Versatile Debounce Circuit


Quantity Pricing

The following are the unit prices, as you vary the quantity purchased:






All prices are in Canadian dollars. We use the total number purchased (ELM409P + ELM409SM) for the calculation.


The ELM409 is digital filter circuit that is used to interface mechanical contacts to electronic circuits.

All mechanical contacts, whether from switches, relays, etc. will have inherent ‘bounce’ when they make or break a connection. When that contact is used for the electrical input to a digital circuit, the bounces can easily be incorrectly interpreted as multiple inputs. The ELM409 contains all of the logic that is typically required to remove the bounce from such signals, and provide a signal that has only one transition.

In addition to providing the standard debounce function, the ELM409 may also be configured for other useful functions such as generating pulses or alternating output levels on signal transitions.

No external components are needed for the operation of the ELM409, as all timing and logic functions are performed internally.


  • Pushbutton interface for logic circuits
  • Limit switch monitoring
  • Time delay generation
  • Power on sequencing


  • Standard and extra long debounce times
  • Schmitt input provides hysteresis
  • Complementary circuit outputs
  • Needs no external timing components
  • Low power CMOS design – typically 1 mA at 5V
  • Wide supply range – 3.0 to 5.5 volt operation
  • High current drive outputs

Connection Diagram

( PDIP or SOIC, top view )
ELM409 connection diagram

Block Diagram

ELM409 block diagram


The ELM409 data sheet (ver A, 51K):

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