Figure 28. Basic AD1385 Digital Interface (16-Bit Complementary 2s Complement Data,
Autozero Not Used, Other Digital and Analog Inputs Not Shown)
Sample Board Layout
Figures 29-34 show the layout of an evaluation board for the
AD1385. This layout incorporates the grounding, power distri-
bution, and interface concepts described in previous sections.
This 4-layer layout makes extensive use of ground and power
planes and provides optimal AD1385 performance.
The layout accommodates buffer amplifiers with standard op
amp pinouts in both 14- and 8-pin DIP packages. The pin
numbers shown for U12 in Figure 29 refer to the 14-pin format.
An 8-pin op amp such as the AD845 should be positioned with
package Pin 4 inserted in layout Pin 6. The AD845 provides
slightly better distortion performance than the AD842, an am-
plifier in a 14-pin package, with no significant increase in noise.