Datasheet Summary
24-stage frequency divider and oscillator
Rev. 7
- 30 March 2016
Product data sheet
1. General description
The HEF4521B consists of a chain of 24 toggle flip-flops with an overriding asynchronous master reset input (MR), and an input circuit that allows three modes of operation. The single inverting stage (A2 to Y2) functions as: a crystal oscillator, an input buffer for an external oscillator or in bination with A1 as an RC oscillator. The crystal oscillator operates in Low-power mode when pins VSS1 and VDD1 are supplied via external resistors.
Each flip-flop divides the frequency of the previous flip-flop by two, consequently the HEF4521B counts up to 224 = 16777216. The...
