ELM381

ELM381 60 Hz Long Interval Counter Description The ELM381 is a digitally configurable, multistage counter circuit in a single 8 pin package. When connected to a 60Hz source, four time periods from one hour to one week are possible, as shown in Table 1 below. Although the circuit has been optimized for a 60Hz input frequency, it is capable of being operated over a very wide range of frequencies. Of particular interest is the ability to interface directly to very low frequencies with varying waveforms due to the use of a Schmitt trigger input circuit. The ELM381 provides two outputs – a standard 50% duty cycle divider output, and a momentarily pulsed output. The pulse output is useful for audibly or visually signalling the beginning of a time period, or as a trigger for other circuitry. Refer to the Example Applications section for two typical circuits. Applications Long term (daily or weekly) event timers Missing event detectors Automatic shutoff circuits Features Low power CMOS design - typically 1mA at 5V Wide supply range – 3.0 to 5.5 volt operation Digitally selectable delays Schmitt trigger circuitry on the clock input Completely static operation Long term accuracy with line frequency clock High current drive outputs – up to 25 mA Reset input provided with a pullup resistor Connection Diagram PDIP and SOIC (top view) VDD 1 D1 2 D0 3 reset 4 8 VSS 7 Out 6 Pulse 5 Clock Block Diagram VDD Clock 5 VSS D1 2 D0 3 reset VDD 4 ELM381DSA Digital Cou...