MCP3421 Microchip Technology, MCP3421 Datasheet - Page 9

• Manufacturer Part Number: MCP3421
• Description: 18-Bit Analog-to-Digital Converter with I2C Interface and On-Board Reference
• Manufacturer: Microchip Technology

MCP3421
4.8
Aliasing and Anti-aliasing Filter
Aliasing occurs when the input signal contains time-
varying signal components with frequency greater than
half the sample rate. In the aliasing conditions, the
device can output unexpected output codes. For
applications that are operating in electrical noise
environments, the time-varying signal noise or high
frequency interference components can be easily
added to the input signals and cause aliasing. Although
the MCP3421 device has an internal first order sinc
filter, its’ filter response may not give enough
attenuation to all aliasing signal components. To avoid
the aliasing, an external anti-aliasing filter, which can
be accomplished with a simple RC low-pass filter, is
typically used at the input pins. The low-pass filter cuts
off the high frequency noise components and provides
a band-limited input signal to the MCP3421 input pins.
© 2006 Microchip Technology Inc.
DS22003B-page 9