4021 IC 8-Bit Parallel-Serial Shift Register

4021 IC 8-Bit Parallel-Serial Shift RegisterThe CD4021BE functions as an 8-bit parallel-in serial-out (PISO) shift register, providing a simple and effective way to read multiple digital inputs using a minimal number of microcontroller pins. It reads 8 digital signals in parallel and shifts them out serially using a clock signal. This capability makes it ideal for expanding input capacity in digital systems.The IC integrates a parallel input latch that captures the input state on a logic-high signal at the strobe (parallel load) pin. Once latched, the data shifts out on each rising edge of the clock pulse. Designers rely on this IC in key scanning, switch monitoring, and remote input reading in microcontroller-based applications.Key Features8-bit parallel-in, serial-out shift registerSerial data output (Q) and complementary output (Q̅)Asynchronous master resetSeparate parallel load and shift operationsWide operating voltage: 3V to 15VHigh noise immunity and low power CMOS designTTL-compatible outputsDIP-16 through-hole packagePin Configuration (DIP-16)PinLabelDescription1D5Parallel Data Input Bit 52D4Parallel Data Input Bit 43D3Parallel Data Input Bit 34D2Parallel Data Input Bit 25D1Parallel Data Input Bit 16D0Parallel Data Input Bit 0 (LSB)7CLOCKSerial Clock Input8GNDGround               ‘9Q̅Complementary Serial Data Output10QSerial Data Output11STROBEParallel Load (Latch Inputs on High)12D6Parallel Data Input Bit 613D7Parallel Data Input Bit 7 (MSB)14MR (Reset)Master Reset (Active High)15CLOCK INHIBITDisables Clock When High16VDDSupply VoltageProduct SpecificationsParameterValueIC Function8-bit Parallel-In Serial-Out Shift RegisterLogic FamilyCMOSPackage TypeDIP-16Operating Voltage3V – 15VMax Clock Frequency8 MHz (typical at 10V)Input TypeCMOS-compatibleOutput TypeBuffered, TTL-compatibleOperating Temperature-55°C to 125°CApplicationsKeypad matrix scanningDigital input expansion for microcontrollersRemote control systemsSwitch status monitoringMultiplexed sensor input readingSerial communication of multiple digital signalsHome automation control panels