Datasheet

DRIVING THE ADS8513 ANALOG INPUT
ADS8513
SLAS486C – JUNE 2007 – REVISED JANUARY 2009 ...................................................................................................................................................... www.ti.com
In general, any reasonably fast, high-quality operational or instrumentation amplifier can be used to drive the
ADS8513 input. When the converter enters the acquisition mode, there is some charge injection from the
converter input to the amplifier output. This charge injection can result in inadequate settling time with slower
amplifiers. Be very careful with single-supply amplifiers, particularly if the output is required to swing very close to
the supply rails.
In addition, be careful with regard to the amplifier linearity. The outputs of single-supply and rail-to-rail amplifiers
can saturate as the outputs approach the supply rails. Rather than the amplifier transfer function being a straight
line, the curve can become severely S-shaped. Also, watch for the point where the amplifier switches from
sourcing current to sinking current. For some amplifiers, the transfer function can be noticeably discontinuous at
this point, causing a significant change in the output voltage for a much smaller change on the input.
Texas Instruments manufactures a wide variety of operational and instrumentation amplifiers that can be used to
drive the input of the ADS8513; these devices include the OPA627 , OPA132 , and INA110 .
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Product Folder Link(s): ADS8513