AD688

REV. A

–7–

Figure 10b. Large-Scale Transient Response

Figure 10c. Fine-Scale Settling for Transient Load

Figure 11 displays the output amplifier characteristic driving a

5 mA-to-10 mA load, a common situation found when the

reference is shared among multiple converters or is used to

provide bipolar offset current.

Figure 11a. Transient and Constant Load Test Circuit

Figure 11b. Transient Response 5–10 mA Load

In some applications, a varying load may be both resistive and

capacitive in nature, or be connected to the AD688 by a long

capacitive cable. Figure 12 displays the output amplifier charac-

teristics driving a 1,000 pF, 0-to-10 mA load.

Figure 12a. Capacitive Load Transient Response Test

Circuit

Figure 12b. Output Response with Capacitive Load

Figure 13 displays the crosstalk between output amplifiers. The

top trace shows the output of A4, dc-coupled and offset by 10

volts, while the output of A3 is subjected to a 0-to-10 mA load

current step. The transient at A4 settles in about 1

µs, and the

load-induced offset is about 100

µV.

Figure 13a. Load Crosstalk Test Circuit

Figure 13b. Load Crosstalk