LM2240

www.DataSheet4U.com LM2240 Programmable Timer Counter August 1990 LM2240 Programmable Timer Counter General Description The LM2240 Programmable Timer Counter is a monolithic controller capable of both monostable and astable operation Monostable operation allows accurate microsecond to five day time delays Long delays up to three years can easily be generated by cascading two timers The timer consists of a time-base oscillator programmable 8-bit counter and control flip-flop An external resistor-capacitor (RC) network sets the oscillator frequency and allows delay times from 1 RC to 255 RC to be selected In the astable mode of operation a single RC network sets the base frequency The frequencies of the squarewaves at the 8 outputs are each at different factors of 2 from the base frequency If 2 or more of the outputs are shorted together various pulse patterns can be generated These frequencies or pulse patterns can also easily be synchronized to an external signal The trigger reset and outputs are all TTL and CMOS compatible for easy interface with digital systems The timer’s high accuracy and versatility in producing a wide range of time delays makes it ideal as a direct replacement for mechanical or electromechanical devices Features Y Y Y Y Y Y Y Y Accurate timing from microseconds to days Programmable delays from 1 RC to 255 RC TTL and CMOS compatible outputs Timing directly proportional to RC time constant High accuracy External sync and modulation capability Wide su...