24−Stage Frequency Divider

The MC14521B consists of a chain of 24 flip−flops with an input circuit that allows three modes of operation. The input will function as a crystal oscillator, an RC oscillator, oras an input buffer for an external oscillator. Each flip−flop divides the frequency of the previous flip−flop by two, consequently this part will count up to 2 24 = 16,777,216. The count advances on the negative going edge of the clock. The outputs of the last seven−stages are available for added flexibility.

Features

•All Stages are Resettable

•Reset Disables the RC Oscillator for Low Standby Power Drain

•RC and Crystal Oscillator Outputs Are Capable of Driving External Loads

•Test Mode to Reduce Test Time

•VDD′and VSS′Pins Brought Out on Crystal Oscillator Inverter to Allow the Connection of External Resistors for Low−Power Operation

•Supply Voltage Range = 3.0 Vdc to 18 Vdc

•Capable of Driving Two Low−Power TTL Loads or One Low−Power Schottky TTL Load over the Rated Temperature Range

•Pb−Free Packages are Available*