onsemi MC14517BDWR2G Dual 64-Bit Static Shift Register: Datasheet, Pinout, and Application Circuit Guide
The onsemi MC14517BDWR2G is a versatile and high-performance integrated circuit from the 4000 series CMOS logic family. This dual 64-bit static shift register is designed for a wide range of digital applications, offering low power consumption and high noise immunity, which are hallmark characteristics of CMOS technology. It is particularly useful in applications requiring temporary data storage, time delay, or serial-to-parallel data conversion.
Datasheet Overview
The device datasheet provides critical information for design engineers. Key specifications include a wide operating voltage range from 3V to 18V, allowing for flexibility in both 5V and higher voltage systems. It features static operation, meaning it can store data indefinitely as long as power is applied, without the need for a continuous clock signal. The typical maximum clock frequency is several MHz, depending on the supply voltage (e.g., ~8 MHz at 10V). The "DWR2G" suffix indicates it comes in a SOIC-16 wide package, which is suitable for automated PCB assembly.
Pinout Configuration
Understanding the pinout is crucial for circuit design. The MC14517BDWR2G has 16 pins, housing two independent 64-bit shift registers.
Pins 1 (Clock 1), 9 (Clock 2): The clock inputs for their respective shift registers. Data is shifted on the positive-going (low-to-high) transition of the clock signal.
Pins 2 (Data In 1), 10 (Data In 2): The serial data inputs for each register.
Pins 3-6, 11-14 (Q Outputs 1-4 for each register): These are the parallel output pins. Each register provides access to the 1st, 16th, 32nd, and 48th bit stages, offering a multiplexed output capability that is highly useful for scanning applications.
Pin 7 (Reset): A master reset pin common to both registers. A high logic level on this pin clears all stages to a low level, providing synchronous initialization.
Pin 8 (Vss): Ground reference (0V).
Pin 16 (Vdd): Positive supply voltage pin.
Application Circuit Guide
A common application for the MC14517 is as a programmable time delay circuit or a digital pulse extender. The basic connection involves:
1. Applying power between Vdd (pin 16) and Vss (pin 8), with a decoupling capacitor (e.g., 100nF) placed close to the IC.
2. Connecting the serial data input (e.g., Pin 2) to the signal source.
3. Feeding a clock signal to the clock input (Pin 1). The clock frequency determines the delay time (`Delay = Number of Stages / Clock Frequency`).
4. Using one of the parallel output pins (e.g., Pin 6, the 48th stage) as the delayed output. The desired delay can be selected by choosing which output pin to use.
5. Controlling the Reset pin (Pin 7), typically pulled down to Vss through a resistor, to clear the register when needed.
For longer delays, multiple MC14517 devices can be easily cascaded by connecting the last parallel output of one register (e.g., Pin 6) to the serial data input (Pin 10) of the next.
The onsemi MC14517BDWR2G is an excellent choice for designers seeking a reliable, low-power solution for data shifting and time-delay generation. Its dual independent registers in a single package provide exceptional design flexibility and board space efficiency for complex digital systems.
Keywords: Shift Register, CMOS Logic, Time Delay Circuit, Serial-to-Parallel Converter, Low Power Consumption.
