DESCRIPTION
HCF4521B is a monolithic integrated circuit fabricated in Metal Oxide Semiconductor technology available in DIP and SOP packages.
HCF4521B has a chain of 24 flip-flops with an input circuit that allows three modes of operation. The input circuit functions as a crystal or RC oscillator or as an input buffer for an external oscillator. Each flip-flop preforms a divide-by-two function giving a total count of 224 = 16,777,216. The count advances on the negative going edge of the clock. Access is available to the final seven stages giving the device added flexibility.

■ HIGH NOISE IMMUNITY
■ VOLTAGE SUPPLY RANGE 3V TO 18V
■ ALL STAGE ARE PRESETTABLE
■ RESET DISABLES THE RC OSCILLATOR FOR LOW STANDBY POWER DRAIN
■ RC AND CRYSTAL OSCILLATOR OUTPUT ARE CAPABLE OF DRIVING EXTERNAL LOADS
■ QUIESCENT CURRENT SPECIF. UP TO 20V
■ 5V, 10V AND 15V PARAMETRIC RATINGS
■ INPUT LEAKAGE CURRENT II = 100nA (MAX) AT VDD = 18V TA = 25°C
■ 100% TESTED FOR QUIESCENT CURRENT
■ MEETS ALL REQUIREMENTS OF JEDEC JESD13B "STANDARD SPECIFICATIONS FOR DESCRIPTION OF B SERIES CMOS DEVICES"