UM3128

The UM3128 has the following features including Number of digits,8 digits (rough estimate calculation possible);Decimal point system,Complete floating decimal point system;Calculations,Chain multiplication and division,Auto-constant  calculation (constant  multiplicand,divisor, addend and subtrahend),Square and reciprocal calculations,Mark-up and mark-down calculations,Extraction of square root,PerFentage calculations.

The UM3128 is a single-chip CMOS calculator LSI with 8-dgit four function arithmetic operations, single memory,extractionof-square-root   and   percentage   calculation functions, leading zero and trailing zero suppression, chain calculations  and  internal  debouncing  and  encoding  of keyboard inputs. It is designed for LCD operation with 1.5V power supply, auto-power-off, low power dissipation and single power supply making the UM3128 ideal for battery or solar cell operated, handheld calculators with low system cost.Stress  above  those  listed  under  "Absolute  Maximum Ratings" may cause  permanent damage to the device.These are stress ratings only. Functional operation of this device at these or any other conditions above those indicated in the operational sections of this specification is not implied and exposure to absolute maximum rating conditions for extended periods may affect device reliability.

The UM3128 has an implied constant mode on +,-,x,/ and%operations. The constant calculation is performed automatically by the=key,%key, or%=keys without a constant switch. The second operand is treated as the constant  for  addition, subtraction and division, while the first operand is the constant for multiplication.The first number key in a sequence will clear the display and enter the digit in the display. Successive entries will shift the display left and enter data in the display register.The first decimal point entered is effective. An attempted entry of more than 8 digits or 7 decimal places will be ignored.The purpose of the percent key is to allow for calculation of add-on and discount. Determination of add-on requires the principal amount to be the first entry followed by the"+"or "x" key, with the percentage being the second entry. Depression of the percent key yields the amount to add on, such as tax or interest. Depression of the "="key adds this amount to be principal.