ELM381

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


Application

• Long term (daily or weekly) event timers
• Missing event detectors
• Automatic shutoff circuits


Specifications

Storage Temperature....................... -65°C to +150°C
Ambient Temperature with
Power Applied.................................... -40°C to +85°C
Voltage on VDD with respect to VSS............  0 to +7.5V
Voltage on any other pin with
respect to VSS...........................  - 0.6V to (VDD + 0.6V)

Note:
Stresses beyond those listed here will likely damage the device. These values are given as a design guideline only. The ability to operate to these levels is neither inferred nor recommended.


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 ELM381 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.