Datasheet

ManualsBrandsANALOG DEVICES ManualsData collecting ICsData acquisition IC - DA converter (DAC) SOT 23 8

AD5680

Rev. A | Page 14 of 20

APPLICATIONS

CLOSED-LOOP APPLICATIONS

The AD5680 is suitable for closed-loop low bandwidth applica-

tions. Ideally, the system bandwidth acts as a filter on the DAC

output. (See the

Filter section for details of the DAC output

prefiltering and postfiltering.) The DAC updates at the

interpolation frequency of 10 kHz.

05854-039

CONTROLLER

PLANT

ADC

DAC

Figure 31. Typical Closed-Loop Application

FILTER

The DAC output voltage for code transition 4092 to 4094 can be

seen in

Figure 32. This is the DAC output unfiltered. Code 4092

does not have any interpolation but Code 4094 has interpolation

with a 50% duty cycle (see

Table 5). Figure 33 shows the DAC

output with a 50 Hz passive RC filter and

Figure 34 shows the

output with a 300 Hz passive RC filter. An RC combination of

320 kΩ and 10 nF has been used to achieve the 50 Hz cutoff

frequency, and an RC combination of 81 kΩ and 10 nF has

been used to achieve the 300 Hz cutoff frequency.

05854-024

CH1 20.0µV

M 500µs CH4 0V

CODE 4092

CODE 4094

Figure 32. DAC Output Unfiltered

05854-025

CODE 4092

CODE 4094

Δ: 2.09ms

@: 1.28ms

CH1 20.0µV CH2 5V

M 500µs CH2 1.4V

Figure 33. DAC Output with 50 Hz Filter on Output

05854-026

CODE 4092

CODE 4094

Δ: 2.09ms

@: 1.28ms

CH1 20.0µV CH2 5V

M 500µs CH2 1.4V

Figure 34. DAC Output with 300 Hz Filter on Output