IC 4085 – 8-Bit Serial-In/Parallel-Out Shift Register with 3-State Outputs

Overview

The IC 4085 – 8-Bit Serial-In/Parallel-Out Shift Register is a CMOS integrated circuit designed as an 8-bit serial-in/parallel-out shift register with three-state outputs. It is used for serial-to-parallel data conversion, allowing data to be shifted in serially and then output in parallel form.

Features

• Type: 8-bit shift register with serial input and parallel output.
• Serial Data Input: Allows for serial data to be shifted into the register.
• Parallel Outputs: Eight parallel outputs provide the data after shifting.
• 3-State Outputs: Outputs can be in high, low, or high-impedance state, which is useful for bus systems.
• Clock Input: Data is shifted on the clock’s rising edge.
• Power Supply: Typically operates between 3V to 15V.
• Package Type: IC 4085 – 8-Bit Serial-In/Parallel-Out Shift Register is Available in various packages, including DIP (Dual In-line Package), SOP (Small Outline Package), and others.

Pin Configuration

• Pin 1: Serial Data Input (DS).
• Pin 2: Shift Clock Input (SH_CP).
• Pin 3: Storage Clock Input (ST_CP).
• Pin 4: Output Enable (OE).
• Pin 5: Q0 (Parallel Output 0).
• Pin 6: Q1 (Parallel Output 1).
• Pin 7: Q2 (Parallel Output 2).
• Pin 8: Q3 (Parallel Output 3).
• Pin 9: Q4 (Parallel Output 4).
• Pin 10: Q5 (Parallel Output 5).
• Pin 11: Q6 (Parallel Output 6).
• Pin 12: Q7 (Parallel Output 7).
• Pin 13: Vcc (Power Supply).
• Pin 14: Ground (GND).

Applications

• Data Conversion: Used for converting serial data into parallel data for further processing or display.
• Bus Systems: The three-state outputs are useful for connecting multiple devices on a bus, allowing for proper data sharing and communication.
• LED Displays: Commonly used in driving LED displays, where data needs to be shifted and displayed in parallel.
• Peripheral Expansion: Suitable for expanding output lines in digital systems to control multiple peripherals.

Working Principle

The IC 4085 shifts data into the 8-bit register on each clock pulse applied to the shift clock input. The serial data is shifted in bit-by-bit, and once all bits are in the register, a pulse on the storage clock input latches the data into the parallel outputs. The output enable pin controls whether the outputs are active or in a high-impedance state.

Advantages

• Versatility: Provides a practical solution for serial-to-parallel data conversion and output expansion.
• Three-State Outputs: Allows for flexible data handling and integration into bus systems.
• Low Power Consumption: CMOS technology ensures efficient power usage.

The IC 4085 is a valuable component for applications requiring the conversion of serial data to parallel form, offering reliable performance and flexibility in various digital and electronic circuits.

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