●Description
BU4015B series ICs are 4-stage static shift registers, each consisting of 2 circuits. The D flip-flops of each stage share a common reset input, enabling asynchronous reset at any time. 
BU4021B series ICs are 8-bit static shift registers configured with 8 register cells, each of which has parallel input.  Control of the parallel/serial input (P/S) enables serial input/output with clock synchronization and well as parallel input/serial output conversions.
BU4094BC series ICs are shift/store registers, each consisting ofan 8-bit shift register and an 8-bit latch. Output can be held in the data transfer mode because the data read into the shift register can be latched by the asynchronous strobe input, 
The BU4538B IC is a monostable multivibrator that can be reset and retriggered from either edge of an input pulse.  A wide range of accurate output pulse widths is available because the output pulse width and accuracy are determined by the external timing constants Cx an Rx.
The BU4028B IC is a decoder which converts BCD signals into decimal signals.  
Of the 10 outputs (Q0 ~ Q9), those corresponding to the input codes A-D are set to “H”, while the others are set to “L”. 

●Features
 1)  Low power consumption
 2)  Wide operating supply voltage range
3) High impedance
 4)  High fan out
 5)  L-TTL2 and LS-TTL1 inputs can be driven directly.

●Applications
BU4015B: serial / parallel data conversion and ring counter. 
BU4021B: control circuits, timing circuits and as a general purpose register requiring high degree of noise tolerance.
BU4094BC: series/parallel data conversion and data receivers.
BU4538B: can obtain the output pulse amplitude with improved accuracy by external capacity and resistance.
BU4028B: code conversion, address decoding, memory selection control, demultiplexing or readout and decoding, etc.