Description
The CD40108BMS is a 4 x 4 multiport register containing four 4-bit registers, write address decoder, two separate read address decoders, and two 3-state output buses.
When the ENABLE input is low, the corresponding output bus is switched, independently of the clock, to a high-impedance state. The high-impedance third state provides the outputs with the capability of being connected to the bus lines in a bus-organized system without the need for interface or pull-up components.

FEATUREs
• High Voltage Type (20V Rating)
• Four 4-Bit Registers
• One Input and Two Output Buses
• Unlimited Expansion in Bit and Word Directions
• Data Lines have latched Inputs
• 3-State Outputs
• Separate Control of Each Bus, Allowing Simultaneous Independent Reading of Any of Four Registers on Bus A and Bus B and Independent Writing Into Any of the Four Registers
• CD40108BMS is Pin-Compatible with Industry Type MC14580
• Standardized Symmetrical Output Characteristics
• 100% Tested for Quiescent Current at 20V
• Maximum Input Current of 1µA at 18V Over Full Package Temperature Range; 100nA at 18V and +25oC
• Noise Margin (Over Full Package/Temperature Range)
   - 1V at VDD = 5V
   - 2V at VDD = 10V
   - 2.5V at VDD = 15V
• 5V, 10V and 15V Parametric Ratings
• Meets All Requirements of JEDEC Tentative Standard No. 13B, “Standard Specifications for Description of ‘B’ Series CMOS Devices”

APPLICATIONs
• Scratch-Pad Memories
• Arithmetic Units
• Data Storage