Debounce Circuit with Latch


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 (ELM411P + ELM411SM) for the calculation.


The ELM411 provides all of the necessary circuitry to connect as many as three independent mechanical contacts to an electronic circuit.

All mechanical contacts, whether from switches, relays, etc. will have inherent ‘bounce’ when they make or break a connection. Depending on the type of switch, this fluctuation can be quite pronounced, often being interpreted as multiple inputs by high speed digital circuits.

All of the logic required to remove the bounce from most mechanical sources is provided by this circuit, without the use of additional components. As well, internal pull-up resistors have been provided so that the switch inputs can be directly connected to the 8 pin package.

The ELM411 is composed of two separate inverters which follow the input directly, and one latch circuit which toggles its state each time a closed circuit is detected on the input.


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


  • Low power CMOS design – typically 1mA at 5V
  • Wide supply range – 3.0 to 5.5 volt operation
  • Simultaneous monitoring of three circuits
  • Full 25msec debounce period on contact closure and opening, without external components
  • Internal pullup resistors for contact monitoring
  • High current drive outputs – up to 25 mA
  • Can be cascaded to provide sequential outputs

Connection Diagram

( PDIP or SOIC, top view )
ELM411 connection diagram

Block Diagram

ELM411 block diagram


The ELM411 data sheet (ver B, 25K):

pdf icon