======================================================================== 74F280 9-BIT PARITY GENERATOR/CHECKER ======================================================================== Family: Fairchild FAST (Advanced Schottky TTL) Source: 1980 Fairchild FAST Data Book, pages 4-85 ... 4-86 Status: PRELIMINARY -- page 4-85 carries a "Preliminary" watermark. Ratings: Vcc = +5.0 V +/-5%, TA = 0 to +70 deg C DESCRIPTION ----------- The 'F280 is a high speed parity generator/checker that accepts nine bits of input data and detects whether an even or an odd number of these inputs is HIGH. If an even number of inputs is HIGH, the Sum Even output is HIGH. If an odd number is HIGH, the Sum Even output is LOW. The Sum Odd output is the complement of the Sum Even output. CONNECTION DIAGRAM (14-pin DIP) ------------------------------- Pin Function Pin Function --- --------------------------- --- -------------------- 1 I6 Data input 6 14 Vcc 2 I7 Data input 7 13 I5 Data input 5 3 NC 12 I4 Data input 4 4 I8 Data input 8 11 I3 Data input 3 5 Sum-E Even Parity output 10 I2 Data input 2 6 Sum-O Odd Parity output 9 I1 Data input 1 7 GND 8 I0 Data input 0 Pin 3 is no-connect. TRUTH TABLE ----------- Number of inputs I0 - I8 that are HIGH Sum EVEN Sum ODD -------------------------------------- -------- ------- 0, 2, 4, 6, 8 H L 1, 3, 5, 7, 9 L H H = HIGH voltage level; L = LOW voltage level. INPUT LOADING / FAN-OUT ----------------------- Pin Names Description U.L. HIGH/LOW --------- ------------------ ------------- I0 - I8 Data Inputs 0.5 / 0.375 Sigma-O Odd Parity Output 25 / 12.5 Sigma-E Even Parity Output 25 / 12.5 DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE --------------------------------------------------- (Unless otherwise specified.) Symbol Parameter Min Typ Max Units Conditions ------ -------------------- --- --- --- ----- ---------- ICC Power Supply Current 25 mA Vcc = Max AC CHARACTERISTICS ------------------ Symbol Propagation Delay Path Min Typ Max Units ------ ---------------------- --- ---- --- ----- tPLH In to Sigma-E -- 12.5 -- ns tPHL In to Sigma-E -- 10.5 -- ns tPLH In to Sigma-O -- 12.5 -- ns tPHL In to Sigma-O -- 10.5 -- ns