ELM401

ELM401 Rotary Encoder Debounce Circuit Description The ELM401 is an 8 pin integrated circuit that is used to ‘debounce’ the signals from a mechanical rotary (quadrature) encoder. The low power CMOS technology used ensures that only a very small current is required over the entire 2.0 to 5.5 volt operating range. There is no need for external filtering or debounce circuits with the ELM401, as this is all performed within the integrated circuit. The ‘A’ and ‘B’ motion sensing encoder signals are both passed through a filter then a comparator circuit, and finally a timer circuit to remove noise and contact bounce, while the switch input receives standard debounce processing. The result are three virtually noise-free signals that are suitable for direct use by an electronic circuit. Note that no inversion or manipulation of any kind is performed on the input signals, other than the debouncing. If your applications requires decoding of the signals, you may wish to look at our ELM402 to ELM408 family of products. Features Low power CMOS design Wide supply range – 2.0 to 5.5 volts Complete debouncing of the encoder signals No external filtering needed Includes switch debouncing circuit Startup delay timer High current drive outputs Connection Diagram PDIP and SOIC (top view) VDD A 1 2 3 4 8 7 6 5 VSS A out B out Sw out Applications Microcontroller Interfaces Monitoring of Encoder Signals General Switch Debouncing B Sw Block Diagram VDD A 2 Debounce Circ...