ADS8331IBRGET datasheet(44/57 Pages) TI1

44 / 57 page

ADS8331, ADS8332

SBAS363D – DECEMBER 2009 – REVISED OCTOBER 2015

www.ti.com

Layout Guidelines (continued)

The power sources to the device must be clean and well-bypassed. Use 10

μF, ceramic bypass capacitors in

close proximity to the analog (VA) and digital (VBD) power-supply pins. Avoid placing vias between the AVDD

and DVDD pins and the bypass capacitors. Connect all ground pins to the ground plane using short, low

impedance paths.

The REF+ reference input is bypassed with a 22

μF, X7S-grade, 0805-size, 10-V rated ceramic capacitors. Place

the reference bypass capacitor as close as possible to the reference REF+ and REF- pins and connect the

bypass capacitor using short, low-inductance connections. Avoid placing vias between the REF+/REF- pins and

the bypass capacitor. If the reference voltage originates from an op amp, make sure that the op amp can drive

the bypass capacitor without oscillation. A small 0.2-

Ω to 0.5-Ω resistors (RREF) is used in series with the

reference bypass capacitor to improve stability.

The fly-wheel RC filters are placed immediately next to the input pins. For applications measuring AC signals,

COG (NPO) ceramic capacitors provide the best capacitance precision. Figure 56 shows input filter capacitors

placed in close proximity to the INx analog input pins of the device.

Submit Documentation Feedback

Product Folder Links: ADS8331 ADS8332

ADS8331IBRGET Datasheet(PDF) 44 Page - Texas Instruments