a low state, regardless of the clock signal status.

What is the behavior of the gated serial inputs?

The device has two serial inputs (A and B) that act as an AND gate. A low level at either input inhibits data entry and resets the first flip-flop. Both inputs must be high to allow new data to enter on the clock edge.